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 handled = true;
  22   IPC_BEGIN_MESSAGE_MAP(HistogramMessageFilter, message)
  23     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ChildHistogramData,
  24                         OnChildHistogramData)
  25     IPC_MESSAGE_HANDLER(ChildProcessHostMsg_GetBrowserHistogram,
  26                         OnGetBrowserHistogram)
  27     IPC_MESSAGE_UNHANDLED(handled = false)
  28   IPC_END_MESSAGE_MAP()
  29   return handled;
  30 }
  31
  32 HistogramMessageFilter::~HistogramMessageFilter() {}
  33
  34 void HistogramMessageFilter::OnChildHistogramData(
  35     int sequence_number,
  36     const std::vector<std::string>& pickled_histograms) {
  37   HistogramController::GetInstance()->OnHistogramDataCollected(
  38       sequence_number, pickled_histograms);
  39 }
  40
  41 void HistogramMessageFilter::OnGetBrowserHistogram(
  42     const std::string& name,
  43     std::string* histogram_json) {
  44   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
  45   // Security: Only allow access to browser histograms when running in the
  46   // context of a test.
  47   bool using_stats_collection_controller =
  48       base::CommandLine::ForCurrentProcess()->HasSwitch(
  49           switches::kStatsCollectionController);
  50   if (!using_stats_collection_controller) {
  51     LOG(ERROR) << "Attempt at reading browser histogram without specifying "
  52                << "--" << switches::kStatsCollectionController << " switch.";
  53     return;
  54   }
  55   base::HistogramBase* histogram =
  56       base::StatisticsRecorder::FindHistogram(name);
  57   if (!histogram) {
  58     *histogram_json = "{}";
  59   } else {
  60     histogram->WriteJSON(histogram_json);
  61   }
  62 }
  63
  64 }  // namespace content