Enable flattening/unflattening with custom unflatten procs

src/core/SkReadBuffer.cpp

 /*
  * 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 "SkBitmap.h"
+#include "SkEndian.h"
 #include "SkErrorInternals.h"
 #include "SkImage.h"
 #include "SkImageGenerator.h"
 #include "SkReadBuffer.h"
 #include "SkStream.h"
 #include "SkTypeface.h"
 
 static uint32_t default_flags() {
     uint32_t flags = 0;
     flags |= SkReadBuffer::kScalarIsFloat_Flag;
@@ skipping 80 matching lines @@
 }
 
 uint32_t SkReadBuffer::readUInt() {
     return fReader.readU32();
 }
 
 int32_t SkReadBuffer::read32() {
     return fReader.readInt();
 }
 
+uint8_t SkReadBuffer::peekByte() {
+    SkASSERT(fReader.available() > 0);
+    return *((uint8_t*) fReader.peek());
+}
+
 void SkReadBuffer::readString(SkString* string) {
     size_t len;
     const char* strContents = fReader.readString(&len);
     string->set(strContents, len);
 }
 
 void* SkReadBuffer::readEncodedString(size_t* length, SkPaint::TextEncoding encoding) {
     SkDEBUGCODE(int32_t encodingType = ) fReader.readInt();
     SkASSERT(encodingType == encoding);
     *length =  fReader.readInt();
@@ skipping 218 matching lines @@
         if (0 == index) {
             return nullptr; // writer failed to give us the flattenable
         }
         index -= 1;     // we stored the index-base-1
         if ((unsigned)index >= (unsigned)fFactoryCount) {
             this->validate(false);
             return nullptr;
         }
         factory = fFactoryArray[index];
     } else {
-        factory = (SkFlattenable::Factory)readFunctionPtr();
-        if (nullptr == factory) {
-            return nullptr; // writer failed to give us the flattenable
+        SkString name;
+        if (this->peekByte()) {
+            // If the first byte is non-zero, the flattenable is specified by a string.
+            this->readString(&name);
+
+            // Add the string to the dictionary.
+            fFlattenableDict.set(fFlattenableDict.count() + 1, name);
+        } else {
+            // Read the index.  We are guaranteed that the first and last bytes
+            // are zeroed, so we must shift down a byte.
+            uint32_t index = fReader.readU32() >> 8;
+            if (0 == index) {
+                return nullptr; // writer failed to give us the flattenable
+            }
+
+            SkString* namePtr = fFlattenableDict.find(index);
+            SkASSERT(namePtr);
+            name = *namePtr;
+        }
+
+        // Check if a custom Factory has been specified for this flattenable.
+        if (!(factory = this->getCustomFactory(name))) {
+            // If there is no custom Factory, check for a default.
+            if (!(factory = SkFlattenable::NameToFactory(name.c_str()))) {
+                return nullptr; // writer failed to give us the flattenable
+            }
         }
     }
 
     // if we get here, factory may still be null, but if that is the case, the
     // failure was ours, not the writer.
     sk_sp<SkFlattenable> obj;
     uint32_t sizeRecorded = fReader.readU32();
     if (factory) {
         size_t offset = fReader.offset();
         obj = (*factory)(*this);
@@ skipping 20 matching lines @@
             return;
         }
     } else {
         if (nullptr == this->readFunctionPtr()) {
             return;
         }
     }
     uint32_t sizeRecorded = fReader.readU32();
     fReader.skip(sizeRecorded);
 }