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      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 "SkBitmapHeap.h"
     12 #include "SkData.h"
     13 #include "SkPixelRef.h"
     14 #include "SkPtrRecorder.h"
     15 #include "SkStream.h"
     16 #include "SkTypeface.h"
     17 
     18 SkWriteBuffer::SkWriteBuffer(uint32_t flags)
     19     : fFlags(flags)
     20     , fFactorySet(NULL)
     21     , fNamedFactorySet(NULL)
     22     , fBitmapHeap(NULL)
     23     , fTFSet(NULL) {
     24 }
     25 
     26 SkWriteBuffer::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 }
     34 
     35 SkWriteBuffer::~SkWriteBuffer() {
     36     SkSafeUnref(fFactorySet);
     37     SkSafeUnref(fNamedFactorySet);
     38     SkSafeUnref(fBitmapHeap);
     39     SkSafeUnref(fTFSet);
     40 }
     41 
     42 void SkWriteBuffer::writeByteArray(const void* data, size_t size) {
     43     fWriter.write32(SkToU32(size));
     44     fWriter.writePad(data, size);
     45 }
     46 
     47 void SkWriteBuffer::writeBool(bool value) {
     48     fWriter.writeBool(value);
     49 }
     50 
     51 void SkWriteBuffer::writeFixed(SkFixed value) {
     52     fWriter.write32(value);
     53 }
     54 
     55 void SkWriteBuffer::writeScalar(SkScalar value) {
     56     fWriter.writeScalar(value);
     57 }
     58 
     59 void SkWriteBuffer::writeScalarArray(const SkScalar* value, uint32_t count) {
     60     fWriter.write32(count);
     61     fWriter.write(value, count * sizeof(SkScalar));
     62 }
     63 
     64 void SkWriteBuffer::writeInt(int32_t value) {
     65     fWriter.write32(value);
     66 }
     67 
     68 void SkWriteBuffer::writeIntArray(const int32_t* value, uint32_t count) {
     69     fWriter.write32(count);
     70     fWriter.write(value, count * sizeof(int32_t));
     71 }
     72 
     73 void SkWriteBuffer::writeUInt(uint32_t value) {
     74     fWriter.write32(value);
     75 }
     76 
     77 void SkWriteBuffer::write32(int32_t value) {
     78     fWriter.write32(value);
     79 }
     80 
     81 void SkWriteBuffer::writeString(const char* value) {
     82     fWriter.writeString(value);
     83 }
     84 
     85 void SkWriteBuffer::writeEncodedString(const void* value, size_t byteLength,
     86                                               SkPaint::TextEncoding encoding) {
     87     fWriter.writeInt(encoding);
     88     fWriter.writeInt(SkToU32(byteLength));
     89     fWriter.write(value, byteLength);
     90 }
     91 
     92 
     93 void SkWriteBuffer::writeColor(const SkColor& color) {
     94     fWriter.write32(color);
     95 }
     96 
     97 void SkWriteBuffer::writeColorArray(const SkColor* color, uint32_t count) {
     98     fWriter.write32(count);
     99     fWriter.write(color, count * sizeof(SkColor));
    100 }
    101 
    102 void SkWriteBuffer::writePoint(const SkPoint& point) {
    103     fWriter.writeScalar(point.fX);
    104     fWriter.writeScalar(point.fY);
    105 }
    106 
    107 void SkWriteBuffer::writePointArray(const SkPoint* point, uint32_t count) {
    108     fWriter.write32(count);
    109     fWriter.write(point, count * sizeof(SkPoint));
    110 }
    111 
    112 void SkWriteBuffer::writeMatrix(const SkMatrix& matrix) {
    113     fWriter.writeMatrix(matrix);
    114 }
    115 
    116 void SkWriteBuffer::writeIRect(const SkIRect& rect) {
    117     fWriter.write(&rect, sizeof(SkIRect));
    118 }
    119 
    120 void SkWriteBuffer::writeRect(const SkRect& rect) {
    121     fWriter.writeRect(rect);
    122 }
    123 
    124 void SkWriteBuffer::writeRegion(const SkRegion& region) {
    125     fWriter.writeRegion(region);
    126 }
    127 
    128 void SkWriteBuffer::writePath(const SkPath& path) {
    129     fWriter.writePath(path);
    130 }
    131 
    132 size_t SkWriteBuffer::writeStream(SkStream* stream, size_t length) {
    133     fWriter.write32(SkToU32(length));
    134     size_t bytesWritten = fWriter.readFromStream(stream, length);
    135     if (bytesWritten < length) {
    136         fWriter.reservePad(length - bytesWritten);
    137     }
    138     return bytesWritten;
    139 }
    140 
    141 bool SkWriteBuffer::writeToStream(SkWStream* stream) {
    142     return fWriter.writeToStream(stream);
    143 }
    144 
    145 static void write_encoded_bitmap(SkWriteBuffer* buffer, SkData* data,
    146                                  const SkIPoint& origin) {
    147     buffer->writeUInt(SkToU32(data->size()));
    148     buffer->getWriter32()->writePad(data->data(), data->size());
    149     buffer->write32(origin.fX);
    150     buffer->write32(origin.fY);
    151 }
    152 
    153 void SkWriteBuffer::writeBitmap(const SkBitmap& bitmap) {
    154     // Record the width and height. This way if readBitmap fails a dummy bitmap can be drawn at the
    155     // right size.
