Helpers to pickle custom data for web copy/paste and drag/drop.

ui/base/clipboard/custom_data_helper.cc

Index: ui/base/clipboard/custom_data_helper.cc
diff --git a/ui/base/clipboard/custom_data_helper.cc b/ui/base/clipboard/custom_data_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..72142b518855cf56bd01665241f481536f09b3c8
--- /dev/null
+++ b/ui/base/clipboard/custom_data_helper.cc
@@ -0,0 +1,127 @@
+// Copyright (c) 2011 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);
+};
+
+SkippablePickle::SkippablePickle(const void* data, size_t data_len)
+    : Pickle(reinterpret_cast<const char*>(data), data_len) {
+}
+
+bool SkippablePickle::SkipString16(void** 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;
+}
+
+}  // namespace
+
+void ReadCustomDataTypes(const void* data,
+                         size_t data_length,
+                         std::vector<string16>* types) {
+  SkippablePickle pickle(data, data_length);
+  void* iter = NULL;
+
+  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;
+
+  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;
+
+  size_t size = 0;
+  if (!pickle.ReadSize(&iter, &size))
+    return;
+
+  for (size_t i = 0; i < size; ++i) {
+    string16 type;
+    string16 data;

[tony, 2011/12/05 18:20:16]

Nit: string16 data shadows the function arg data.  Maybe give it a different
name to make it more clear.

[dcheng, 2011/12/05 18:34:10]

Done. Not needed any more since we saved a copy below.

+    if (!pickle.ReadString16(&iter, &type) ||
+        !pickle.ReadString16(&iter, &data)) {
+      // Data is corrupt, return an empty map.
+      result->clear();
+      return;
+    }
+    result->insert(std::make_pair(type, data));

[tony, 2011/12/05 18:20:16]

Nit: I think we can save a copy of |data| by reading the type, then calling
map::insert and passing the returned value into ReadString16.

[dcheng, 2011/12/05 18:34:10]

Done.

+  }
+}
+
+void WriteCustomDataToPickle(const std::map<string16, string16>& data,
+                             Pickle* pickle) {
+  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