Sky: Add a CustomDart attribute to the IDL compiler, and use that with Canvas

to provide a better Dart API.

When the attribute is present on an IDL interface, the generate Dart code will be a private interface that can extended by custom dart code.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1135283005

engine/bindings/IDLExtendedAttributes.txt

@@ -42,6 +42,10 @@ Constructor
 ConstructorCallWith=ExecutionContext|Document
 Custom=|Getter|Setter|VisitDOMWrapper|Wrap|PropertyGetter|PropertyEnumerator|PropertyQuery
 CustomConstructor
+# Sky addition: if present, the IDL compiler will generate a private Dart
+# interface to be extended by an auxilary file <Interface>.dart next to
+# <Interface>.idl.
+CustomDart
 CustomElementCallbacks
 Default=Undefined
 DependentLifetime

engine/bindings/scripts/code_generator_dart.py

@@ -106,8 +106,8 @@ class CodeGeneratorDart(object):
             (interface_name, interface_info['component_dir'])
             for interface_name, interface_info in interfaces_info.iteritems()))
 
-    def generate_code(self, definitions, interface_name, idl_pickle_filename,
-                      only_if_changed):
+    def generate_code(self, definitions, interface_name,
+                      idl_filename, idl_pickle_filename, only_if_changed):
         """Returns .h/.cpp/.dart code as (header_text, cpp_text, dart_text)."""
         try:
             interface = definitions.interfaces[interface_name]
@@ -149,6 +149,15 @@ class CodeGeneratorDart(object):
 
         template_contents['cpp_includes'] = sorted(includes)
 
+        # If CustomDart is set, read the custom dart file and add it to our
+        # template parameters.
+        if 'CustomDart' in interface.extended_attributes:
+          dart_filename = os.path.join(os.path.dirname(idl_filename),
+                                       interface.name + ".dart")
+          with open(dart_filename) as dart_file:
+              custom_dartcode = dart_file.read()
+              template_contents['custom_dartcode'] = custom_dartcode
+
         idl_world = {'interface': None, 'callback': None}
 
         # Load the pickle file for this IDL.
@@ -178,6 +187,7 @@ class CodeGeneratorDart(object):
         header_text = header_template.render(template_contents)
         cpp_text = cpp_template.render(template_contents)
         dart_text = dart_template.render(template_contents)
+
         return header_text, cpp_text, dart_text
 
     def load_global_pickles(self, global_entries):

engine/bindings/scripts/dart_compiler.py

@@ -83,6 +83,7 @@ class IdlCompiler(object):
         definitions = self.reader.read_idl_definitions(idl_filename)
         output_code_list = self.code_generator.generate_code(definitions,
                                                              interface_name,
+                                                             idl_filename,
                                                              idl_pickle_filename,
                                                              self.only_if_changed)
 

engine/bindings/scripts/templates/interface_dart.template

@@ -19,8 +19,10 @@ part of dart.sky;
     {%- endfor -%}
 {%- endmacro -%}
 
+{%- set prefix = "_" if custom_dartcode else "" -%}
 {% if not constructors and not custom_constructors %}abstract {% endif -%}
-class {{interface_name}} extends {{ parent_interface if parent_interface else 'NativeFieldWrapperClass2' }} {
+class {{prefix}}{{interface_name}} extends
+    {{ parent_interface if parent_interface else 'NativeFieldWrapperClass2' }} {
     // Constructors
 {# TODO(eseidel): We only ever have one constructor. #}
 {%- for constructor in constructors + custom_constructors %}
@@ -38,15 +40,15 @@ class {{interface_name}} extends {{ parent_interface if parent_interface else 'N
 
     // Attributes
 {% for attribute in attributes %}
-    {{ attribute.dart_type }} get {{ attribute.name }} native "{{interface_name}}_{{ attribute.name }}_Getter";
+    {{ attribute.dart_type }} get {{prefix}}{{ attribute.name }} native "{{interface_name}}_{{ attribute.name }}_Getter";
 {% if not attribute.is_read_only %}
-    void set {{ attribute.name }}({{ attribute.dart_type }} value) native "{{interface_name}}_{{ attribute.name }}_Setter";
+    void set {{prefix}}{{ attribute.name }}({{ attribute.dart_type }} value) native "{{interface_name}}_{{ attribute.name }}_Setter";
 {% endif %}
 {% endfor %}
 
