Refactor local engine logic (#27765)

* Refactor for iOS.

* For android_xxx_unopt_arm64&ios_xxx_unopt_arm, remove the _arm64/_arm suffix.
dart generated in host_xxx_unopt/host_xxx has an arch of x86_64 which supports arm64/arm.

* Remove suffixes for various archs.

packages/flutter_tools/bin/xcode_backend.sh

@@ -96,10 +96,15 @@ BuildApp() {
 
   RunCommand rm -rf -- "${derived_dir}/App.framework"
 
+  local flutter_engine_flag=""
   local local_engine_flag=""
   local flutter_framework="${framework_path}/Flutter.framework"
   local flutter_podspec="${framework_path}/Flutter.podspec"
 
+  if [[ -n "$FLUTTER_ENGINE" ]]; then
+    flutter_engine_flag="--local-engine-src-path=${FLUTTER_ENGINE}"
+  fi
+
   if [[ -n "$LOCAL_ENGINE" ]]; then
     if [[ $(echo "$LOCAL_ENGINE" | tr "[:upper:]" "[:lower:]") != *"$build_mode"* ]]; then
       EchoError "========================================================================"
@@ -114,8 +119,8 @@ BuildApp() {
       exit -1
     fi
     local_engine_flag="--local-engine=${LOCAL_ENGINE}"
-    flutter_framework="${LOCAL_ENGINE}/Flutter.framework"
-    flutter_podspec="${LOCAL_ENGINE}/Flutter.podspec"
+    flutter_framework="${FLUTTER_ENGINE}/out/${LOCAL_ENGINE}/Flutter.framework"
+    flutter_podspec="${FLUTTER_ENGINE}/out/${LOCAL_ENGINE}/Flutter.podspec"
   fi
 
   if [[ -e "${project_path}/.ios" ]]; then
@@ -168,6 +173,7 @@ BuildApp() {
       --target="${target_path}"                                             \
       --${build_mode}                                                       \
       --ios-arch="${archs}"                                                 \
+      ${flutter_engine_flag}                                                \
       ${local_engine_flag}                                                  \
       ${track_widget_creation_flag}
 
@@ -244,6 +250,7 @@ BuildApp() {
     --depfile="${build_dir}/snapshot_blob.bin.d"                            \
     --asset-dir="${derived_dir}/App.framework/flutter_assets"               \
     ${precompilation_flag}                                                  \
+    ${flutter_engine_flag}                                                  \
     ${local_engine_flag}                                                    \
     ${track_widget_creation_flag}
 

packages/flutter_tools/lib/src/base/user_messages.dart

@@ -243,8 +243,8 @@ class UserMessages {
       'Warning: this bug report contains local paths, device identifiers, and log snippets.';
   String get runnerNoRecordTo => 'record-to location not specified';
   String get runnerNoReplayFrom => 'replay-from location not specified';
-  String runnerNoEngineBuildDir(String enginePackageName, String engineEnvVar) =>
-      'Unable to detect local Flutter engine build directory.\n'
+  String runnerNoEngineSrcDir(String enginePackageName, String engineEnvVar) =>
+      'Unable to detect local Flutter engine src directory.\n'
       'Either specify a dependency_override for the $enginePackageName package in your pubspec.yaml and '
       'ensure --package-root is set if necessary, or set the \$$engineEnvVar environment variable, or '
       'use --local-engine-src-path to specify the path to the root of your flutter/engine repository.';

packages/flutter_tools/lib/src/ios/xcodeproj.dart

@@ -74,7 +74,9 @@ Future<void> updateGeneratedXcodeProperties({
 
   if (artifacts is LocalEngineArtifacts) {
     final LocalEngineArtifacts localEngineArtifacts = artifacts;
-    localsBuffer.writeln('LOCAL_ENGINE=${localEngineArtifacts.engineOutPath}');
+    final String engineOutPath = localEngineArtifacts.engineOutPath;
+    localsBuffer.writeln('FLUTTER_ENGINE=${fs.path.dirname(fs.path.dirname(engineOutPath))}');
+    localsBuffer.writeln('LOCAL_ENGINE=${fs.path.basename(engineOutPath)}');
 
