content/browser/histogram_message_filter.cc

   1 // Copyright (c) 2012 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 "content/browser/histogram_message_filter.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/metrics/statistics_recorder.h"
  10 #include "content/browser/histogram_controller.h"
  11 #include "content/browser/tcmalloc_internals_request_job.h"
  12 #include "content/common/child_process_messages.h"
  13 #include "content/public/common/content_switches.h"
  14
  15 namespace content {
  16
  17 HistogramMessageFilter::HistogramMessageFilter()
  18     : BrowserMessageFilter(ChildProcessMsgStart) {}
  19
  20 bool HistogramMessageFilter::OnMessageReceived(const IPC::Message& message,
  21                                               bool* message_was_ok) {
  22   bool handled = true;
  23   IPC_BEGIN_MESSAGE_MAP_EX(HistogramMessageFilter, message, *message_was_ok)
  24     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ChildHistogramData,
  25                         OnChildHistogramData)
  26     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_GetBrowserHistogram,
  27                         OnGetBrowserHistogram)
  28     IPC_MESSAGE_UNHANDLED(handled = false)
  29   IPC_END_MESSAGE_MAP_EX()
  30   return handled;
  31 }
  32
  33 HistogramMessageFilter::~HistogramMessageFilter() {}
  34
  35 void HistogramMessageFilter::OnChildHistogramData(
  36     int sequence_number,
  37     const std::vector<std::string>& pickled_histograms) {
  38   HistogramController::GetInstance()->OnHistogramDataCollected(
  39       sequence_number, pickled_histograms);
  40 }
  41
  42 void HistogramMessageFilter::OnGetBrowserHistogram(
  43     const std::string& name,
  44     std::string* histogram_json) {
  45   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
  46   // Security: Only allow access to browser histograms when running in the
  47   // context of a test.
  48   bool using_stats_collection_controller =
  49       CommandLine::ForCurrentProcess()->HasSwitch(
  50           switches::kStatsCollectionController);
  51   if (!using_stats_collection_controller) {
  52     LOG(ERROR) << "Attempt at reading browser histogram without specifying "
  53                << "--" << switches::kStatsCollectionController << " switch.";
  54     return;
  55   }
  56   base::HistogramBase* histogram =
  57       base::StatisticsRecorder::FindHistogram(name);
  58   if (!histogram) {
  59     *histogram_json = "{}";
  60   } else {
  61     histogram->WriteJSON(histogram_json);
  62   }
  63 }
  64
  65 }  // namespace content