    156     this->writeInt(bitmap.width());
    157     this->writeInt(bitmap.height());
    158 
    159     // Record information about the bitmap in one of three ways, in order of priority:
    160     // 1. If there is an SkBitmapHeap, store it in the heap. The client can avoid serializing the
    161     //    bitmap entirely or serialize it later as desired. A boolean value of true will be written
    162     //    to the stream to signify that a heap was used.
    163     // 2. If there is a function for encoding bitmaps, use it to write an encoded version of the
    164     //    bitmap. After writing a boolean value of false, signifying that a heap was not used, write
    165     //    the size of the encoded data. A non-zero size signifies that encoded data was written.
    166     // 3. Call SkBitmap::flatten. After writing a boolean value of false, signifying that a heap was
    167     //    not used, write a zero to signify that the data was not encoded.
    168     bool useBitmapHeap = fBitmapHeap != NULL;
    169     // Write a bool: true if the SkBitmapHeap is to be used, in which case the reader must use an
    170     // SkBitmapHeapReader to read the SkBitmap. False if the bitmap was serialized another way.
    171     this->writeBool(useBitmapHeap);
    172     if (useBitmapHeap) {
    173         SkASSERT(NULL == fPixelSerializer);
    174         int32_t slot = fBitmapHeap->insert(bitmap);
    175         fWriter.write32(slot);
    176         // crbug.com/155875
    177         // The generation ID is not required information. We write it to prevent collisions
    178         // in SkFlatDictionary.  It is possible to get a collision when a previously
    179         // unflattened (i.e. stale) instance of a similar flattenable is in the dictionary
    180         // and the instance currently being written is re-using the same slot from the
    181         // bitmap heap.
    182         fWriter.write32(bitmap.getGenerationID());
    183         return;
    184     }
    185 
    186     SkPixelRef* pixelRef = bitmap.pixelRef();
    187     if (pixelRef) {
    188         // see if the pixelref already has an encoded version
    189         SkAutoDataUnref existingData(pixelRef->refEncodedData());
    190         if (existingData.get() != NULL) {
    191             // Assumes that if the client did not set a serializer, they are
    192             // happy to get the encoded data.
    193             if (!fPixelSerializer || fPixelSerializer->useEncodedData(existingData->data(),
    194                                                                       existingData->size())) {
    195                 write_encoded_bitmap(this, existingData, bitmap.pixelRefOrigin());
    196                 return;
    197             }
    198         }
    199 
    200         // see if the caller wants to manually encode
    201         if (fPixelSerializer) {
    202             SkASSERT(NULL == fBitmapHeap);
    203             SkAutoLockPixels alp(bitmap);
    204             SkAutoDataUnref data(fPixelSerializer->encodePixels(bitmap.info(),
    205                                                                 bitmap.getPixels(),
    206                                                                 bitmap.rowBytes()));
    207             if (data.get() != NULL) {
    208                 // if we have to "encode" the bitmap, then we assume there is no
    209                 // offset to share, since we are effectively creating a new pixelref
    210                 write_encoded_bitmap(this, data, SkIPoint::Make(0, 0));
    211                 return;
    212             }
    213         }
    214     }
    215 
    216     this->writeUInt(0); // signal raw pixels
    217     SkBitmap::WriteRawPixels(this, bitmap);
    218 }
    219 
    220 void SkWriteBuffer::writeTypeface(SkTypeface* obj) {
    221     if (NULL == obj || NULL == fTFSet) {
    222         fWriter.write32(0);
    223     } else {
    224         fWriter.write32(fTFSet->add(obj));
    225     }
    226 }
    227 
    228 SkFactorySet* SkWriteBuffer::setFactoryRecorder(SkFactorySet* rec) {
    229     SkRefCnt_SafeAssign(fFactorySet, rec);
    230     if (fNamedFactorySet != NULL) {
