widget_inspector.dart 104 KB
Newer Older
Ian Hickson's avatar
Ian Hickson committed
1
// Copyright 2014 The Flutter Authors. All rights reserved.
2 3 4
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

5
import 'dart:async';
6
import 'dart:convert';
7 8
import 'dart:developer' as developer;
import 'dart:math' as math;
9 10 11 12 13
import 'dart:typed_data';
import 'dart:ui' as ui
    show
        ClipOp,
        Image,
14
        ImageByteFormat,
15 16 17 18 19 20 21
        Paragraph,
        Picture,
        PictureRecorder,
        PointMode,
        SceneBuilder,
        Vertices;
import 'dart:ui' show Canvas, Offset;
22 23 24 25

import 'package:flutter/foundation.dart';
import 'package:flutter/painting.dart';
import 'package:flutter/rendering.dart';
26
import 'package:flutter/scheduler.dart';
27
import 'package:vector_math/vector_math_64.dart';
28

29
import 'app.dart';
30 31
import 'basic.dart';
import 'binding.dart';
32
import 'debug.dart';
33 34 35 36 37
import 'framework.dart';
import 'gesture_detector.dart';

/// Signature for the builder callback used by
/// [WidgetInspector.selectButtonBuilder].
38
typedef InspectorSelectButtonBuilder = Widget Function(BuildContext context, VoidCallback onPressed);
39

40
typedef _RegisterServiceExtensionCallback = void Function({
41
  @required String name,
42
  @required ServiceExtensionCallback callback,
43 44
});

45 46 47 48 49 50 51
/// A layer that mimics the behavior of another layer.
///
/// A proxy layer is used for cases where a layer needs to be placed into
/// multiple trees of layers.
class _ProxyLayer extends Layer {
  _ProxyLayer(this._layer);

52 53
  final Layer _layer;

54
  @override
55 56
  void addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
    _layer.addToScene(builder, layerOffset);
57 58 59
  }

  @override
60 61 62 63 64 65 66 67
  @protected
  bool findAnnotations<S>(
    AnnotationResult<S> result,
    Offset localPosition, {
    @required bool onlyFirst,
  }) {
    return _layer.findAnnotations(result, localPosition, onlyFirst: onlyFirst);
  }
68 69 70 71 72 73 74 75 76 77 78 79 80 81
}

/// A [Canvas] that multicasts all method calls to a main canvas and a
/// secondary screenshot canvas so that a screenshot can be recorded at the same
/// time as performing a normal paint.
class _MulticastCanvas implements Canvas {
  _MulticastCanvas({
    @required Canvas main,
    @required Canvas screenshot,
  }) : assert(main != null),
       assert(screenshot != null),
       _main = main,
       _screenshot = screenshot;

82 83 84
  final Canvas _main;
  final Canvas _screenshot;

85
  @override
86
  void clipPath(Path path, { bool doAntiAlias = true }) {
87 88 89 90 91
    _main.clipPath(path, doAntiAlias: doAntiAlias);
    _screenshot.clipPath(path, doAntiAlias: doAntiAlias);
  }

  @override
92
  void clipRRect(RRect rrect, { bool doAntiAlias = true }) {
93 94 95 96 97
    _main.clipRRect(rrect, doAntiAlias: doAntiAlias);
    _screenshot.clipRRect(rrect, doAntiAlias: doAntiAlias);
  }

  @override
98
  void clipRect(Rect rect, { ui.ClipOp clipOp = ui.ClipOp.intersect, bool doAntiAlias = true }) {
99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
    _main.clipRect(rect, clipOp: clipOp, doAntiAlias: doAntiAlias);
    _screenshot.clipRect(rect, clipOp: clipOp, doAntiAlias: doAntiAlias);
  }

  @override
  void drawArc(Rect rect, double startAngle, double sweepAngle, bool useCenter, Paint paint) {
    _main.drawArc(rect, startAngle, sweepAngle, useCenter, paint);
    _screenshot.drawArc(rect, startAngle, sweepAngle, useCenter, paint);
  }

  @override
  void drawAtlas(ui.Image atlas, List<RSTransform> transforms, List<Rect> rects, List<Color> colors, BlendMode blendMode, Rect cullRect, Paint paint) {
    _main.drawAtlas(atlas, transforms, rects, colors, blendMode, cullRect, paint);
    _screenshot.drawAtlas(atlas, transforms, rects, colors, blendMode, cullRect, paint);
  }

  @override
  void drawCircle(Offset c, double radius, Paint paint) {
    _main.drawCircle(c, radius, paint);
    _screenshot.drawCircle(c, radius, paint);
  }

  @override
  void drawColor(Color color, BlendMode blendMode) {
    _main.drawColor(color, blendMode);
    _screenshot.drawColor(color, blendMode);
  }

  @override
  void drawDRRect(RRect outer, RRect inner, Paint paint) {
    _main.drawDRRect(outer, inner, paint);
    _screenshot.drawDRRect(outer, inner, paint);
  }

  @override
  void drawImage(ui.Image image, Offset p, Paint paint) {
    _main.drawImage(image, p, paint);
    _screenshot.drawImage(image, p, paint);
  }

  @override
  void drawImageNine(ui.Image image, Rect center, Rect dst, Paint paint) {
    _main.drawImageNine(image, center, dst, paint);
    _screenshot.drawImageNine(image, center, dst, paint);
  }

  @override
  void drawImageRect(ui.Image image, Rect src, Rect dst, Paint paint) {
    _main.drawImageRect(image, src, dst, paint);
    _screenshot.drawImageRect(image, src, dst, paint);
  }

  @override
  void drawLine(Offset p1, Offset p2, Paint paint) {
    _main.drawLine(p1, p2, paint);
    _screenshot.drawLine(p1, p2, paint);
  }

  @override
  void drawOval(Rect rect, Paint paint) {
    _main.drawOval(rect, paint);
    _screenshot.drawOval(rect, paint);
  }

  @override
  void drawPaint(Paint paint) {
    _main.drawPaint(paint);
    _screenshot.drawPaint(paint);
  }

  @override
  void drawParagraph(ui.Paragraph paragraph, Offset offset) {
    _main.drawParagraph(paragraph, offset);
    _screenshot.drawParagraph(paragraph, offset);
  }

  @override
  void drawPath(Path path, Paint paint) {
    _main.drawPath(path, paint);
    _screenshot.drawPath(path, paint);
  }

  @override
  void drawPicture(ui.Picture picture) {
    _main.drawPicture(picture);
    _screenshot.drawPicture(picture);
  }

  @override
  void drawPoints(ui.PointMode pointMode, List<Offset> points, Paint paint) {
    _main.drawPoints(pointMode, points, paint);
    _screenshot.drawPoints(pointMode, points, paint);
  }

  @override
  void drawRRect(RRect rrect, Paint paint) {
    _main.drawRRect(rrect, paint);
    _screenshot.drawRRect(rrect, paint);
  }

  @override
  void drawRawAtlas(ui.Image atlas, Float32List rstTransforms, Float32List rects, Int32List colors, BlendMode blendMode, Rect cullRect, Paint paint) {
    _main.drawRawAtlas(atlas, rstTransforms, rects, colors, blendMode, cullRect, paint);
    _screenshot.drawRawAtlas(atlas, rstTransforms, rects, colors, blendMode, cullRect, paint);
  }

  @override
  void drawRawPoints(ui.PointMode pointMode, Float32List points, Paint paint) {
    _main.drawRawPoints(pointMode, points, paint);
    _screenshot.drawRawPoints(pointMode, points, paint);
  }

  @override
  void drawRect(Rect rect, Paint paint) {
    _main.drawRect(rect, paint);
    _screenshot.drawRect(rect, paint);
  }

  @override
  void drawShadow(Path path, Color color, double elevation, bool transparentOccluder) {
    _main.drawShadow(path, color, elevation, transparentOccluder);
    _screenshot.drawShadow(path, color, elevation, transparentOccluder);
  }

  @override
  void drawVertices(ui.Vertices vertices, BlendMode blendMode, Paint paint) {
    _main.drawVertices(vertices, blendMode, paint);
    _screenshot.drawVertices(vertices, blendMode, paint);
  }

  @override
  int getSaveCount() {
    // The main canvas is used instead of the screenshot canvas as the main
    // canvas is guaranteed to be consistent with the canvas expected by the
    // normal paint pipeline so any logic depending on getSaveCount() will
    // behave the same as for the regular paint pipeline.
    return _main.getSaveCount();
  }

  @override
  void restore() {
    _main.restore();
    _screenshot.restore();
  }

  @override
  void rotate(double radians) {
    _main.rotate(radians);
    _screenshot.rotate(radians);
  }

  @override
  void save() {
    _main.save();
    _screenshot.save();
  }

  @override
  void saveLayer(Rect bounds, Paint paint) {
    _main.saveLayer(bounds, paint);
    _screenshot.saveLayer(bounds, paint);
  }

  @override
263
  void scale(double sx, [ double sy ]) {
264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312
    _main.scale(sx, sy);
    _screenshot.scale(sx, sy);
  }

  @override
  void skew(double sx, double sy) {
    _main.skew(sx, sy);
    _screenshot.skew(sx, sy);
  }

  @override
  void transform(Float64List matrix4) {
    _main.transform(matrix4);
    _screenshot.transform(matrix4);
  }

  @override
  void translate(double dx, double dy) {
    _main.translate(dx, dy);
    _screenshot.translate(dx, dy);
  }
}

Rect _calculateSubtreeBoundsHelper(RenderObject object, Matrix4 transform) {
  Rect bounds = MatrixUtils.transformRect(transform, object.semanticBounds);

  object.visitChildren((RenderObject child) {
    final Matrix4 childTransform = transform.clone();
    object.applyPaintTransform(child, childTransform);
    Rect childBounds = _calculateSubtreeBoundsHelper(child, childTransform);
    final Rect paintClip = object.describeApproximatePaintClip(child);
    if (paintClip != null) {
      final Rect transformedPaintClip = MatrixUtils.transformRect(
        transform,
        paintClip,
      );
      childBounds = childBounds.intersect(transformedPaintClip);
    }

    if (childBounds.isFinite && !childBounds.isEmpty) {
      bounds = bounds.isEmpty ? childBounds : bounds.expandToInclude(childBounds);
    }
  });

  return bounds;
}

/// Calculate bounds for a render object and all of its descendants.
Rect _calculateSubtreeBounds(RenderObject object) {
313
  return _calculateSubtreeBoundsHelper(object, Matrix4.identity());
314 315 316 317 318 319
}

/// A layer that omits its own offset when adding children to the scene so that
/// screenshots render to the scene in the local coordinate system of the layer.
class _ScreenshotContainerLayer extends OffsetLayer {
  @override
320
  void addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
321 322 323 324 325 326 327 328 329 330
    addChildrenToScene(builder, layerOffset);
  }
}

/// Data shared between nested [_ScreenshotPaintingContext] objects recording
/// a screenshot.
class _ScreenshotData {
  _ScreenshotData({
    @required this.target,
  }) : assert(target != null),
331
       containerLayer = _ScreenshotContainerLayer();
332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374

  /// Target to take a screenshot of.
  final RenderObject target;

  /// Root of the layer tree containing the screenshot.
  final OffsetLayer containerLayer;

  /// Whether the screenshot target has already been found in the render tree.
  bool foundTarget = false;

  /// Whether paint operations should record to the screenshot.
  ///
  /// At least one of [includeInScreenshot] and [includeInRegularContext] must
  /// be true.
  bool includeInScreenshot = false;

  /// Whether paint operations should record to the regular context.
  ///
  /// This should only be set to false before paint operations that should only
  /// apply to the screenshot such rendering debug information about the
  /// [target].
  ///
  /// At least one of [includeInScreenshot] and [includeInRegularContext] must
  /// be true.
  bool includeInRegularContext = true;

  /// Offset of the screenshot corresponding to the offset [target] was given as
  /// part of the regular paint.
  Offset get screenshotOffset {
    assert(foundTarget);
    return containerLayer.offset;
  }
  set screenshotOffset(Offset offset) {
    containerLayer.offset = offset;
  }
}

/// A place to paint to build screenshots of [RenderObject]s.
///
/// Requires that the render objects have already painted successfully as part
/// of the regular rendering pipeline.
/// This painting context behaves the same as standard [PaintingContext] with
/// instrumentation added to compute a screenshot of a specified [RenderObject]
375
/// added. To correctly mimic the behavior of the regular rendering pipeline, the
376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428
/// full subtree of the first [RepaintBoundary] ancestor of the specified
/// [RenderObject] will also be rendered rather than just the subtree of the
/// render object.
class _ScreenshotPaintingContext extends PaintingContext {
  _ScreenshotPaintingContext({
    @required ContainerLayer containerLayer,
    @required Rect estimatedBounds,
    @required _ScreenshotData screenshotData,
  }) : _data = screenshotData,
       super(containerLayer, estimatedBounds);

  final _ScreenshotData _data;

  // Recording state
  PictureLayer _screenshotCurrentLayer;
  ui.PictureRecorder _screenshotRecorder;
  Canvas _screenshotCanvas;
  _MulticastCanvas _multicastCanvas;

  @override
  Canvas get canvas {
    if (_data.includeInScreenshot) {
      if (_screenshotCanvas == null) {
        _startRecordingScreenshot();
      }
      assert(_screenshotCanvas != null);
      return _data.includeInRegularContext ? _multicastCanvas : _screenshotCanvas;
    } else {
      assert(_data.includeInRegularContext);
      return super.canvas;
    }
  }

  bool get _isScreenshotRecording {
    final bool hasScreenshotCanvas = _screenshotCanvas != null;
    assert(() {
      if (hasScreenshotCanvas) {
        assert(_screenshotCurrentLayer != null);
        assert(_screenshotRecorder != null);
        assert(_screenshotCanvas != null);
      } else {
        assert(_screenshotCurrentLayer == null);
        assert(_screenshotRecorder == null);
        assert(_screenshotCanvas == null);
      }
      return true;
    }());
    return hasScreenshotCanvas;
  }

  void _startRecordingScreenshot() {
    assert(_data.includeInScreenshot);
    assert(!_isScreenshotRecording);
429 430 431
    _screenshotCurrentLayer = PictureLayer(estimatedBounds);
    _screenshotRecorder = ui.PictureRecorder();
    _screenshotCanvas = Canvas(_screenshotRecorder);
432 433
    _data.containerLayer.append(_screenshotCurrentLayer);
    if (_data.includeInRegularContext) {
434
      _multicastCanvas = _MulticastCanvas(
435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467
        main: super.canvas,
        screenshot: _screenshotCanvas,
      );
    } else {
      _multicastCanvas = null;
    }
  }

