Refactor Pickle Read methods to use higher performance PickleIterator.

ui/base/clipboard/custom_data_helper.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // TODO(dcheng): For efficiency reasons, consider passing custom data around
 // as a vector instead. It allows us to append a
 // std::pair<string16, string16> and swap the deserialized values in.
 
 #include "ui/base/clipboard/custom_data_helper.h"
 
 #include <utility>
 
 #include "base/pickle.h"
 
 namespace ui {
 
 namespace {
 
 class SkippablePickle : public Pickle {
  public:
   SkippablePickle(const void* data, size_t data_len);
-  bool SkipString16(void** iter);
+  bool SkipString16(PickleIterator* iter);
 };
 
 SkippablePickle::SkippablePickle(const void* data, size_t data_len)
     : Pickle(reinterpret_cast<const char*>(data), data_len) {
 }
 
-bool SkippablePickle::SkipString16(void** iter) {
+bool SkippablePickle::SkipString16(PickleIterator* iter) {
   DCHECK(iter);
 
   int len;
   if (!ReadLength(iter, &len))
     return false;
-  if (!IteratorHasRoomFor(*iter, len * sizeof(char16)))
-    return false;
-
-  UpdateIter(iter, len * sizeof(char16));
-  return true;
+  return iter->SkipBytes(len * sizeof(char16));
 }
 
 }  // namespace
 
 void ReadCustomDataTypes(const void* data,
                          size_t data_length,
                          std::vector<string16>* types) {
   SkippablePickle pickle(data, data_length);
-  void* iter = NULL;
+  PickleIterator iter(pickle);
 
   size_t size = 0;
   if (!pickle.ReadSize(&iter, &size))
     return;
 
   // Keep track of the original elements in the types vector. On failure, we
   // truncate the vector to the original size since we want to ignore corrupt
   // custom data pickles.
   size_t original_size = types->size();
 
   for (size_t i = 0; i < size; ++i) {
     types->push_back(string16());
     if (!pickle.ReadString16(&iter, &types->back()) ||
         !pickle.SkipString16(&iter)) {
       types->resize(original_size);
       return;
     }
   }
 }
 
 void ReadCustomDataForType(const void* data,
                            size_t data_length,
                            const string16& type,
                            string16* result) {
   SkippablePickle pickle(data, data_length);
-  void* iter = NULL;
+  PickleIterator iter(pickle);
 
   size_t size = 0;
   if (!pickle.ReadSize(&iter, &size))
     return;
 
   for (size_t i = 0; i < size; ++i) {
     string16 deserialized_type;
     if (!pickle.ReadString16(&iter, &deserialized_type))
       return;
     if (deserialized_type == type) {
       pickle.ReadString16(&iter, result);
       return;
     }
     if (!pickle.SkipString16(&iter))
       return;
   }
 }
 
 void ReadCustomDataIntoMap(const void* data,
                            size_t data_length,
                            std::map<string16, string16>* result) {
   Pickle pickle(reinterpret_cast<const char*>(data), data_length);
-  void* iter = NULL;
+  PickleIterator iter(pickle);
 
   size_t size = 0;
   if (!pickle.ReadSize(&iter, &size))
     return;
 
   for (size_t i = 0; i < size; ++i) {
     string16 type;
     if (!pickle.ReadString16(&iter, &type)) {
       // Data is corrupt, return an empty map.
       result->clear();
@@ skipping 14 matching lines @@
   pickle->WriteSize(data.size());
   for (std::map<string16, string16>::const_iterator it = data.begin();
        it != data.end();
        ++it) {
     pickle->WriteString16(it->first);
     pickle->WriteString16(it->second);
   }
 }
 
 }  // namespace ui