aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/lazy/SkLazyPixelRef.cpp
blob: 9e023c4a7c8859369886fe07a650c85fe1c69e23 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
/*
 * Copyright 2012 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "Sk64.h"
#include "SkLazyPixelRef.h"
#include "SkColorTable.h"
#include "SkData.h"
#include "SkImageCache.h"
#include "SkImagePriv.h"

#if LAZY_CACHE_STATS
#include "SkThread.h"

int32_t SkLazyPixelRef::gCacheHits;
int32_t SkLazyPixelRef::gCacheMisses;
#endif

SkLazyPixelRef::SkLazyPixelRef(SkData* data, SkBitmapFactory::DecodeProc proc, SkImageCache* cache)
    // Pass NULL for the Mutex so that the default (ring buffer) will be used.
    : INHERITED(NULL)
    , fDecodeProc(proc)
    , fImageCache(cache)
    , fCacheId(SkImageCache::UNINITIALIZED_ID)
    , fRowBytes(0) {
    SkASSERT(fDecodeProc != NULL);
    if (NULL == data) {
        fData = SkData::NewEmpty();
        fErrorInDecoding = true;
    } else {
        fData = data;
        fData->ref();
        fErrorInDecoding = data->size() == 0;
    }
    SkASSERT(cache != NULL);
    cache->ref();
    // Since this pixel ref bases its data on encoded data, it should never change.
    this->setImmutable();
}

SkLazyPixelRef::~SkLazyPixelRef() {
    SkASSERT(fData != NULL);
    fData->unref();
    SkASSERT(fImageCache);
    if (fCacheId != SkImageCache::UNINITIALIZED_ID) {
        fImageCache->throwAwayCache(fCacheId);
    }
    fImageCache->unref();
}

static size_t ComputeMinRowBytesAndSize(const SkImage::Info& info, size_t* rowBytes) {
    *rowBytes = SkImageMinRowBytes(info);

    Sk64 safeSize;
    safeSize.setZero();
    if (info.fHeight > 0) {
        safeSize.setMul(info.fHeight, SkToS32(*rowBytes));
    }
    SkASSERT(!safeSize.isNeg());
    return safeSize.is32() ? safeSize.get32() : 0;
}

void* SkLazyPixelRef::onLockPixels(SkColorTable**) {
    if (fErrorInDecoding) {
        return NULL;
    }
    SkBitmapFactory::Target target;
    // Check to see if the pixels still exist in the cache.
    if (SkImageCache::UNINITIALIZED_ID == fCacheId) {
        target.fAddr = NULL;
    } else {
        SkImageCache::DataStatus status;
        target.fAddr = fImageCache->pinCache(fCacheId, &status);
        if (target.fAddr == NULL) {
            fCacheId = SkImageCache::UNINITIALIZED_ID;
        } else {
            if (SkImageCache::kRetained_DataStatus == status) {
#if LAZY_CACHE_STATS
                sk_atomic_inc(&gCacheHits);
#endif
                return target.fAddr;
            }
            SkASSERT(SkImageCache::kUninitialized_DataStatus == status);
        }
        // Cache miss. Either pinCache returned NULL or it returned a memory address without the old
        // data
#if LAZY_CACHE_STATS
        sk_atomic_inc(&gCacheMisses);
#endif
    }
    SkImage::Info info;
    SkASSERT(fData != NULL && fData->size() > 0);
    if (NULL == target.fAddr) {
        // Determine the size of the image in order to determine how much memory to allocate.
        // FIXME: As an optimization, only do this part once.
        fErrorInDecoding = !fDecodeProc(fData->data(), fData->size(), &info, NULL);
        if (fErrorInDecoding) {
            // We can only reach here if fCacheId was already set to UNINITIALIZED_ID, or if
            // pinCache returned NULL, in which case it was reset to UNINITIALIZED_ID.
            SkASSERT(SkImageCache::UNINITIALIZED_ID == fCacheId);
            return NULL;
        }

        size_t bytes = ComputeMinRowBytesAndSize(info, &target.fRowBytes);
        target.fAddr = fImageCache->allocAndPinCache(bytes, &fCacheId);
        if (NULL == target.fAddr) {
            // Space could not be allocated.
            // Just like the last assert, fCacheId must be UNINITIALIZED_ID.
            SkASSERT(SkImageCache::UNINITIALIZED_ID == fCacheId);
            return NULL;
        }
    } else {
        // pinCache returned purged memory to which target.fAddr already points. Set
        // target.fRowBytes properly.
        target.fRowBytes = fRowBytes;
        // Assume that the size is correct, since it was determined by this same function
        // previously.
    }
    SkASSERT(target.fAddr != NULL);
    SkASSERT(SkImageCache::UNINITIALIZED_ID != fCacheId);
    fErrorInDecoding = !fDecodeProc(fData->data(), fData->size(), &info, &target);
    if (fErrorInDecoding) {
        fImageCache->throwAwayCache(fCacheId);
        fCacheId = SkImageCache::UNINITIALIZED_ID;
        return NULL;
    }
    // Upon success, store fRowBytes so it can be used in case pinCache later returns purged memory.
    fRowBytes = target.fRowBytes;
    return target.fAddr;
}

void SkLazyPixelRef::onUnlockPixels() {
    if (fErrorInDecoding) {
        return;
    }
    if (fCacheId != SkImageCache::UNINITIALIZED_ID) {
        fImageCache->releaseCache(fCacheId);
    }
}

SkData* SkLazyPixelRef::onRefEncodedData() {
    fData->ref();
    return fData;
}

#include "SkImagePriv.h"

static bool init_from_info(SkBitmap* bm, const SkImage::Info& info,
                           size_t rowBytes) {
    bool isOpaque;
    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
    if (SkBitmap::kNo_Config == config) {
        return false;
    }

    bm->setConfig(config, info.fWidth, info.fHeight, rowBytes);
    bm->setIsOpaque(isOpaque);
    return bm->allocPixels();
}

bool SkLazyPixelRef::onImplementsDecodeInto() {
    return true;
}

bool SkLazyPixelRef::onDecodeInto(int pow2, SkBitmap* bitmap) {
    SkASSERT(fData != NULL && fData->size() > 0);
    if (fErrorInDecoding) {
        return false;
    }

    SkImage::Info info;
    // Determine the size of the image in order to determine how much memory to allocate.
    // FIXME: As an optimization, only do this part once.
    fErrorInDecoding = !fDecodeProc(fData->data(), fData->size(), &info, NULL);
    if (fErrorInDecoding) {
        return false;
    }

    SkBitmapFactory::Target target;
    (void)ComputeMinRowBytesAndSize(info, &target.fRowBytes);

    SkBitmap tmp;
    if (!init_from_info(&tmp, info, target.fRowBytes)) {
        return false;
    }

    target.fAddr = tmp.getPixels();
    fErrorInDecoding = !fDecodeProc(fData->data(), fData->size(), &info, &target);
    if (fErrorInDecoding) {
        return false;
    }

    *bitmap = tmp;
    return true;
}