SkWriteBuffer.cpp revision 210a6aa8bd0c8031b2990caaa956b0ed5ce275ed 
1
2/*
3 * Copyright 2012 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9#include "SkWriteBuffer.h"
10#include "SkBitmap.h"
11#include "SkData.h"
12#include "SkPixelRef.h"
13#include "SkPtrRecorder.h"
14#include "SkStream.h"
15#include "SkTypeface.h"
16
17SkWriteBuffer::SkWriteBuffer(uint32_t flags)
18    : fFlags(flags)
19    , fFactorySet(NULL)
20    , fNamedFactorySet(NULL)
21    , fBitmapHeap(NULL)
22    , fTFSet(NULL)
23    , fBitmapEncoder(NULL) {
24}
25
26SkWriteBuffer::SkWriteBuffer(void* storage, size_t storageSize, uint32_t flags)
27    : fFlags(flags)
28    , fFactorySet(NULL)
29    , fNamedFactorySet(NULL)
30    , fWriter(storage, storageSize)
31    , fBitmapHeap(NULL)
32    , fTFSet(NULL)
33    , fBitmapEncoder(NULL) {
34}
35
36SkWriteBuffer::~SkWriteBuffer() {
37    SkSafeUnref(fFactorySet);
38    SkSafeUnref(fNamedFactorySet);
39    SkSafeUnref(fBitmapHeap);
40    SkSafeUnref(fTFSet);
41}
42
43void SkWriteBuffer::writeByteArray(const void* data, size_t size) {
44    fWriter.write32(SkToU32(size));
45    fWriter.writePad(data, size);
46}
47
48void SkWriteBuffer::writeBool(bool value) {
49    fWriter.writeBool(value);
50}
51
52void SkWriteBuffer::writeFixed(SkFixed value) {
53    fWriter.write32(value);
54}
55
56void SkWriteBuffer::writeScalar(SkScalar value) {
57    fWriter.writeScalar(value);
58}
59
60void SkWriteBuffer::writeScalarArray(const SkScalar* value, uint32_t count) {
61    fWriter.write32(count);
62    fWriter.write(value, count * sizeof(SkScalar));
63}
64
65void SkWriteBuffer::writeInt(int32_t value) {
66    fWriter.write32(value);
67}
68
69void SkWriteBuffer::writeIntArray(const int32_t* value, uint32_t count) {
70    fWriter.write32(count);
71    fWriter.write(value, count * sizeof(int32_t));
72}
73
74void SkWriteBuffer::writeUInt(uint32_t value) {
75    fWriter.write32(value);
76}
77
78void SkWriteBuffer::write32(int32_t value) {
79    fWriter.write32(value);
80}
81
82void SkWriteBuffer::writeString(const char* value) {
83    fWriter.writeString(value);
84}
85
86void SkWriteBuffer::writeEncodedString(const void* value, size_t byteLength,
87                                              SkPaint::TextEncoding encoding) {
88    fWriter.writeInt(encoding);
89    fWriter.writeInt(SkToU32(byteLength));
90    fWriter.write(value, byteLength);
91}
92
93
94void SkWriteBuffer::writeColor(const SkColor& color) {
95    fWriter.write32(color);
96}
97
98void SkWriteBuffer::writeColorArray(const SkColor* color, uint32_t count) {
99    fWriter.write32(count);
100    fWriter.write(color, count * sizeof(SkColor));
101}
102
103void SkWriteBuffer::writePoint(const SkPoint& point) {
104    fWriter.writeScalar(point.fX);
105    fWriter.writeScalar(point.fY);
106}
107
108void SkWriteBuffer::writePointArray(const SkPoint* point, uint32_t count) {
109    fWriter.write32(count);
110    fWriter.write(point, count * sizeof(SkPoint));
111}
112
113void SkWriteBuffer::writeMatrix(const SkMatrix& matrix) {
114    fWriter.writeMatrix(matrix);
115}
116
117void SkWriteBuffer::writeIRect(const SkIRect& rect) {
118    fWriter.write(&rect, sizeof(SkIRect));
119}
120
121void SkWriteBuffer::writeRect(const SkRect& rect) {
122    fWriter.writeRect(rect);
123}
124
125void SkWriteBuffer::writeRegion(const SkRegion& region) {
126    fWriter.writeRegion(region);
127}
128
129void SkWriteBuffer::writePath(const SkPath& path) {
130    fWriter.writePath(path);
131}
132
133size_t SkWriteBuffer::writeStream(SkStream* stream, size_t length) {
134    fWriter.write32(SkToU32(length));
135    size_t bytesWritten = fWriter.readFromStream(stream, length);
136    if (bytesWritten < length) {
137        fWriter.reservePad(length - bytesWritten);
138    }
139    return bytesWritten;
140}
141
142bool SkWriteBuffer::writeToStream(SkWStream* stream) {
143    return fWriter.writeToStream(stream);
144}
145
146static void write_encoded_bitmap(SkWriteBuffer* buffer, SkData* data,
147                                 const SkIPoint& origin) {
148    buffer->writeUInt(SkToU32(data->size()));
149    buffer->getWriter32()->writePad(data->data(), data->size());
150    buffer->write32(origin.fX);
151    buffer->write32(origin.fY);
152}
153
154void SkWriteBuffer::writeBitmap(const SkBitmap& bitmap) {
155    // Record the width and height. This way if readBitmap fails a dummy bitmap can be drawn at the
156    // right size.
