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   ppapi::thunk::PPB_ImageData_API* AsPPB_ImageData_API() override;
  88
  89   // PPB_ImageData_API implementation.
  90   PP_Bool Describe(PP_ImageDataDesc* desc) override;
  91   void* Map() override;
  92   void Unmap() override;
  93   int32_t GetSharedMemory(int* handle, uint32_t* byte_count) override;
  94   SkCanvas* GetPlatformCanvas() override;
  95   SkCanvas* GetCanvas() override;
  96   void SetIsCandidateForReuse() override;
  97
  98   const SkBitmap* GetMappedBitmap() const;
  99
 100  private:
 101   ~PPB_ImageData_Impl() override;
 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();
 116   ~ImageDataPlatformBackend() override;
 117
 118   // PPB_ImageData_Impl::Backend implementation.
 119   bool Init(PPB_ImageData_Impl* impl,
 120             PP_ImageDataFormat format,
 121             int width,
 122             int height,
 123             bool init_to_zero) override;
 124   bool IsMapped() const override;
 125   TransportDIB* GetTransportDIB() const override;
 126   void* Map() override;
 127   void Unmap() override;
 128   int32_t GetSharedMemory(int* handle, uint32_t* byte_count) override;
 129   SkCanvas* GetPlatformCanvas() override;
 130   SkCanvas* GetCanvas() override;
 131   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   // When the device is mapped, this is the image. Null when umapped.
 141   scoped_ptr<SkCanvas> mapped_canvas_;
 142
 143   DISALLOW_COPY_AND_ASSIGN(ImageDataPlatformBackend);
 144 };
 145
 146 class ImageDataSimpleBackend : public PPB_ImageData_Impl::Backend {
 147  public:
 148   ImageDataSimpleBackend();
 149   ~ImageDataSimpleBackend() override;
 150
 151   // PPB_ImageData_Impl::Backend implementation.
 152   bool Init(PPB_ImageData_Impl* impl,
 153             PP_ImageDataFormat format,
 154             int width,
 155             int height,
 156             bool init_to_zero) override;
 157   bool IsMapped() const override;
 158   TransportDIB* GetTransportDIB() const override;
 159   void* Map() override;
 160   void Unmap() override;
 161   int32_t GetSharedMemory(int* handle, uint32_t* byte_count) override;
 162   SkCanvas* GetPlatformCanvas() override;
 163   SkCanvas* GetCanvas() override;
 164   const SkBitmap* GetMappedBitmap() const override;
 165
 166  private:
 167   scoped_ptr<base::SharedMemory> shared_memory_;
 168   // skia_bitmap_ is backed by shared_memory_.
 169   SkBitmap skia_bitmap_;
 170   scoped_ptr<SkCanvas> skia_canvas_;
 171   uint32 map_count_;
 172
 173   DISALLOW_COPY_AND_ASSIGN(ImageDataSimpleBackend);
 174 };
 175
 176 // Manages mapping an image resource if necessary. Use this to ensure the
 177 // image is mapped. The destructor will put the image back into the previous
 178 // state. You must check is_valid() to make sure the image was successfully
 179 // mapped before using it.
 180 //
 181 // Example:
 182 //   ImageDataAutoMapper mapper(image_data);
 183 //   if (!mapper.is_valid())
 184 //     return utter_failure;
 185 //   image_data->mapped_canvas()->blah();  // Guaranteed valid.
 186 class ImageDataAutoMapper {
 187  public:
 188   explicit ImageDataAutoMapper(PPB_ImageData_Impl* image_data)
 189       : image_data_(image_data) {
 190     if (image_data_->IsMapped()) {
 191       is_valid_ = true;
 192       needs_unmap_ = false;
 193     } else {
 194       is_valid_ = needs_unmap_ = !!image_data_->Map();
 195     }
 196   }
 197
 198   ~ImageDataAutoMapper() {
 199     if (needs_unmap_)
 200       image_data_->Unmap();
 201   }
 202
 203   // Check this to see if the image was successfully mapped. If this is false,
 204   // the image could not be mapped and is unusable.
 205   bool is_valid() const { return is_valid_; }
 206
 207  private:
 208   PPB_ImageData_Impl* image_data_;
 209   bool is_valid_;
 210   bool needs_unmap_;
 211
 212   DISALLOW_COPY_AND_ASSIGN(ImageDataAutoMapper);
 213 };
 214
 215 }  // namespace content
 216
 217 #endif  // CONTENT_RENDERER_PEPPER_PPB_IMAGE_DATA_IMPL_H_