Add a mode flag to the tracing framework.

content/browser/devtools/devtools_tracing_handler.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 "content/browser/devtools/devtools_tracing_handler.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/json/json_writer.h"
 #include "base/location.h"
+#include "base/string_split.h"
 #include "base/values.h"
 #include "content/browser/devtools/devtools_http_handler_impl.h"
 #include "content/public/browser/trace_controller.h"
 #include "content/public/browser/trace_subscriber.h"
 
 namespace content {
 
 namespace {
 
 const char kTracingStartCommand[] = "Tracing.start";
 const char kTracingEndCommand[] = "Tracing.end";
 
 const char kTracingCompleteNotification[] = "Tracing.tracingComplete";
 const char kTracingDataCollected[] = "Tracing.dataCollected";
 
 const char kCategoriesParam[] = "categories";
 
+const char kTraceOptionsParam[] = "trace-options";
+const char kRecordUntilFull[]   = "record-until-full";
+
 }  // namespace
 
 const char DevToolsTracingHandler::kDomain[] = "Tracing";
 
 DevToolsTracingHandler::DevToolsTracingHandler()
     : is_running_(false) {
   RegisterCommandHandler(kTracingStartCommand,
                          base::Bind(&DevToolsTracingHandler::OnStart,
                                     base::Unretained(this)));
   RegisterCommandHandler(kTracingEndCommand,
@@ skipping 11 matching lines @@
 
 void DevToolsTracingHandler::OnTraceDataCollected(
     const scoped_refptr<base::RefCountedString>& trace_fragment) {
   if (is_running_) {
     base::DictionaryValue* params = new base::DictionaryValue();
     params->SetString("value", trace_fragment->data());
     SendNotification(kTracingDataCollected, params);
   }
 }
 
+// Note, if you add more options here you also need to update:
+// base/debug/trace_event_impl:TraceOptionsFromString
+int DevToolsTracingHandler::TraceOptionsFromString(const std::string& options) {
+  std::vector<std::string> split;
+  std::vector<std::string>::iterator iter;
+  int ret = 0;
+
+  base::SplitString(options, ',', &split);
+  for (iter = split.begin(); iter != split.end(); ++iter) {
+    if (*iter == kRecordUntilFull) {

[pfeldman, 2013/02/21 16:33:05]

Do you need to trim it before comparison?

[dsinclair, 2013/02/21 16:35:59]

SplitString will trim leading and trailing whitespace when it does the split.

+      ret |= base::debug::TraceLog::RECORD_UNTIL_FULL;
+    }
+  }
+  if (ret == 0)
+    ret = base::debug::TraceLog::RECORD_UNTIL_FULL;
+
+  return ret;

[pfeldman, 2013/02/21 16:33:05]

Not sure I follow, but it sounds like it always returns RECORD_UNTIL_FULL no
matter what the input it?

[dsinclair, 2013/02/21 16:35:59]

It does at the moment. I have another patch in the works which will add a
RECORD_CONTINUOUS option and there is a third patch being worked on to add a
SAMPLING option as well.

This is just getting the foundation in place which is why it looks a bit weird
at the moment.

+}
+
 scoped_ptr<DevToolsProtocol::Response>
 DevToolsTracingHandler::OnStart(DevToolsProtocol::Command* command) {
   std::string categories;
   base::DictionaryValue* params = command->params();
   if (params && params->HasKey(kCategoriesParam))
     params->GetString(kCategoriesParam, &categories);
-  TraceController::GetInstance()->BeginTracing(this, categories);
+
+  int options = base::debug::TraceLog::RECORD_UNTIL_FULL;
+  if (params && params->HasKey(kTraceOptionsParam)) {
+    std::string options_param;
+    params->GetString(kTraceOptionsParam, &options_param);
+    options = TraceOptionsFromString(options_param);
+  }
+
+  TraceController::GetInstance()->BeginTracing(this, categories, options);
   is_running_ = true;
   return command->SuccessResponse(NULL);
 }
 
 
 scoped_ptr<DevToolsProtocol::Response>
 DevToolsTracingHandler::OnEnd(DevToolsProtocol::Command* command) {
   TraceController::GetInstance()->EndTracingAsync(this);
   return command->SuccessResponse(NULL);
 }
 
 }  // namespace content