Refactor ModelTypePayloadMap and ObjectIdPayloadMap to StateMaps.

sync/internal_api/public/base/model_type_state_map.cc

Index: sync/internal_api/public/base/model_type_state_map.cc
diff --git a/sync/internal_api/public/base/model_type_state_map.cc b/sync/internal_api/public/base/model_type_state_map.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fbdff7d7f48dbdc4d8a35c0c5f92591e9647a401
--- /dev/null
+++ b/sync/internal_api/public/base/model_type_state_map.cc
@@ -0,0 +1,76 @@
+// 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.
+
+#include "sync/internal_api/public/base/model_type_state_map.h"
+
+#include <vector>
+
+#include "base/json/json_writer.h"
+#include "base/json/string_escape.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+
+namespace syncer {
+
+ModelTypeStateMap ModelTypeSetToStateMap(ModelTypeSet types,
+                                         const std::string& payload) {
+  ModelTypeStateMap type_state_map;
+  for (ModelTypeSet::Iterator it = types.First(); it.Good(); it.Inc()) {
+    // TODO(dcheng): Do we need to set ack_handle?
+    type_state_map[it.Get()].payload = payload;
+  }
+  return type_state_map;
+}
+
+ModelTypeSet ModelTypeStateMapToSet(
+    const ModelTypeStateMap& type_state_map) {
+  ModelTypeSet types;
+  for (ModelTypeStateMap::const_iterator it = type_state_map.begin();
+       it != type_state_map.end(); ++it) {
+    types.Put(it->first);
+  }
+  return types;
+}
+
+std::string ModelTypeStateMapToString(const ModelTypeStateMap& type_state_map) {
+  scoped_ptr<DictionaryValue> value(ModelTypeStateMapToValue(type_state_map));
+  std::string json;
+  base::JSONWriter::Write(value.get(), &json);
+  return json;
+}
+
+DictionaryValue* ModelTypeStateMapToValue(
+    const ModelTypeStateMap& type_state_map) {
+  DictionaryValue* value = new DictionaryValue();
+  for (ModelTypeStateMap::const_iterator it = type_state_map.begin();
+       it != type_state_map.end(); ++it) {
+    std::string printable_payload;
+    base::JsonDoubleQuote(it->second.payload,
+                          false /* put_in_quotes */,
+                          &printable_payload);
+    value->SetString(ModelTypeToString(it->first), printable_payload);
+  }
+  return value;
+}
+
+void CoalesceStates(ModelTypeStateMap* original,
+                    const ModelTypeStateMap& update) {
+  // TODO(dcheng): Where is this called? Do we need to add more clever logic for
+  // handling ack_handle? We probably want to always use the "latest"
+  // ack_handle, which might imply always using the one in update?
+  for (ModelTypeStateMap::const_iterator i = update.begin();
+       i != update.end(); ++i) {
+    if (original->count(i->first) == 0) {
+      // If this datatype isn't already in our map, add it with
+      // whatever payload it has.
+      (*original)[i->first] = i->second;
+    } else if (i->second.payload.length() > 0) {
+      // If this datatype is already in our map, we only overwrite the
+      // payload if the new one is non-empty.
+      (*original)[i->first].payload = i->second.payload;
+    }
+  }
+}
+
+}  // namespace syncer