content/renderer/pepper/ppb_image_data_impl.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_PEPPER_PPB_IMAGE_DATA_IMPL_H_
   6 #define CONTENT_RENDERER_PEPPER_PPB_IMAGE_DATA_IMPL_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "content/common/content_export.h"
  11 #include "ppapi/c/ppb_image_data.h"
  12 #include "ppapi/shared_impl/ppb_image_data_shared.h"
  13 #include "ppapi/shared_impl/resource.h"
  14 #include "ppapi/thunk/ppb_image_data_api.h"
  15 #include "third_party/skia/include/core/SkCanvas.h"
  16
  17 class SkBitmap;
  18 class SkCanvas;
  19 class TransportDIB;
  20
  21 namespace base {
  22 class SharedMemory;
  23 }
  24
  25 namespace content {
  26
  27 class CONTENT_EXPORT PPB_ImageData_Impl
  28     : public ppapi::Resource,
  29       public ppapi::PPB_ImageData_Shared,
  30       public NON_EXPORTED_BASE(ppapi::thunk::PPB_ImageData_API) {
  31  public:
  32   // We delegate most of our implementation to a back-end class that either uses
  33   // a PlatformCanvas (for most trusted stuff) or bare shared memory (for use by
  34   // NaCl, or trusted plugins when the PlatformCanvas isn't needed). This makes
  35   // it cheap & easy to implement Swap.
  36   class Backend {
  37    public:
  38     virtual ~Backend() {};
  39     virtual bool Init(PPB_ImageData_Impl* impl,
  40                       PP_ImageDataFormat format,
  41                       int width,
  42                       int height,
  43                       bool init_to_zero) = 0;
  44     virtual bool IsMapped() const = 0;
  45     virtual TransportDIB* GetTransportDIB() const = 0;
  46     virtual void* Map() = 0;
  47     virtual void Unmap() = 0;
  48     virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) = 0;
  49     virtual SkCanvas* GetPlatformCanvas() = 0;
  50     virtual SkCanvas* GetCanvas() = 0;
  51     virtual const SkBitmap* GetMappedBitmap() const = 0;
  52   };
  53
  54   // If you call this constructor, you must also call Init before use. Normally
  55   // you should use the static Create function, but this constructor is needed
  56   // for some internal uses of ImageData (like Graphics2D).
  57   PPB_ImageData_Impl(PP_Instance instance,
  58                      PPB_ImageData_Shared::ImageDataType type);
  59
  60   // Constructor used for unittests. The ImageData is always allocated locally.
  61   struct ForTest {};
  62   PPB_ImageData_Impl(PP_Instance instance, ForTest);
  63
  64   bool Init(PP_ImageDataFormat format,
  65             int width,
  66             int height,
  67             bool init_to_zero);
  68
  69   static PP_Resource Create(PP_Instance pp_instance,
  70                             PPB_ImageData_Shared::ImageDataType type,
  71                             PP_ImageDataFormat format,
  72                             const PP_Size& size,
  73                             PP_Bool init_to_zero);
  74
  75   int width() const { return width_; }
  76   int height() const { return height_; }
  77
  78   // Returns the image format.
  79   PP_ImageDataFormat format() const { return format_; }
  80
  81   // Returns true if this image is mapped. False means that the image is either
  82   // invalid or not mapped. See ImageDataAutoMapper below.
  83   bool IsMapped() const;
  84   TransportDIB* GetTransportDIB() const;
  85
  86   // Resource override.
  87   virtual ppapi::thunk::PPB_ImageData_API* AsPPB_ImageData_API() OVERRIDE;
  88
  89   // PPB_ImageData_API implementation.
  90   virtual PP_Bool Describe(PP_ImageDataDesc* desc) OVERRIDE;
  91   virtual void* Map() OVERRIDE;
  92   virtual void Unmap() OVERRIDE;
  93   virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
  94   virtual SkCanvas* GetPlatformCanvas() OVERRIDE;
  95   virtual SkCanvas* GetCanvas() OVERRIDE;
  96   virtual void SetIsCandidateForReuse() OVERRIDE;
  97
  98   const SkBitmap* GetMappedBitmap() const;
  99
 100  private:
 101   virtual ~PPB_ImageData_Impl();
 102
 103   PP_ImageDataFormat format_;
 104   int width_;
 105   int height_;
 106   scoped_ptr<Backend> backend_;
 107
 108   DISALLOW_COPY_AND_ASSIGN(PPB_ImageData_Impl);
 109 };
 110
 111 class ImageDataPlatformBackend : public PPB_ImageData_Impl::Backend {
 112  public:
 113   // |is_browser_allocated| indicates whether the backing shared memory should
 114   // be allocated by the browser process.
