1/*
2 * Copyright 2011 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#include "include/core/SkPixelRef.h"
9#include "include/private/SkMutex.h"
10#include "src/core/SkBitmapCache.h"
11#include "src/core/SkNextID.h"
12#include "src/core/SkPixelRefPriv.h"
13#include "src/core/SkTraceEvent.h"
14
15#include <atomic>
16
17uint32_t SkNextID::ImageID() {
18 // We never set the low bit.... see SkPixelRef::genIDIsUnique().
19 static std::atomic<uint32_t> nextID{2};
20
21 uint32_t id;
22 do {
23 id = nextID.fetch_add(2);
24 } while (id == 0);
25 return id;
26}
27
28///////////////////////////////////////////////////////////////////////////////
29
30SkPixelRef::SkPixelRef(int width, int height, void* pixels, size_t rowBytes)
31 : fWidth(width)
32 , fHeight(height)
33 , fPixels(pixels)
34 , fRowBytes(rowBytes)
35 , fAddedToCache(false)
36{
37 this->needsNewGenID();
38 fMutability = kMutable;
39}
40
41SkPixelRef::~SkPixelRef() {
42 this->callGenIDChangeListeners();
43}
44
45// This is undefined if there are clients in-flight trying to use us
46void SkPixelRef::android_only_reset(int width, int height, size_t rowBytes) {
47 fWidth = width;
48 fHeight = height;
49 fRowBytes = rowBytes;
50 // note: we do not change fPixels
51
52 // conservative, since its possible the "new" settings are the same as the old.
53 this->notifyPixelsChanged();
54}
55
56void SkPixelRef::needsNewGenID() {
57 fTaggedGenID.store(0);
58 SkASSERT(!this->genIDIsUnique()); // This method isn't threadsafe, so the assert should be fine.
59}
60
61uint32_t SkPixelRef::getGenerationID() const {
62 uint32_t id = fTaggedGenID.load();
63 if (0 == id) {
64 uint32_t next = SkNextID::ImageID() | 1u;
65 if (fTaggedGenID.compare_exchange_strong(id, next)) {
66 id = next; // There was no race or we won the race. fTaggedGenID is next now.
67 } else {
68 // We lost a race to set fTaggedGenID. compare_exchange() filled id with the winner.
69 }
70 // We can't quite SkASSERT(this->genIDIsUnique()). It could be non-unique
71 // if we got here via the else path (pretty unlikely, but possible).
72 }
73 return id & ~1u; // Mask off bottom unique bit.
74}
75
76void SkPixelRef::addGenIDChangeListener(sk_sp<SkIDChangeListener> listener) {
77 if (!listener || !this->genIDIsUnique()) {
78 // No point in tracking this if we're not going to call it.
79 return;
80 }
81 SkASSERT(!listener->shouldDeregister());
82 bool singleThreaded = this->unique();
83 fGenIDChangeListeners.add(std::move(listener), singleThreaded);
84}
85
86// we need to be called *before* the genID gets changed or zerod
87void SkPixelRef::callGenIDChangeListeners() {
88 bool singleThreaded = this->unique();
89 // We don't invalidate ourselves if we think another SkPixelRef is sharing our genID.
90 if (this->genIDIsUnique()) {
91 fGenIDChangeListeners.changed(singleThreaded);
92 if (fAddedToCache.exchange(false)) {
93 SkNotifyBitmapGenIDIsStale(this->getGenerationID());
94 }
95 } else {
96 // Listeners get at most one shot, so even though these weren't triggered or not, blow them
97 // away.
98 fGenIDChangeListeners.reset(singleThreaded);
99 }
100}
101
102void SkPixelRef::notifyPixelsChanged() {
103#ifdef SK_DEBUG
104 if (this->isImmutable()) {
105 SkDebugf("========== notifyPixelsChanged called on immutable pixelref");
106 }
107#endif
108 this->callGenIDChangeListeners();
109 this->needsNewGenID();
110}
111
112void SkPixelRef::setImmutable() {
113 fMutability = kImmutable;
114}
115
116void SkPixelRef::setImmutableWithID(uint32_t genID) {
117 /*
118 * We are forcing the genID to match an external value. The caller must ensure that this
119 * value does not conflict with other content.
120 *
121 * One use is to force this pixelref's id to match an SkImage's id
122 */
123 fMutability = kImmutable;
124 fTaggedGenID.store(genID);
125}
126
127void SkPixelRef::setTemporarilyImmutable() {
128 SkASSERT(fMutability != kImmutable);
129 fMutability = kTemporarilyImmutable;
130}
131
132void SkPixelRef::restoreMutability() {
133 SkASSERT(fMutability != kImmutable);
134 fMutability = kMutable;
135}
136
137sk_sp<SkPixelRef> SkMakePixelRefWithProc(int width, int height, size_t rowBytes, void* addr,
138 void (*releaseProc)(void* addr, void* ctx), void* ctx) {
139 SkASSERT(width >= 0 && height >= 0);
140 if (nullptr == releaseProc) {
141 return sk_make_sp<SkPixelRef>(width, height, addr, rowBytes);
142 }
143 struct PixelRef final : public SkPixelRef {
144 void (*fReleaseProc)(void*, void*);
145 void* fReleaseProcContext;
146 PixelRef(int w, int h, void* s, size_t r, void (*proc)(void*, void*), void* ctx)
147 : SkPixelRef(w, h, s, r), fReleaseProc(proc), fReleaseProcContext(ctx) {}
148 ~PixelRef() override { fReleaseProc(this->pixels(), fReleaseProcContext); }
149 };
150 return sk_sp<SkPixelRef>(new PixelRef(width, height, addr, rowBytes, releaseProc, ctx));
151}
152