Fix accessing prototypes of Canvas, Image, Context2d

Fixes #803

Author: zbjornson

History.md

@@ -1,3 +1,8 @@
+unreleased
+===================
+
+* Fix accessing prototypes of Canvas, Image, Context2d (#808)
+
 1.6.0 / 2016-10-16
 ==================
 
@@ -13,7 +18,7 @@
  * Add issue template (#791)
 
 1.4.0 / 2016-06-03
-==================
+===================
 
  * Add support for evenodd fill rule (#762)
 

src/Canvas.cc

@@ -46,6 +46,7 @@ Canvas::Initialize(Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target) {
 
   // Prototype
   Local<ObjectTemplate> proto = ctor->PrototypeTemplate();
+  proto->SetInternalFieldCount(1);
   Nan::SetPrototypeMethod(ctor, "toBuffer", ToBuffer);
   Nan::SetPrototypeMethod(ctor, "streamPNGSync", StreamPNGSync);
   Nan::SetPrototypeMethod(ctor, "streamPDFSync", StreamPDFSync);

src/CanvasRenderingContext2d.cc

@@ -84,6 +84,7 @@ Context2d::Initialize(Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target) {
 
   // Prototype
   Local<ObjectTemplate> proto = ctor->PrototypeTemplate();
+  proto->SetInternalFieldCount(1);
   Nan::SetPrototypeMethod(ctor, "drawImage", DrawImage);
   Nan::SetPrototypeMethod(ctor, "putImageData", PutImageData);
   Nan::SetPrototypeMethod(ctor, "getImageData", GetImageData);

src/Image.cc

@@ -45,6 +45,7 @@ Image::Initialize(Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target) {
 
   // Prototype
   Local<ObjectTemplate> proto = ctor->PrototypeTemplate();
+  proto->SetInternalFieldCount(1);
   Nan::SetAccessor(proto, Nan::New("source").ToLocalChecked(), GetSource, SetSource);
   Nan::SetAccessor(proto, Nan::New("complete").ToLocalChecked(), GetComplete);
   Nan::SetAccessor(proto, Nan::New("width").ToLocalChecked(), GetWidth);

src/ImageData.cc

@@ -25,6 +25,7 @@ ImageData::Initialize(Nan::ADDON_REGISTER_FUNCTION_ARGS_TYPE target) {
 
   // Prototype
   Local<ObjectTemplate> proto = ctor->PrototypeTemplate();
+  proto->SetInternalFieldCount(1);
   Nan::SetAccessor(proto, Nan::New("width").ToLocalChecked(), GetWidth);
   Nan::SetAccessor(proto, Nan::New("height").ToLocalChecked(), GetHeight);
   Nan::Set(target, Nan::New("ImageData").ToLocalChecked(), ctor->GetFunction());

test/canvas.test.js

@@ -25,6 +25,16 @@ describe('Canvas', function () {
     assert.ok(/^\d+\.\d+\.\d+$/.test(Canvas.cairoVersion));
   });
 
+  it('Allows accessing the prototype on the constructor (GH-803)', function () {
+    // Fails for 0.8 and 0.10.
+    if (/v0.(8|10)/.test(process.version)) return;
+    var c = new Canvas(10, 10);
+    Canvas.prototype.width;
+    assert(!c.hasOwnProperty('width'));
+    assert('width' in c);
+    assert(Canvas.prototype.hasOwnProperty('width'));
+  });
+
   it('.parseFont()', function () {
     var tests = [
         '20px Arial'
@@ -607,6 +617,11 @@ describe('Canvas', function () {
     });
   });
 
+  xit('Context2d allows accessing the prototype on the constructor (GH-803)', function () {
+    // Seems like a bug in libcairo2 causes a crash if this is evaluated.
+    Canvas.Context2d.prototype.patternQuality;
+  });
+
   it('Context2d#createImageData(width, height)', function () {
     var canvas = new Canvas(20, 20)
       , ctx = canvas.getContext('2d');
@@ -622,6 +637,10 @@ describe('Canvas', function () {
     assert.equal(0, imageData.data[3]);
   });
 
+  it('ImageData allows accessing the prototype on the constructor (GH-803)', function () {
+    Canvas.ImageData.prototype.width;
+  });
+
   it('Context2d#measureText().width', function () {
     var canvas = new Canvas(20, 20)
       , ctx = canvas.getContext('2d');

test/image.test.js

@@ -19,6 +19,16 @@ describe('Image', function () {
     assert.ok(Image instanceof Function);
   });
 
+  it('Allows accessing the prototype on the constructor (GH-803)', function () {
+    // Fails for 0.8 and 0.10.
+    if (/v0.(8|10)/.test(process.version)) return;
+    var img = new Image();
+    Image.prototype.width;
+    assert(!img.hasOwnProperty('width'));
+    assert('width' in img);
+    assert(Image.prototype.hasOwnProperty('width'));
+  });
+
   it('Image#onload', function () {
     var img = new Image
       , onloadCalled = 0;