text: /*
   * Copyright 2015 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #ifndef GrResourceProvider_DEFINED
  #define GrResourceProvider_DEFINED
  
  #include "GrBuffer.h"
  #include "GrContextOptions.h"
  #include "GrResourceCache.h"
  #include "SkImageInfoPriv.h"
  #include "SkScalerContext.h"
  
  class GrBackendRenderTarget;
  class GrBackendSemaphore;
  class GrBackendTexture;
  class GrGpu;
  class GrPath;
  class GrRenderTarget;
  class GrResourceProviderPriv;
  class GrSemaphore;
  class GrSingleOwner;
  class GrStencilAttachment;
  class GrTexture;
  
  class GrStyle;
  class SkDescriptor;
  class SkPath;
  class SkTypeface;
  
  /**
   * A factory for arbitrary resource types. This class is intended for use within the Gr code base.
   *
   * Some members force callers to make a flags (pendingIO) decision. This can be relaxed once
   * https://bug.skia.org/4156 is fixed.
   */
  class GrResourceProvider {
  public:
      GrResourceProvider(GrGpu*, GrResourceCache*, GrSingleOwner*,
                         GrContextOptions::Enable explicitlyAllocateGPUResources);
  
      /**
       * Finds a resource in the cache, based on the specified key. Prior to calling this, the caller
       * must be sure that if a resource of exists in the cache with the given unique key then it is
       * of type T.
       */
      template <typename T>
      sk_sp<T> findByUniqueKey(const GrUniqueKey& key) {
          return sk_sp<T>(static_cast<T*>(this->findResourceByUniqueKey(key).release()));
      }
  
      ///////////////////////////////////////////////////////////////////////////
      // Textures
  
      /**
       * Finds a texture that approximately matches the descriptor. Will be at least as large in width
       * and height as desc specifies. If desc specifies that the texture should be a render target
       * then result will be a render target. Format and sample count will always match the request.
       * The contents of the texture are undefined.
       */
      sk_sp<GrTexture> createApproxTexture(const GrSurfaceDesc&, uint32_t flags);
  
      /** Create an exact fit texture with no initial data to upload.
       */
      sk_sp<GrTexture> createTexture(const GrSurfaceDesc&, SkBudgeted, uint32_t flags = 0);
  
      sk_sp<GrTexture> createTexture(const GrSurfaceDesc&, SkBudgeted, const GrMipLevel texels[],
                                     int mipLevelCount);
  
      // Create a potentially loose fit texture with the provided data
      sk_sp<GrTexture> createTexture(const GrSurfaceDesc&, SkBudgeted, SkBackingFit,
                                     const GrMipLevel&);
  
      ///////////////////////////////////////////////////////////////////////////
      // Wrapped Backend Surfaces
  
      /**
       * Wraps an existing texture with a GrTexture object.
       *
       * OpenGL: if the object is a texture Gr may change its GL texture params
       *         when it is drawn.
       *
       * @return GrTexture object or NULL on failure.
       */
      sk_sp<GrTexture> wrapBackendTexture(const GrBackendTexture& tex,
                                          GrWrapOwnership = kBorrow_GrWrapOwnership);
  
      /**
       * This makes the backend texture be renderable. If sampleCnt is > 1 and the underlying API
       * uses separate MSAA render buffers then a MSAA render buffer is created that resolves
       * to the texture.
       */
      sk_sp<GrTexture> wrapRenderableBackendTexture(const GrBackendTexture& tex,
                                                    int sampleCnt,
                                                    GrWrapOwnership = kBorrow_GrWrapOwnership);
  
      /**
       * Wraps an existing render target with a GrRenderTarget object. It is
       * similar to wrapBackendTexture but can be used to draw into surfaces
       * that are not also textures (e.g. FBO 0 in OpenGL, or an MSAA buffer that
       * the client will resolve to a texture). Currently wrapped render targets
       * always use the kBorrow_GrWrapOwnership semantics.
       *
       * @return GrRenderTarget object or NULL on failure.
       */
      sk_sp<GrRenderTarget> wrapBackendRenderTarget(const GrBackendRenderTarget&);
  
      static const uint32_t kMinScratchTextureSize;
  