     // Tell Xcode not to build universal binaries for local engines, which are
     // single-architecture.
@@ -82,7 +84,7 @@ Future<void> updateGeneratedXcodeProperties({
     // NOTE: this assumes that local engine binary paths are consistent with
     // the conventions uses in the engine: 32-bit iOS engines are built to
     // paths ending in _arm, 64-bit builds are not.
-    final String arch = localEngineArtifacts.engineOutPath.endsWith('_arm') ? 'armv7' : 'arm64';
+    final String arch = engineOutPath.endsWith('_arm') ? 'armv7' : 'arm64';
     localsBuffer.writeln('ARCHS=$arch');
   }
 

packages/flutter_tools/lib/src/runner/flutter_command_runner.dart

@@ -409,25 +409,28 @@ class FlutterCommandRunner extends CommandRunner<void> {
 
     if (engineSourcePath == null && globalResults['local-engine'] != null) {
       try {
-        final Uri engineUri = PackageMap(PackageMap.globalPackagesPath).map[kFlutterEnginePackageName];
-        if (engineUri != null) {
-          engineSourcePath = fs.path.dirname(fs.path.dirname(fs.path.dirname(fs.path.dirname(engineUri.path))));
-          final bool dirExists = fs.isDirectorySync(fs.path.join(engineSourcePath, 'out'));
-          if (engineSourcePath == '/' || engineSourcePath.isEmpty || !dirExists)
+        Uri engineUri = PackageMap(PackageMap.globalPackagesPath).map[kFlutterEnginePackageName];
+        // Skip if sky_engine is the self-contained one.
+        if (fs.path.join(Cache.flutterRoot, 'bin', 'cache', 'pkg', kFlutterEnginePackageName, 'lib') + fs.path.separator == engineUri?.path) {
+          engineUri = null;
+        }
+        // If sky_engine is specified and the engineSourcePath not set, try to determine the engineSourcePath by sky_engine setting.
+        // A typical engineUri looks like: file://flutter-engine-local-path/src/out/host_debug_unopt/gen/dart-pkg/sky_engine/lib/
+        if (engineUri?.path != null) {
+          engineSourcePath = fs.directory(engineUri.path)?.parent?.parent?.parent?.parent?.parent?.parent?.path;
+          if (engineSourcePath != null && (engineSourcePath == fs.path.dirname(engineSourcePath) || engineSourcePath.isEmpty)) {
             engineSourcePath = null;
+            throwToolExit(userMessages.runnerNoEngineSrcDir(kFlutterEnginePackageName, kFlutterEngineEnvironmentVariableName),
+              exitCode: 2);
+          }
         }
       } on FileSystemException {
         engineSourcePath = null;
       } on FormatException {
         engineSourcePath = null;
       }
-
-      engineSourcePath ??= _tryEnginePath(fs.path.join(Cache.flutterRoot, '../engine/src'));
-
-      if (engineSourcePath == null) {
-        throwToolExit(userMessages.runnerNoEngineBuildDir(kFlutterEnginePackageName, kFlutterEngineEnvironmentVariableName),
-          exitCode: 2);
-      }
+      // If engineSourcePath is still not set, try to determine it by flutter root.
+      engineSourcePath ??= _tryEnginePath(fs.path.join(fs.directory(Cache.flutterRoot).parent.path, 'engine', 'src'));
     }
 
     if (engineSourcePath != null && _tryEnginePath(engineSourcePath) == null) {
@@ -438,6 +441,19 @@ class FlutterCommandRunner extends CommandRunner<void> {
     return engineSourcePath;
   }
 
