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      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 "components/feedback/tracing_manager.h"
      6 
      7 #include "base/bind.h"
      8 #include "base/memory/ref_counted_memory.h"
      9 #include "base/message_loop/message_loop_proxy.h"
     10 #include "components/feedback/feedback_util.h"
     11 #include "content/public/browser/tracing_controller.h"
     12 
     13 namespace {
     14 
     15 // Only once trace manager can exist at a time.
     16 TracingManager* g_tracing_manager = NULL;
     17 // Trace IDs start at 1 and increase.
     18 int g_next_trace_id = 1;
     19 // Name of the file to store the tracing data as.
     20 const base::FilePath::CharType kTracingFilename[] =
     21     FILE_PATH_LITERAL("tracing.json");
     22 }
     23 
     24 TracingManager::TracingManager()
     25     : current_trace_id_(0),
     26       weak_ptr_factory_(this) {
     27   DCHECK(!g_tracing_manager);
     28   g_tracing_manager = this;
     29   StartTracing();
     30 }
     31 
     32 TracingManager::~TracingManager() {
     33   DCHECK(g_tracing_manager == this);
     34   g_tracing_manager = NULL;
     35 }
     36 
     37 int TracingManager::RequestTrace() {
     38   // Return the current trace if one is being collected.
     39   if (current_trace_id_)
     40     return current_trace_id_;
     41 
     42   current_trace_id_ = g_next_trace_id;
     43   ++g_next_trace_id;
     44   content::TracingController::GetInstance()->DisableRecording(
     45       content::TracingController::CreateStringSink(
     46           base::Bind(&TracingManager::OnTraceDataCollected,
     47                      weak_ptr_factory_.GetWeakPtr())));
     48   return current_trace_id_;
     49 }
     50 
     51 bool TracingManager::GetTraceData(int id, const TraceDataCallback& callback) {
     52   // If a trace is being collected currently, send it via callback when
     53   // complete.
     54   if (current_trace_id_) {
     55     // Only allow one trace data request at a time.
     56     if (trace_callback_.is_null()) {
     57       trace_callback_ = callback;
     58       return true;
     59     } else {
     60       return false;
     61     }
     62   } else {
     63     std::map<int, scoped_refptr<base::RefCountedString> >::iterator data =
     64         trace_data_.find(id);
     65     if (data == trace_data_.end())
     66       return false;
     67 
     68     // Always return the data asychronously, so the behavior is consistant.
     69     base::MessageLoopProxy::current()->PostTask(
     70         FROM_HERE,
     71         base::Bind(callback, data->second));
     72     return true;
     73   }
     74 }
     75 
     76 void TracingManager::DiscardTraceData(int id) {
     77   trace_data_.erase(id);
     78 
     79   // If the trace is discarded before it is complete, clean up the accumulators.
     80   if (id == current_trace_id_) {
     81     current_trace_id_ = 0;
     82 
     83     // If the trace has already been requested, provide an empty string.
     84     if (!trace_callback_.is_null()) {
     85       trace_callback_.Run(scoped_refptr<base::RefCountedString>());
     86       trace_callback_.Reset();
     87     }
     88   }
     89 }
     90 
     91 void TracingManager::StartTracing() {
     92   content::TracingController::GetInstance()->EnableRecording(
     93       base::debug::CategoryFilter(),
     94       base::debug::TraceOptions(),
     95       content::TracingController::EnableRecordingDoneCallback());
     96 }
     97 
     98 void TracingManager::OnTraceDataCollected(base::RefCountedString* trace_data) {
     99   if (!current_trace_id_)
    100     return;
    101 
    102   std::string output_val;
    103   feedback_util::ZipString(
    104       base::FilePath(kTracingFilename), trace_data->data(), &output_val);
    105 
    106   scoped_refptr<base::RefCountedString> output(
    107       base::RefCountedString::TakeString(&output_val));
    108 
    109   trace_data_[current_trace_id_] = output;
    110 
    111   if (!trace_callback_.is_null()) {
    112     trace_callback_.Run(output);
    113     trace_callback_.Reset();
    114   }
    115 
    116   current_trace_id_ = 0;
    117 
    118   // Tracing has to be restarted asynchronous, so the TracingController can
    119   // clean up.
    120   base::MessageLoopProxy::current()->PostTask(
    121       FROM_HERE,
    122       base::Bind(&TracingManager::StartTracing,
    123                  weak_ptr_factory_.GetWeakPtr()));
    124 }
    125 
    126 // static
    127 scoped_ptr<TracingManager> TracingManager::Create() {
    128   if (g_tracing_manager)
    129     return scoped_ptr<TracingManager>();
    130   return scoped_ptr<TracingManager>(new TracingManager());
    131 }
    132 
    133 TracingManager* TracingManager::Get() {
    134   return g_tracing_manager;
    135 }
    136