Refactor trace_event_impl's SetEnabled to use TraceOptions. Propagate this through the whole stack.

base/debug/trace_event_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/trace_event_impl.h"
 
 #include <algorithm>
 
 #include "base/base_switches.h"
 #include "base/bind.h"
@@ skipping 952 matching lines @@
     : bucket(bucket),
       bucket_name(name),
       callback(callback) {
 }
 
 TraceBucketData::~TraceBucketData() {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 //
+// TraceOptions
+//
+////////////////////////////////////////////////////////////////////////////////
+
+TraceOptions::TraceOptions(StringPiece options)
+    : record_mode(RECORD_UNTIL_FULL), enable_sampling(false) {
+  std::vector<std::string> split;
+  std::vector<std::string>::iterator iter;
+
+  base::SplitString(options.as_string(), ',', &split);
+  for (iter = split.begin(); iter != split.end(); ++iter) {
+    if (*iter == kRecordUntilFull) {
+      record_mode = RECORD_UNTIL_FULL;
+    } else if (*iter == kRecordContinuously) {
+      record_mode = RECORD_CONTINUOUSLY;
+    } else if (*iter == kTraceToConsole) {
+      record_mode = ECHO_TO_CONSOLE;
+    } else if (*iter == kEnableSampling) {
+      enable_sampling = true;
+    }
+  }
+}
+
+std::string TraceOptions::ToString() const {
+  std::string ret;
+  switch (record_mode) {
+    case RECORD_UNTIL_FULL:
+      ret = kRecordUntilFull;
+      break;
+    case RECORD_CONTINUOUSLY:
+      ret = kRecordContinuously;
+      break;
+    case ECHO_TO_CONSOLE:
+      ret = kTraceToConsole;
+      break;
+    default:
+      NOTREACHED();
+  }
+  return enable_sampling ? ret + "," + kEnableSampling : ret;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
 // TraceLog
 //
 ////////////////////////////////////////////////////////////////////////////////
 
 class TraceLog::ThreadLocalEventBuffer
     : public MessageLoop::DestructionObserver {
  public:
   ThreadLocalEventBuffer(TraceLog* trace_log);
   virtual ~ThreadLocalEventBuffer();
 
@@ skipping 185 matching lines @@
         switches::kTraceToConsole);
     if (filter.empty()) {
       filter = kEchoToConsoleCategoryFilter;
     } else {
       filter.append(",");
       filter.append(kEchoToConsoleCategoryFilter);
     }
 
     LOG(ERROR) << "Start " << switches::kTraceToConsole
                << " with CategoryFilter '" << filter << "'.";
-    SetEnabled(CategoryFilter(filter), RECORDING_MODE, ECHO_TO_CONSOLE);
+    SetEnabled(CategoryFilter(filter),
+               RECORDING_MODE,
+               TraceOptions(TraceOptions::ECHO_TO_CONSOLE, false));
   }
 #endif
 
   logged_events_.reset(CreateTraceBuffer());
 }
 
 TraceLog::~TraceLog() {
 }
 
 const unsigned char* TraceLog::GetCategoryGroupEnabled(
@@ skipping 129 matching lines @@
   AutoLock lock(lock_);
   category_groups->push_back(
       g_category_groups[g_category_trace_event_overhead]);
   size_t category_index = base::subtle::NoBarrier_Load(&g_category_index);
   for (size_t i = g_num_builtin_categories; i < category_index; i++)
     category_groups->push_back(g_category_groups[i]);
 }
 
 void TraceLog::SetEnabled(const CategoryFilter& category_filter,
                           Mode mode,
-                          Options options) {
+                          TraceOptions options) {
   std::vector<EnabledStateObserver*> observer_list;
   {
     AutoLock lock(lock_);
 
     // Can't enable tracing when Flush() is in progress.
     DCHECK(!flush_message_loop_proxy_.get());
 
-    Options old_options = trace_options();
+    InternalTraceOptions new_options =
+        GetInternalOptionsFromTraceOptions(options);
+
+   InternalTraceOptions old_options = trace_options();
 
     if (IsEnabled()) {
-      if (options != old_options) {
+      if (new_options != old_options) {
         DLOG(ERROR) << "Attempting to re-enable tracing with a different "
                     << "set of options.";
       }
 
       if (mode != mode_) {
         DLOG(ERROR) << "Attempting to re-enable tracing with a different mode.";
       }
 
       category_filter_.Merge(category_filter);
       UpdateCategoryGroupEnabledFlags();
       return;
     }
 
     if (dispatching_to_observer_list_) {
       DLOG(ERROR) <<
           "Cannot manipulate TraceLog::Enabled state from an observer.";
       return;
     }
 
     mode_ = mode;
 