    231         fNamedFactorySet->unref();
    232         fNamedFactorySet = NULL;
    233     }
    234     return rec;
    235 }
    236 
    237 SkNamedFactorySet* SkWriteBuffer::setNamedFactoryRecorder(SkNamedFactorySet* rec) {
    238     SkRefCnt_SafeAssign(fNamedFactorySet, rec);
    239     if (fFactorySet != NULL) {
    240         fFactorySet->unref();
    241         fFactorySet = NULL;
    242     }
    243     return rec;
    244 }
    245 
    246 SkRefCntSet* SkWriteBuffer::setTypefaceRecorder(SkRefCntSet* rec) {
    247     SkRefCnt_SafeAssign(fTFSet, rec);
    248     return rec;
    249 }
    250 
    251 void SkWriteBuffer::setBitmapHeap(SkBitmapHeap* bitmapHeap) {
    252     SkRefCnt_SafeAssign(fBitmapHeap, bitmapHeap);
    253     if (bitmapHeap != NULL) {
    254         SkASSERT(NULL == fPixelSerializer);
    255         fPixelSerializer.reset(NULL);
    256     }
    257 }
    258 
    259 void SkWriteBuffer::setPixelSerializer(SkPixelSerializer* serializer) {
    260     fPixelSerializer.reset(serializer);
    261     if (serializer) {
    262         serializer->ref();
    263         SkASSERT(NULL == fBitmapHeap);
    264         SkSafeUnref(fBitmapHeap);
    265         fBitmapHeap = NULL;
    266     }
    267 }
    268 
    269 void SkWriteBuffer::writeFlattenable(const SkFlattenable* flattenable) {
    270     /*
    271      *  If we have a factoryset, then the first 32bits tell us...
    272      *       0: failure to write the flattenable
    273      *      >0: (1-based) index into the SkFactorySet or SkNamedFactorySet
    274      *  If we don't have a factoryset, then the first "ptr" is either the
    275      *  factory, or null for failure.
    276      *
    277      *  The distinction is important, since 0-index is 32bits (always), but a
    278      *  0-functionptr might be 32 or 64 bits.
    279      */
    280     if (NULL == flattenable) {
    281         if (this->isValidating()) {
    282             this->writeString("");
    283         } else if (fFactorySet != NULL || fNamedFactorySet != NULL) {
    284             this->write32(0);
    285         } else {
    286             this->writeFunctionPtr(NULL);
    287         }
    288         return;
    289     }
    290 
    291     SkFlattenable::Factory factory = flattenable->getFactory();
    292     SkASSERT(factory != NULL);
    293 
    294     /*
    295      *  We can write 1 of 3 versions of the flattenable:
    296      *  1.  function-ptr : this is the fastest for the reader, but assumes that
    297      *      the writer and reader are in the same process.
    298      *  2.  index into fFactorySet : This is assumes the writer will later
    299      *      resolve the function-ptrs into strings for its reader. SkPicture
    300      *      does exactly this, by writing a table of names (matching the indices)
    301      *      up front in its serialized form.
    302      *  3.  index into fNamedFactorySet. fNamedFactorySet will also store the
    303      *      name. SkGPipe uses this technique so it can write the name to its
    304      *      stream before writing the flattenable.
    305      */
    306     if (this->isValidating()) {
    307         this->writeString(flattenable->getTypeName());
    308     } else if (fFactorySet) {
    309         this->write32(fFactorySet->add(factory));
    310     } else if (fNamedFactorySet) {
    311         int32_t index = fNamedFactorySet->find(factory);
    312         this->write32(index);
    313         if (0 == index) {
    314             return;
    315         }
    316     } else {
    317         this->writeFunctionPtr((void*)factory);
    318     }
    319 
    320     // make room for the size of the flattened object
    321     (void)fWriter.reserve(sizeof(uint32_t));
    322     // record the current size, so we can subtract after the object writes.
    323     size_t offset = fWriter.bytesWritten();
    324     // now flatten the object
    325     flattenable->flatten(*this);
    326     size_t objSize = fWriter.bytesWritten() - offset;
    327     // record the obj's size
    328     fWriter.overwriteTAt(offset - sizeof(uint32_t), SkToU32(objSize));
    329 }
    330