     // Methods
 {% for method in methods %}
-    {{method.dart_type}} {{method.name}}({{ args_macro(method.arguments)}}) native "{{interface_name}}_{{ method.name }}_Callback";
+    {{method.dart_type}} {{prefix}}{{method.name}}({{ args_macro(method.arguments)}}) native "{{interface_name}}_{{ method.name }}_Callback";
 {% endfor %}
 
     // Operators
@@ -57,3 +59,5 @@ class {{interface_name}} extends {{ parent_interface if parent_interface else 'N
     void operator[]=(String name, String value) native "{{interface_name}}___setter___Callback";
 {% endif %}
 }
+
+{{custom_dartcode}}

engine/core/painting/Canvas.cpp

@@ -120,7 +120,7 @@ void Canvas::drawPicture(Picture* picture)
     m_canvas->drawPicture(picture->displayList()->picture());
 }
 
-void Canvas::drawPaint(Paint* paint)
+void Canvas::drawPaint(const Paint* paint)
 {
     if (!m_canvas)
         return;
@@ -147,7 +147,7 @@ void Canvas::drawOval(const Vector<float>& rect, const Paint* paint)
     m_canvas->drawOval(toSkRect(rect), paint->paint());
 }
 
-void Canvas::drawCircle(float x, float y, float radius, Paint* paint)
+void Canvas::drawCircle(float x, float y, float radius, const Paint* paint)
 {
     if (!m_canvas)
         return;

engine/core/painting/Canvas.dart

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This extends the Canvas.dart generated from Canvas.idl.
+
+class Rect {
+  List<double> _value;
+  double get left => _value[0];
+  double get top => _value[1];
+  double get right => _value[2];
+  double get bottom => _value[3];
+
+  void setLTRB(double left, double top, double right, double bottom) {
+    _value = [left, top, right, bottom];
+  }
+}
+
+class Canvas extends _Canvas {
+  double get height => _height;
+  double get width => _width;
+
+  void save() => _save();
+  void saveLayer(Rect bounds, Paint paint) =>
+      _saveLayer(bounds._value, Paint paint);
+  void restore() => _restore();
+  void translate(double dx, double dy) => _translate(dx, dy);
+  void scale(double sx, double sy) => _scale(sx, sy);
+  void rotateDegrees(double degrees) => _rotateDegrees(degrees);
+  void skew(double sx, double sy) => _skew(sx, sy);
+  void concat(List<double> matrix9) => _concat(matrix9);
+  void clipRect(Rect rect) => _clipRect(rect._value);
+
+  void drawPicture(Picture picture) => _drawPicture(picture);
+  void drawPaint(Paint paint) => _drawPaint(paint);
+  void drawRect(Rect rect, Paint paint) => _drawRect(rect._value, paint);
+  void drawOval(Rect rect, Paint paint) => _drawOval(rect._value, paint);
+  void drawCircle(double x, double y, double radius, Paint paint) =>
+      _drawCircle(x, y, radius, paint);
+}

engine/core/painting/Canvas.h

@@ -39,11 +39,10 @@ public:
     void clipRect(const Vector<float>& rect);
 
     void drawPicture(Picture* picture);
-
-    void drawPaint(Paint* paint);
+    void drawPaint(const Paint* paint);
     void drawRect(const Vector<float>& rect, const Paint* paint);
     void drawOval(const Vector<float>& rect, const Paint* paint);
-    void drawCircle(float x, float y, float radius, Paint* paint);
+    void drawCircle(float x, float y, float radius, const Paint* paint);
 
     SkCanvas* skCanvas() { return m_canvas; }
 

engine/core/painting/Canvas.idl

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(mpcomplete): Figure out a better SkMatrix/SkRect representation.
-interface Canvas {
+// TODO(mpcomplete): Figure out a better SkMatrix representation.
+[CustomDart] interface Canvas {
   // Height and width are used for culling optimizations and do not necessarily
   // imply that the Canvas is backed by a buffer with any specific bounds.
   readonly attribute float height;

examples/raw/painting.sky

@@ -18,12 +18,14 @@ void main() {
 
     context.save();
 
-    context.clipRect([0.0, 0.0, context.width, radius]);
+    context.clipRect(new Rect()..setLTRB(0.0, 0.0, context.width, radius));
 
     context.translate(context.width / 2.0, context.height / 2.0);
     paint.setARGB(128, 255, 0, 255);
     context.rotateDegrees(45.0);
-    context.drawRect([-radius, -radius, radius, radius], paint);
+
+    context.drawRect(new Rect()..setLTRB(-radius, -radius, radius, radius),
+                     paint);
 
     // Scale x and y by 0.5.
     var scaleMatrix = [