1/*
2 * Copyright 2014 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef GrProgramElement_DEFINED
9#define GrProgramElement_DEFINED
10
11#include "SkRefCnt.h"
12#include "SkTArray.h"
13
14class GrGpuResourceRef;
15
16/**
17 * Base class for GrProcessor. GrDrawState uses this to manage
18 * transitioning a GrProcessor from being owned by a client to being scheduled for execution. It
19 * converts resources owned by the effect from being ref'ed to having pending reads/writes.
20 *
21 * All GrGpuResource objects owned by a GrProgramElement or derived classes (either directly or
22 * indirectly) must be wrapped in a GrGpuResourceRef and registered with the GrProgramElement using
23 * addGpuResource(). This allows the regular refs to be converted to pending IO events
24 * when the program element is scheduled for deferred execution.
25 */
26class GrProgramElement : public SkNoncopyable {
27public:
28    SK_DECLARE_INST_COUNT_ROOT(GrProgramElement)
29
30    virtual ~GrProgramElement() {
31        // fRefCnt can be one when an effect is created statically using GR_CREATE_STATIC_EFFECT
32        SkASSERT((0 == fRefCnt || 1 == fRefCnt) && 0 == fPendingExecutions);
33        // Set to invalid values.
34        SkDEBUGCODE(fRefCnt = fPendingExecutions = -10;)
35    }
36
37    void ref() const {
38        // Once the ref cnt reaches zero it should never be ref'ed again.
39        SkASSERT(fRefCnt > 0);
40        this->validate();
41        ++fRefCnt;
42    }
43
44    void unref() const {
45        this->validate();
46        --fRefCnt;
47        if (0 == fRefCnt && 0 == fPendingExecutions) {
48            SkDELETE(this);
49        }
50    }
51
52    /**
53     * Gets an id that is unique for this GrProgramElement object. This will never return 0.
54     */
55    uint32_t getUniqueID() const { return fUniqueID; }
56
57    void validate() const {
58#ifdef SK_DEBUG
59        SkASSERT(fRefCnt >= 0);
60        SkASSERT(fPendingExecutions >= 0);
61        SkASSERT(fRefCnt + fPendingExecutions > 0);
62#endif
63    }
64
65protected:
66    GrProgramElement() : fRefCnt(1), fPendingExecutions(0), fUniqueID(CreateUniqueID()) {}
67
68    /** Subclasses registers their resources using this function. It is assumed the GrProgramResouce
69        is and will remain owned by the subclass and this function will retain a raw ptr. Once a
70        GrGpuResourceRef is registered its setResource must not be called.
71     */
72    void addGpuResource(const GrGpuResourceRef* res) {
73        fGpuResources.push_back(res);
74    }
75
76private:
77    static uint32_t CreateUniqueID();
78
79    void convertRefToPendingExecution() const;
80
81    void completedExecution() const;
82
83    mutable int32_t fRefCnt;
84    // Count of deferred executions not yet issued to the 3D API.
85    mutable int32_t fPendingExecutions;
86    uint32_t        fUniqueID;
87
88    SkSTArray<4, const GrGpuResourceRef*, true> fGpuResources;
89
90    // Only this class can access convertRefToPendingExecution() and completedExecution().
91    template <typename T> friend class GrProgramElementRef;
92
93    typedef SkNoncopyable INHERITED;
94};
95
96#endif
97