Introduce RawVarData and associated classes for serializing PP_Vars

ppapi/shared_impl/var_graph.cc

+// Copyright (c) 2013 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 "ppapi/shared_impl/var_graph.h"
+
+#include <stack>
+
+#include "base/stl_util.h"
+#include "ppapi/shared_impl/array_var.h"
+#include "ppapi/shared_impl/dictionary_var.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/var.h"
+#include "ppapi/shared_impl/var_tracker.h"
+
+namespace ppapi {
+
+// static
+bool VarGraph::Create(const PP_Var& start_node, VarGraph* var_graph) {
+  std::stack<PP_Var> stack;
+  stack.push(start_node);
+
+  // Traverse the PP_Var graph with DFS and add each reference node to |nodes|
+  // exactly once.
+  while (!stack.empty()) {
+    PP_Var current = stack.top();
+    stack.pop();
+    if (!PpapiGlobals::Get()->GetVarTracker()->GetVar(current.value.as_id) ||
+        ContainsKey(var_graph->id_map, current.value.as_id)) {
+      continue;
+    }
+    var_graph->nodes.push_back(current);

[dmichael (off chromium), 2013/04/12 22:40:38]

Why have the vector at all? You could just stick PP_Vars in the map.

[raymes, 2013/04/14 16:32:57]

This has changed.

+    var_graph->id_map[current.value.as_id] = var_graph->nodes.size() - 1;
+
+    // Add child nodes to the stack.
+    if (current.type == PP_VARTYPE_ARRAY) {
+      ArrayVar* array_var = ArrayVar::FromPPVar(current);
+      if (!array_var) {
+        NOTREACHED();
+        return false;
+      }
+      for (ArrayVar::ElementVector::const_iterator iter =
+               array_var->elements().begin();
+           iter != array_var->elements().end();
+           ++iter) {
+        stack.push(iter->get());
+      }
+    } else if (current.type == PP_VARTYPE_DICTIONARY) {
+      DictionaryVar* dict_var = DictionaryVar::FromPPVar(current);
+      if (!dict_var) {
+        NOTREACHED();
+        return false;
+      }
+      for (DictionaryVar::KeyValueMap::const_iterator iter =
+               dict_var->key_value_map().begin();
+           iter != dict_var->key_value_map().end();
+           ++iter) {
+        stack.push(iter->second.get());
+      }
+    }
+  }
+  DCHECK(var_graph->nodes.size() == var_graph->id_map.size());
+  return true;
+}
+
+}  // namespace ppapi