  @override
  void stopRecordingIfNeeded() {
    super.stopRecordingIfNeeded();
    _stopRecordingScreenshotIfNeeded();
  }

  void _stopRecordingScreenshotIfNeeded() {
    if (!_isScreenshotRecording)
      return;
    // There is no need to ever draw repaint rainbows as part of the screenshot.
    _screenshotCurrentLayer.picture = _screenshotRecorder.endRecording();
    _screenshotCurrentLayer = null;
    _screenshotRecorder = null;
    _multicastCanvas = null;
    _screenshotCanvas = null;
  }

  @override
  void appendLayer(Layer layer) {
    if (_data.includeInRegularContext) {
      super.appendLayer(layer);
      if (_data.includeInScreenshot) {
        assert(!_isScreenshotRecording);
        // We must use a proxy layer here as the layer is already attached to
        // the regular layer tree.
468
        _data.containerLayer.append(_ProxyLayer(layer));
469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486
      }
    } else {
      // Only record to the screenshot.
      assert(!_isScreenshotRecording);
      assert(_data.includeInScreenshot);
      layer.remove();
      _data.containerLayer.append(layer);
      return;
    }
  }

  @override
  PaintingContext createChildContext(ContainerLayer childLayer, Rect bounds) {
    if (_data.foundTarget) {
      // We have already found the screenshotTarget in the layer tree
      // so we can optimize and use a standard PaintingContext.
      return super.createChildContext(childLayer, bounds);
    } else {
487
      return _ScreenshotPaintingContext(
488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524
        containerLayer: childLayer,
        estimatedBounds: bounds,
        screenshotData: _data,
      );
    }
  }

  @override
  void paintChild(RenderObject child, Offset offset) {
    final bool isScreenshotTarget = identical(child, _data.target);
    if (isScreenshotTarget) {
      assert(!_data.includeInScreenshot);
      assert(!_data.foundTarget);
      _data.foundTarget = true;
      _data.screenshotOffset = offset;
      _data.includeInScreenshot = true;
    }
    super.paintChild(child, offset);
    if (isScreenshotTarget) {
      _stopRecordingScreenshotIfNeeded();
      _data.includeInScreenshot = false;
    }
  }

  /// Captures an image of the current state of [renderObject] and its children.
  ///
  /// The returned [ui.Image] has uncompressed raw RGBA bytes, will be offset
  /// by the top-left corner of [renderBounds], and have dimensions equal to the
  /// size of [renderBounds] multiplied by [pixelRatio].
  ///
  /// To use [toImage], the render object must have gone through the paint phase
  /// (i.e. [debugNeedsPaint] must be false).
  ///
  /// The [pixelRatio] describes the scale between the logical pixels and the
  /// size of the output image. It is independent of the
  /// [window.devicePixelRatio] for the device, so specifying 1.0 (the default)
  /// will give you a 1:1 mapping between logical pixels and the output pixels
525
  /// in the image.
526 527 528
  ///
  /// The [debugPaint] argument specifies whether the image should include the
  /// output of [RenderObject.debugPaint] for [renderObject] with
529
  /// [debugPaintSizeEnabled] set to true. Debug paint information is not
530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546
  /// included for the children of [renderObject] so that it is clear precisely
  /// which object the debug paint information references.
  ///
  /// See also:
  ///
  ///  * [RenderRepaintBoundary.toImage] for a similar API for [RenderObject]s
  ///    that are repaint boundaries that can be used outside of the inspector.
  ///  * [OffsetLayer.toImage] for a similar API at the layer level.
  ///  * [dart:ui.Scene.toImage] for more information about the image returned.
  static Future<ui.Image> toImage(
    RenderObject renderObject,
    Rect renderBounds, {
    double pixelRatio = 1.0,
    bool debugPaint = false,
  }) {
    RenderObject repaintBoundary = renderObject;
    while (repaintBoundary != null && !repaintBoundary.isRepaintBoundary) {
547
      repaintBoundary = repaintBoundary.parent as RenderObject;
548 549
    }
    assert(repaintBoundary != null);
550 551
    final _ScreenshotData data = _ScreenshotData(target: renderObject);
    final _ScreenshotPaintingContext context = _ScreenshotPaintingContext(
552 553 554 555 556 557 558 559 560
      containerLayer: repaintBoundary.debugLayer,
      estimatedBounds: repaintBoundary.paintBounds,
      screenshotData: data,
    );

    if (identical(renderObject, repaintBoundary)) {
      // Painting the existing repaint boundary to the screenshot is sufficient.
      // We don't just take a direct screenshot of the repaint boundary as we
      // want to capture debugPaint information as well.
561
      data.containerLayer.append(_ProxyLayer(repaintBoundary.debugLayer));
562
      data.foundTarget = true;
563
      final OffsetLayer offsetLayer = repaintBoundary.debugLayer as OffsetLayer;
564
      data.screenshotOffset = offsetLayer.offset;
565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596
    } else {
      // Repaint everything under the repaint boundary.
      // We call debugInstrumentRepaintCompositedChild instead of paintChild as
      // we need to force everything under the repaint boundary to repaint.
      PaintingContext.debugInstrumentRepaintCompositedChild(
        repaintBoundary,
        customContext: context,
      );
    }

    // The check that debugPaintSizeEnabled is false exists to ensure we only
    // call debugPaint when it wasn't already called.
    if (debugPaint && !debugPaintSizeEnabled) {
      data.includeInRegularContext = false;
      // Existing recording may be to a canvas that draws to both the normal and
      // screenshot canvases.
      context.stopRecordingIfNeeded();
      assert(data.foundTarget);
      data.includeInScreenshot = true;

      debugPaintSizeEnabled = true;
      try {
        renderObject.debugPaint(context, data.screenshotOffset);
      } finally {
        debugPaintSizeEnabled = false;
        context.stopRecordingIfNeeded();
      }
    }

    // We must build the regular scene before we can build the screenshot
    // scene as building the screenshot scene assumes addToScene has already
    // been called successfully for all layers in the regular scene.
597
    repaintBoundary.debugLayer.buildScene(ui.SceneBuilder());
598 599 600 601 602

    return data.containerLayer.toImage(renderBounds, pixelRatio: pixelRatio);
  }
}

603 604 605 606 607 608 609 610 611 612
/// A class describing a step along a path through a tree of [DiagnosticsNode]
/// objects.
///
/// This class is used to bundle all data required to display the tree with just
/// the nodes along a path expanded into a single JSON payload.
class _DiagnosticsPathNode {
  /// Creates a full description of a step in a path through a tree of
  /// [DiagnosticsNode] objects.
  ///
  /// The [node] and [child] arguments must not be null.
613 614 615 616 617 618
  _DiagnosticsPathNode({
    @required this.node,
    @required this.children,
    this.childIndex,
  }) : assert(node != null),
       assert(children != null);
619 620 621 622 623 624 625 626 627 628 629 630 631 632

  /// Node at the point in the path this [_DiagnosticsPathNode] is describing.
  final DiagnosticsNode node;

  /// Children of the [node] being described.
  ///
  /// This value is cached instead of relying on `node.getChildren()` as that
  /// method call might create new [DiagnosticsNode] objects for each child
  /// and we would prefer to use the identical [DiagnosticsNode] for each time
  /// a node exists in the path.
  final List<DiagnosticsNode> children;

  /// Index of the child that the path continues on.
  ///
633
  /// Equal to null if the path does not continue.
634 635 636
  final int childIndex;
}

637
List<_DiagnosticsPathNode> _followDiagnosticableChain(
638
  List<Diagnosticable> chain, {
639 640 641 642 643 644 645 646
  String name,
  DiagnosticsTreeStyle style,
}) {
  final List<_DiagnosticsPathNode> path = <_DiagnosticsPathNode>[];
  if (chain.isEmpty)
    return path;
  DiagnosticsNode diagnostic = chain.first.toDiagnosticsNode(name: name, style: style);
  for (int i = 1; i < chain.length; i += 1) {
647
    final Diagnosticable target = chain[i];
648 649 650 651 652 653
    bool foundMatch = false;
    final List<DiagnosticsNode> children = diagnostic.getChildren();
    for (int j = 0; j < children.length; j += 1) {
      final DiagnosticsNode child = children[j];
      if (child.value == target) {
        foundMatch = true;
654
        path.add(_DiagnosticsPathNode(
655 656 657 658 659 660 661 662 663 664
          node: diagnostic,
          children: children,
          childIndex: j,
        ));
        diagnostic = child;
        break;
      }
    }
    assert(foundMatch);
  }
665
  path.add(_DiagnosticsPathNode(node: diagnostic, children: diagnostic.getChildren()));
666 667 668 669 670
  return path;
}

/// Signature for the selection change callback used by
/// [WidgetInspectorService.selectionChangedCallback].
671
typedef InspectorSelectionChangedCallback = void Function();
672 673 674 675 676 677 678 679 680 681

/// Structure to help reference count Dart objects referenced by a GUI tool
/// using [WidgetInspectorService].
class _InspectorReferenceData {
  _InspectorReferenceData(this.object);

  final Object object;
  int count = 1;
}

682 683
// Production implementation of [WidgetInspectorService].
class _WidgetInspectorService = Object with WidgetInspectorService;
684

685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
/// Service used by GUI tools to interact with the [WidgetInspector].
///
/// Calls to this object are typically made from GUI tools such as the [Flutter
/// IntelliJ Plugin](https://github.com/flutter/flutter-intellij/blob/master/README.md)
/// using the [Dart VM Service protocol](https://github.com/dart-lang/sdk/blob/master/runtime/vm/service/service.md).
/// This class uses its own object id and manages object lifecycles itself
/// instead of depending on the [object ids](https://github.com/dart-lang/sdk/blob/master/runtime/vm/service/service.md#getobject)
/// specified by the VM Service Protocol because the VM Service Protocol ids
/// expire unpredictably. Object references are tracked in groups so that tools
/// that clients can use dereference all objects in a group with a single
/// operation making it easier to avoid memory leaks.
///
/// All methods in this class are appropriate to invoke from debugging tools
/// using the Observatory service protocol to evaluate Dart expressions of the
/// form `WidgetInspectorService.instance.methodName(arg1, arg2, ...)`. If you
/// make changes to any instance method of this class you need to verify that
/// the [Flutter IntelliJ Plugin](https://github.com/flutter/flutter-intellij/blob/master/README.md)
/// widget inspector support still works with the changes.
///
/// All methods returning String values return JSON.
705
mixin WidgetInspectorService {
706
  /// Ring of cached JSON values to prevent JSON from being garbage
707
  /// collected before it can be requested over the Observatory protocol.
708
  final List<String> _serializeRing = List<String>(20);
709 710
  int _serializeRingIndex = 0;

711 712
  /// The current [WidgetInspectorService].
  static WidgetInspectorService get instance => _instance;
713
  static WidgetInspectorService _instance = _WidgetInspectorService();
714 715 716 717 718 719
  @protected
  static set instance(WidgetInspectorService instance) {
    _instance = instance;
  }

  static bool _debugServiceExtensionsRegistered = false;
720 721 722 723

  /// Ground truth tracking what object(s) are currently selected used by both
  /// GUI tools such as the Flutter IntelliJ Plugin and the [WidgetInspector]
  /// displayed on the device.
724
  final InspectorSelection selection = InspectorSelection();
725 726 727 728 729 730 731 732 733 734 735 736 737 738

  /// Callback typically registered by the [WidgetInspector] to receive
  /// notifications when [selection] changes.
  ///
  /// The Flutter IntelliJ Plugin does not need to listen for this event as it
  /// instead listens for `dart:developer` `inspect` events which also trigger
  /// when the inspection target changes on device.
  InspectorSelectionChangedCallback selectionChangedCallback;

  /// The Observatory protocol does not keep alive object references so this
  /// class needs to manually manage groups of objects that should be kept
  /// alive.
  final Map<String, Set<_InspectorReferenceData>> _groups = <String, Set<_InspectorReferenceData>>{};
  final Map<String, _InspectorReferenceData> _idToReferenceData = <String, _InspectorReferenceData>{};
739
  final Map<Object, String> _objectToId = Map<Object, String>.identity();
740 741
  int _nextId = 0;

742 743
  List<String> _pubRootDirectories;

744 745 746
  bool _trackRebuildDirtyWidgets = false;
  bool _trackRepaintWidgets = false;

747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
  _RegisterServiceExtensionCallback _registerServiceExtensionCallback;
  /// Registers a service extension method with the given name (full
  /// name "ext.flutter.inspector.name").
  ///
  /// The given callback is called when the extension method is called. The
  /// callback must return a value that can be converted to JSON using
  /// `json.encode()` (see [JsonEncoder]). The return value is stored as a
  /// property named `result` in the JSON. In case of failure, the failure is
  /// reported to the remote caller and is dumped to the logs.
  @protected
  void registerServiceExtension({
    @required String name,
    @required ServiceExtensionCallback callback,
  }) {
    _registerServiceExtensionCallback(
      name: 'inspector.$name',
      callback: callback,
    );
  }

  /// Registers a service extension method with the given name (full
  /// name "ext.flutter.inspector.name"), which takes no arguments.
  void _registerSignalServiceExtension({
    @required String name,
    @required FutureOr<Object> callback(),
  }) {
    registerServiceExtension(
      name: name,
      callback: (Map<String, String> parameters) async {
        return <String, Object>{'result': await callback()};
      },
    );
  }

