Migrate Path to AssociateWithDartWrapper (flutter#16753)

Author: dnfield

lib/ui/painting.dart

@@ -1893,20 +1893,20 @@ class Path extends NativeFieldWrapperClass2 {
   Path() { _constructor(); }
   void _constructor() native 'Path_constructor';
 
-  // Workaround for tonic, which expects classes with native fields to have a
-  // private constructor.
-  // TODO(dnfield): rework this to use ClaimNativeField - https://github.com/flutter/flutter/issues/50997
-  @pragma('vm:entry-point')
-  Path._() { _constructor(); }
+  /// Avoids creating a new native backing for the path for methods that will
+  /// create it later, such as [Path.from], [shift] and [transform].
+  Path._();
 
   /// Creates a copy of another [Path].
   ///
   /// This copy is fast and does not require additional memory unless either
   /// the `source` path or the path returned by this constructor are modified.
   factory Path.from(Path source) {
-    return source._clone();
+    final Path clonedPath = Path._();
+    source._clone(clonedPath);
+    return clonedPath;
   }
-  Path _clone() native 'Path_clone';
+  void _clone(Path outPath) native 'Path_clone';
 
   /// Determines how the interior of this path is calculated.
   ///
@@ -2169,17 +2169,21 @@ class Path extends NativeFieldWrapperClass2 {
   /// sub-path translated by the given offset.
   Path shift(Offset offset) {
     assert(_offsetIsValid(offset));
-    return _shift(offset.dx, offset.dy);
+    final Path path = Path._();
+    _shift(path, offset.dx, offset.dy);
+    return path;
   }
-  Path _shift(double dx, double dy) native 'Path_shift';
+  void _shift(Path outPath, double dx, double dy) native 'Path_shift';
 
   /// Returns a copy of the path with all the segments of every
   /// sub-path transformed by the given matrix.
   Path transform(Float64List matrix4) {
     assert(_matrix4IsValid(matrix4));
-    return _transform(matrix4);
+    final Path path = Path._();
+    _transform(path, matrix4);
+    return path;
   }
-  Path _transform(Float64List matrix4) native 'Path_transform';
+  void _transform(Path outPath, Float64List matrix4) native 'Path_transform';
 
   /// Computes the bounding rectangle for this path.
   ///
@@ -2455,9 +2459,11 @@ class _PathMeasure extends NativeFieldWrapperClass2 {
 
   Path extractPath(int contourIndex, double start, double end, {bool startWithMoveTo = true}) {
     assert(contourIndex <= currentContourIndex, 'Iterator must be advanced before index $contourIndex can be used.');
-    return _extractPath(contourIndex, start, end, startWithMoveTo: startWithMoveTo);
+    final Path path = Path._();
+    _extractPath(path, contourIndex, start, end, startWithMoveTo: startWithMoveTo);
+    return path;
   }
-  Path _extractPath(int contourIndex, double start, double end, {bool startWithMoveTo = true}) native 'PathMeasure_getSegment';
+  void _extractPath(Path outPath, int contourIndex, double start, double end, {bool startWithMoveTo = true}) native 'PathMeasure_getSegment';
 
   bool isClosed(int contourIndex) {
     assert(contourIndex <= currentContourIndex, 'Iterator must be advanced before index $contourIndex can be used.');

lib/ui/painting/path.cc

@@ -20,7 +20,7 @@ namespace flutter {
 typedef CanvasPath Path;
 
 static void Path_constructor(Dart_NativeArguments args) {
-  DartCallConstructor(&CanvasPath::Create, args);
+  DartCallConstructor(&CanvasPath::CreateNew, args);
 }
 
 IMPLEMENT_WRAPPERTYPEINFO(ui, Path);
@@ -262,17 +262,16 @@ bool CanvasPath::contains(double x, double y) {
   return path_.contains(x, y);
 }
 
