content/browser/trace_subscriber_stdio.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/trace_subscriber_stdio.h"
   6
   7 #include "base/bind.h"
   8 #include "base/debug/trace_event.h"
   9 #include "base/logging.h"
  10 #include "base/threading/sequenced_worker_pool.h"
  11 #include "content/public/browser/browser_thread.h"
  12
  13 namespace content {
  14
  15 // All method calls on this class are done on a SequencedWorkerPool thread.
  16 class TraceSubscriberStdioImpl
  17     : public base::RefCountedThreadSafe<TraceSubscriberStdioImpl> {
  18  public:
  19   explicit TraceSubscriberStdioImpl(const FilePath& path)
  20       : path_(path),
  21         file_(0) {}
  22
  23   void OnStart() {
  24     DCHECK(!file_);
  25     trace_buffer_.SetOutputCallback(
  26         base::Bind(&TraceSubscriberStdioImpl::Write, this));
  27     file_ = file_util::OpenFile(path_, "w+");
  28     if (IsValid()) {
  29       LOG(INFO) << "Logging performance trace to file: " << path_.value();
  30       trace_buffer_.Start();
  31     } else {
  32       LOG(ERROR) << "Failed to open performance trace file: " << path_.value();
  33     }
  34   }
  35
  36   void OnData(const scoped_refptr<base::RefCountedString>& data_ptr) {
  37     trace_buffer_.AddFragment(data_ptr->data());
  38   }
  39
  40   void OnEnd() {
  41     trace_buffer_.Finish();
  42     CloseFile();
  43   }
  44
  45  private:
  46   friend class base::RefCountedThreadSafe<TraceSubscriberStdioImpl>;
  47
  48   ~TraceSubscriberStdioImpl() {
  49     CloseFile();
  50   }
  51
  52   bool IsValid() const {
  53     return file_ && (0 == ferror(file_));
  54   }
  55
  56   void CloseFile() {
  57     if (file_) {
  58       fclose(file_);
  59       file_ = 0;
  60     }
  61     // This is important, as it breaks a reference cycle.
  62     trace_buffer_.SetOutputCallback(
  63         base::debug::TraceResultBuffer::OutputCallback());
  64   }
  65
  66   void Write(const std::string& output_str) {
  67     if (IsValid()) {
  68       size_t written = fwrite(output_str.data(), 1, output_str.size(), file_);
  69       if (written != output_str.size()) {
  70         LOG(ERROR) << "Error " << ferror(file_) << " in fwrite() to trace file";
  71         CloseFile();
  72       }
  73     }
  74   }
  75
  76   FilePath path_;
  77   FILE* file_;
  78   base::debug::TraceResultBuffer trace_buffer_;
  79 };
  80
  81 TraceSubscriberStdio::TraceSubscriberStdio(const FilePath& path)
  82     : impl_(new TraceSubscriberStdioImpl(path)) {
  83   BrowserThread::PostBlockingPoolSequencedTask(
  84       __FILE__, FROM_HERE,
  85       base::Bind(&TraceSubscriberStdioImpl::OnStart, impl_));
  86 }
  87
  88 TraceSubscriberStdio::~TraceSubscriberStdio() {
  89 }
  90
  91 void TraceSubscriberStdio::OnEndTracingComplete() {
  92   BrowserThread::PostBlockingPoolSequencedTask(
  93       __FILE__, FROM_HERE,
  94       base::Bind(&TraceSubscriberStdioImpl::OnEnd, impl_));
  95 }
  96
  97 void TraceSubscriberStdio::OnTraceDataCollected(
  98     const scoped_refptr<base::RefCountedString>& data_ptr) {
  99   BrowserThread::PostBlockingPoolSequencedTask(
 100       __FILE__, FROM_HERE,
 101       base::Bind(&TraceSubscriberStdioImpl::OnData, impl_, data_ptr));
 102 }
 103
 104 }  // namespace content