  /// Registers a service extension method with the given name (full
782
  /// name "ext.flutter.inspector.name"), which takes a single optional argument
783 784
  /// "objectGroup" specifying what group is used to manage lifetimes of
  /// object references in the returned JSON (see [disposeGroup]).
785 786
  /// If "objectGroup" is omitted, the returned JSON will not include any object
  /// references to avoid leaking memory.
787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813
  void _registerObjectGroupServiceExtension({
    @required String name,
    @required FutureOr<Object> callback(String objectGroup),
  }) {
    registerServiceExtension(
      name: name,
      callback: (Map<String, String> parameters) async {
        return <String, Object>{'result': await callback(parameters['objectGroup'])};
      },
    );
  }

  /// Registers a service extension method with the given name (full
  /// name "ext.flutter.inspector.name"), which takes a single argument
  /// "enabled" which can have the value "true" or the value "false"
  /// or can be omitted to read the current value. (Any value other
  /// than "true" is considered equivalent to "false". Other arguments
  /// are ignored.)
  ///
  /// Calls the `getter` callback to obtain the value when
  /// responding to the service extension method being called.
  ///
  /// Calls the `setter` callback with the new value when the
  /// service extension method is called with a new value.
  void _registerBoolServiceExtension({
    @required String name,
    @required AsyncValueGetter<bool> getter,
814
    @required AsyncValueSetter<bool> setter,
815 816 817 818 819 820 821
  }) {
    assert(name != null);
    assert(getter != null);
    assert(setter != null);
    registerServiceExtension(
      name: name,
      callback: (Map<String, String> parameters) async {
822 823 824 825 826
        if (parameters.containsKey('enabled')) {
          final bool value = parameters['enabled'] == 'true';
          await setter(value);
          _postExtensionStateChangedEvent(name, value);
        }
827
        return <String, dynamic>{'enabled': await getter() ? 'true' : 'false'};
828 829 830 831
      },
    );
  }

832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
  /// Sends an event when a service extension's state is changed.
  ///
  /// Clients should listen for this event to stay aware of the current service
  /// extension state. Any service extension that manages a state should call
  /// this method on state change.
  ///
  /// `value` reflects the newly updated service extension value.
  ///
  /// This will be called automatically for service extensions registered via
  /// [registerBoolServiceExtension].
  void _postExtensionStateChangedEvent(String name, dynamic value) {
    postEvent(
      'Flutter.ServiceExtensionStateChanged',
      <String, dynamic>{
        'extension': 'ext.flutter.inspector.$name',
        'value': value,
      },
    );
  }

852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896
  /// Registers a service extension method with the given name (full
  /// name "ext.flutter.inspector.name") which takes an optional parameter named
  /// "arg" and a required parameter named "objectGroup" used to control the
  /// lifetimes of object references in the returned JSON (see [disposeGroup]).
  void _registerServiceExtensionWithArg({
    @required String name,
    @required FutureOr<Object> callback(String objectId, String objectGroup),
  }) {
    registerServiceExtension(
      name: name,
      callback: (Map<String, String> parameters) async {
        assert(parameters.containsKey('objectGroup'));
        return <String, Object>{
          'result': await callback(parameters['arg'], parameters['objectGroup']),
        };
      },
    );
  }

  /// Registers a service extension method with the given name (full
  /// name "ext.flutter.inspector.name"), that takes arguments
  /// "arg0", "arg1", "arg2", ..., "argn".
  void _registerServiceExtensionVarArgs({
    @required String name,
    @required FutureOr<Object> callback(List<String> args),
  }) {
    registerServiceExtension(
      name: name,
      callback: (Map<String, String> parameters) async {
        const String argPrefix = 'arg';
        final List<String> args = <String>[];
        parameters.forEach((String name, String value) {
          if (name.startsWith(argPrefix)) {
            final int index = int.parse(name.substring(argPrefix.length));
            if (index >= args.length) {
              args.length = index + 1;
            }
            args[index] = value;
          }
        });
        return <String, Object>{'result': await callback(args)};
      },
    );
  }

897 898 899 900 901
  /// Cause the entire tree to be rebuilt. This is used by development tools
  /// when the application code has changed and is being hot-reloaded, to cause
  /// the widget tree to pick up any changed implementations.
  ///
  /// This is expensive and should not be called except during development.
902
  @protected
903
  Future<void> forceRebuild() {
904 905 906 907 908
    final WidgetsBinding binding = WidgetsBinding.instance;
    if (binding.renderViewElement != null) {
      binding.buildOwner.reassemble(binding.renderViewElement);
      return binding.endOfFrame;
    }
909
    return Future<void>.value();
910 911
  }

912 913
  static const String _consoleObjectGroup = 'console-group';

914 915
  int _errorsSinceReload = 0;

916
  void _reportError(FlutterErrorDetails details) {
917
    final Map<String, Object> errorJson = _nodeToJson(
918
      details.toDiagnosticsNode(),
919
      InspectorSerializationDelegate(
920 921 922 923 924
        groupName: _consoleObjectGroup,
        subtreeDepth: 5,
        includeProperties: true,
        expandPropertyValues: true,
        maxDescendentsTruncatableNode: 5,
925
        service: this,
926
      ),
927 928 929 930 931 932 933 934 935 936 937 938 939 940 941
    );

    errorJson['errorsSinceReload'] = _errorsSinceReload;
    _errorsSinceReload += 1;

    postEvent('Flutter.Error', errorJson);
  }

  /// Resets the count of errors since the last hot reload.
  ///
  /// This data is sent to clients as part of the 'Flutter.Error' service
  /// protocol event. Clients may choose to display errors received after the
  /// first error differently.
  void _resetErrorCount() {
    _errorsSinceReload = 0;
942 943
  }

944 945 946 947 948
  /// Called to register service extensions.
  ///
  /// See also:
  ///
  ///  * <https://github.com/dart-lang/sdk/blob/master/runtime/vm/service/service.md#rpcs-requests-and-responses>
949 950
  ///  * [BindingBase.initServiceExtensions], which explains when service
  ///    extensions can be used.
951
  void initServiceExtensions(_RegisterServiceExtensionCallback registerServiceExtensionCallback) {
952 953
    _registerServiceExtensionCallback = registerServiceExtensionCallback;
    assert(!_debugServiceExtensionsRegistered);
954 955 956 957
    assert(() {
      _debugServiceExtensionsRegistered = true;
      return true;
    }());
958

959 960
    SchedulerBinding.instance.addPersistentFrameCallback(_onFrameStart);

961
    final FlutterExceptionHandler structuredExceptionHandler = _reportError;
962
    final FlutterExceptionHandler defaultExceptionHandler = FlutterError.presentError;
963 964 965

    _registerBoolServiceExtension(
      name: 'structuredErrors',
966
      getter: () async => FlutterError.presentError == structuredExceptionHandler,
967
      setter: (bool value) {
968
        FlutterError.presentError = value ? structuredExceptionHandler : defaultExceptionHandler;
969 970 971 972
        return Future<void>.value();
      },
    );

973 974 975 976 977
    _registerBoolServiceExtension(
      name: 'show',
      getter: () async => WidgetsApp.debugShowWidgetInspectorOverride,
      setter: (bool value) {
        if (WidgetsApp.debugShowWidgetInspectorOverride == value) {
978
          return Future<void>.value();
979 980 981 982 983 984
        }
        WidgetsApp.debugShowWidgetInspectorOverride = value;
        return forceRebuild();
      },
    );

985 986 987 988 989 990 991 992
    if (isWidgetCreationTracked()) {
      // Service extensions that are only supported if widget creation locations
      // are tracked.
      _registerBoolServiceExtension(
        name: 'trackRebuildDirtyWidgets',
        getter: () async => _trackRebuildDirtyWidgets,
        setter: (bool value) async {
          if (value == _trackRebuildDirtyWidgets) {
993
            return;
994 995 996 997 998 999 1000 1001
          }
          _rebuildStats.resetCounts();
          _trackRebuildDirtyWidgets = value;
          if (value) {
            assert(debugOnRebuildDirtyWidget == null);
            debugOnRebuildDirtyWidget = _onRebuildWidget;
            // Trigger a rebuild so there are baseline stats for rebuilds
            // performed by the app.
1002 1003
            await forceRebuild();
            return;
1004 1005
          } else {
            debugOnRebuildDirtyWidget = null;
1006
            return;
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039
          }
        },
      );

      _registerBoolServiceExtension(
        name: 'trackRepaintWidgets',
        getter: () async => _trackRepaintWidgets,
        setter: (bool value) async {
          if (value == _trackRepaintWidgets) {
            return;
          }
          _repaintStats.resetCounts();
          _trackRepaintWidgets = value;
          if (value) {
            assert(debugOnProfilePaint == null);
            debugOnProfilePaint = _onPaint;
            // Trigger an immediate paint so the user has some baseline painting
            // stats to view.
            void markTreeNeedsPaint(RenderObject renderObject) {
              renderObject.markNeedsPaint();
              renderObject.visitChildren(markTreeNeedsPaint);
            }
            final RenderObject root = RendererBinding.instance.renderView;
            if (root != null) {
              markTreeNeedsPaint(root);
            }
          } else {
            debugOnProfilePaint = null;
          }
        },
      );
    }

1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
    _registerSignalServiceExtension(
      name: 'disposeAllGroups',
      callback: disposeAllGroups,
    );
    _registerObjectGroupServiceExtension(
      name: 'disposeGroup',
      callback: disposeGroup,
    );
    _registerSignalServiceExtension(
      name: 'isWidgetTreeReady',
      callback: isWidgetTreeReady,
    );
    _registerServiceExtensionWithArg(
      name: 'disposeId',
      callback: disposeId,
    );
    _registerServiceExtensionVarArgs(
      name: 'setPubRootDirectories',
      callback: setPubRootDirectories,
    );
    _registerServiceExtensionWithArg(
      name: 'setSelectionById',
      callback: setSelectionById,
    );
    _registerServiceExtensionWithArg(
      name: 'getParentChain',
      callback: _getParentChain,
    );
    _registerServiceExtensionWithArg(
      name: 'getProperties',
      callback: _getProperties,
    );
    _registerServiceExtensionWithArg(
      name: 'getChildren',
      callback: _getChildren,
    );
1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086

    _registerServiceExtensionWithArg(
      name: 'getChildrenSummaryTree',
      callback: _getChildrenSummaryTree,
    );

    _registerServiceExtensionWithArg(
      name: 'getChildrenDetailsSubtree',
      callback: _getChildrenDetailsSubtree,
    );

1087 1088 1089 1090 1091 1092 1093 1094
    _registerObjectGroupServiceExtension(
      name: 'getRootWidget',
      callback: _getRootWidget,
    );
    _registerObjectGroupServiceExtension(
      name: 'getRootRenderObject',
      callback: _getRootRenderObject,
    );
1095 1096 1097 1098
    _registerObjectGroupServiceExtension(
      name: 'getRootWidgetSummaryTree',
      callback: _getRootWidgetSummaryTree,
    );
1099
    registerServiceExtension(
1100
      name: 'getDetailsSubtree',
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
      callback: (Map<String, String> parameters) async {
        assert(parameters.containsKey('objectGroup'));
        final String subtreeDepth = parameters['subtreeDepth'];
        return <String, Object>{
          'result': _getDetailsSubtree(
            parameters['arg'],
            parameters['objectGroup'],
            subtreeDepth != null ? int.parse(subtreeDepth) : 2,
          ),
        };
      },
1112
    );
1113 1114 1115 1116 1117 1118 1119 1120
    _registerServiceExtensionWithArg(
      name: 'getSelectedRenderObject',
      callback: _getSelectedRenderObject,
    );
    _registerServiceExtensionWithArg(
      name: 'getSelectedWidget',
      callback: _getSelectedWidget,
    );
1121 1122 1123 1124 1125
    _registerServiceExtensionWithArg(
      name: 'getSelectedSummaryWidget',
      callback: _getSelectedSummaryWidget,
    );

1126 1127 1128 1129
    _registerSignalServiceExtension(
      name: 'isWidgetCreationTracked',
      callback: isWidgetCreationTracked,
    );
1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150
    registerServiceExtension(
      name: 'screenshot',
      callback: (Map<String, String> parameters) async {
        assert(parameters.containsKey('id'));
        assert(parameters.containsKey('width'));
        assert(parameters.containsKey('height'));

        final ui.Image image = await screenshot(
          toObject(parameters['id']),
          width: double.parse(parameters['width']),
          height: double.parse(parameters['height']),
          margin: parameters.containsKey('margin') ?
              double.parse(parameters['margin']) : 0.0,
          maxPixelRatio: parameters.containsKey('maxPixelRatio') ?
              double.parse(parameters['maxPixelRatio']) : 1.0,
          debugPaint: parameters['debugPaint'] == 'true',
        );
        if (image == null) {
          return <String, Object>{'result': null};
        }
        final ByteData byteData = await image.toByteData(format:ui.ImageByteFormat.png);
1151

1152 1153 1154 1155 1156
        return <String, Object>{
          'result': base64.encoder.convert(Uint8List.view(byteData.buffer)),
        };
      },
    );
1157 1158
  }

1159 1160 1161 1162 1163
  void _clearStats() {
    _rebuildStats.resetCounts();
    _repaintStats.resetCounts();
  }

1164 1165 1166 1167
  /// Clear all InspectorService object references.
  ///
  /// Use this method only for testing to ensure that object references from one
  /// test case do not impact other test cases.
1168
  @protected
1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
  void disposeAllGroups() {
    _groups.clear();
    _idToReferenceData.clear();
    _objectToId.clear();
    _nextId = 0;
  }

  /// Free all references to objects in a group.
  ///
  /// Objects and their associated ids in the group may be kept alive by
  /// references from a different group.
1180
  @protected
1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
  void disposeGroup(String name) {
    final Set<_InspectorReferenceData> references = _groups.remove(name);
    if (references == null)
      return;
    references.forEach(_decrementReferenceCount);
  }

  void _decrementReferenceCount(_InspectorReferenceData reference) {
    reference.count -= 1;
    assert(reference.count >= 0);
    if (reference.count == 0) {
      final String id = _objectToId.remove(reference.object);
      assert(id != null);
      _idToReferenceData.remove(id);
    }
  }