-fml::RefPtr<CanvasPath> CanvasPath::shift(double dx, double dy) {
-  fml::RefPtr<CanvasPath> path = CanvasPath::Create();
+void CanvasPath::shift(Dart_Handle path_handle, double dx, double dy) {
+  fml::RefPtr<CanvasPath> path = CanvasPath::Create(path_handle);
   path_.offset(dx, dy, &path->path_);
-  return path;
 }
 
-fml::RefPtr<CanvasPath> CanvasPath::transform(tonic::Float64List& matrix4) {
-  fml::RefPtr<CanvasPath> path = CanvasPath::Create();
+void CanvasPath::transform(Dart_Handle path_handle,
+                           tonic::Float64List& matrix4) {
+  fml::RefPtr<CanvasPath> path = CanvasPath::Create(path_handle);
   path_.transform(ToSkMatrix(matrix4), &path->path_);
   matrix4.Release();
-  return path;
 }
 
 tonic::Float32List CanvasPath::getBounds() {
@@ -289,12 +288,11 @@ bool CanvasPath::op(CanvasPath* path1, CanvasPath* path2, int operation) {
   return Op(path1->path(), path2->path(), (SkPathOp)operation, &path_);
 }
 
-fml::RefPtr<CanvasPath> CanvasPath::clone() {
-  fml::RefPtr<CanvasPath> path = CanvasPath::Create();
+void CanvasPath::clone(Dart_Handle path_handle) {
+  fml::RefPtr<CanvasPath> path = CanvasPath::Create(path_handle);
   // per Skia docs, this will create a fast copy
   // data is shared until the source path or dest path are mutated
   path->path_ = path_;
-  return path;
 }
 
 }  // namespace flutter

lib/ui/painting/path.h

@@ -23,12 +23,19 @@ class CanvasPath : public RefCountedDartWrappable<CanvasPath> {
 
  public:
   ~CanvasPath() override;
-  static fml::RefPtr<CanvasPath> Create() {
+  static fml::RefPtr<CanvasPath> CreateNew(Dart_Handle path_handle) {
     return fml::MakeRefCounted<CanvasPath>();
   }
 
-  static fml::RefPtr<CanvasPath> CreateFrom(const SkPath& src) {
-    fml::RefPtr<CanvasPath> path = CanvasPath::Create();
+  static fml::RefPtr<CanvasPath> Create(Dart_Handle path_handle) {
+    auto path = fml::MakeRefCounted<CanvasPath>();
+    path->AssociateWithDartWrapper(path_handle);
+    return path;
+  }
+
+  static fml::RefPtr<CanvasPath> CreateFrom(Dart_Handle path_handle,
+                                            const SkPath& src) {
+    fml::RefPtr<CanvasPath> path = CanvasPath::Create(path_handle);
     path->path_ = src;
     return path;
   }
@@ -95,11 +102,11 @@ class CanvasPath : public RefCountedDartWrappable<CanvasPath> {
   void close();
   void reset();
   bool contains(double x, double y);
-  fml::RefPtr<CanvasPath> shift(double dx, double dy);
-  fml::RefPtr<CanvasPath> transform(tonic::Float64List& matrix4);
+  void shift(Dart_Handle path_handle, double dx, double dy);
+  void transform(Dart_Handle path_handle, tonic::Float64List& matrix4);
   tonic::Float32List getBounds();
   bool op(CanvasPath* path1, CanvasPath* path2, int operation);
-  fml::RefPtr<CanvasPath> clone();
+  void clone(Dart_Handle path_handle);
 
   const SkPath& path() const { return path_; }
 

lib/ui/painting/path_measure.cc

@@ -65,26 +65,26 @@ void CanvasPathMeasure::setPath(const CanvasPath* path, bool isClosed) {
   path_measure_->reset(skPath, isClosed);
 }
 
