Support JellyBean MR2 style of systrace

base/debug/trace_event_android.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 <fcntl.h>
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/stringprintf.h"
 
 namespace {
 
 int g_atrace_fd = -1;
 const char* kATraceMarkerFile = "/sys/kernel/debug/tracing/trace_marker";
 
 }  // namespace
 
 namespace base {
 namespace debug {
 
-// static
-void TraceLog::InitATrace() {
-  DCHECK(g_atrace_fd == -1);
-  g_atrace_fd = open(kATraceMarkerFile, O_WRONLY | O_APPEND);
-  if (g_atrace_fd == -1)
-    LOG(WARNING) << "Couldn't open " << kATraceMarkerFile;
+void TraceLog::StartATrace() {
+  AutoLock lock(lock_);
+  if (g_atrace_fd == -1) {
+    g_atrace_fd = open(kATraceMarkerFile, O_WRONLY);
+    if (g_atrace_fd == -1)
+      LOG(WARNING) << "Couldn't open " << kATraceMarkerFile;
+  }
+}
+
+void TraceLog::StopATrace() {
+  AutoLock lock(lock_);
+  if (g_atrace_fd != -1) {
+    close(g_atrace_fd);
+    g_atrace_fd = -1;
+  }
 }
 
 void TraceLog::SendToATrace(char phase,
                             const char* category,
                             const char* name,
                             int num_args,
                             const char** arg_names,
                             const unsigned char* arg_types,
                             const unsigned long long* arg_values) {
   if (g_atrace_fd == -1)
@@ skipping 45 matching lines @@
     default:
       // Do nothing.
       break;
   }
 }
 
 // Must be called with lock_ locked.
 void TraceLog::ApplyATraceEnabledFlag(unsigned char* category_enabled) {
   if (g_atrace_fd != -1)
     *category_enabled |= ATRACE_ENABLED;
+  else
+    *category_enabled &= ~ATRACE_ENABLED;
 }
 
 }  // namespace debug
 }  // namespace base