  /// Returns a unique id for [object] that will remain live at least until
  /// [disposeGroup] is called on [groupName] or [dispose] is called on the id
  /// returned by this method.
1201
  @protected
1202 1203 1204 1205
  String toId(Object object, String groupName) {
    if (object == null)
      return null;

1206
    final Set<_InspectorReferenceData> group = _groups.putIfAbsent(groupName, () => Set<_InspectorReferenceData>.identity());
1207 1208 1209 1210 1211 1212
    String id = _objectToId[object];
    _InspectorReferenceData referenceData;
    if (id == null) {
      id = 'inspector-$_nextId';
      _nextId += 1;
      _objectToId[object] = id;
1213
      referenceData = _InspectorReferenceData(object);
1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
      _idToReferenceData[id] = referenceData;
      group.add(referenceData);
    } else {
      referenceData = _idToReferenceData[id];
      if (group.add(referenceData))
        referenceData.count += 1;
    }
    return id;
  }

1224 1225
  /// Returns whether the application has rendered its first frame and it is
  /// appropriate to display the Widget tree in the inspector.
1226
  @protected
1227
  bool isWidgetTreeReady([ String groupName ]) {
1228 1229 1230 1231
    return WidgetsBinding.instance != null &&
           WidgetsBinding.instance.debugDidSendFirstFrameEvent;
  }

1232 1233 1234 1235 1236
  /// Returns the Dart object associated with a reference id.
  ///
  /// The `groupName` parameter is not required by is added to regularize the
  /// API surface of the methods in this class called from the Flutter IntelliJ
  /// Plugin.
1237
  @protected
1238
  Object toObject(String id, [ String groupName ]) {
1239 1240 1241 1242
    if (id == null)
      return null;

    final _InspectorReferenceData data = _idToReferenceData[id];
1243
    if (data == null) {
1244
      throw FlutterError.fromParts(<DiagnosticsNode>[ErrorSummary('Id does not exist.')]);
1245
    }
1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257
    return data.object;
  }

  /// Returns the object to introspect to determine the source location of an
  /// object's class.
  ///
  /// The Dart object for the id is returned for all cases but [Element] objects
  /// where the [Widget] configuring the [Element] is returned instead as the
  /// class of the [Widget] is more relevant than the class of the [Element].
  ///
  /// The `groupName` parameter is not required by is added to regularize the
  /// API surface of methods called from the Flutter IntelliJ Plugin.
1258
  @protected
1259
  Object toObjectForSourceLocation(String id, [ String groupName ]) {
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271
    final Object object = toObject(id);
    if (object is Element) {
      return object.widget;
    }
    return object;
  }

  /// Remove the object with the specified `id` from the specified object
  /// group.
  ///
  /// If the object exists in other groups it will remain alive and the object
  /// id will remain valid.
1272
  @protected
1273 1274 1275 1276 1277 1278
  void disposeId(String id, String groupName) {
    if (id == null)
      return;

    final _InspectorReferenceData referenceData = _idToReferenceData[id];
    if (referenceData == null)
1279
      throw FlutterError.fromParts(<DiagnosticsNode>[ErrorSummary('Id does not exist')]);
1280
    if (_groups[groupName]?.remove(referenceData) != true)
1281
      throw FlutterError.fromParts(<DiagnosticsNode>[ErrorSummary('Id is not in group')]);
1282 1283 1284
    _decrementReferenceCount(referenceData);
  }

1285 1286 1287 1288 1289
  /// Set the list of directories that should be considered part of the local
  /// project.
  ///
  /// The local project directories are used to distinguish widgets created by
  /// the local project over widgets created from inside the framework.
1290
  @protected
1291 1292 1293 1294
  void setPubRootDirectories(List<String> pubRootDirectories) {
    _pubRootDirectories = pubRootDirectories
      .map<String>((String directory) => Uri.parse(directory).path)
      .toList();
1295 1296
  }

1297 1298 1299
  /// Set the [WidgetInspector] selection to the object matching the specified
  /// id if the object is valid object to set as the inspector selection.
  ///
1300
  /// Returns true if the selection was changed.
1301 1302 1303
  ///
  /// The `groupName` parameter is not required by is added to regularize the
  /// API surface of methods called from the Flutter IntelliJ Plugin.
1304
  @protected
1305
  bool setSelectionById(String id, [ String groupName ]) {
1306 1307 1308 1309 1310 1311
    return setSelection(toObject(id), groupName);
  }

  /// Set the [WidgetInspector] selection to the specified `object` if it is
  /// a valid object to set as the inspector selection.
  ///
1312
  /// Returns true if the selection was changed.
1313 1314 1315
  ///
  /// The `groupName` parameter is not needed but is specified to regularize the
  /// API surface of methods called from the Flutter IntelliJ Plugin.
1316
  @protected
1317
  bool setSelection(Object object, [ String groupName ]) {
1318 1319 1320 1321 1322 1323
    if (object is Element || object is RenderObject) {
      if (object is Element) {
        if (object == selection.currentElement) {
          return false;
        }
        selection.currentElement = object;
1324
        developer.inspect(selection.currentElement);
1325 1326 1327 1328
      } else {
        if (object == selection.current) {
          return false;
        }
1329
        selection.current = object as RenderObject;
1330
        developer.inspect(selection.current);
1331 1332
      }
      if (selectionChangedCallback != null) {
1333
        if (SchedulerBinding.instance.schedulerPhase == SchedulerPhase.idle) {
1334 1335 1336 1337 1338 1339 1340 1341 1342
          selectionChangedCallback();
        } else {
          // It isn't safe to trigger the selection change callback if we are in
          // the middle of rendering the frame.
          SchedulerBinding.instance.scheduleTask(
            selectionChangedCallback,
            Priority.touch,
          );
        }
1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353
      }
      return true;
    }
    return false;
  }

  /// Returns JSON representing the chain of [DiagnosticsNode] instances from
  /// root of thee tree to the [Element] or [RenderObject] matching `id`.
  ///
  /// The JSON contains all information required to display a tree view with
  /// all nodes other than nodes along the path collapsed.
1354
  @protected
1355
  String getParentChain(String id, String groupName) {
1356
    return _safeJsonEncode(_getParentChain(id, groupName));
1357 1358 1359
  }

  List<Object> _getParentChain(String id, String groupName) {
1360 1361 1362 1363 1364 1365 1366
    final Object value = toObject(id);
    List<_DiagnosticsPathNode> path;
    if (value is RenderObject)
      path = _getRenderObjectParentChain(value, groupName);
    else if (value is Element)
      path = _getElementParentChain(value, groupName);
    else
1367
      throw FlutterError.fromParts(<DiagnosticsNode>[ErrorSummary('Cannot get parent chain for node of type ${value.runtimeType}')]);
1368

1369
    return path.map<Object>((_DiagnosticsPathNode node) => _pathNodeToJson(
1370
      node,
1371
      InspectorSerializationDelegate(groupName: groupName, service: this),
1372
    )).toList();
1373 1374
  }

1375
  Map<String, Object> _pathNodeToJson(_DiagnosticsPathNode pathNode, InspectorSerializationDelegate delegate) {
1376 1377 1378
    if (pathNode == null)
      return null;
    return <String, Object>{
1379 1380
      'node': _nodeToJson(pathNode.node, delegate),
      'children': _nodesToJson(pathNode.children, delegate, parent: pathNode.node),
1381 1382 1383 1384
      'childIndex': pathNode.childIndex,
    };
  }

1385
  List<Element> _getRawElementParentChain(Element element, { int numLocalParents }) {
1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400
    List<Element> elements = element?.debugGetDiagnosticChain();
    if (numLocalParents != null) {
      for (int i = 0; i < elements.length; i += 1) {
        if (_isValueCreatedByLocalProject(elements[i])) {
          numLocalParents--;
          if (numLocalParents <= 0) {
            elements = elements.take(i + 1).toList();
            break;
          }
        }
      }
    }
    return elements?.reversed?.toList();
  }

1401
  List<_DiagnosticsPathNode> _getElementParentChain(Element element, String groupName, { int numLocalParents }) {
1402 1403 1404
    return _followDiagnosticableChain(
      _getRawElementParentChain(element, numLocalParents: numLocalParents),
    ) ?? const <_DiagnosticsPathNode>[];
1405 1406
  }

1407
  List<_DiagnosticsPathNode> _getRenderObjectParentChain(RenderObject renderObject, String groupName, { int maxparents }) {
1408
    final List<RenderObject> chain = <RenderObject>[];
1409
    while (renderObject != null) {
1410
      chain.add(renderObject);
1411
      renderObject = renderObject.parent as RenderObject;
1412 1413 1414 1415
    }
    return _followDiagnosticableChain(chain.reversed.toList());
  }

1416 1417
  Map<String, Object> _nodeToJson(
    DiagnosticsNode node,
1418
    InspectorSerializationDelegate delegate,
1419
  ) {
1420
    return node?.toJsonMap(delegate);
1421 1422
  }

1423 1424 1425 1426 1427 1428 1429 1430
  bool _isValueCreatedByLocalProject(Object value) {
    final _Location creationLocation = _getCreationLocation(value);
    if (creationLocation == null) {
      return false;
    }
    return _isLocalCreationLocation(creationLocation);
  }

1431
  bool _isLocalCreationLocation(_Location location) {
1432
    if (location == null || location.file == null) {
1433 1434 1435
      return false;
    }
    final String file = Uri.parse(location.file).path;
1436 1437 1438 1439 1440 1441 1442

    // By default check whether the creation location was within package:flutter.
    if (_pubRootDirectories == null) {
      // TODO(chunhtai): Make it more robust once
      // https://github.com/flutter/flutter/issues/32660 is fixed.
      return !file.contains('packages/flutter/');
    }
1443
    for (final String directory in _pubRootDirectories) {
1444 1445 1446 1447 1448 1449 1450
      if (file.startsWith(directory)) {
        return true;
      }
    }
    return false;
  }

1451 1452 1453 1454 1455
  /// Wrapper around `json.encode` that uses a ring of cached values to prevent
  /// the Dart garbage collector from collecting objects between when
  /// the value is returned over the Observatory protocol and when the
  /// separate observatory protocol command has to be used to retrieve its full
  /// contents.
1456 1457 1458
  //
  // TODO(jacobr): Replace this with a better solution once
  // https://github.com/dart-lang/sdk/issues/32919 is fixed.
1459 1460 1461 1462 1463
  String _safeJsonEncode(Object object) {
    final String jsonString = json.encode(object);
    _serializeRing[_serializeRingIndex] = jsonString;
    _serializeRingIndex = (_serializeRingIndex + 1)  % _serializeRing.length;
    return jsonString;
1464 1465
  }

1466
  List<DiagnosticsNode> _truncateNodes(Iterable<DiagnosticsNode> nodes, int maxDescendentsTruncatableNode) {
1467 1468 1469 1470 1471 1472 1473
    if (nodes.every((DiagnosticsNode node) => node.value is Element) && isWidgetCreationTracked()) {
      final List<DiagnosticsNode> localNodes = nodes.where((DiagnosticsNode node) =>
          _isValueCreatedByLocalProject(node.value)).toList();
      if (localNodes.isNotEmpty) {
        return localNodes;
      }
    }
1474
    return nodes.take(maxDescendentsTruncatableNode).toList();
1475 1476
  }

1477
  List<Map<String, Object>> _nodesToJson(
1478
    List<DiagnosticsNode> nodes,
1479
    InspectorSerializationDelegate delegate, {
1480 1481
    @required DiagnosticsNode parent,
  }) {
1482
    return DiagnosticsNode.toJsonList(nodes, parent, delegate);
1483 1484 1485 1486
  }

  /// Returns a JSON representation of the properties of the [DiagnosticsNode]
  /// object that `diagnosticsNodeId` references.
1487
  @protected
1488
  String getProperties(String diagnosticsNodeId, String groupName) {
1489
    return _safeJsonEncode(_getProperties(diagnosticsNodeId, groupName));
1490 1491 1492
  }

  List<Object> _getProperties(String diagnosticsNodeId, String groupName) {
1493
    final DiagnosticsNode node = toObject(diagnosticsNodeId) as DiagnosticsNode;
1494
    return _nodesToJson(node == null ? const <DiagnosticsNode>[] : node.getProperties(), InspectorSerializationDelegate(groupName: groupName, service: this), parent: node);
1495 1496 1497 1498 1499
  }

  /// Returns a JSON representation of the children of the [DiagnosticsNode]
  /// object that `diagnosticsNodeId` references.
  String getChildren(String diagnosticsNodeId, String groupName) {
1500
    return _safeJsonEncode(_getChildren(diagnosticsNodeId, groupName));
1501 1502 1503
  }

  List<Object> _getChildren(String diagnosticsNodeId, String groupName) {
1504
    final DiagnosticsNode node = toObject(diagnosticsNodeId) as DiagnosticsNode;
1505
    final InspectorSerializationDelegate delegate = InspectorSerializationDelegate(groupName: groupName, service: this);
1506
    return _nodesToJson(node == null ? const <DiagnosticsNode>[] : _getChildrenFiltered(node, delegate), delegate, parent: node);
1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525
  }

  /// Returns a JSON representation of the children of the [DiagnosticsNode]
  /// object that `diagnosticsNodeId` references only including children that
  /// were created directly by user code.
  ///
  /// Requires [Widget] creation locations which are only available for debug
  /// mode builds when the `--track-widget-creation` flag is passed to
  /// `flutter_tool`.
  ///
  /// See also:
  ///
  ///  * [isWidgetCreationTracked] which indicates whether this method can be
  ///    used.
  String getChildrenSummaryTree(String diagnosticsNodeId, String groupName) {
    return _safeJsonEncode(_getChildrenSummaryTree(diagnosticsNodeId, groupName));
  }

