Pull cache out of GrContext

include/gpu/GrTextureProvider.h

+/*
+ * 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 GrTextureProvider_DEFINED
+#define GrTextureProvider_DEFINED
+
+#include "GrTexture.h"
+
+class SK_API GrTextureProvider {
+public:
+    ///////////////////////////////////////////////////////////////////////////
+    // Textures
+
+    /**
+     * Creates a new texture in the resource cache and returns it. The caller owns a
+     * ref on the returned texture which must be balanced by a call to unref.
+     *
+     * @param desc      Description of the texture properties.
+     * @param budgeted  Does the texture count against the resource cache budget?
+     * @param srcData   Pointer to the pixel values (optional).
+     * @param rowBytes  The number of bytes between rows of the texture. Zero
+     *                  implies tightly packed rows. For compressed pixel configs, this
+     *                  field is ignored.
+     */
+    GrTexture* createTexture(const GrSurfaceDesc& desc, bool budgeted, const void* srcData,
+                             size_t rowBytes);
+
+    /** Shortcut for creating a texture with no initial data to upload. */
+    GrTexture* createTexture(const GrSurfaceDesc& desc, bool budgeted) {
+        return this->createTexture(desc, budgeted, NULL, 0);
+    }
+
+    /** Assigns a unique key to the texture. The texture will be findable via this key using
+        findTextureByUniqueKey(). If an existing texture has this key, it's key will be removed. */
+    void assignUniqueKeyToTexture(const GrUniqueKey& key, GrTexture* texture) {
+        this->assignUniqueKeyToResource(key, texture);
+    }
+
+    /** Finds a texture by unique key. If the texture is found it is ref'ed and returned. */
+    GrTexture* findAndRefTextureByUniqueKey(const GrUniqueKey& key) {
+        GrGpuResource* resource = this->findAndRefResourceByUniqueKey(key);
+        if (resource) {
+            GrTexture* texture = static_cast<GrSurface*>(resource)->asTexture();
+            SkASSERT(texture);
+            return texture;
+        }
+        return NULL;
+    }
+
+    /**
+     * Determines whether a texture is associated with the unique key. If the texture is found it
+     * will not be locked or returned. This call does not affect the priority of the resource for
+     * deletion.
+     */
+    bool existsTextureWithUniqueKey(const GrUniqueKey& key) const {
+        return this->existsResourceWithUniqueKey(key);
+    }
+
+    /**
+     * Enum that determines how closely a returned scratch texture must match
+     * a provided GrSurfaceDesc. TODO: Remove this. createTexture() should be used
+     * for exact match and refScratchTexture() should be replaced with createApproxTexture().
+     */
+    enum ScratchTexMatch {
+        /**
+         * Finds a texture that exactly matches the descriptor.
+         */
+        kExact_ScratchTexMatch,
+        /**
+         * 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 texture is a render target then result will be a
+         * render target. If desc specifies a render target and doesn't set the
+         * no stencil flag then result will have a stencil. Format and aa level
+         * will always match.
+         */
+        kApprox_ScratchTexMatch
+    };
+
+    /**
+     * Returns a texture matching the desc. It's contents are unknown. The caller
+     * owns a ref on the returned texture and must balance with a call to unref.
+     * It is guaranteed that the same texture will not be returned in subsequent
+     * calls until all refs to the texture are dropped.
+     *
+     * internalFlag is a temporary workaround until changes in the internal
+     * architecture are complete. Use the default value.
+     *
+     * TODO: Once internal flag can be removed, this should be replaced with
+     * createApproxTexture() and exact textures should be created with
+     * createTexture().
+     */
+    GrTexture* refScratchTexture(const GrSurfaceDesc&, ScratchTexMatch match,
+                                 bool internalFlag = false);
+
+    ///////////////////////////////////////////////////////////////////////////
+    // 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.
+     *
+     * @param  desc     description of the object to create.
+     *
+     * @return GrTexture object or NULL on failure.
+     */
+    GrTexture* wrapBackendTexture(const GrBackendTextureDesc& desc);
+
+    /**
+     * 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).
+     *
+     * @param  desc     description of the object to create.
+     *
+     * @return GrTexture object or NULL on failure.
+     */
+     GrRenderTarget* wrapBackendRenderTarget(const GrBackendRenderTargetDesc& desc);
+
+protected:
+    GrTextureProvider(GrGpu* gpu, GrResourceCache* cache) : fCache(cache), fGpu(gpu) {}
+
+    /**
+     * 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*);
+
+    /**
+     * Finds a resource in the cache, based on the specified key. This is intended for use in
+     * conjunction with addResourceToCache(). The return value will be NULL if not found. The
+     * caller must balance with a call to unref().
+     */
+    GrGpuResource* findAndRefResourceByUniqueKey(const GrUniqueKey&);
+
+    /**
+     * Determines whether a resource is in the cache. If the resource is found it
+     * will not be locked or returned. This call does not affect the priority of
+     * the resource for deletion.
+     */
+    bool existsResourceWithUniqueKey(const GrUniqueKey& key) const;
+
+    GrTexture* internalRefScratchTexture(const GrSurfaceDesc&, uint32_t flags);
+
+    void abandon() {
+        fCache = NULL;
+        fGpu = NULL;
+    }
+
+private:
+    bool isAbandoned() const {
+        SkASSERT(SkToBool(fGpu) == SkToBool(fCache));
+        return !SkToBool(fCache);
+    }
+
+    GrResourceCache* fCache;
+    GrGpu* fGpu;
+};
+
+#endif