GrGpuResourceRef.h

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrGpuResourceRef_DEFINED
#define GrGpuResourceRef_DEFINED

#include "GrGpuResource.h"
#include "GrRenderTarget.h"
#include "GrTexture.h"
#include "SkRefCnt.h"

class GrGpuResourceRef : SkNoncopyable {
public:
    ~GrGpuResourceRef();

    GrGpuResource* getResource() const { return fResource; }

    bool ownsPendingIO() const { return fPendingIO; }

    void reset();

protected:
    GrGpuResourceRef();

    GrGpuResourceRef(GrGpuResource*, GrIOType);

    void setResource(GrGpuResource*, GrIOType);

private:
    void markPendingIO() const;

    void removeRef() const;

    void pendingIOComplete() const;

    friend class GrProgramElement;

    GrGpuResource*  fResource;
    mutable bool    fOwnRef;
    mutable bool    fPendingIO;
    GrIOType        fIOType;

    typedef SkNoncopyable INHERITED;
};

template <typename T> class GrTGpuResourceRef : public GrGpuResourceRef {
public:
    GrTGpuResourceRef() {}

    GrTGpuResourceRef(T* resource, GrIOType ioType) : INHERITED(resource, ioType) { }

    T* get() const { return static_cast<T*>(this->getResource()); }

    void set(T* resource, GrIOType ioType) { this->setResource(resource, ioType); }

private:
    typedef GrGpuResourceRef INHERITED;
};

// Specializations for GrTexture and GrRenderTarget because they use virtual inheritance.
template<> class GrTGpuResourceRef<GrTexture> : public GrGpuResourceRef {
public:
    GrTGpuResourceRef() {}

    GrTGpuResourceRef(GrTexture* texture, GrIOType ioType) : INHERITED(texture, ioType) { }

    GrTexture* get() const {
        GrSurface* surface = static_cast<GrSurface*>(this->getResource());
        if (surface) {
            return surface->asTexture();
        } else {
            return NULL;
        }
    }

    void set(GrTexture* texture, GrIOType ioType) { this->setResource(texture, ioType); }

private:
    typedef GrGpuResourceRef INHERITED;
};

template<> class GrTGpuResourceRef<GrRenderTarget> : public GrGpuResourceRef {
public:
    GrTGpuResourceRef() {}

    GrTGpuResourceRef(GrRenderTarget* rt, GrIOType ioType) : INHERITED(rt, ioType) { }

    GrRenderTarget* get() const {
        GrSurface* surface = static_cast<GrSurface*>(this->getResource());
        if (surface) {
            return surface->asRenderTarget();
        } else {
            return NULL;
        }
    }

    void set(GrRenderTarget* rt, GrIOType ioType) { this->setResource(rt, ioType); }

private:
    typedef GrGpuResourceRef INHERITED;
};

template <typename T, GrIOType IO_TYPE> class GrPendingIOResource : SkNoncopyable {
public:
    GrPendingIOResource(T* resource = NULL) : fResource(NULL) {
        this->reset(resource);
    }

    void reset(T* resource) {
        if (resource) {
            switch (IO_TYPE) {
                case kRead_GrIOType:
                    resource->addPendingRead();
                    break;
                case kWrite_GrIOType:
                    resource->addPendingWrite();
                    break;
                case kRW_GrIOType:
                    resource->addPendingRead();
                    resource->addPendingWrite();
                    break;
            }
        }
        this->release();
        fResource = resource;
    }

    ~GrPendingIOResource() {
        this->release();
    }

    explicit operator bool() const { return SkToBool(fResource); }

    bool operator==(const GrPendingIOResource& other) const {
        return fResource == other.fResource;
    }

    T* get() const { return fResource; }

private:
    void release() {
        if (fResource) {
            switch (IO_TYPE) {
                case kRead_GrIOType:
                    fResource->completedRead();
                    break;
                case kWrite_GrIOType:
                    fResource->completedWrite();
                    break;
                case kRW_GrIOType:
                    fResource->completedRead();
                    fResource->completedWrite();
                    break;
            }
        }
    }

    T* fResource;
};
#endif