  List<Object> _getChildrenSummaryTree(String diagnosticsNodeId, String groupName) {
1526
    final DiagnosticsNode node = toObject(diagnosticsNodeId) as DiagnosticsNode;
1527
    final InspectorSerializationDelegate delegate = InspectorSerializationDelegate(groupName: groupName, summaryTree: true, service: this);
1528
    return _nodesToJson(node == null ? const <DiagnosticsNode>[] : _getChildrenFiltered(node, delegate), delegate, parent: node);
1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
  }

  /// Returns a JSON representation of the children of the [DiagnosticsNode]
  /// object that `diagnosticsNodeId` references providing information needed
  /// for the details subtree view.
  ///
  /// The details subtree shows properties inline and includes all children
  /// rather than a filtered set of important children.
  String getChildrenDetailsSubtree(String diagnosticsNodeId, String groupName) {
    return _safeJsonEncode(_getChildrenDetailsSubtree(diagnosticsNodeId, groupName));
  }

  List<Object> _getChildrenDetailsSubtree(String diagnosticsNodeId, String groupName) {
1542
    final DiagnosticsNode node = toObject(diagnosticsNodeId) as DiagnosticsNode;
1543
    // With this value of minDepth we only expand one extra level of important nodes.
1544
    final InspectorSerializationDelegate delegate = InspectorSerializationDelegate(groupName: groupName, subtreeDepth: 1, includeProperties: true, service: this);
1545
    return _nodesToJson(node == null ? const <DiagnosticsNode>[] : _getChildrenFiltered(node, delegate), delegate, parent: node);
1546 1547 1548
  }

  bool _shouldShowInSummaryTree(DiagnosticsNode node) {
1549 1550 1551
    if (node.level == DiagnosticLevel.error) {
      return true;
    }
1552
    final Object value = node.value;
1553
    if (value is! Diagnosticable) {
1554 1555 1556
      return true;
    }
    if (value is! Element || !isWidgetCreationTracked()) {
Chris Bracken's avatar
Chris Bracken committed
1557
      // Creation locations are not available so include all nodes in the
1558 1559 1560 1561 1562 1563 1564 1565
      // summary tree.
      return true;
    }
    return _isValueCreatedByLocalProject(value);
  }

  List<DiagnosticsNode> _getChildrenFiltered(
    DiagnosticsNode node,
1566
    InspectorSerializationDelegate delegate,
1567
  ) {
1568 1569
    return _filterChildren(node.getChildren(), delegate);
  }
1570

1571 1572
  List<DiagnosticsNode> _filterChildren(
    List<DiagnosticsNode> nodes,
1573
    InspectorSerializationDelegate delegate,
1574
  ) {
1575
    final List<DiagnosticsNode> children = <DiagnosticsNode>[
1576
      for (final DiagnosticsNode child in nodes)
1577 1578 1579 1580 1581
        if (!delegate.summaryTree || _shouldShowInSummaryTree(child))
          child
        else
          ..._getChildrenFiltered(child, delegate),
    ];
1582
    return children;
1583 1584 1585 1586 1587
  }

  /// Returns a JSON representation of the [DiagnosticsNode] for the root
  /// [Element].
  String getRootWidget(String groupName) {
1588
    return _safeJsonEncode(_getRootWidget(groupName));
1589 1590 1591
  }

  Map<String, Object> _getRootWidget(String groupName) {
1592
    return _nodeToJson(WidgetsBinding.instance?.renderViewElement?.toDiagnosticsNode(), InspectorSerializationDelegate(groupName: groupName, service: this));
1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603
  }

  /// Returns a JSON representation of the [DiagnosticsNode] for the root
  /// [Element] showing only nodes that should be included in a summary tree.
  String getRootWidgetSummaryTree(String groupName) {
    return _safeJsonEncode(_getRootWidgetSummaryTree(groupName));
  }

  Map<String, Object> _getRootWidgetSummaryTree(String groupName) {
    return _nodeToJson(
      WidgetsBinding.instance?.renderViewElement?.toDiagnosticsNode(),
1604
      InspectorSerializationDelegate(groupName: groupName, subtreeDepth: 1000000, summaryTree: true, service: this),
1605
    );
1606 1607 1608 1609
  }

  /// Returns a JSON representation of the [DiagnosticsNode] for the root
  /// [RenderObject].
1610
  @protected
1611
  String getRootRenderObject(String groupName) {
1612
    return _safeJsonEncode(_getRootRenderObject(groupName));
1613 1614 1615
  }

  Map<String, Object> _getRootRenderObject(String groupName) {
1616
    return _nodeToJson(RendererBinding.instance?.renderView?.toDiagnosticsNode(), InspectorSerializationDelegate(groupName: groupName, service: this));
1617 1618 1619 1620 1621 1622
  }

  /// Returns a JSON representation of the subtree rooted at the
  /// [DiagnosticsNode] object that `diagnosticsNodeId` references providing
  /// information needed for the details subtree view.
  ///
1623 1624 1625 1626
  /// The number of levels of the subtree that should be returned is specified
  /// by the [subtreeDepth] parameter. This value defaults to 2 for backwards
  /// compatibility.
  ///
1627
  /// See also:
1628
  ///
1629 1630
  ///  * [getChildrenDetailsSubtree], a method to get children of a node
  ///    in the details subtree.
1631
  String getDetailsSubtree(
1632 1633 1634 1635
    String id,
    String groupName, {
    int subtreeDepth = 2,
  }) {
1636 1637 1638 1639
    return _safeJsonEncode(_getDetailsSubtree( id, groupName, subtreeDepth));
  }

  Map<String, Object> _getDetailsSubtree(
1640 1641 1642
    String id,
    String groupName,
    int subtreeDepth,
1643
  ) {
1644
    final DiagnosticsNode root = toObject(id) as DiagnosticsNode;
1645 1646 1647 1648 1649
    if (root == null) {
      return null;
    }
    return _nodeToJson(
      root,
1650
      InspectorSerializationDelegate(
1651 1652
        groupName: groupName,
        summaryTree: false,
1653
        subtreeDepth: subtreeDepth,
1654
        includeProperties: true,
1655
        service: this,
1656 1657
      ),
    );
1658 1659 1660 1661 1662 1663 1664
  }

  /// Returns a [DiagnosticsNode] representing the currently selected
  /// [RenderObject].
  ///
  /// If the currently selected [RenderObject] is identical to the
  /// [RenderObject] referenced by `previousSelectionId` then the previous
Dan Field's avatar
Dan Field committed
1665
  /// [DiagnosticsNode] is reused.
1666
  @protected
1667
  String getSelectedRenderObject(String previousSelectionId, String groupName) {
1668
    return _safeJsonEncode(_getSelectedRenderObject(previousSelectionId, groupName));
1669 1670 1671
  }

  Map<String, Object> _getSelectedRenderObject(String previousSelectionId, String groupName) {
1672
    final DiagnosticsNode previousSelection = toObject(previousSelectionId) as DiagnosticsNode;
1673
    final RenderObject current = selection?.current;
1674
    return _nodeToJson(current == previousSelection?.value ? previousSelection : current?.toDiagnosticsNode(), InspectorSerializationDelegate(groupName: groupName, service: this));
1675 1676 1677 1678 1679
  }

  /// Returns a [DiagnosticsNode] representing the currently selected [Element].
  ///
  /// If the currently selected [Element] is identical to the [Element]
Dan Field's avatar
Dan Field committed
1680
  /// referenced by `previousSelectionId` then the previous [DiagnosticsNode] is
1681
  /// reused.
1682
  @protected
1683
  String getSelectedWidget(String previousSelectionId, String groupName) {
1684
    return _safeJsonEncode(_getSelectedWidget(previousSelectionId, groupName));
1685 1686
  }

1687 1688 1689 1690 1691 1692 1693
  /// Captures an image of the current state of an [object] that is a
  /// [RenderObject] or [Element].
  ///
  /// The returned [ui.Image] has uncompressed raw RGBA bytes and will be scaled
  /// to be at most [width] pixels wide and [height] pixels tall. The returned
  /// image will never have a scale between logical pixels and the
  /// size of the output image larger than maxPixelRatio.
1694
  /// [margin] indicates the number of pixels relative to the un-scaled size of
1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710
  /// the [object] to include as a margin to include around the bounds of the
  /// [object] in the screenshot. Including a margin can be useful to capture
  /// areas that are slightly outside of the normal bounds of an object such as
  /// some debug paint information.
  @protected
  Future<ui.Image> screenshot(
    Object object, {
    @required double width,
    @required double height,
    double margin = 0.0,
    double maxPixelRatio = 1.0,
    bool debugPaint = false,
  }) async {
    if (object is! Element && object is! RenderObject) {
      return null;
    }
1711
    final RenderObject renderObject = object is Element ? object.renderObject : (object as RenderObject);
1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757
    if (renderObject == null || !renderObject.attached) {
      return null;
    }

    if (renderObject.debugNeedsLayout) {
      final PipelineOwner owner = renderObject.owner;
      assert(owner != null);
      assert(!owner.debugDoingLayout);
      owner
        ..flushLayout()
        ..flushCompositingBits()
        ..flushPaint();

      // If we still need layout, then that means that renderObject was skipped
      // in the layout phase and therefore can't be painted. It is clearer to
      // return null indicating that a screenshot is unavailable than to return
      // an empty image.
      if (renderObject.debugNeedsLayout) {
        return null;
      }
    }

    Rect renderBounds = _calculateSubtreeBounds(renderObject);
    if (margin != 0.0) {
      renderBounds = renderBounds.inflate(margin);
    }
    if (renderBounds.isEmpty) {
      return null;
    }

    final double pixelRatio = math.min(
      maxPixelRatio,
      math.min(
        width / renderBounds.width,
        height / renderBounds.height,
      ),
    );

    return _ScreenshotPaintingContext.toImage(
      renderObject,
      renderBounds,
      pixelRatio: pixelRatio,
      debugPaint: debugPaint,
    );
  }

1758
  Map<String, Object> _getSelectedWidget(String previousSelectionId, String groupName) {
1759
    final DiagnosticsNode previousSelection = toObject(previousSelectionId) as DiagnosticsNode;
1760
    final Element current = selection?.currentElement;
1761
    return _nodeToJson(current == previousSelection?.value ? previousSelection : current?.toDiagnosticsNode(), InspectorSerializationDelegate(groupName: groupName, service: this));
1762 1763 1764 1765 1766 1767 1768 1769
  }

  /// Returns a [DiagnosticsNode] representing the currently selected [Element]
  /// if the selected [Element] should be shown in the summary tree otherwise
  /// returns the first ancestor of the selected [Element] shown in the summary
  /// tree.
  ///
  /// If the currently selected [Element] is identical to the [Element]
Dan Field's avatar
Dan Field committed
1770
  /// referenced by `previousSelectionId` then the previous [DiagnosticsNode] is
1771 1772 1773 1774 1775 1776 1777 1778 1779
  /// reused.
  String getSelectedSummaryWidget(String previousSelectionId, String groupName) {
    return _safeJsonEncode(_getSelectedSummaryWidget(previousSelectionId, groupName));
  }

  Map<String, Object> _getSelectedSummaryWidget(String previousSelectionId, String groupName) {
    if (!isWidgetCreationTracked()) {
      return _getSelectedWidget(previousSelectionId, groupName);
    }
1780
    final DiagnosticsNode previousSelection = toObject(previousSelectionId) as DiagnosticsNode;
1781 1782 1783
    Element current = selection?.currentElement;
    if (current != null && !_isValueCreatedByLocalProject(current)) {
      Element firstLocal;
1784
      for (final Element candidate in current.debugGetDiagnosticChain()) {
1785 1786 1787 1788 1789 1790 1791
        if (_isValueCreatedByLocalProject(candidate)) {
          firstLocal = candidate;
          break;
        }
      }
      current = firstLocal;
    }
1792
    return _nodeToJson(current == previousSelection?.value ? previousSelection : current?.toDiagnosticsNode(), InspectorSerializationDelegate(groupName: groupName, service: this));
1793
  }
1794 1795 1796

  /// Returns whether [Widget] creation locations are available.
  ///
1797
  /// [Widget] creation locations are only available for debug mode builds when
1798 1799 1800
  /// the `--track-widget-creation` flag is passed to `flutter_tool`. Dart 2.0
  /// is required as injecting creation locations requires a
  /// [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
1801
  bool isWidgetCreationTracked() {
1802
    _widgetCreationTracked ??= _WidgetForTypeTests() is _HasCreationLocation;
1803 1804 1805 1806
    return _widgetCreationTracked;
  }

  bool _widgetCreationTracked;
1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845

  Duration _frameStart;

  void _onFrameStart(Duration timeStamp) {
    _frameStart = timeStamp;
    SchedulerBinding.instance.addPostFrameCallback(_onFrameEnd);
  }

  void _onFrameEnd(Duration timeStamp) {
    if (_trackRebuildDirtyWidgets) {
      _postStatsEvent('Flutter.RebuiltWidgets', _rebuildStats);
    }
    if (_trackRepaintWidgets) {
      _postStatsEvent('Flutter.RepaintWidgets', _repaintStats);
    }
  }

  void _postStatsEvent(String eventName, _ElementLocationStatsTracker stats) {
    postEvent(eventName, stats.exportToJson(_frameStart));
  }

  /// All events dispatched by a [WidgetInspectorService] use this method
  /// instead of calling [developer.postEvent] directly so that tests for
  /// [WidgetInspectorService] can track which events were dispatched by
  /// overriding this method.
  @protected
  void postEvent(String eventKind, Map<Object, Object> eventData) {
    developer.postEvent(eventKind, eventData);
  }

  final _ElementLocationStatsTracker _rebuildStats = _ElementLocationStatsTracker();
  final _ElementLocationStatsTracker _repaintStats = _ElementLocationStatsTracker();

  void _onRebuildWidget(Element element, bool builtOnce) {
    _rebuildStats.add(element);
  }

  void _onPaint(RenderObject renderObject) {
    try {
1846
      final Element element = renderObject.debugCreator?.element as Element;
1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884
      if (element is! RenderObjectElement) {
        // This branch should not hit as long as all RenderObjects were created
        // by Widgets. It is possible there might be some render objects
        // created directly without using the Widget layer so we add this check
        // to improve robustness.
        return;
      }
      _repaintStats.add(element);

