PPAPI/NaCl: Make ImageData for NaCl just use shared memory

webkit/plugins/ppapi/ppb_image_data_impl.h

 // Copyright (c) 2011 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.
 
 #ifndef WEBKIT_PLUGINS_PPAPI_PPB_IMAGE_DATA_IMPL_H_
 #define WEBKIT_PLUGINS_PPAPI_PPB_IMAGE_DATA_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ppapi/c/ppb_image_data.h"
 #include "ppapi/shared_impl/ppb_image_data_shared.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/thunk/ppb_image_data_api.h"
+#include "third_party/skia/include/core/SkCanvas.h"
 #include "webkit/plugins/ppapi/plugin_delegate.h"
 #include "webkit/plugins/webkit_plugins_export.h"
 
 namespace skia {
 class PlatformCanvas;
 }
 
 class SkBitmap;
 
 namespace webkit {
 namespace ppapi {
 
 class PPB_ImageData_Impl : public ::ppapi::Resource,
                            public ::ppapi::PPB_ImageData_Shared,
                            public ::ppapi::thunk::PPB_ImageData_API {
  public:
   // If you call this constructor, you must also call Init before use. Normally
   // you should use the static Create function, but this constructor is needed
   // for some internal uses of ImageData (like Graphics2D).
-  WEBKIT_PLUGINS_EXPORT explicit PPB_ImageData_Impl(PP_Instance instance);
+  enum ImageDataType { PLATFORM, NACL };
+  WEBKIT_PLUGINS_EXPORT PPB_ImageData_Impl(PP_Instance instance,
+                                           ImageDataType type);
   virtual ~PPB_ImageData_Impl();
 
-  static PP_Resource Create(PP_Instance pp_instance,
-                            PP_ImageDataFormat format,
-                            const PP_Size& size,
-                            PP_Bool init_to_zero);
-
   WEBKIT_PLUGINS_EXPORT bool Init(PP_ImageDataFormat format,
                                   int width, int height,
                                   bool init_to_zero);
 
+  // Create an ImageData backed by a PlatformCanvas. You must use this if you
+  // intend the ImageData to be usable in platform-specific APIs (like font
+  // rendering or rendering widgets like scrollbars).
+  static PP_Resource CreatePlatform(PP_Instance pp_instance,
+                                    PP_ImageDataFormat format,
+                                    const PP_Size& size,
+                                    PP_Bool init_to_zero);
+  // Use this to create an ImageData for use with NaCl. This is backed by a

[brettw, 2012/07/20 21:57:04]

I'd probably put a blank line here.

+  // simple shared memory buffer.
+  static PP_Resource CreateNaCl(PP_Instance pp_instance,
+                                PP_ImageDataFormat format,
+                                const PP_Size& size,
+                                PP_Bool init_to_zero);
+
   int width() const { return width_; }
   int height() const { return height_; }
 
   // Returns the image format.
   PP_ImageDataFormat format() const { return format_; }
 
+  // Resource override.

[brettw, 2012/07/20 21:57:04]

I'm not sure why you moved this.

[dmichael (off chromium), 2012/07/20 22:32:40]

Just a casualty of lots of churn in the file. Moved back.

+  virtual ::ppapi::thunk::PPB_ImageData_API* AsPPB_ImageData_API() OVERRIDE;
+
   // Returns true if this image is mapped. False means that the image is either
   // invalid or not mapped. See ImageDataAutoMapper below.
-  bool is_mapped() const { return !!mapped_canvas_.get(); }
-
-  PluginDelegate::PlatformImage2D* platform_image() const {
-    return platform_image_.get();
-  }
-
-  virtual ::ppapi::thunk::PPB_ImageData_API* AsPPB_ImageData_API() OVERRIDE;
+  WEBKIT_PLUGINS_EXPORT bool IsMapped() const;

[brettw, 2012/07/20 21:57:04]

I'd probably just annotate this whole class as exported rather than the several
functions you've done.

[dmichael (off chromium), 2012/07/20 22:32:40]

Done.

+  PluginDelegate::PlatformImage2D* PlatformImage() const;
 
   // PPB_ImageData_API implementation.
   virtual PP_Bool Describe(PP_ImageDataDesc* desc) OVERRIDE;
   virtual void* Map() OVERRIDE;
   virtual void Unmap() OVERRIDE;
   virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
   virtual skia::PlatformCanvas* GetPlatformCanvas() OVERRIDE;
+  virtual SkCanvas* GetCanvas() OVERRIDE;
 
   const SkBitmap* GetMappedBitmap() const;
 
   // Swaps the guts of this image data with another.
   void Swap(PPB_ImageData_Impl* other);
 
+  // We delegate most of our implementation to a class that either uses a

[brettw, 2012/07/20 21:57:04]

Since this is a typedef it should be first (before the constructors).

+  // PlatformCanvas (for most trusted stuff) or bare shared memory (for use by
+  // NaCl). This makes it cheap & easy to implement Swap.
+  class Delegate {

[brettw, 2012/07/20 21:57:04]

I don't really feel like this is a "delegate" the way we normally use it.
Normally I'd expect a delegate to be passed to the constructor to allow
something to talk to the embedder. Here, it seems more like a "Backend" or
something.

