content/browser/browser_shutdown_profile_dumper.cc

   1 // Copyright 2013 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/browser_shutdown_profile_dumper.h"
   6
   7 #include "base/base_switches.h"
   8 #include "base/command_line.h"
   9 #include "base/debug/trace_event.h"
  10 #include "base/debug/trace_event_impl.h"
  11 #include "base/file_util.h"
  12 #include "base/files/file_path.h"
  13 #include "base/logging.h"
  14 #include "base/synchronization/waitable_event.h"
  15 #include "base/threading/thread.h"
  16 #include "base/threading/thread_restrictions.h"
  17 #include "content/public/common/content_switches.h"
  18
  19 namespace content {
  20
  21 BrowserShutdownProfileDumper::BrowserShutdownProfileDumper(
  22     const base::FilePath& dump_file_name)
  23     : dump_file_name_(dump_file_name),
  24       blocks_(0),
  25       dump_file_(NULL) {
  26 }
  27
  28 BrowserShutdownProfileDumper::~BrowserShutdownProfileDumper() {
  29   WriteTracesToDisc();
  30 }
  31
  32 void BrowserShutdownProfileDumper::WriteTracesToDisc() {
  33   // Note: I have seen a usage of 0.000xx% when dumping - which fits easily.
  34   // Since the tracer stops when the trace buffer is filled, we'd rather save
  35   // what we have than nothing since we might see from the amount of events
  36   // that caused the problem.
  37   DVLOG(1) << "Flushing shutdown traces to disc. The buffer is %" <<
  38       base::debug::TraceLog::GetInstance()->GetBufferPercentFull() <<
  39       " full.";
  40   DCHECK(!dump_file_);
  41   dump_file_ = base::OpenFile(dump_file_name_, "w+");
  42   if (!IsFileValid()) {
  43     LOG(ERROR) << "Failed to open performance trace file: "
  44                << dump_file_name_.value();
  45     return;
  46   }
  47   WriteString("{\"traceEvents\":");
  48   WriteString("[");
  49
  50   // TraceLog::Flush() requires the calling thread to have a message loop.
  51   // As the message loop of the current thread may have quit, start another
  52   // thread for flushing the trace.
  53   base::WaitableEvent flush_complete_event(false, false);
  54   base::Thread flush_thread("browser_shutdown_trace_event_flush");
  55   flush_thread.Start();
  56   flush_thread.message_loop()->PostTask(
  57       FROM_HERE,
  58       base::Bind(&BrowserShutdownProfileDumper::EndTraceAndFlush,
  59                  base::Unretained(this),
  60                  base::Unretained(&flush_complete_event)));
  61
  62   bool original_wait_allowed = base::ThreadRestrictions::SetWaitAllowed(true);
  63   flush_complete_event.Wait();
  64   base::ThreadRestrictions::SetWaitAllowed(original_wait_allowed);
  65 }
  66
  67 void BrowserShutdownProfileDumper::EndTraceAndFlush(
  68     base::WaitableEvent* flush_complete_event) {
  69   base::debug::TraceLog::GetInstance()->SetDisabled();
  70   base::debug::TraceLog::GetInstance()->Flush(
  71       base::Bind(&BrowserShutdownProfileDumper::WriteTraceDataCollected,
  72                  base::Unretained(this),
  73                  base::Unretained(flush_complete_event)));
  74 }
  75
  76 // static
  77 base::FilePath BrowserShutdownProfileDumper::GetShutdownProfileFileName() {
  78   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
  79   base::FilePath trace_file =
  80       command_line.GetSwitchValuePath(switches::kTraceShutdownFile);
  81
  82   if (!trace_file.empty())
  83     return trace_file;
  84
  85   // Default to saving the startup trace into the current dir.
  86   return base::FilePath().AppendASCII("chrometrace.log");
  87 }
  88
  89 void BrowserShutdownProfileDumper::WriteTraceDataCollected(
  90     base::WaitableEvent* flush_complete_event,
  91     const scoped_refptr<base::RefCountedString>& events_str,
  92     bool has_more_events) {
  93   if (!IsFileValid()) {
  94     flush_complete_event->Signal();
  95     return;
  96   }
  97   if (blocks_) {
  98     // Blocks are not comma separated. Beginning with the second block we
  99     // start therefore to add one in front of the previous block.
 100     WriteString(",");
 101   }
 102   ++blocks_;
 103   WriteString(events_str->data());
 104
 105   if (!has_more_events) {
 106     WriteString("]");
 107     WriteString("}");
 108     CloseFile();
 109     flush_complete_event->Signal();
 110   }
 111 }
 112
 113 bool BrowserShutdownProfileDumper::IsFileValid() {
 114   return dump_file_ && (ferror(dump_file_) == 0);
 115 }
 116
 117 void BrowserShutdownProfileDumper::WriteString(const std::string& string) {
 118   WriteChars(string.data(), string.size());
 119 }
 120
 121 void BrowserShutdownProfileDumper::WriteChars(const char* chars, size_t size) {
 122   if (!IsFileValid())
 123     return;
 124
 125   size_t written = fwrite(chars, 1, size, dump_file_);
 126   if (written != size) {
 127     LOG(ERROR) << "Error " << ferror(dump_file_)
 128                << " in fwrite() to trace file '" << dump_file_name_.value()
 129                << "'";
 130     CloseFile();
 131   }
 132 }
 133
 134 void BrowserShutdownProfileDumper::CloseFile() {
 135   if (!dump_file_)
 136     return;
 137   base::CloseFile(dump_file_);
 138   dump_file_ = NULL;
 139 }
 140
 141 }  // namespace content