      // Give all ancestor elements credit for repainting as long as they do
      // not have their own associated RenderObject.
      element.visitAncestorElements((Element ancestor) {
        if (ancestor is RenderObjectElement) {
          // This ancestor has its own RenderObject so we can precisely track
          // when it repaints.
          return false;
        }
        _repaintStats.add(ancestor);
        return true;
      });
    }
    catch (exception, stack) {
      FlutterError.reportError(
        FlutterErrorDetails(
          exception: exception,
          stack: stack,
        ),
      );
    }
  }

  /// This method is called by [WidgetBinding.performReassemble] to flush caches
  /// of obsolete values after a hot reload.
  ///
  /// Do not call this method directly. Instead, use
  /// [BindingBase.reassembleApplication].
  void performReassemble() {
    _clearStats();
1885
    _resetErrorCount();
1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960
  }
}

/// Accumulator for a count associated with a specific source location.
///
/// The accumulator stores whether the source location is [local] and what its
/// [id] for efficiency encoding terse JSON payloads describing counts.
class _LocationCount {
  _LocationCount({
    @required this.location,
    @required this.id,
    @required this.local,
  });

  /// Location id.
  final int id;

  /// Whether the location is local to the current project.
  final bool local;

  final _Location location;

  int get count => _count;
  int _count = 0;

  /// Reset the count.
  void reset() {
    _count = 0;
  }

  /// Increment the count.
  void increment() {
    _count++;
  }
}

/// A stat tracker that aggregates a performance metric for [Element] objects at
/// the granularity of creation locations in source code.
///
/// This class is optimized to minimize the size of the JSON payloads describing
/// the aggregate statistics, for stable memory usage, and low CPU usage at the
/// expense of somewhat higher overall memory usage. Stable memory usage is more
/// important than peak memory usage to avoid the false impression that the
/// user's app is leaking memory each frame.
///
/// The number of unique widget creation locations tends to be at most in the
/// low thousands for regular flutter apps so the peak memory usage for this
/// class is not an issue.
class _ElementLocationStatsTracker {
  // All known creation location tracked.
  //
  // This could also be stored as a `Map<int, _LocationCount>` but this
  // representation is more efficient as all location ids from 0 to n are
  // typically present.
  //
  // All logic in this class assumes that if `_stats[i]` is not null
  // `_stats[i].id` equals `i`.
  final List<_LocationCount> _stats = <_LocationCount>[];

  /// Locations with a non-zero count.
  final List<_LocationCount> active = <_LocationCount>[];

  /// Locations that were added since stats were last exported.
  ///
  /// Only locations local to the current project are included as a performance
  /// optimization.
  final List<_LocationCount> newLocations = <_LocationCount>[];

  /// Increments the count associated with the creation location of [element] if
  /// the creation location is local to the current project.
  void add(Element element) {
    final Object widget = element.widget;
    if (widget is! _HasCreationLocation) {
      return;
    }
1961
    final _HasCreationLocation creationLocationSource = widget as _HasCreationLocation;
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
    final _Location location = creationLocationSource._location;
    final int id = _toLocationId(location);

    _LocationCount entry;
    if (id >= _stats.length || _stats[id] == null) {
      // After the first frame, almost all creation ids will already be in
      // _stats so this slow path will rarely be hit.
      while (id >= _stats.length) {
        _stats.add(null);
      }
      entry = _LocationCount(
        location: location,
        id: id,
        local: WidgetInspectorService.instance._isLocalCreationLocation(location),
      );
      if (entry.local) {
        newLocations.add(entry);
      }
      _stats[id] = entry;
    } else {
      entry = _stats[id];
    }

    // We could in the future add an option to track stats for all widgets but
    // that would significantly increase the size of the events posted using
    // [developer.postEvent] and current use cases for this feature focus on
    // helping users find problems with their widgets not the platform
    // widgets.
    if (entry.local) {
      if (entry.count == 0) {
        active.add(entry);
      }
      entry.increment();
    }
  }

  /// Clear all aggregated statistics.
  void resetCounts() {
    // We chose to only reset the active counts instead of clearing all data
    // to reduce the number memory allocations performed after the first frame.
    // Once an app has warmed up, location stats tracking should not
    // trigger significant additional memory allocations. Avoiding memory
    // allocations is important to minimize the impact this class has on cpu
    // and memory performance of the running app.
2006
    for (final _LocationCount entry in active) {
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
      entry.reset();
    }
    active.clear();
  }

  /// Exports the current counts and then resets the stats to prepare to track
  /// the next frame of data.
  Map<String, dynamic> exportToJson(Duration startTime) {
    final List<int> events = List<int>.filled(active.length * 2, 0);
    int j = 0;
2017
    for (final _LocationCount stat in active) {
2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029
      events[j++] = stat.id;
      events[j++] = stat.count;
    }

    final Map<String, dynamic> json = <String, dynamic>{
      'startTime': startTime.inMicroseconds,
      'events': events,
    };

    if (newLocations.isNotEmpty) {
      // Add all newly used location ids to the JSON.
      final Map<String, List<int>> locationsJson = <String, List<int>>{};
2030
      for (final _LocationCount entry in newLocations) {
2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
        final _Location location = entry.location;
        final List<int> jsonForFile = locationsJson.putIfAbsent(
          location.file,
          () => <int>[],
        );
        jsonForFile..add(entry.id)..add(location.line)..add(location.column);
      }
      json['newLocations'] = locationsJson;
    }
    resetCounts();
    newLocations.clear();
    return json;
  }
2044 2045 2046 2047 2048
}

class _WidgetForTypeTests extends Widget {
  @override
  Element createElement() => null;
2049 2050
}

2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093
/// A widget that enables inspecting the child widget's structure.
///
/// Select a location on your device or emulator and view what widgets and
/// render object that best matches the location. An outline of the selected
/// widget and terse summary information is shown on device with detailed
/// information is shown in the observatory or in IntelliJ when using the
/// Flutter Plugin.
///
/// The inspector has a select mode and a view mode.
///
/// In the select mode, tapping the device selects the widget that best matches
/// the location of the touch and switches to view mode. Dragging a finger on
/// the device selects the widget under the drag location but does not switch
/// modes. Touching the very edge of the bounding box of a widget triggers
/// selecting the widget even if another widget that also overlaps that
/// location would otherwise have priority.
///
/// In the view mode, the previously selected widget is outlined, however,
/// touching the device has the same effect it would have if the inspector
/// wasn't present. This allows interacting with the application and viewing how
/// the selected widget changes position. Clicking on the select icon in the
/// bottom left corner of the application switches back to select mode.
class WidgetInspector extends StatefulWidget {
  /// Creates a widget that enables inspection for the child.
  ///
  /// The [child] argument must not be null.
  const WidgetInspector({
    Key key,
    @required this.child,
    @required this.selectButtonBuilder,
  }) : assert(child != null),
       super(key: key);

  /// The widget that is being inspected.
  final Widget child;

  /// A builder that is called to create the select button.
  ///
  /// The `onPressed` callback passed as an argument to the builder should be
  /// hooked up to the returned widget.
  final InspectorSelectButtonBuilder selectButtonBuilder;

  @override
2094
  _WidgetInspectorState createState() => _WidgetInspectorState();
2095 2096 2097 2098 2099
}

class _WidgetInspectorState extends State<WidgetInspector>
    with WidgetsBindingObserver {

2100 2101
  _WidgetInspectorState() : selection = WidgetInspectorService.instance.selection;

2102 2103
  Offset _lastPointerLocation;

2104
  final InspectorSelection selection;
2105 2106 2107 2108 2109 2110 2111 2112

  /// Whether the inspector is in select mode.
  ///
  /// In select mode, pointer interactions trigger widget selection instead of
  /// normal interactions. Otherwise the previously selected widget is
  /// highlighted but the application can be interacted with normally.
  bool isSelectMode = true;

2113
  final GlobalKey _ignorePointerKey = GlobalKey();
2114

Shi-Hao Hong's avatar
Shi-Hao Hong committed
2115
  /// Distance from the edge of the bounding box for an element to consider
2116
  /// as selecting the edge of the bounding box.
2117
  static const double _edgeHitMargin = 2.0;
2118

2119
  InspectorSelectionChangedCallback _selectionChangedCallback;
2120 2121 2122
  @override
  void initState() {
    super.initState();
2123 2124

    _selectionChangedCallback = () {
2125 2126 2127 2128 2129
      setState(() {
        // The [selection] property which the build method depends on has
        // changed.
      });
    };
2130 2131 2132 2133 2134 2135 2136 2137 2138
    WidgetInspectorService.instance.selectionChangedCallback = _selectionChangedCallback;
  }

  @override
  void dispose() {
    if (WidgetInspectorService.instance.selectionChangedCallback == _selectionChangedCallback) {
      WidgetInspectorService.instance.selectionChangedCallback = null;
    }
    super.dispose();
2139 2140
  }

2141 2142 2143 2144 2145 2146 2147 2148
  bool _hitTestHelper(
    List<RenderObject> hits,
    List<RenderObject> edgeHits,
    Offset position,
    RenderObject object,
    Matrix4 transform,
  ) {
    bool hit = false;
2149 2150
    final Matrix4 inverse = Matrix4.tryInvert(transform);
    if (inverse == null) {
2151 2152 2153 2154
      // We cannot invert the transform. That means the object doesn't appear on
      // screen and cannot be hit.
      return false;
    }
2155 2156 2157 2158 2159
    final Offset localPosition = MatrixUtils.transformPoint(inverse, position);

    final List<DiagnosticsNode> children = object.debugDescribeChildren();
    for (int i = children.length - 1; i >= 0; i -= 1) {
      final DiagnosticsNode diagnostics = children[i];
2160
      assert(diagnostics != null);
2161 2162 2163
      if (diagnostics.style == DiagnosticsTreeStyle.offstage ||
          diagnostics.value is! RenderObject)
        continue;
2164
      final RenderObject child = diagnostics.value as RenderObject;
2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180
      final Rect paintClip = object.describeApproximatePaintClip(child);
      if (paintClip != null && !paintClip.contains(localPosition))
        continue;

      final Matrix4 childTransform = transform.clone();
      object.applyPaintTransform(child, childTransform);
      if (_hitTestHelper(hits, edgeHits, position, child, childTransform))
        hit = true;
    }

    final Rect bounds = object.semanticBounds;
    if (bounds.contains(localPosition)) {
      hit = true;
      // Hits that occur on the edge of the bounding box of an object are
      // given priority to provide a way to select objects that would
      // otherwise be hard to select.
2181
      if (!bounds.deflate(_edgeHitMargin).contains(localPosition))
2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203
        edgeHits.add(object);
    }
    if (hit)
      hits.add(object);
    return hit;
  }

  /// Returns the list of render objects located at the given position ordered
  /// by priority.
  ///
  /// All render objects that are not offstage that match the location are
  /// included in the list of matches. Priority is given to matches that occur
  /// on the edge of a render object's bounding box and to matches found by
  /// [RenderBox.hitTest].
  List<RenderObject> hitTest(Offset position, RenderObject root) {
    final List<RenderObject> regularHits = <RenderObject>[];
    final List<RenderObject> edgeHits = <RenderObject>[];

    _hitTestHelper(regularHits, edgeHits, position, root, root.getTransformTo(null));
    // Order matches by the size of the hit area.
    double _area(RenderObject object) {
      final Size size = object.semanticBounds?.size;
2204
      return size == null ? double.maxFinite : size.width * size.height;
2205 2206
    }
    regularHits.sort((RenderObject a, RenderObject b) => _area(a).compareTo(_area(b)));
2207 2208 2209 2210
    final Set<RenderObject> hits = <RenderObject>{
      ...edgeHits,
      ...regularHits,
    };
2211 2212 2213 2214 2215 2216 2217
    return hits.toList();
  }

  void _inspectAt(Offset position) {
    if (!isSelectMode)
      return;

2218
    final RenderIgnorePointer ignorePointer = _ignorePointerKey.currentContext.findRenderObject() as RenderIgnorePointer;
2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242
    final RenderObject userRender = ignorePointer.child;
    final List<RenderObject> selected = hitTest(position, userRender);

    setState(() {
      selection.candidates = selected;
    });
  }

  void _handlePanDown(DragDownDetails event) {
    _lastPointerLocation = event.globalPosition;
    _inspectAt(event.globalPosition);
  }

  void _handlePanUpdate(DragUpdateDetails event) {
    _lastPointerLocation = event.globalPosition;
    _inspectAt(event.globalPosition);
  }

  void _handlePanEnd(DragEndDetails details) {
    // If the pan ends on the edge of the window assume that it indicates the
    // pointer is being dragged off the edge of the display not a regular touch
    // on the edge of the display. If the pointer is being dragged off the edge
    // of the display we do not want to select anything. A user can still select
    // a widget that is only at the exact screen margin by tapping.
2243
    final Rect bounds = (Offset.zero & (WidgetsBinding.instance.window.physicalSize / WidgetsBinding.instance.window.devicePixelRatio)).deflate(_kOffScreenMargin);
2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276
    if (!bounds.contains(_lastPointerLocation)) {
      setState(() {
        selection.clear();
      });
    }
  }

  void _handleTap() {
    if (!isSelectMode)
      return;
    if (_lastPointerLocation != null) {
      _inspectAt(_lastPointerLocation);

      if (selection != null) {
        // Notify debuggers to open an inspector on the object.
        developer.inspect(selection.current);
      }
    }
    setState(() {
      // Only exit select mode if there is a button to return to select mode.
      if (widget.selectButtonBuilder != null)
        isSelectMode = false;
    });
  }

  void _handleEnableSelect() {
    setState(() {
      isSelectMode = true;
    });
  }

