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 "base/memory/shared_memory.h"
  11 #include "content/common/content_export.h"
  12 #include "ppapi/c/ppb_image_data.h"
  13 #include "ppapi/shared_impl/ppb_image_data_shared.h"
  14 #include "ppapi/shared_impl/resource.h"
  15 #include "ppapi/thunk/ppb_image_data_api.h"
  16 #include "third_party/skia/include/core/SkCanvas.h"
  17
  18 class SkBitmap;
  19 class SkCanvas;
  20 class TransportDIB;
  21
  22 namespace base {
  23 class SharedMemory;
  24 }
  25
  26 namespace content {
  27
  28 class CONTENT_EXPORT PPB_ImageData_Impl
  29     : public ppapi::Resource,
  30       public ppapi::PPB_ImageData_Shared,
  31       public NON_EXPORTED_BASE(ppapi::thunk::PPB_ImageData_API) {
  32  public:
  33   // We delegate most of our implementation to a back-end class that either uses
  34   // a PlatformCanvas (for most trusted stuff) or bare shared memory (for use by
  35   // NaCl, or trusted plugins when the PlatformCanvas isn't needed). This makes
  36   // it cheap & easy to implement Swap.
  37   class Backend {
  38    public:
  39     virtual ~Backend() {};
  40     virtual bool Init(PPB_ImageData_Impl* impl,
  41                       PP_ImageDataFormat format,
  42                       int width,
  43                       int height,
  44                       bool init_to_zero) = 0;
  45     virtual bool IsMapped() const = 0;
  46     virtual TransportDIB* GetTransportDIB() const = 0;
  47     virtual void* Map() = 0;
  48     virtual void Unmap() = 0;
  49     virtual int32_t GetSharedMemory(base::SharedMemory** shm,
  50                                     uint32_t* byte_count) = 0;
  51     virtual SkCanvas* GetPlatformCanvas() = 0;
  52     virtual SkCanvas* GetCanvas() = 0;
  53     virtual const SkBitmap* GetMappedBitmap() const = 0;
  54   };
  55
  56   // If you call this constructor, you must also call Init before use. Normally
  57   // you should use the static Create function, but this constructor is needed
  58   // for some internal uses of ImageData (like Graphics2D).
  59   PPB_ImageData_Impl(PP_Instance instance,
  60                      PPB_ImageData_Shared::ImageDataType type);
  61
  62   // Constructor used for unittests. The ImageData is always allocated locally.
  63   struct ForTest {};
  64   PPB_ImageData_Impl(PP_Instance instance, ForTest);
  65
  66   bool Init(PP_ImageDataFormat format,
  67             int width,
  68             int height,
  69             bool init_to_zero);
  70
  71   static PP_Resource Create(PP_Instance pp_instance,
  72                             PPB_ImageData_Shared::ImageDataType type,
  73                             PP_ImageDataFormat format,
  74                             const PP_Size& size,
  75                             PP_Bool init_to_zero);
  76
  77   int width() const { return width_; }
  78   int height() const { return height_; }
  79
  80   // Returns the image format.
  81   PP_ImageDataFormat format() const { return format_; }
  82
  83   // Returns true if this image is mapped. False means that the image is either
  84   // invalid or not mapped. See ImageDataAutoMapper below.
  85   bool IsMapped() const;
  86   TransportDIB* GetTransportDIB() const;
  87
  88   // Resource override.
  89   ppapi::thunk::PPB_ImageData_API* AsPPB_ImageData_API() override;
  90
  91   // PPB_ImageData_API implementation.
  92   PP_Bool Describe(PP_ImageDataDesc* desc) override;
  93   void* Map() override;
  94   void Unmap() override;
  95   int32_t GetSharedMemory(base::SharedMemory** shm,
  96                           uint32_t* byte_count) override;
  97   SkCanvas* GetPlatformCanvas() override;
  98   SkCanvas* GetCanvas() override;
  99   void SetIsCandidateForReuse() override;
 100
 101   const SkBitmap* GetMappedBitmap() const;
 102
 103  private:
 104   ~PPB_ImageData_Impl() override;
 105
 106   PP_ImageDataFormat format_;
 107   int width_;
 108   int height_;
 109   scoped_ptr<Backend> backend_;
 110
 111   DISALLOW_COPY_AND_ASSIGN(PPB_ImageData_Impl);
 112 };
 113
 114 class ImageDataPlatformBackend : public PPB_ImageData_Impl::Backend {
 115  public:
 116   // |is_browser_allocated| indicates whether the backing shared memory should
 117   // be allocated by the browser process.