157    this->writeInt(bitmap.width());
158    this->writeInt(bitmap.height());
159
160    // Record information about the bitmap in one of three ways, in order of priority:
161    // 1. If there is an SkBitmapHeap, store it in the heap. The client can avoid serializing the
162    //    bitmap entirely or serialize it later as desired. A boolean value of true will be written
163    //    to the stream to signify that a heap was used.
164    // 2. If there is a function for encoding bitmaps, use it to write an encoded version of the
165    //    bitmap. After writing a boolean value of false, signifying that a heap was not used, write
166    //    the size of the encoded data. A non-zero size signifies that encoded data was written.
167    // 3. Call SkBitmap::flatten. After writing a boolean value of false, signifying that a heap was
168    //    not used, write a zero to signify that the data was not encoded.
169    bool useBitmapHeap = fBitmapHeap != NULL;
170    // Write a bool: true if the SkBitmapHeap is to be used, in which case the reader must use an
171    // SkBitmapHeapReader to read the SkBitmap. False if the bitmap was serialized another way.
172    this->writeBool(useBitmapHeap);
173    if (useBitmapHeap) {
174        SkASSERT(NULL == fBitmapEncoder);
175        int32_t slot = fBitmapHeap->insert(bitmap);
176        fWriter.write32(slot);
177        // crbug.com/155875
178        // The generation ID is not required information. We write it to prevent collisions
179        // in SkFlatDictionary.  It is possible to get a collision when a previously
180        // unflattened (i.e. stale) instance of a similar flattenable is in the dictionary
181        // and the instance currently being written is re-using the same slot from the
182        // bitmap heap.
183        fWriter.write32(bitmap.getGenerationID());
184        return;
185    }
186
187    // see if the pixelref already has an encoded version
188    if (bitmap.pixelRef()) {
189        SkAutoDataUnref data(bitmap.pixelRef()->refEncodedData());
190        if (data.get() != NULL) {
191            write_encoded_bitmap(this, data, bitmap.pixelRefOrigin());
192            return;
193        }
194    }
195
196    // see if the caller wants to manually encode
197    if (fBitmapEncoder != NULL) {
198        SkASSERT(NULL == fBitmapHeap);
199        size_t offset = 0;  // this parameter is deprecated/ignored
200        // if we have to "encode" the bitmap, then we assume there is no
201        // offset to share, since we are effectively creating a new pixelref
202        SkAutoDataUnref data(fBitmapEncoder(&offset, bitmap));
203        if (data.get() != NULL) {
204            write_encoded_bitmap(this, data, SkIPoint::Make(0, 0));
205            return;
206        }
207    }
208
209    // Bitmap was not encoded. Record a zero, implying that the reader need not decode.