  @override
  Widget build(BuildContext context) {
2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290
    return Stack(children: <Widget>[
      GestureDetector(
        onTap: _handleTap,
        onPanDown: _handlePanDown,
        onPanEnd: _handlePanEnd,
        onPanUpdate: _handlePanUpdate,
        behavior: HitTestBehavior.opaque,
        excludeFromSemantics: true,
        child: IgnorePointer(
          ignoring: isSelectMode,
          key: _ignorePointerKey,
          ignoringSemantics: false,
          child: widget.child,
        ),
2291
      ),
2292 2293 2294 2295 2296 2297 2298 2299
      if (!isSelectMode && widget.selectButtonBuilder != null)
        Positioned(
          left: _kInspectButtonMargin,
          bottom: _kInspectButtonMargin,
          child: widget.selectButtonBuilder(context, _handleEnableSelect),
        ),
      _InspectorOverlay(selection: selection),
    ]);
2300 2301 2302 2303 2304 2305 2306
  }
}

/// Mutable selection state of the inspector.
class InspectorSelection {
  /// Render objects that are candidates to be selected.
  ///
2307
  /// Tools may wish to iterate through the list of candidates.
2308
  List<RenderObject> get candidates => _candidates;
2309
  List<RenderObject> _candidates = <RenderObject>[];
2310 2311
  set candidates(List<RenderObject> value) {
    _candidates = value;
2312 2313
    _index = 0;
    _computeCurrent();
2314 2315 2316
  }

  /// Index within the list of candidates that is currently selected.
2317 2318 2319 2320 2321 2322
  int get index => _index;
  int _index = 0;
  set index(int value) {
    _index = value;
    _computeCurrent();
  }
2323

2324
  /// Set the selection to empty.
2325 2326
  void clear() {
    _candidates = <RenderObject>[];
2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340
    _index = 0;
    _computeCurrent();
  }

  /// Selected render object typically from the [candidates] list.
  ///
  /// Setting [candidates] or calling [clear] resets the selection.
  ///
  /// Returns null if the selection is invalid.
  RenderObject get current => _current;
  RenderObject _current;
  set current(RenderObject value) {
    if (_current != value) {
      _current = value;
2341
      _currentElement = value.debugCreator.element as Element;
2342
    }
2343 2344
  }

2345
  /// Selected [Element] consistent with the [current] selected [RenderObject].
2346 2347 2348 2349
  ///
  /// Setting [candidates] or calling [clear] resets the selection.
  ///
  /// Returns null if the selection is invalid.
2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361
  Element get currentElement => _currentElement;
  Element _currentElement;
  set currentElement(Element element) {
    if (currentElement != element) {
      _currentElement = element;
      _current = element.findRenderObject();
    }
  }

  void _computeCurrent() {
    if (_index < candidates.length) {
      _current = candidates[index];
2362
      _currentElement = _current.debugCreator.element as Element;
2363 2364 2365 2366
    } else {
      _current = null;
      _currentElement = null;
    }
2367 2368
  }

2369 2370
  /// Whether the selected render object is attached to the tree or has gone
  /// out of scope.
2371
  bool get active => _current != null && _current.attached;
2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383
}

class _InspectorOverlay extends LeafRenderObjectWidget {
  const _InspectorOverlay({
    Key key,
    @required this.selection,
  }) : super(key: key);

  final InspectorSelection selection;

  @override
  _RenderInspectorOverlay createRenderObject(BuildContext context) {
2384
    return _RenderInspectorOverlay(selection: selection);
2385 2386 2387 2388 2389 2390 2391 2392 2393 2394
  }

  @override
  void updateRenderObject(BuildContext context, _RenderInspectorOverlay renderObject) {
    renderObject.selection = selection;
  }
}

class _RenderInspectorOverlay extends RenderBox {
  /// The arguments must not be null.
2395 2396 2397
  _RenderInspectorOverlay({ @required InspectorSelection selection })
    : _selection = selection,
      assert(selection != null);
2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415

  InspectorSelection get selection => _selection;
  InspectorSelection _selection;
  set selection(InspectorSelection value) {
    if (value != _selection) {
      _selection = value;
    }
    markNeedsPaint();
  }

  @override
  bool get sizedByParent => true;

  @override
  bool get alwaysNeedsCompositing => true;

  @override
  void performResize() {
2416
    size = constraints.constrain(const Size(double.infinity, double.infinity));
2417 2418 2419 2420 2421
  }

  @override
  void paint(PaintingContext context, Offset offset) {
    assert(needsCompositing);
2422 2423
    context.addLayer(_InspectorOverlayLayer(
      overlayRect: Rect.fromLTWH(offset.dx, offset.dy, size.width, size.height),
2424 2425 2426 2427 2428
      selection: selection,
    ));
  }
}

2429
@immutable
2430
class _TransformedRect {
2431 2432 2433
  _TransformedRect(RenderObject object)
    : rect = object.semanticBounds,
      transform = object.getTransformTo(null);
2434 2435 2436 2437 2438

  final Rect rect;
  final Matrix4 transform;

  @override
2439
  bool operator ==(Object other) {
2440 2441
    if (other.runtimeType != runtimeType)
      return false;
2442 2443 2444
    return other is _TransformedRect
        && other.rect == rect
        && other.transform == transform;
2445 2446 2447 2448 2449 2450 2451 2452 2453 2454
  }

  @override
  int get hashCode => hashValues(rect, transform);
}

/// State describing how the inspector overlay should be rendered.
///
/// The equality operator can be used to determine whether the overlay needs to
/// be rendered again.
2455
@immutable
2456
class _InspectorOverlayRenderState {
2457
  const _InspectorOverlayRenderState({
2458 2459 2460 2461
    @required this.overlayRect,
    @required this.selected,
    @required this.candidates,
    @required this.tooltip,
Ian Hickson's avatar
Ian Hickson committed
2462
    @required this.textDirection,
2463 2464 2465 2466 2467 2468
  });

  final Rect overlayRect;
  final _TransformedRect selected;
  final List<_TransformedRect> candidates;
  final String tooltip;
Ian Hickson's avatar
Ian Hickson committed
2469
  final TextDirection textDirection;
2470 2471

  @override
2472
  bool operator ==(Object other) {
2473 2474
    if (other.runtimeType != runtimeType)
      return false;
2475 2476 2477 2478 2479
    return other is _InspectorOverlayRenderState
        && other.overlayRect == overlayRect
        && other.selected == selected
        && listEquals<_TransformedRect>(other.candidates, candidates)
        && other.tooltip == tooltip;
2480 2481 2482 2483 2484 2485
  }

  @override
  int get hashCode => hashValues(overlayRect, selected, hashList(candidates), tooltip);
}

2486
const int _kMaxTooltipLines = 5;
2487 2488 2489
const Color _kTooltipBackgroundColor = Color.fromARGB(230, 60, 60, 60);
const Color _kHighlightedRenderObjectFillColor = Color.fromARGB(128, 128, 128, 255);
const Color _kHighlightedRenderObjectBorderColor = Color.fromARGB(128, 64, 64, 128);
2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500

/// A layer that outlines the selected [RenderObject] and candidate render
/// objects that also match the last pointer location.
///
/// This approach is horrific for performance and is only used here because this
/// is limited to debug mode. Do not duplicate the logic in production code.
class _InspectorOverlayLayer extends Layer {
  /// Creates a layer that displays the inspector overlay.
  _InspectorOverlayLayer({
    @required this.overlayRect,
    @required this.selection,
2501 2502
  }) : assert(overlayRect != null),
       assert(selection != null) {
2503 2504 2505 2506
    bool inDebugMode = false;
    assert(() {
      inDebugMode = true;
      return true;
2507
    }());
2508
    if (inDebugMode == false) {
2509 2510 2511 2512
      throw FlutterError.fromParts(<DiagnosticsNode>[
        ErrorSummary(
          'The inspector should never be used in production mode due to the '
          'negative performance impact.'
2513
        ),
2514
      ]);
2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535
    }
  }

  InspectorSelection selection;

  /// The rectangle in this layer's coordinate system that the overlay should
  /// occupy.
  ///
  /// The scene must be explicitly recomposited after this property is changed
  /// (as described at [Layer]).
  final Rect overlayRect;

  _InspectorOverlayRenderState _lastState;

  /// Picture generated from _lastState.
  ui.Picture _picture;

  TextPainter _textPainter;
  double _textPainterMaxWidth;

  @override
2536
  void addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
2537
    if (!selection.active)
2538
      return;
2539 2540 2541

    final RenderObject selected = selection.current;
    final List<_TransformedRect> candidates = <_TransformedRect>[];
2542
    for (final RenderObject candidate in selection.candidates) {
2543 2544
      if (candidate == selected || !candidate.attached)
        continue;
2545
      candidates.add(_TransformedRect(candidate));
2546 2547
    }

2548
    final _InspectorOverlayRenderState state = _InspectorOverlayRenderState(
2549
      overlayRect: overlayRect,
2550
      selected: _TransformedRect(selected),
2551
      tooltip: selection.currentElement.toStringShort(),
Ian Hickson's avatar
Ian Hickson committed
2552
      textDirection: TextDirection.ltr,
2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563
      candidates: candidates,
    );

    if (state != _lastState) {
      _lastState = state;
      _picture = _buildPicture(state);
    }
    builder.addPicture(layerOffset, _picture);
  }

  ui.Picture _buildPicture(_InspectorOverlayRenderState state) {
2564 2565
    final ui.PictureRecorder recorder = ui.PictureRecorder();
    final Canvas canvas = Canvas(recorder, state.overlayRect);
2566 2567
    final Size size = state.overlayRect.size;

2568
    final Paint fillPaint = Paint()
2569 2570 2571
      ..style = PaintingStyle.fill
      ..color = _kHighlightedRenderObjectFillColor;

2572
    final Paint borderPaint = Paint()
2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588
      ..style = PaintingStyle.stroke
      ..strokeWidth = 1.0
      ..color = _kHighlightedRenderObjectBorderColor;

    // Highlight the selected renderObject.
    final Rect selectedPaintRect = state.selected.rect.deflate(0.5);
    canvas
      ..save()
      ..transform(state.selected.transform.storage)
      ..drawRect(selectedPaintRect, fillPaint)
      ..drawRect(selectedPaintRect, borderPaint)
      ..restore();

    // Show all other candidate possibly selected elements. This helps selecting
    // render objects by selecting the edge of the bounding box shows all
    // elements the user could toggle the selection between.
2589
    for (final _TransformedRect transformedRect in state.candidates) {
2590 2591 2592 2593 2594 2595 2596 2597 2598
      canvas
        ..save()
        ..transform(transformedRect.transform.storage)
        ..drawRect(transformedRect.rect.deflate(0.5), borderPaint)
        ..restore();
    }

    final Rect targetRect = MatrixUtils.transformRect(
        state.selected.transform, state.selected.rect);
2599
    final Offset target = Offset(targetRect.left, targetRect.center.dy);
2600
    const double offsetFromWidget = 9.0;
2601 2602
    final double verticalOffset = (targetRect.height) / 2 + offsetFromWidget;

Ian Hickson's avatar
Ian Hickson committed
2603
    _paintDescription(canvas, state.tooltip, state.textDirection, target, verticalOffset, size, targetRect);
2604 2605 2606 2607 2608 2609

    // TODO(jacobr): provide an option to perform a debug paint of just the
    // selected widget.
    return recorder.endRecording();
  }

Ian Hickson's avatar
Ian Hickson committed
2610 2611 2612 2613 2614 2615 2616 2617 2618
  void _paintDescription(
    Canvas canvas,
    String message,
    TextDirection textDirection,
    Offset target,
    double verticalOffset,
    Size size,
    Rect targetRect,
  ) {
2619 2620
    canvas.save();
    final double maxWidth = size.width - 2 * (_kScreenEdgeMargin + _kTooltipPadding);
2621
    final TextSpan textSpan = _textPainter?.text as TextSpan;
2622
    if (_textPainter == null || textSpan.text != message || _textPainterMaxWidth != maxWidth) {
2623
      _textPainterMaxWidth = maxWidth;
2624
      _textPainter = TextPainter()
2625 2626
        ..maxLines = _kMaxTooltipLines
        ..ellipsis = '...'
2627
        ..text = TextSpan(style: _messageStyle, text: message)
Ian Hickson's avatar
Ian Hickson committed
2628
        ..textDirection = textDirection
2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640
        ..layout(maxWidth: maxWidth);
    }

    final Size tooltipSize = _textPainter.size + const Offset(_kTooltipPadding * 2, _kTooltipPadding * 2);
    final Offset tipOffset = positionDependentBox(
      size: size,
      childSize: tooltipSize,
      target: target,
      verticalOffset: verticalOffset,
      preferBelow: false,
    );

2641
    final Paint tooltipBackground = Paint()
2642 2643 2644
      ..style = PaintingStyle.fill
      ..color = _kTooltipBackgroundColor;
    canvas.drawRect(
2645
      Rect.fromPoints(
2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656
        tipOffset,
        tipOffset.translate(tooltipSize.width, tooltipSize.height),
      ),
      tooltipBackground,
    );

    double wedgeY = tipOffset.dy;
    final bool tooltipBelow = tipOffset.dy > target.dy;
    if (!tooltipBelow)
      wedgeY += tooltipSize.height;

2657
    const double wedgeSize = _kTooltipPadding * 2;
2658 2659 2660
    double wedgeX = math.max(tipOffset.dx, target.dx) + wedgeSize * 2;
    wedgeX = math.min(wedgeX, tipOffset.dx + tooltipSize.width - wedgeSize * 2);
    final List<Offset> wedge = <Offset>[
2661 2662 2663
      Offset(wedgeX - wedgeSize, wedgeY),
      Offset(wedgeX + wedgeSize, wedgeY),
      Offset(wedgeX, wedgeY + (tooltipBelow ? -wedgeSize : wedgeSize)),
2664
    ];
2665
    canvas.drawPath(Path()..addPolygon(wedge, true,), tooltipBackground);
2666 2667 2668
    _textPainter.paint(canvas, tipOffset + const Offset(_kTooltipPadding, _kTooltipPadding));
    canvas.restore();
  }
2669 2670

