Move IPC::MessageFilter and router to a separate file

ipc/message_filter_router.cc

+// Copyright (c) 2014 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 "ipc/message_filter_router.h"
+
+#include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message_utils.h"
+#include "ipc/message_filter.h"
+
+namespace IPC {
+
+namespace {
+
+bool TryFiltersImpl(MessageFilterRouter::MessageFilters& filters,
+                    const IPC::Message& message) {
+  for (size_t i = 0; i < filters.size(); ++i) {
+    if (filters[i]->OnMessageReceived(message)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool RemoveFilterImpl(MessageFilterRouter::MessageFilters& filters,
+                      MessageFilter* filter) {
+  MessageFilterRouter::MessageFilters::iterator it =
+      std::remove(filters.begin(), filters.end(), filter);
+  if (it == filters.end())
+    return false;
+
+  filters.erase(it, filters.end());
+  return true;
+}
+
+bool ValidMessageClass(int message_class) {
+  return message_class >= 0 && message_class < LastIPCMsgStart;
+}
+
+}  // namespace
+
+MessageFilterRouter::MessageFilterRouter() {}
+MessageFilterRouter::~MessageFilterRouter() {}
+
+void MessageFilterRouter::AddFilter(MessageFilter* filter) {
+  // Determine if the filter should be applied to all messages, or only
+  // messages of a certain class.
+  std::vector<uint32> supported_message_classes;
+  if (filter->GetSupportedMessageClasses(&supported_message_classes)) {
+    DCHECK(!supported_message_classes.empty());
+    for (size_t i = 0; i < supported_message_classes.size(); ++i) {
+      const int message_class = supported_message_classes[i];
+      DCHECK(ValidMessageClass(message_class));
+      // Safely ignore repeated subscriptions to a given message class for the
+      // current filter being added.
+      if (!message_class_filters_[message_class].empty() &&
+          message_class_filters_[message_class].back() == filter) {
+        continue;
+      }
+      message_class_filters_[message_class].push_back(filter);
+    }
+  } else {
+    global_filters_.push_back(filter);
+  }
+}
+
+void MessageFilterRouter::RemoveFilter(MessageFilter* filter) {
+  if (RemoveFilterImpl(global_filters_, filter))
+    return;
+
+  for (size_t i = 0; i < arraysize(message_class_filters_); ++i)
+    RemoveFilterImpl(message_class_filters_[i], filter);
+}
+
+bool MessageFilterRouter::TryFilters(const Message& message) {
+  if (TryFiltersImpl(global_filters_, message))
+    return true;
+
+  const int message_class = IPC_MESSAGE_CLASS(message);
+  if (!ValidMessageClass(message_class))
+    return false;
+
+  return TryFiltersImpl(message_class_filters_[message_class], message);
+}
+
+void MessageFilterRouter::Clear() {
+  global_filters_.clear();
+  for (size_t i = 0; i < arraysize(message_class_filters_); ++i)
+    message_class_filters_[i].clear();
+}
+
+}  // namespace IPC