210    this->writeUInt(0);
211    bitmap.flatten(*this);
212}
213
214void SkWriteBuffer::writeTypeface(SkTypeface* obj) {
215    if (NULL == obj || NULL == fTFSet) {
216        fWriter.write32(0);
217    } else {
218        fWriter.write32(fTFSet->add(obj));
219    }
220}
221
222SkFactorySet* SkWriteBuffer::setFactoryRecorder(SkFactorySet* rec) {
223    SkRefCnt_SafeAssign(fFactorySet, rec);
224    if (fNamedFactorySet != NULL) {
225        fNamedFactorySet->unref();
226        fNamedFactorySet = NULL;
227    }
228    return rec;
229}
230
231SkNamedFactorySet* SkWriteBuffer::setNamedFactoryRecorder(SkNamedFactorySet* rec) {
232    SkRefCnt_SafeAssign(fNamedFactorySet, rec);
233    if (fFactorySet != NULL) {
234        fFactorySet->unref();
235        fFactorySet = NULL;
236    }
237    return rec;
238}
239
240SkRefCntSet* SkWriteBuffer::setTypefaceRecorder(SkRefCntSet* rec) {
241    SkRefCnt_SafeAssign(fTFSet, rec);
242    return rec;
243}
244
245void SkWriteBuffer::setBitmapHeap(SkBitmapHeap* bitmapHeap) {
246    SkRefCnt_SafeAssign(fBitmapHeap, bitmapHeap);
247    if (bitmapHeap != NULL) {
248        SkASSERT(NULL == fBitmapEncoder);
249        fBitmapEncoder = NULL;
250    }
251}
252
253void SkWriteBuffer::setBitmapEncoder(SkPicture::EncodeBitmap bitmapEncoder) {
254    fBitmapEncoder = bitmapEncoder;
255    if (bitmapEncoder != NULL) {
256        SkASSERT(NULL == fBitmapHeap);
257        SkSafeUnref(fBitmapHeap);
258        fBitmapHeap = NULL;
259    }
260}
261
262void SkWriteBuffer::writeFlattenable(const SkFlattenable* flattenable) {
263    /*
264     *  If we have a factoryset, then the first 32bits tell us...
265     *       0: failure to write the flattenable
266     *      >0: (1-based) index into the SkFactorySet or SkNamedFactorySet
267     *  If we don't have a factoryset, then the first "ptr" is either the
268     *  factory, or null for failure.
269     *
270     *  The distinction is important, since 0-index is 32bits (always), but a
271     *  0-functionptr might be 32 or 64 bits.
272     */
273    if (NULL == flattenable) {
274        if (this->isValidating()) {
275            this->writeString("");
276        } else if (fFactorySet != NULL || fNamedFactorySet != NULL) {
277            this->write32(0);
278        } else {
279            this->writeFunctionPtr(NULL);
280        }
281        return;
282    }
283
284    SkFlattenable::Factory factory = flattenable->getFactory();
285    SkASSERT(factory != NULL);
286
287    /*
288     *  We can write 1 of 3 versions of the flattenable:
289     *  1.  function-ptr : this is the fastest for the reader, but assumes that
290     *      the writer and reader are in the same process.
291     *  2.  index into fFactorySet : This is assumes the writer will later
292     *      resolve the function-ptrs into strings for its reader. SkPicture
293     *      does exactly this, by writing a table of names (matching the indices)
294     *      up front in its serialized form.
295     *  3.  index into fNamedFactorySet. fNamedFactorySet will also store the
296     *      name. SkGPipe uses this technique so it can write the name to its
297     *      stream before writing the flattenable.
298     */
299    if (this->isValidating()) {
300        this->writeString(flattenable->getTypeName());
301    } else if (fFactorySet) {
302        this->write32(fFactorySet->add(factory));
303    } else if (fNamedFactorySet) {
304        int32_t index = fNamedFactorySet->find(factory);
305        this->write32(index);
306        if (0 == index) {
307            return;
308        }
309    } else {
310        this->writeFunctionPtr((void*)factory);
311    }
312
313    // make room for the size of the flattened object
314    (void)fWriter.reserve(sizeof(uint32_t));
315    // record the current size, so we can subtract after the object writes.
316    size_t offset = fWriter.bytesWritten();
317    // now flatten the object
318    flattenable->flatten(*this);
319    size_t objSize = fWriter.bytesWritten() - offset;
320    // record the obj's size
321    fWriter.overwriteTAt(offset - sizeof(uint32_t), SkToU32(objSize));
322}
323