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 <stddef.h>
   8 #include <stdint.h>
   9
  10 #include "base/stl_util.h"
  11 #include "ipc/ipc_message_macros.h"
  12 #include "ipc/ipc_message_utils.h"
  13 #include "ipc/message_filter.h"
  14
  15 namespace IPC {
  16
  17 namespace {
  18
  19 bool TryFiltersImpl(MessageFilterRouter::MessageFilters& filters,
  20                     const IPC::Message& message) {
  21   for (size_t i = 0; i < filters.size(); ++i) {
  22     if (filters[i]->OnMessageReceived(message)) {
  23       return true;
  24     }
  25   }
  26   return false;
  27 }
  28
  29 bool RemoveFilterImpl(MessageFilterRouter::MessageFilters& filters,
  30                       MessageFilter* filter) {
  31   MessageFilterRouter::MessageFilters::iterator it =
  32       std::remove(filters.begin(), filters.end(), filter);
  33   if (it == filters.end())
  34     return false;
  35
  36   filters.erase(it, filters.end());
  37   return true;
  38 }
  39
  40 bool ValidMessageClass(int message_class) {
  41   return message_class >= 0 && message_class < LastIPCMsgStart;
  42 }
  43
  44 }  // namespace
  45
  46 MessageFilterRouter::MessageFilterRouter() = default;
  47 MessageFilterRouter::~MessageFilterRouter() = default;
  48
  49 void MessageFilterRouter::AddFilter(MessageFilter* filter) {
  50   // Determine if the filter should be applied to all messages, or only
  51   // messages of a certain class.
  52   std::vector<uint32_t> supported_message_classes;
  53   if (filter->GetSupportedMessageClasses(&supported_message_classes)) {
  54     DCHECK(!supported_message_classes.empty());
  55     for (size_t i = 0; i < supported_message_classes.size(); ++i) {
  56       const int message_class = supported_message_classes[i];
  57       DCHECK(ValidMessageClass(message_class));
  58       // Safely ignore repeated subscriptions to a given message class for the
  59       // current filter being added.
  60       if (!message_class_filters_[message_class].empty() &&
  61           message_class_filters_[message_class].back() == filter) {
  62         continue;
  63       }
  64       message_class_filters_[message_class].push_back(filter);
  65     }
  66   } else {
  67     global_filters_.push_back(filter);
  68   }
  69 }
  70
  71 void MessageFilterRouter::RemoveFilter(MessageFilter* filter) {
  72   if (RemoveFilterImpl(global_filters_, filter))
  73     return;
  74
  75   for (size_t i = 0; i < base::size(message_class_filters_); ++i)
  76     RemoveFilterImpl(message_class_filters_[i], filter);
  77 }
  78
  79 bool MessageFilterRouter::TryFilters(const Message& message) {
  80   if (TryFiltersImpl(global_filters_, message))
  81     return true;
  82
  83   const int message_class = IPC_MESSAGE_CLASS(message);
  84   if (!ValidMessageClass(message_class))
  85     return false;
  86
  87   return TryFiltersImpl(message_class_filters_[message_class], message);
  88 }
  89
  90 void MessageFilterRouter::Clear() {
  91   global_filters_.clear();
  92   for (size_t i = 0; i < base::size(message_class_filters_); ++i)
  93     message_class_filters_[i].clear();
  94 }
  95
  96 }  // namespace IPC