 115   ImageDataPlatformBackend(bool is_browser_allocated);
 116   virtual ~ImageDataPlatformBackend();
 117
 118   // PPB_ImageData_Impl::Backend implementation.
 119   virtual bool Init(PPB_ImageData_Impl* impl,
 120                     PP_ImageDataFormat format,
 121                     int width,
 122                     int height,
 123                     bool init_to_zero) OVERRIDE;
 124   virtual bool IsMapped() const OVERRIDE;
 125   virtual TransportDIB* GetTransportDIB() const OVERRIDE;
 126   virtual void* Map() OVERRIDE;
 127   virtual void Unmap() OVERRIDE;
 128   virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
 129   virtual SkCanvas* GetPlatformCanvas() OVERRIDE;
 130   virtual SkCanvas* GetCanvas() OVERRIDE;
 131   virtual const SkBitmap* GetMappedBitmap() const OVERRIDE;
 132
 133  private:
 134   // This will be NULL before initialization, and if this PPB_ImageData_Impl is
 135   // swapped with another.
 136   int width_;
 137   int height_;
 138   scoped_ptr<TransportDIB> dib_;
 139
 140   bool is_browser_allocated_;
 141
 142   // When the device is mapped, this is the image. Null when umapped.
 143   scoped_ptr<SkCanvas> mapped_canvas_;
 144
 145   DISALLOW_COPY_AND_ASSIGN(ImageDataPlatformBackend);
 146 };
 147
 148 class ImageDataSimpleBackend : public PPB_ImageData_Impl::Backend {
 149  public:
 150   ImageDataSimpleBackend();
 151   virtual ~ImageDataSimpleBackend();
 152
 153   // PPB_ImageData_Impl::Backend implementation.
 154   virtual bool Init(PPB_ImageData_Impl* impl,
 155                     PP_ImageDataFormat format,
 156                     int width,
 157                     int height,
 158                     bool init_to_zero) OVERRIDE;
 159   virtual bool IsMapped() const OVERRIDE;
 160   virtual TransportDIB* GetTransportDIB() const OVERRIDE;
 161   virtual void* Map() OVERRIDE;
 162   virtual void Unmap() OVERRIDE;
 163   virtual int32_t GetSharedMemory(int* handle, uint32_t* byte_count) OVERRIDE;
 164   virtual SkCanvas* GetPlatformCanvas() OVERRIDE;
 165   virtual SkCanvas* GetCanvas() OVERRIDE;
 166   virtual const SkBitmap* GetMappedBitmap() const OVERRIDE;
 167
 168  private:
 169   scoped_ptr<base::SharedMemory> shared_memory_;
 170   // skia_bitmap_ is backed by shared_memory_.
 171   SkBitmap skia_bitmap_;
 172   scoped_ptr<SkCanvas> skia_canvas_;
 173   uint32 map_count_;
 174
 175   DISALLOW_COPY_AND_ASSIGN(ImageDataSimpleBackend);
 176 };
 177
 178 // Manages mapping an image resource if necessary. Use this to ensure the
 179 // image is mapped. The destructor will put the image back into the previous
 180 // state. You must check is_valid() to make sure the image was successfully
 181 // mapped before using it.
 182 //
 183 // Example:
 184 //   ImageDataAutoMapper mapper(image_data);
 185 //   if (!mapper.is_valid())
 186 //     return utter_failure;
 187 //   image_data->mapped_canvas()->blah();  // Guaranteed valid.
 188 class ImageDataAutoMapper {
 189  public:
 190   explicit ImageDataAutoMapper(PPB_ImageData_Impl* image_data)
 191       : image_data_(image_data) {
 192     if (image_data_->IsMapped()) {
 193       is_valid_ = true;
 194       needs_unmap_ = false;
 195     } else {
 196       is_valid_ = needs_unmap_ = !!image_data_->Map();
 197     }
 198   }
 199
 200   ~ImageDataAutoMapper() {
 201     if (needs_unmap_)
 202       image_data_->Unmap();
 203   }
 204
 205   // Check this to see if the image was successfully mapped. If this is false,
 206   // the image could not be mapped and is unusable.
 207   bool is_valid() const { return is_valid_; }
 208
 209  private:
 210   PPB_ImageData_Impl* image_data_;
 211   bool is_valid_;
 212   bool needs_unmap_;
 213
 214   DISALLOW_COPY_AND_ASSIGN(ImageDataAutoMapper);
 215 };
 216
 217 }  // namespace content
 218
 219 #endif  // CONTENT_RENDERER_PEPPER_PPB_IMAGE_DATA_IMPL_H_