[dmichael (off chromium), 2012/07/20 22:32:40]

Yeah...  I was thinking of it as "pImpl" pattern, but "Impl" was taken. I agree
it's not the usual Chrome-style delegate. "Backend" WFM.

+   public:
+    virtual ~Delegate() {};
+    virtual bool Init(PPB_ImageData_Impl* impl, PP_ImageDataFormat format,
+                      int width, int height, bool init_to_zero) = 0;
+    virtual bool IsMapped() const = 0;
+    virtual PluginDelegate::PlatformImage2D* PlatformImage() const = 0;
+    virtual void* Map() = 0;
+    virtual void Unmap() = 0;
+    virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) = 0;
+    virtual skia::PlatformCanvas* GetPlatformCanvas() = 0;
+    virtual SkCanvas* GetCanvas() = 0;
+    virtual const SkBitmap* GetMappedBitmap() const = 0;
+  };
+
+ private:
+  PP_ImageDataFormat format_;
+  int width_;
+  int height_;
+  scoped_ptr<Delegate> delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPB_ImageData_Impl);
+};
+
+class ImageDataPlatformDelegate : public PPB_ImageData_Impl::Delegate {
+ public:
+  ImageDataPlatformDelegate();
+  virtual ~ImageDataPlatformDelegate();
+
+  // PPB_ImageData_Impl::Delegate implementation.
+  virtual bool Init(PPB_ImageData_Impl* impl, PP_ImageDataFormat format,
+                    int width, int height, bool init_to_zero) OVERRIDE;
+  virtual bool IsMapped() const OVERRIDE;
+  virtual PluginDelegate::PlatformImage2D* PlatformImage() const OVERRIDE;
+  virtual void* Map() OVERRIDE;
+  virtual void Unmap() OVERRIDE;
+  virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
+  virtual skia::PlatformCanvas* GetPlatformCanvas() OVERRIDE;
+  virtual SkCanvas* GetCanvas() OVERRIDE;
+  virtual const SkBitmap* GetMappedBitmap() const OVERRIDE;
+
  private:
   // This will be NULL before initialization, and if this PPB_ImageData_Impl is
   // swapped with another.
   scoped_ptr<PluginDelegate::PlatformImage2D> platform_image_;
 
   // When the device is mapped, this is the image. Null when umapped.
   scoped_ptr<skia::PlatformCanvas> mapped_canvas_;
 
-  PP_ImageDataFormat format_;
-  int width_;
-  int height_;
+  DISALLOW_COPY_AND_ASSIGN(ImageDataPlatformDelegate);
+};
 
-  DISALLOW_COPY_AND_ASSIGN(PPB_ImageData_Impl);
+class ImageDataNaClDelegate : public PPB_ImageData_Impl::Delegate {
+ public:
+  ImageDataNaClDelegate();
+  virtual ~ImageDataNaClDelegate();
+
+  // PPB_ImageData_Impl::Delegate implementation.
+  bool Init(PPB_ImageData_Impl* impl, PP_ImageDataFormat format,
+            int width, int height, bool init_to_zero) OVERRIDE;
+  virtual bool IsMapped() const OVERRIDE;
+  PluginDelegate::PlatformImage2D* PlatformImage() const OVERRIDE;
+  virtual void* Map() OVERRIDE;
+  virtual void Unmap() OVERRIDE;
+  virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
+  virtual skia::PlatformCanvas* GetPlatformCanvas() OVERRIDE;
+  virtual SkCanvas* GetCanvas() OVERRIDE;
+  virtual const SkBitmap* GetMappedBitmap() const OVERRIDE;
+
+ private:
+  scoped_ptr<base::SharedMemory> shared_memory_;
+  // skia_bitmap_ is backed by shared_memory_.
+  SkBitmap skia_bitmap_;
+  SkCanvas skia_canvas_;
+  uint32 map_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(ImageDataNaClDelegate);
 };
 
 // Manages mapping an image resource if necessary. Use this to ensure the
 // image is mapped. The destructor will put the image back into the previous
 // state. You must check is_valid() to make sure the image was successfully
 // mapped before using it.
 //
 // Example:
 //   ImageDataAutoMapper mapper(image_data);
 //   if (!mapper.is_valid())
 //     return utter_failure;
 //   image_data->mapped_canvas()->blah();  // Guaranteed valid.
 class ImageDataAutoMapper {
  public:
   explicit ImageDataAutoMapper(PPB_ImageData_Impl* image_data)
         : image_data_(image_data) {
-    if (image_data_->is_mapped()) {
+    if (image_data_->IsMapped()) {
       is_valid_ = true;
       needs_unmap_ = false;
     } else {
       is_valid_ = needs_unmap_ = !!image_data_->Map();
     }
   }
 
   ~ImageDataAutoMapper() {
     if (needs_unmap_)
       image_data_->Unmap();
   }
 
   // Check this to see if the image was successfully mapped. If this is false,
   // the image could not be mapped and is unusable.
   bool is_valid() const { return is_valid_; }
 
  private:
   PPB_ImageData_Impl* image_data_;
   bool is_valid_;
   bool needs_unmap_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageDataAutoMapper);
 };
 
 }  // namespace ppapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_PPAPI_PPB_IMAGE_DATA_IMPL_H_