 118   ImageDataPlatformBackend();
 119   ~ImageDataPlatformBackend() override;
 120
 121   // PPB_ImageData_Impl::Backend implementation.
 122   bool Init(PPB_ImageData_Impl* impl,
 123             PP_ImageDataFormat format,
 124             int width,
 125             int height,
 126             bool init_to_zero) override;
 127   bool IsMapped() const override;
 128   TransportDIB* GetTransportDIB() const override;
 129   void* Map() override;
 130   void Unmap() override;
 131   int32_t GetSharedMemory(base::SharedMemory** shm,
 132                           uint32_t* byte_count) override;
 133   SkCanvas* GetPlatformCanvas() override;
 134   SkCanvas* GetCanvas() override;
 135   const SkBitmap* GetMappedBitmap() const override;
 136
 137  private:
 138   // This will be NULL before initialization, and if this PPB_ImageData_Impl is
 139   // swapped with another.
 140   int width_;
 141   int height_;
 142   scoped_ptr<TransportDIB> dib_;
 143
 144   // When the device is mapped, this is the image. Null when umapped.
 145   scoped_ptr<SkCanvas> mapped_canvas_;
 146
 147   DISALLOW_COPY_AND_ASSIGN(ImageDataPlatformBackend);
 148 };
 149
 150 class ImageDataSimpleBackend : public PPB_ImageData_Impl::Backend {
 151  public:
 152   ImageDataSimpleBackend();
 153   ~ImageDataSimpleBackend() override;
 154
 155   // PPB_ImageData_Impl::Backend implementation.
 156   bool Init(PPB_ImageData_Impl* impl,
 157             PP_ImageDataFormat format,
 158             int width,
 159             int height,
 160             bool init_to_zero) override;
 161   bool IsMapped() const override;
 162   TransportDIB* GetTransportDIB() const override;
 163   void* Map() override;
 164   void Unmap() override;
 165   int32_t GetSharedMemory(base::SharedMemory** shm,
 166                           uint32_t* byte_count) override;
 167   SkCanvas* GetPlatformCanvas() override;
 168   SkCanvas* GetCanvas() override;
 169   const SkBitmap* GetMappedBitmap() const override;
 170
 171  private:
 172   scoped_ptr<base::SharedMemory> shared_memory_;
 173   // skia_bitmap_ is backed by shared_memory_.
 174   SkBitmap skia_bitmap_;
 175   scoped_ptr<SkCanvas> skia_canvas_;
 176   uint32 map_count_;
 177
 178   DISALLOW_COPY_AND_ASSIGN(ImageDataSimpleBackend);
 179 };
 180
 181 // Manages mapping an image resource if necessary. Use this to ensure the
 182 // image is mapped. The destructor will put the image back into the previous
 183 // state. You must check is_valid() to make sure the image was successfully
 184 // mapped before using it.
 185 //
 186 // Example:
 187 //   ImageDataAutoMapper mapper(image_data);
 188 //   if (!mapper.is_valid())
 189 //     return utter_failure;
 190 //   image_data->mapped_canvas()->blah();  // Guaranteed valid.
 191 class ImageDataAutoMapper {
 192  public:
 193   explicit ImageDataAutoMapper(PPB_ImageData_Impl* image_data)
 194       : image_data_(image_data) {
 195     if (image_data_->IsMapped()) {
 196       is_valid_ = true;
 197       needs_unmap_ = false;
 198     } else {
 199       is_valid_ = needs_unmap_ = !!image_data_->Map();
 200     }
 201   }
 202
 203   ~ImageDataAutoMapper() {
 204     if (needs_unmap_)
 205       image_data_->Unmap();
 206   }
 207
 208   // Check this to see if the image was successfully mapped. If this is false,
 209   // the image could not be mapped and is unusable.
 210   bool is_valid() const { return is_valid_; }
 211
 212  private:
 213   PPB_ImageData_Impl* image_data_;
 214   bool is_valid_;
 215   bool needs_unmap_;
 216
 217   DISALLOW_COPY_AND_ASSIGN(ImageDataAutoMapper);
 218 };
 219
 220 }  // namespace content
 221
 222 #endif  // CONTENT_RENDERER_PEPPER_PPB_IMAGE_DATA_IMPL_H_