-float CanvasPathMeasure::getLength(int contourIndex) {
+float CanvasPathMeasure::getLength(int contour_index) {
   if (static_cast<std::vector<sk_sp<SkContourMeasure>>::size_type>(
-          contourIndex) < measures_.size()) {
-    return measures_[contourIndex]->length();
+          contour_index) < measures_.size()) {
+    return measures_[contour_index]->length();
   }
   return -1;
 }
 
-tonic::Float32List CanvasPathMeasure::getPosTan(int contourIndex,
+tonic::Float32List CanvasPathMeasure::getPosTan(int contour_index,
                                                 float distance) {
   tonic::Float32List posTan(Dart_NewTypedData(Dart_TypedData_kFloat32, 5));
   posTan[0] = 0;  // dart code will check for this for failure
   if (static_cast<std::vector<sk_sp<SkContourMeasure>>::size_type>(
-          contourIndex) >= measures_.size()) {
+          contour_index) >= measures_.size()) {
     return posTan;
   }
 
   SkPoint pos;
   SkVector tan;
-  bool success = measures_[contourIndex]->getPosTan(distance, &pos, &tan);
+  bool success = measures_[contour_index]->getPosTan(distance, &pos, &tan);
 
   if (success) {
     posTan[0] = 1;  // dart code will check for this for success
@@ -97,28 +97,29 @@ tonic::Float32List CanvasPathMeasure::getPosTan(int contourIndex,
   return posTan;
 }
 
-fml::RefPtr<CanvasPath> CanvasPathMeasure::getSegment(int contourIndex,
-                                                      float startD,
-                                                      float stopD,
-                                                      bool startWithMoveTo) {
+void CanvasPathMeasure::getSegment(Dart_Handle path_handle,
+                                   int contour_index,
+                                   float start_d,
+                                   float stop_d,
+                                   bool start_with_move_to) {
   if (static_cast<std::vector<sk_sp<SkContourMeasure>>::size_type>(
-          contourIndex) >= measures_.size()) {
-    return CanvasPath::Create();
+          contour_index) >= measures_.size()) {
+    CanvasPath::Create(path_handle);
   }
   SkPath dst;
-  bool success =
-      measures_[contourIndex]->getSegment(startD, stopD, &dst, startWithMoveTo);
+  bool success = measures_[contour_index]->getSegment(start_d, stop_d, &dst,
+                                                      start_with_move_to);
   if (!success) {
-    return CanvasPath::Create();
+    CanvasPath::Create(path_handle);
   } else {
-    return CanvasPath::CreateFrom(dst);
+    CanvasPath::CreateFrom(path_handle, dst);
   }
 }
 
-bool CanvasPathMeasure::isClosed(int contourIndex) {
+bool CanvasPathMeasure::isClosed(int contour_index) {
   if (static_cast<std::vector<sk_sp<SkContourMeasure>>::size_type>(
-          contourIndex) < measures_.size()) {
-    return measures_[contourIndex]->isClosed();
+          contour_index) < measures_.size()) {
+    return measures_[contour_index]->isClosed();
   }
   return false;
 }

lib/ui/painting/path_measure.h

@@ -32,13 +32,14 @@ class CanvasPathMeasure : public RefCountedDartWrappable<CanvasPathMeasure> {
                                                bool forceClosed);
 
   void setPath(const CanvasPath* path, bool isClosed);
-  float getLength(int contourIndex);
-  tonic::Float32List getPosTan(int contourIndex, float distance);
-  fml::RefPtr<CanvasPath> getSegment(int contourIndex,
-                                     float startD,
-                                     float stopD,
-                                     bool startWithMoveTo);
-  bool isClosed(int contourIndex);
+  float getLength(int contour_index);
+  tonic::Float32List getPosTan(int contour_index, float distance);
+  void getSegment(Dart_Handle path_handle,
+                  int contour_index,
+                  float start_d,
+                  float stop_d,
+                  bool start_with_move_to);
+  bool isClosed(int contour_index);
   bool nextContour();
 
   static void RegisterNatives(tonic::DartLibraryNatives* natives);