-    if (options != old_options) {
-      subtle::NoBarrier_Store(&trace_options_, options);
+    if (new_options != old_options) {
+      subtle::NoBarrier_Store(&trace_options_, new_options);
       UseNextTraceBuffer();
     }
 
     num_traces_recorded_++;
 
     category_filter_ = CategoryFilter(category_filter);
     UpdateCategoryGroupEnabledFlags();
     UpdateSyntheticDelaysFromCategoryFilter();
 
-    if (options & ENABLE_SAMPLING) {
+    if (new_options & ENABLE_SAMPLING) {
       sampling_thread_.reset(new TraceSamplingThread);
       sampling_thread_->RegisterSampleBucket(
           &g_trace_state[0],
           "bucket0",
           Bind(&TraceSamplingThread::DefaultSamplingCallback));
       sampling_thread_->RegisterSampleBucket(
           &g_trace_state[1],
           "bucket1",
           Bind(&TraceSamplingThread::DefaultSamplingCallback));
       sampling_thread_->RegisterSampleBucket(
@@ skipping 12 matching lines @@
   // Notify observers outside the lock in case they trigger trace events.
   for (size_t i = 0; i < observer_list.size(); ++i)
     observer_list[i]->OnTraceLogEnabled();
 
   {
     AutoLock lock(lock_);
     dispatching_to_observer_list_ = false;
   }
 }
 
+TraceLog::InternalTraceOptions TraceLog::GetInternalOptionsFromTraceOptions(

[dsinclair, 2014/07/28 18:52:36]

The spit between trace options and internal trace options seems like it's going
to cause bugs in the future.

When can we use one, and when the other? What happens if we grab the
non-internal one at some point, does things get out of sync?

[nednguyen, 2014/07/28 20:27:22]

The InternalTraceOptions is only used by the trace_event_impl's implementation
as they are private. So all callers of TraceLog must use the TraceOptions. 

There maybe a better way to convey this, maybe a private namespace? I am not
sure, please give some advices.

+    const TraceOptions& options) {
+  InternalTraceOptions ret = options.enable_sampling ? ENABLE_SAMPLING : NONE;
+  switch (options.record_mode) {
+    case TraceOptions::RECORD_UNTIL_FULL:
+      return ret | RECORD_UNTIL_FULL;
+    case TraceOptions::RECORD_CONTINUOUSLY:
+      return ret | RECORD_CONTINUOUSLY;
+    case TraceOptions::ECHO_TO_CONSOLE:
+      return ret | ECHO_TO_CONSOLE;
+  }
+  NOTREACHED();
+  return NONE;
+}
+
 CategoryFilter TraceLog::GetCurrentCategoryFilter() {
   AutoLock lock(lock_);
   return category_filter_;
 }
 
+TraceOptions TraceLog::GetCurrentTraceOptions() const {
+  TraceOptions ret;
+  InternalTraceOptions option = trace_options();
+  ret.enable_sampling = (option & ENABLE_SAMPLING) != 0;
+  if (option & RECORD_UNTIL_FULL)
+    ret.record_mode = TraceOptions::RECORD_UNTIL_FULL;
+  else if (option & RECORD_CONTINUOUSLY)
+    ret.record_mode = TraceOptions::RECORD_CONTINUOUSLY;
+  else if (option & ECHO_TO_CONSOLE)
+    ret.record_mode = TraceOptions::ECHO_TO_CONSOLE;
+  else
+    NOTREACHED();
+  return ret;
+}
+
 void TraceLog::SetDisabled() {
   AutoLock lock(lock_);
   SetDisabledWhileLocked();
 }
 
 void TraceLog::SetDisabledWhileLocked() {
   lock_.AssertAcquired();
 
   if (!IsEnabled())
     return;
@@ skipping 69 matching lines @@
   return static_cast<float>(static_cast<double>(logged_events_->Size()) /
                             logged_events_->Capacity());
 }
 
 bool TraceLog::BufferIsFull() const {
   AutoLock lock(lock_);
   return logged_events_->IsFull();
 }
 
 TraceBuffer* TraceLog::CreateTraceBuffer() {
-  Options options = trace_options();
+  InternalTraceOptions options = trace_options();
   if (options & RECORD_CONTINUOUSLY)
     return new TraceBufferRingBuffer(kTraceEventRingBufferChunks);
   else if ((options & ENABLE_SAMPLING) && mode_ == MONITORING_MODE)
     return new TraceBufferRingBuffer(kMonitorTraceEventBufferChunks);
   else if (options & ECHO_TO_CONSOLE)
     return new TraceBufferRingBuffer(kEchoToConsoleTraceEventBufferChunks);
   return CreateTraceBufferVectorOfSize(kTraceEventVectorBufferChunks);
 }
 
 TraceBuffer* TraceLog::CreateTraceBufferVectorOfSize(size_t max_chunks) {
@@ skipping 937 matching lines @@
 }
 
 ScopedTraceBinaryEfficient::~ScopedTraceBinaryEfficient() {
   if (*category_group_enabled_) {
     TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_group_enabled_,
                                                 name_, event_handle_);
   }
 }
 
 }  // namespace trace_event_internal