ipc/message_filter_router.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ipc/message_filter_router.h"
   6
   7 #include "ipc/ipc_message_macros.h"
   8 #include "ipc/ipc_message_utils.h"
   9 #include "ipc/message_filter.h"
  10
  11 namespace IPC {
  12
  13 namespace {
  14
  15 bool TryFiltersImpl(MessageFilterRouter::MessageFilters& filters,
  16                     const IPC::Message& message) {
  17   for (size_t i = 0; i < filters.size(); ++i) {
  18     if (filters[i]->OnMessageReceived(message)) {
  19       return true;
  20     }
  21   }
  22   return false;
  23 }
  24
  25 bool RemoveFilterImpl(MessageFilterRouter::MessageFilters& filters,
  26                       MessageFilter* filter) {
  27   MessageFilterRouter::MessageFilters::iterator it =
  28       std::remove(filters.begin(), filters.end(), filter);
  29   if (it == filters.end())
  30     return false;
  31
  32   filters.erase(it, filters.end());
  33   return true;
  34 }
  35
  36 bool ValidMessageClass(int message_class) {
  37   return message_class >= 0 && message_class < LastIPCMsgStart;
  38 }
  39
  40 }  // namespace
  41
  42 MessageFilterRouter::MessageFilterRouter() {}
  43 MessageFilterRouter::~MessageFilterRouter() {}
  44
  45 void MessageFilterRouter::AddFilter(MessageFilter* filter) {
  46   // Determine if the filter should be applied to all messages, or only
  47   // messages of a certain class.
  48   std::vector<uint32> supported_message_classes;
  49   if (filter->GetSupportedMessageClasses(&supported_message_classes)) {
  50     DCHECK(!supported_message_classes.empty());
  51     for (size_t i = 0; i < supported_message_classes.size(); ++i) {
  52       const int message_class = supported_message_classes[i];
  53       DCHECK(ValidMessageClass(message_class));
  54       // Safely ignore repeated subscriptions to a given message class for the
  55       // current filter being added.
  56       if (!message_class_filters_[message_class].empty() &&
  57           message_class_filters_[message_class].back() == filter) {
  58         continue;
  59       }
  60       message_class_filters_[message_class].push_back(filter);
  61     }
  62   } else {
  63     global_filters_.push_back(filter);
  64   }
  65 }
  66
  67 void MessageFilterRouter::RemoveFilter(MessageFilter* filter) {
  68   if (RemoveFilterImpl(global_filters_, filter))
  69     return;
  70
  71   for (size_t i = 0; i < arraysize(message_class_filters_); ++i)
  72     RemoveFilterImpl(message_class_filters_[i], filter);
  73 }
  74
  75 bool MessageFilterRouter::TryFilters(const Message& message) {
  76   if (TryFiltersImpl(global_filters_, message))
  77     return true;
  78
  79   const int message_class = IPC_MESSAGE_CLASS(message);
  80   if (!ValidMessageClass(message_class))
  81     return false;
  82
  83   return TryFiltersImpl(message_class_filters_[message_class], message);
  84 }
  85
  86 void MessageFilterRouter::Clear() {
  87   global_filters_.clear();
  88   for (size_t i = 0; i < arraysize(message_class_filters_); ++i)
  89     message_class_filters_[i].clear();
  90 }
  91
  92 }  // namespace IPC