      /**
       * Either finds and refs, or creates a static buffer with the given parameters and contents.
       *
       * @param intendedType    hint to the graphics subsystem about what the buffer will be used for.
       * @param size            minimum size of buffer to return.
       * @param data            optional data with which to initialize the buffer.
       * @param key             Key to be assigned to the buffer.
       *
       * @return The buffer if successful, otherwise nullptr.
       */
      sk_sp<const GrBuffer> findOrMakeStaticBuffer(GrBufferType intendedType, size_t size,
                                                   const void* data, const GrUniqueKey& key);
  
      /**
       * Either finds and refs, or creates an index buffer with a repeating pattern for drawing
       * contiguous vertices of a repeated mesh. If the return is non-null, the caller owns a ref on
       * the returned GrBuffer.
       *
       * @param pattern     the pattern of indices to repeat
       * @param patternSize size in bytes of the pattern
       * @param reps        number of times to repeat the pattern
       * @param vertCount   number of vertices the pattern references
       * @param key         Key to be assigned to the index buffer.
       *
       * @return The index buffer if successful, otherwise nullptr.
       */
      sk_sp<const GrBuffer> findOrCreatePatternedIndexBuffer(const uint16_t* pattern,
                                                             int patternSize,
                                                             int reps,
                                                             int vertCount,
                                                             const GrUniqueKey& key) {
          if (auto buffer = this->findByUniqueKey<GrBuffer>(key)) {
              return std::move(buffer);
          }
          return this->createPatternedIndexBuffer(pattern, patternSize, reps, vertCount, key);
      }
  
      /**
       * Returns an index buffer that can be used to render quads.
       * Six indices per quad: 0, 1, 2, 2, 1, 3, etc.
       * The max number of quads is the buffer's index capacity divided by 6.
       * Draw with GrPrimitiveType::kTriangles
       * @ return the quad index buffer
       */
      sk_sp<const GrBuffer> refQuadIndexBuffer() {
          if (auto buffer = this->findByUniqueKey<const GrBuffer>(fQuadIndexBufferKey)) {
              return buffer;
          }
          return this->createQuadIndexBuffer();
      }
  
      static int QuadCountOfQuadBuffer();
  
      /**
       * Factories for GrPath objects. It's an error to call these if path rendering
       * is not supported.
       */
      sk_sp<GrPath> createPath(const SkPath&, const GrStyle&);
  
      /** These flags govern which scratch resources we are allowed to return */
      enum Flags {
          kNone_Flag            = 0x0,
  
          /** If the caller intends to do direct reads/writes to/from the CPU then this flag must be
           *  set when accessing resources during a GrOpList flush. This includes the execution of
           *  GrOp objects. The reason is that these memory operations are done immediately and
           *  will occur out of order WRT the operations being flushed.
           *  Make this automatic: https://bug.skia.org/4156
           */
          kNoPendingIO_Flag     = 0x1,
  
          /** Normally the caps may indicate a preference for client-side buffers. Set this flag when
           *  creating a buffer to guarantee it resides in GPU memory.
           */
          kRequireGpuMemory_Flag = 0x2,
      };
  
      /**
       * Returns a buffer.
       *
       * @param size            minimum size of buffer to return.
       * @param intendedType    hint to the graphics subsystem about what the buffer will be used for.
       * @param GrAccessPattern hint to the graphics subsystem about how the data will be accessed.
       * @param flags           see Flags enum.
       * @param data            optional data with which to initialize the buffer.
       *
       * @return the buffer if successful, otherwise nullptr.
       */
      GrBuffer* createBuffer(size_t size, GrBufferType intendedType, GrAccessPattern, uint32_t flags,
                             const void* data = nullptr);
  
