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(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        this->validate();
39        // Once the ref cnt reaches zero it should never be ref'ed again.
40        SkASSERT(fRefCnt > 0);
41        ++fRefCnt;
42        this->validate();
43    }
44
45    void unref() const {
46        this->validate();
47        --fRefCnt;
48        if (0 == fRefCnt) {
49            if (0 == fPendingExecutions) {
50                SkDELETE(this);
51                return;
52            } else {
53                this->removeRefs();
54            }
55        }
56        this->validate();
57    }
58
59    /**
60     * Gets an id that is unique for this GrProgramElement object. This will never return 0.
61     */
62    uint32_t getUniqueID() const { return fUniqueID; }
63
64    void validate() const {
65#ifdef SK_DEBUG
66        SkASSERT(fRefCnt >= 0);
67        SkASSERT(fPendingExecutions >= 0);
68        SkASSERT(fRefCnt + fPendingExecutions > 0);
69#endif
70    }
71
72protected:
73    GrProgramElement() : fRefCnt(1), fPendingExecutions(0), fUniqueID(CreateUniqueID()) {}
74
75    /** Subclasses registers their resources using this function. It is assumed the GrProgramResouce
76        is and will remain owned by the subclass and this function will retain a raw ptr. Once a
77        GrGpuResourceRef is registered its setResource must not be called.
78     */
79    void addGpuResource(const GrGpuResourceRef* res) {
80        fGpuResources.push_back(res);
81    }
82
83private:
84    static uint32_t CreateUniqueID();
85
86    void addPendingExecution() const {
87        this->validate();
88        SkASSERT(fRefCnt > 0);
89        if (0 == fPendingExecutions) {
90            this->addPendingIOs();
91        }
92        ++fPendingExecutions;
93        this->validate();
94    }
95
96    void completedExecution() const {
97        this->validate();
98        --fPendingExecutions;
99        if (0 == fPendingExecutions) {
100            if (0 == fRefCnt) {
101                SkDELETE(this);
102                return;
103            } else {
104                this->pendingIOComplete();
105            }
106        }
107        this->validate();
108    }
109
110    void removeRefs() const;
111    void addPendingIOs() const;
112    void pendingIOComplete() const;
113
114    mutable int32_t fRefCnt;
115    // Count of deferred executions not yet issued to the 3D API.
116    mutable int32_t fPendingExecutions;
117    uint32_t        fUniqueID;
118
119    SkSTArray<4, const GrGpuResourceRef*, true> fGpuResources;
120
121    // Only this class can access addPendingExecution() and completedExecution().
122    template <typename T> friend class GrPendingProgramElement;
123
124    typedef SkNoncopyable INHERITED;
125};
126
127#endif
128