GrProgramElement.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 GrProgramElement_DEFINED
#define GrProgramElement_DEFINED

#include "../private/SkTArray.h"
#include "SkRefCnt.h"

class GrGpuResourceRef;

class GrProgramElement : public SkNoncopyable {
public:
    virtual ~GrProgramElement() {
        // fRefCnt can be one when an effect is created statically using GR_CREATE_STATIC_EFFECT
        SkASSERT((0 == fRefCnt || 1 == fRefCnt) && 0 == fPendingExecutions);
        // Set to invalid values.
        SkDEBUGCODE(fRefCnt = fPendingExecutions = -10;)
    }

    void ref() const {
        this->validate();
        // Once the ref cnt reaches zero it should never be ref'ed again.
        SkASSERT(fRefCnt > 0);
        ++fRefCnt;
        this->validate();
    }

    void unref() const {
        this->validate();
        --fRefCnt;
        if (0 == fRefCnt) {
            this->notifyRefCntIsZero();
            if (0 == fPendingExecutions) {
                delete this;
                return;
            } else {
                this->removeRefs();
            }
        }
        this->validate();
    }

    uint32_t getUniqueID() const { return fUniqueID; }

    void validate() const {
#ifdef SK_DEBUG
        SkASSERT(fRefCnt >= 0);
        SkASSERT(fPendingExecutions >= 0);
        SkASSERT(fRefCnt + fPendingExecutions > 0);
#endif
    }

protected:
    GrProgramElement() : fRefCnt(1), fPendingExecutions(0), fUniqueID(CreateUniqueID()) {}

    void addGpuResource(const GrGpuResourceRef* res) {
        fGpuResources.push_back(res);
    }

    void addPendingExecution() const {
        this->validate();
        SkASSERT(fRefCnt > 0);
        if (0 == fPendingExecutions) {
            this->addPendingIOs();
        }
        ++fPendingExecutions;
        this->validate();
    }

    void completedExecution() const {
        this->validate();
        --fPendingExecutions;
        if (0 == fPendingExecutions) {
            if (0 == fRefCnt) {
                delete this;
                return;
            } else {
                this->pendingIOComplete();
            }
        }
        this->validate();
    }

private:
    virtual void notifyRefCntIsZero() const = 0;

    static uint32_t CreateUniqueID();

    void removeRefs() const;
    void addPendingIOs() const;
    void pendingIOComplete() const;

    mutable int32_t fRefCnt;
    // Count of deferred executions not yet issued to the 3D API.
    mutable int32_t fPendingExecutions;
    uint32_t        fUniqueID;

    SkSTArray<4, const GrGpuResourceRef*, true> fGpuResources;

    // Only this class can access addPendingExecution() and completedExecution().
    template <typename T> friend class GrPendingProgramElement;

    typedef SkNoncopyable INHERITED;
};

#endif