+  String _getHostEngineBasename(String localEngineBasename) {
+    // Determine the host engine directory associated with the local engine:
+    // Strip '_sim_' since there are no host simulator builds.
+    String tmpBasename = localEngineBasename.replaceFirst('_sim_', '_');
+    tmpBasename = tmpBasename.substring(tmpBasename.indexOf('_') + 1);
+    // Strip suffix for various archs.
+    final List<String> suffixes = <String>['_arm', '_arm64', '_x86', '_x64'];
+    for (String suffix in suffixes) {
+      tmpBasename = tmpBasename.replaceFirst(RegExp('$suffix\$'), '');
+    }
+    return 'host_' + tmpBasename;
+  }
+
   EngineBuildPaths _findEngineBuildPath(ArgResults globalResults, String enginePath) {
     String localEngine;
     if (globalResults['local-engine'] != null) {
@@ -451,11 +467,8 @@ class FlutterCommandRunner extends CommandRunner<void> {
       throwToolExit(userMessages.runnerNoEngineBuild(engineBuildPath), exitCode: 2);
     }
 
-    // Determine the host engine directory associated with the local engine:
-    // * strip '_sim_' since there are no host simulator builds.
-    // * replace the target platform with host.
     final String basename = fs.path.basename(engineBuildPath);
-    final String hostBasename = 'host_' + basename.replaceFirst('_sim_', '_').substring(basename.indexOf('_') + 1);
+    final String hostBasename = _getHostEngineBasename(basename);
     final String engineHostBuildPath = fs.path.normalize(fs.path.join(fs.path.dirname(engineBuildPath), hostBasename));
     if (!fs.isDirectorySync(engineHostBuildPath)) {
       throwToolExit(userMessages.runnerNoEngineBuild(engineHostBuildPath), exitCode: 2);

packages/flutter_tools/test/runner/flutter_command_runner_test.dart

@@ -21,6 +21,7 @@ import 'utils.dart';
 
 const String _kFlutterRoot = '/flutter/flutter';
 const String _kEngineRoot = '/flutter/engine';
+const String _kArbitraryEngineRoot = '/arbitrary/engine';
 const String _kProjectRoot = '/project';
 const String _kDotPackages = '.packages';
 
@@ -68,8 +69,26 @@ void main() {
         Platform: () => platform,
       }, initializeFlutterRoot: false);
 
-      testUsingContext('works if --local-engine is specified', () async {
-        fs.file(_kDotPackages).writeAsStringSync('sky_engine:file://$_kFlutterRoot/bin/cache/pkg/sky_engine/lib/');
+      testUsingContext('works if --local-engine is specified and --local-engine-src-path is determined by sky_engine', () async {
+        fs.directory('$_kArbitraryEngineRoot/src/out/ios_debug/gen/dart-pkg/sky_engine/lib/').createSync(recursive: true);
+        fs.directory('$_kArbitraryEngineRoot/src/out/host_debug').createSync(recursive: true);
+        fs.file(_kDotPackages).writeAsStringSync('sky_engine:file://$_kArbitraryEngineRoot/src/out/ios_debug/gen/dart-pkg/sky_engine/lib/');
+        await runner.run(<String>['dummy', '--local-engine=ios_debug']);
+      }, overrides: <Type, Generator>{
+        FileSystem: () => fs,
+        Platform: () => platform,
+      }, initializeFlutterRoot: false);
+
+      testUsingContext('works if --local-engine is specified and --local-engine-src-path is specified', () async {
+        fs.directory('$_kArbitraryEngineRoot/src/out/ios_debug').createSync(recursive: true);
+        fs.directory('$_kArbitraryEngineRoot/src/out/host_debug').createSync(recursive: true);
+        await runner.run(<String>['dummy', '--local-engine-src-path=$_kArbitraryEngineRoot/src', '--local-engine=ios_debug']);
+      }, overrides: <Type, Generator>{
+        FileSystem: () => fs,
+        Platform: () => platform,
+      }, initializeFlutterRoot: false);
+
+      testUsingContext('works if --local-engine is specified and --local-engine-src-path is determined by flutter root', () async {
         fs.directory('$_kEngineRoot/src/out/ios_debug').createSync(recursive: true);
         fs.directory('$_kEngineRoot/src/out/host_debug').createSync(recursive: true);
         await runner.run(<String>['dummy', '--local-engine=ios_debug']);