  
      /**
       * If passed in render target already has a stencil buffer, return true. Otherwise attempt to
       * attach one and return true on success.
       */
      bool attachStencilAttachment(GrRenderTarget* rt);
  
       /**
        * Wraps an existing texture with a GrRenderTarget object. This is useful when the provided
        * texture has a format that cannot be textured from by Skia, but we want to raster to it.
        *
        * The texture is wrapped as borrowed. The texture object will not be freed once the
        * render target is destroyed.
        *
        * @return GrRenderTarget object or NULL on failure.
        */
       sk_sp<GrRenderTarget> wrapBackendTextureAsRenderTarget(const GrBackendTexture&,
                                                              int sampleCnt);
  
      /**
       * Assigns a unique key to a resource. If the key is associated with another resource that
       * association is removed and replaced by this resource.
       */
      void assignUniqueKeyToResource(const GrUniqueKey&, GrGpuResource*);
  
      sk_sp<GrSemaphore> SK_WARN_UNUSED_RESULT makeSemaphore(bool isOwned = true);
  
      enum class SemaphoreWrapType {
          kWillSignal,
          kWillWait,
      };
  
      sk_sp<GrSemaphore> wrapBackendSemaphore(const GrBackendSemaphore&,
                                              SemaphoreWrapType wrapType,
                                              GrWrapOwnership = kBorrow_GrWrapOwnership);
  
      void abandon() {
          fCache = nullptr;
          fGpu = nullptr;
      }
  
      uint32_t contextUniqueID() const { return fCache->contextUniqueID(); }
      const GrCaps* caps() const { return fCaps.get(); }
      bool overBudget() const { return fCache->overBudget(); }
  
      inline GrResourceProviderPriv priv();
      inline const GrResourceProviderPriv priv() const;
  
      bool explicitlyAllocateGPUResources() const { return fExplicitlyAllocateGPUResources; }
  
      bool testingOnly_setExplicitlyAllocateGPUResources(bool newValue);
  
  private:
      sk_sp<GrGpuResource> findResourceByUniqueKey(const GrUniqueKey&);
  
      // Attempts to find a resource in the cache that exactly matches the GrSurfaceDesc. Failing that
      // it returns null. If non-null, the resulting texture is always budgeted.
      sk_sp<GrTexture> refScratchTexture(const GrSurfaceDesc&, uint32_t scratchTextureFlags);
  
      /*
       * Try to find an existing scratch texture that exactly matches 'desc'. If successful
       * update the budgeting accordingly.
       */
      sk_sp<GrTexture> getExactScratch(const GrSurfaceDesc&, SkBudgeted, uint32_t flags);
  
      GrResourceCache* cache() { return fCache; }
      const GrResourceCache* cache() const { return fCache; }
  
      friend class GrResourceProviderPriv;
  
      // Method made available via GrResourceProviderPriv
      GrGpu* gpu() { return fGpu; }
      const GrGpu* gpu() const { return fGpu; }
  
      bool isAbandoned() const {
          SkASSERT(SkToBool(fGpu) == SkToBool(fCache));
          return !SkToBool(fCache);
      }
  
      sk_sp<const GrBuffer> createPatternedIndexBuffer(const uint16_t* pattern,
                                                       int patternSize,
                                                       int reps,
                                                       int vertCount,
                                                       const GrUniqueKey& key);
  
      sk_sp<const GrBuffer> createQuadIndexBuffer();
  
      GrResourceCache*    fCache;
      GrGpu*              fGpu;
      sk_sp<const GrCaps> fCaps;
      GrUniqueKey         fQuadIndexBufferKey;
      bool                fExplicitlyAllocateGPUResources;
  
      // In debug builds we guard against improper thread handling
      SkDEBUGCODE(mutable GrSingleOwner* fSingleOwner;)
  };
  
  #endif
  