Unverified Commit 15fa68ab authored by Polina Cherkasova's avatar Polina Cherkasova Committed by GitHub

Instrument ImageInfo. (#141411)

parent 7ff5f81a
......@@ -8,38 +8,55 @@ import 'dart:ui' as ui show Codec, FrameInfo, Image;
import 'package:flutter/foundation.dart';
import 'package:flutter/scheduler.dart';
const String _flutterWidgetsLibrary = 'package:flutter/widgets.dart';
const String _flutterPaintingLibrary = 'package:flutter/painting.dart';
/// A [dart:ui.Image] object with its corresponding scale.
///
/// ImageInfo objects are used by [ImageStream] objects to represent the
/// actual data of the image once it has been obtained.
///
/// The receiver of an [ImageInfo] object must call [dispose]. To safely share
/// the object with other clients, use the [clone] method before calling
/// dispose.
/// The disposing contract for [ImageInfo] (as well as for [ui.Image])
/// is different from traditional one, where
/// an object should dispose a member if the object created the member.
/// Instead, the disposal contract is as follows:
///
/// * [ImageInfo] disposes [image], even if it is received as a constructor argument.
/// * [ImageInfo] is expected to be disposed not by the object, that created it,
/// but by the object that owns reference to it.
/// * It is expected that only one object owns reference to [ImageInfo] object.
///
/// Safety tips:
///
/// * To share the [ImageInfo] or [ui.Image] between objects, use the [clone] method,
/// which will not clone the entire underlying image, but only reference to it and information about it.
/// * After passing a [ui.Image] or [ImageInfo] reference to another object,
/// release the reference.
@immutable
class ImageInfo {
/// Creates an [ImageInfo] object for the given [image] and [scale].
///
/// The [debugLabel] may be used to identify the source of this image.
const ImageInfo({ required this.image, this.scale = 1.0, this.debugLabel });
///
/// See details for disposing contract in the class description.
ImageInfo({ required this.image, this.scale = 1.0, this.debugLabel }) {
if (kFlutterMemoryAllocationsEnabled) {
MemoryAllocations.instance.dispatchObjectCreated(
library: _flutterPaintingLibrary,
className: '$ImageInfo',
object: this,
);
}
}
/// Creates an [ImageInfo] with a cloned [image].
///
/// Once all outstanding references to the [image] are disposed, it is no
/// longer safe to access properties of it or attempt to draw it. Clones serve
/// to create new references to the underlying image data that can safely be
/// disposed without knowledge of whether some other reference holder will
/// still need access to the underlying image. Once a client disposes of its
/// own image reference, it can no longer access the image, but other clients
/// will be able to access their own references.
///
/// This method must be used in cases where a client holding an [ImageInfo]
/// needs to share the image info object with another client and will still
/// need to access the underlying image data at some later point, e.g. to
/// share it again with another client.
///
/// See details for disposing contract in the class description.
///
/// See also:
///
/// * [Image.clone], which describes how and why to clone images.
......@@ -125,6 +142,9 @@ class ImageInfo {
/// and no clones of it or the image it contains can be made.
void dispose() {
assert((image.debugGetOpenHandleStackTraces()?.length ?? 1) > 0);
if (kFlutterMemoryAllocationsEnabled) {
MemoryAllocations.instance.dispatchObjectDisposed(object: this);
}
image.dispose();
}
......@@ -443,7 +463,7 @@ class ImageStreamCompleterHandle {
// https://github.com/flutter/flutter/issues/137435
if (kFlutterMemoryAllocationsEnabled) {
FlutterMemoryAllocations.instance.dispatchObjectCreated(
library: _flutterWidgetsLibrary,
library: _flutterPaintingLibrary,
className: '$ImageStreamCompleterHandle',
object: this,
);
......
......@@ -891,4 +891,17 @@ void main() {
areCreateAndDispose,
);
});
testWidgets('ImageInfo dispatches memory events', (WidgetTester tester) async {
await expectLater(
await memoryEvents(
() async {
final ImageInfo info = ImageInfo(image: image20x10);
info.dispose();
},
ImageInfo,
),
areCreateAndDispose,
);
});
}
......@@ -9,7 +9,7 @@ import 'package:flutter/foundation.dart';
import 'package:flutter/painting.dart';
class TestImageInfo extends ImageInfo {
const TestImageInfo(this.value, {
TestImageInfo(this.value, {
required super.image,
super.scale,
super.debugLabel,
......
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