  @override
2671 2672 2673 2674 2675 2676 2677 2678
  @protected
  bool findAnnotations<S>(
    AnnotationResult<S> result,
    Offset localPosition, {
    bool onlyFirst,
  }) {
    return false;
  }
2679 2680 2681 2682 2683 2684 2685 2686 2687 2688
}

const double _kScreenEdgeMargin = 10.0;
const double _kTooltipPadding = 5.0;
const double _kInspectButtonMargin = 10.0;

/// Interpret pointer up events within with this margin as indicating the
/// pointer is moving off the device.
const double _kOffScreenMargin = 1.0;

2689 2690
const TextStyle _messageStyle = TextStyle(
  color: Color(0xFFFFFFFF),
2691 2692 2693
  fontSize: 10.0,
  height: 1.2,
);
2694 2695 2696 2697 2698

/// Interface for classes that track the source code location the their
/// constructor was called from.
///
/// A [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
2699
/// adds this interface to the [Widget] class when the
2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715
/// `--track-widget-creation` flag is passed to `flutter_tool`. Dart 2.0 is
/// required as injecting creation locations requires a
/// [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
// ignore: unused_element
abstract class _HasCreationLocation {
  _Location get _location;
}

/// A tuple with file, line, and column number, for displaying human-readable
/// file locations.
class _Location {
  const _Location({
    this.file,
    this.line,
    this.column,
    this.name,
2716
    this.parameterLocations,
2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738
  });

  /// File path of the location.
  final String file;

  /// 1-based line number.
  final int line;
  /// 1-based column number.
  final int column;

  /// Optional name of the parameter or function at this location.
  final String name;

  /// Optional locations of the parameters of the member at this location.
  final List<_Location> parameterLocations;

  Map<String, Object> toJsonMap() {
    final Map<String, Object> json = <String, Object>{
      'file': file,
      'line': line,
      'column': column,
    };
2739 2740 2741
    if (name != null) {
      json['name'] = name;
    }
2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762
    if (parameterLocations != null) {
      json['parameterLocations'] = parameterLocations.map<Map<String, Object>>(
          (_Location location) => location.toJsonMap()).toList();
    }
    return json;
  }

  @override
  String toString() {
    final List<String> parts = <String>[];
    if (name != null) {
      parts.add(name);
    }
    if (file != null) {
      parts.add(file);
    }
    parts..add('$line')..add('$column');
    return parts.join(':');
  }
}

2763 2764 2765 2766 2767 2768 2769 2770 2771
bool _isDebugCreator(DiagnosticsNode node) => node is DiagnosticsDebugCreator;

/// Transformer to parse and gather information about [DiagnosticsDebugCreator].
///
/// This function will be registered to [FlutterErrorDetails.propertiesTransformers]
/// in [WidgetsBinding.initInstances].
Iterable<DiagnosticsNode> transformDebugCreator(Iterable<DiagnosticsNode> properties) sync* {
  final List<DiagnosticsNode> pending = <DiagnosticsNode>[];
  bool foundStackTrace = false;
2772
  for (final DiagnosticsNode node in properties) {
2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793
    if (!foundStackTrace && node is DiagnosticsStackTrace)
      foundStackTrace = true;
    if (_isDebugCreator(node)) {
      yield* _parseDiagnosticsNode(node);
    } else {
      if (foundStackTrace) {
        pending.add(node);
      } else {
        yield node;
      }
    }
  }
  yield* pending;
}

/// Transform the input [DiagnosticsNode].
///
/// Return null if input [DiagnosticsNode] is not applicable.
Iterable<DiagnosticsNode> _parseDiagnosticsNode(DiagnosticsNode node) {
  if (!_isDebugCreator(node))
    return null;
2794
  final DebugCreator debugCreator = node.value as DebugCreator;
2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810
  final Element element = debugCreator.element;
  return _describeRelevantUserCode(element);
}

Iterable<DiagnosticsNode> _describeRelevantUserCode(Element element) {
  if (!WidgetInspectorService.instance.isWidgetCreationTracked()) {
    return <DiagnosticsNode>[
      ErrorDescription(
        'Widget creation tracking is currently disabled. Enabling '
        'it enables improved error messages. It can be enabled by passing '
        '`--track-widget-creation` to `flutter run` or `flutter test`.',
      ),
      ErrorSpacer(),
    ];
  }
  final List<DiagnosticsNode> nodes = <DiagnosticsNode>[];
2811
  bool processElement(Element target) {
2812 2813
    // TODO(chunhtai): should print out all the widgets that are about to cross
    // package boundaries.
2814
    if (_isLocalCreationLocation(target)) {
2815 2816
      nodes.add(
        DiagnosticsBlock(
2817
          name: 'The relevant error-causing widget was',
2818
          children: <DiagnosticsNode>[
2819
            ErrorDescription('${target.widget.toStringShort()} ${_describeCreationLocation(target)}'),
2820
          ],
2821
        ),
2822 2823 2824 2825 2826
      );
      nodes.add(ErrorSpacer());
      return false;
    }
    return true;
2827 2828 2829
  }
  if (processElement(element))
    element.visitAncestorElements(processElement);
2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863
  return nodes;
}

/// Returns if an object is user created.
///
/// This function will only work in debug mode builds when
/// the `--track-widget-creation` flag is passed to `flutter_tool`. Dart 2.0 is
/// required as injecting creation locations requires a
/// [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
///
/// Currently is local creation locations are only available for
/// [Widget] and [Element].
bool _isLocalCreationLocation(Object object) {
  final _Location location = _getCreationLocation(object);
  if (location == null)
    return false;
  return WidgetInspectorService.instance._isLocalCreationLocation(location);
}

/// Returns the creation location of an object in String format if one is available.
///
/// ex: "file:///path/to/main.dart:4:3"
///
/// Creation locations are only available for debug mode builds when
/// the `--track-widget-creation` flag is passed to `flutter_tool`. Dart 2.0 is
/// required as injecting creation locations requires a
/// [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
///
/// Currently creation locations are only available for [Widget] and [Element].
String _describeCreationLocation(Object object) {
  final _Location location = _getCreationLocation(object);
  return location?.toString();
}

2864 2865
/// Returns the creation location of an object if one is available.
///
2866
/// Creation locations are only available for debug mode builds when
2867 2868 2869 2870
/// the `--track-widget-creation` flag is passed to `flutter_tool`. Dart 2.0 is
/// required as injecting creation locations requires a
/// [Dart Kernel Transformer](https://github.com/dart-lang/sdk/wiki/Kernel-Documentation).
///
2871
/// Currently creation locations are only available for [Widget] and [Element].
2872 2873 2874 2875
_Location _getCreationLocation(Object object) {
  final Object candidate =  object is Element ? object.widget : object;
  return candidate is _HasCreationLocation ? candidate._location : null;
}
2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892

// _Location objects are always const so we don't need to worry about the GC
// issues that are a concern for other object ids tracked by
// [WidgetInspectorService].
final Map<_Location, int> _locationToId = <_Location, int>{};
final List<_Location> _locations = <_Location>[];

int _toLocationId(_Location location) {
  int id = _locationToId[location];
  if (id != null) {
    return id;
  }
  id = _locations.length;
  _locations.add(location);
  _locationToId[location] = id;
  return id;
}
2893

2894 2895 2896 2897 2898 2899 2900
/// A delegate that configures how a hierarchy of [DiagnosticsNode]s are
/// serialized by the Flutter Inspector.
@visibleForTesting
class InspectorSerializationDelegate implements DiagnosticsSerializationDelegate {
  /// Creates an [InspectorSerializationDelegate] that serialize [DiagnosticsNode]
  /// for Flutter Inspector service.
  InspectorSerializationDelegate({
2901 2902 2903 2904 2905 2906 2907
    this.groupName,
    this.summaryTree = false,
    this.maxDescendentsTruncatableNode = -1,
    this.expandPropertyValues = true,
    this.subtreeDepth = 1,
    this.includeProperties = false,
    @required this.service,
2908
    this.addAdditionalPropertiesCallback,
2909 2910
  });

2911
  /// Service used by GUI tools to interact with the [WidgetInspector].
2912
  final WidgetInspectorService service;
2913 2914 2915 2916 2917 2918

  /// Optional `groupName` parameter which indicates that the json should
  /// contain live object ids.
  ///
  /// Object ids returned as part of the json will remain live at least until
  /// [WidgetInspectorService.disposeGroup()] is called on [groupName].
2919
  final String groupName;
2920 2921

  /// Whether the tree should only include nodes created by the local project.
2922
  final bool summaryTree;
2923 2924

  /// Maximum descendents of [DiagnosticsNode] before truncating.
2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935
  final int maxDescendentsTruncatableNode;

  @override
  final bool includeProperties;

  @override
  final int subtreeDepth;

  @override
  final bool expandPropertyValues;

2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981
  /// Callback to add additional experimental serialization properties.
  ///
  /// This callback can be used to customize the serialization of DiagnosticsNode
  /// objects for experimental features in widget inspector clients such as
  /// [Dart DevTools](https://github.com/flutter/devtools).
  /// For example, [Dart DevTools](https://github.com/flutter/devtools)
  /// can evaluate the following expression to register a VM Service API
  /// with a custom serialization to experiment with visualizing layouts.
  ///
  /// The following code samples demonstrates adding the [RenderObject] associated
  /// with an [Element] to the serialized data for all elements in the tree:
  ///
  /// ```dart
  /// Map<String, Object> getDetailsSubtreeWithRenderObject(
  ///   String id,
  ///   String groupName,
  ///   int subtreeDepth,
  /// ) {
  ///   return _nodeToJson(
  ///     root,
  ///     InspectorSerializationDelegate(
  ///       groupName: groupName,
  ///       summaryTree: false,
  ///       subtreeDepth: subtreeDepth,
  ///       includeProperties: true,
  ///       service: this,
  ///       addAdditionalPropertiesCallback: (DiagnosticsNode node, _SerializationDelegate delegate) {
  ///         final Map<String, Object> additionalJson = <String, Object>{};
  ///         final Object value = node.value;
  ///         if (value is Element) {
  ///           final renderObject = value.renderObject;
  ///           additionalJson['renderObject'] = renderObject?.toDiagnosticsNode()?.toJsonMap(
  ///             delegate.copyWith(
  ///               subtreeDepth: 0,
  ///               includeProperties: true,
  ///             ),
  ///           );
  ///         }
  ///         return additionalJson;
  ///       },
  ///     ),
  ///  );
  /// }
  /// ```
  final Map<String, Object> Function(DiagnosticsNode, InspectorSerializationDelegate) addAdditionalPropertiesCallback;

2982 2983
  final List<DiagnosticsNode> _nodesCreatedByLocalProject = <DiagnosticsNode>[];

2984
  bool get _interactive => groupName != null;
2985 2986 2987 2988 2989

  @override
  Map<String, Object> additionalNodeProperties(DiagnosticsNode node) {
    final Map<String, Object> result = <String, Object>{};
    final Object value = node.value;
2990
    if (_interactive) {
2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005
      result['objectId'] = service.toId(node, groupName);
      result['valueId'] = service.toId(value, groupName);
    }
    if (summaryTree) {
      result['summaryTree'] = true;
    }
    final _Location creationLocation = _getCreationLocation(value);
    if (creationLocation != null) {
      result['locationId'] = _toLocationId(creationLocation);
      result['creationLocation'] = creationLocation.toJsonMap();
      if (service._isLocalCreationLocation(creationLocation)) {
        _nodesCreatedByLocalProject.add(node);
        result['createdByLocalProject'] = true;
      }
    }
3006 3007 3008
    if (addAdditionalPropertiesCallback != null) {
      result.addAll(addAdditionalPropertiesCallback(node, this) ?? <String, Object>{});
    }
3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048
    return result;
  }

  @override
  DiagnosticsSerializationDelegate delegateForNode(DiagnosticsNode node) {
    // The tricky special case here is that when in the detailsTree,
    // we keep subtreeDepth from going down to zero until we reach nodes
    // that also exist in the summary tree. This ensures that every time
    // you expand a node in the details tree, you expand the entire subtree
    // up until you reach the next nodes shared with the summary tree.
    return summaryTree || subtreeDepth > 1 || service._shouldShowInSummaryTree(node)
        ? copyWith(subtreeDepth: subtreeDepth - 1)
        : this;
  }

  @override
  List<DiagnosticsNode> filterChildren(List<DiagnosticsNode> children, DiagnosticsNode owner) {
    return service._filterChildren(children, this);
  }

  @override
  List<DiagnosticsNode> filterProperties(List<DiagnosticsNode> properties, DiagnosticsNode owner) {
    final bool createdByLocalProject = _nodesCreatedByLocalProject.contains(owner);
    return properties.where((DiagnosticsNode node) {
      return !node.isFiltered(createdByLocalProject ? DiagnosticLevel.fine : DiagnosticLevel.info);
    }).toList();
  }

  @override
  List<DiagnosticsNode> truncateNodesList(List<DiagnosticsNode> nodes, DiagnosticsNode owner) {
    if (maxDescendentsTruncatableNode >= 0 &&
        owner?.allowTruncate == true &&
        nodes.length > maxDescendentsTruncatableNode) {
      nodes = service._truncateNodes(nodes, maxDescendentsTruncatableNode);
    }
    return nodes;
  }

  @override
  DiagnosticsSerializationDelegate copyWith({int subtreeDepth, bool includeProperties}) {
3049
    return InspectorSerializationDelegate(
3050 3051 3052 3053 3054 3055 3056
      groupName: groupName,
      summaryTree: summaryTree,
      maxDescendentsTruncatableNode: maxDescendentsTruncatableNode,
      expandPropertyValues: expandPropertyValues,
      subtreeDepth: subtreeDepth ?? this.subtreeDepth,
      includeProperties: includeProperties ?? this.includeProperties,
      service: service,
3057
      addAdditionalPropertiesCallback: addAdditionalPropertiesCallback,
3058 3059 3060
    );
  }
}