Add a Content API around TracingController.

content/browser/trace_controller.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/trace_controller.h"
-
-#include "base/bind.h"
-#include "base/command_line.h"
-#include "base/debug/trace_event.h"
-#include "base/string_number_conversions.h"
-#include "content/browser/trace_message_filter.h"
-#include "content/browser/trace_subscriber_stdio.h"
-#include "content/common/child_process_messages.h"
-#include "content/public/browser/browser_message_filter.h"
-#include "content/public/common/content_switches.h"
-
-using base::debug::TraceLog;
-using content::BrowserMessageFilter;
-using content::BrowserThread;
-
-namespace {
-
-class AutoStopTraceSubscriberStdio : public content::TraceSubscriberStdio {
- public:
-  AutoStopTraceSubscriberStdio(const FilePath& file_path)
-      : TraceSubscriberStdio(file_path) {}
-
-  static void EndStartupTrace(TraceSubscriberStdio* subscriber) {
-    if (!TraceController::GetInstance()->EndTracingAsync(subscriber))
-      delete subscriber;
-    // else, the tracing will end asynchronously in OnEndTracingComplete().
-  }
-
-  virtual void OnEndTracingComplete() {
-    TraceSubscriberStdio::OnEndTracingComplete();
-    delete this;
-    // TODO(joth): this would be the time to automatically open up
-    // chrome://tracing/ and load up the trace data collected.
-  }
-};
-
-}  // namespace
-
-void TraceSubscriber::OnKnownCategoriesCollected(
-      const std::set<std::string>& known_categories) {}
-
-void TraceSubscriber::OnTraceBufferPercentFullReply(float percent_full) {}
-
-TraceSubscriber::~TraceSubscriber() {}
-
-TraceController::TraceController() :
-    subscriber_(NULL),
-    pending_end_ack_count_(0),
-    pending_bpf_ack_count_(0),
-    maximum_bpf_(0.0f),
-    is_tracing_(false),
-    is_get_categories_(false) {
-  TraceLog::GetInstance()->SetOutputCallback(
-      base::Bind(&TraceController::OnTraceDataCollected,
-                 base::Unretained(this)));
-}
-
-TraceController::~TraceController() {
-  if (TraceLog* trace_log = TraceLog::GetInstance())
-    trace_log->SetOutputCallback(TraceLog::OutputCallback());
-}
-
-TraceController* TraceController::GetInstance() {
-  return Singleton<TraceController>::get();
-}
-
-void TraceController::InitStartupTracing(const CommandLine& command_line) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  FilePath trace_file = command_line.GetSwitchValuePath(
-      switches::kTraceStartupFile);
-  // trace_file = "none" means that startup events will show up for the next
-  // begin/end tracing (via about:tracing or AutomationProxy::BeginTracing/
-  // EndTracing, for example).
-  if (trace_file == FilePath().AppendASCII("none"))
-    return;
-
-  if (trace_file.empty()) {
-    // Default to saving the startup trace into the current dir.
-    trace_file = FilePath().AppendASCII("chrometrace.log");
-  }
-  scoped_ptr<AutoStopTraceSubscriberStdio> subscriber(
-      new AutoStopTraceSubscriberStdio(trace_file));
-  DCHECK(can_begin_tracing(subscriber.get()));
-
-  std::string delay_str = command_line.GetSwitchValueASCII(
-      switches::kTraceStartupDuration);
-  int delay_secs = 5;
-  if (!delay_str.empty() && !base::StringToInt(delay_str, &delay_secs)) {
-    DLOG(WARNING) << "Could not parse --" << switches::kTraceStartupDuration
-        << "=" << delay_str << " defaulting to 5 (secs)";
-    delay_secs = 5;
-  }
-
-  OnTracingBegan(subscriber.get());
-  BrowserThread::PostDelayedTask(
-      BrowserThread::UI,
-      FROM_HERE,
-      base::Bind(&AutoStopTraceSubscriberStdio::EndStartupTrace,
-                 base::Unretained(subscriber.release())),
-      base::TimeDelta::FromSeconds(delay_secs));
-}
-
-bool TraceController::GetKnownCategoriesAsync(TraceSubscriber* subscriber) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  // Known categories come back from child processes with the EndTracingAck
-  // message. So to get known categories, just begin and end tracing immediately
-  // afterwards. This will ping all the child processes for categories.
-  is_get_categories_ = true;
-  bool success = BeginTracing(subscriber) && EndTracingAsync(subscriber);
-  is_get_categories_ = success;
-  return success;
-}
-
-bool TraceController::BeginTracing(TraceSubscriber* subscriber) {
-  std::vector<std::string> include, exclude;
-  // By default, exclude all categories that begin with test_
-  exclude.push_back("test_*");
-  return BeginTracing(subscriber, include, exclude);
-}
-
-bool TraceController::BeginTracing(
-    TraceSubscriber* subscriber,
-    const std::vector<std::string>& included_categories,
-    const std::vector<std::string>& excluded_categories) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  if (!can_begin_tracing(subscriber))
-    return false;
-
-  // Enable tracing
-  TraceLog::GetInstance()->SetEnabled(included_categories, excluded_categories);
-  OnTracingBegan(subscriber);
-
-  return true;
-}
-
-bool TraceController::BeginTracing(TraceSubscriber* subscriber,
-                                   const std::string& categories) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  if (!can_begin_tracing(subscriber))
-    return false;
-
-  // Enable tracing
-  TraceLog::GetInstance()->SetEnabled(categories);
-
-  OnTracingBegan(subscriber);
-
-  return true;
-}
-
-bool TraceController::EndTracingAsync(TraceSubscriber* subscriber) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  if (!can_end_tracing() || subscriber != subscriber_)
-    return false;
-
-  // There could be a case where there are no child processes and filters_
-  // is empty. In that case we can immediately tell the subscriber that tracing
-  // has ended. To avoid recursive calls back to the subscriber, we will just
-  // use the existing asynchronous OnEndTracingAck code.
-  // Count myself (local trace) in pending_end_ack_count_, acked below.
-  pending_end_ack_count_ = filters_.size() + 1;
-
-  // Handle special case of zero child processes.
-  if (pending_end_ack_count_ == 1) {
-    // Ack asynchronously now, because we don't have any children to wait for.
-    std::vector<std::string> categories;
-    TraceLog::GetInstance()->GetKnownCategories(&categories);
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnEndTracingAck, base::Unretained(this),
-                   categories));
-  }
-
-  // Notify all child processes.
-  for (FilterMap::iterator it = filters_.begin(); it != filters_.end(); ++it) {
-    it->get()->SendEndTracing();
-  }
-
-  return true;
-}
-
-bool TraceController::GetTraceBufferPercentFullAsync(
-    TraceSubscriber* subscriber) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  if (!can_get_buffer_percent_full() || subscriber != subscriber_)
-    return false;
-
-  maximum_bpf_ = 0.0f;
-  pending_bpf_ack_count_ = filters_.size() + 1;
-
-  // Handle special case of zero child processes.
-  if (pending_bpf_ack_count_ == 1) {
-    // Ack asynchronously now, because we don't have any children to wait for.
-    float bpf = TraceLog::GetInstance()->GetBufferPercentFull();
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnTraceBufferPercentFullReply,
-                   base::Unretained(this), bpf));
-  }
-
-  // Message all child processes.
-  for (FilterMap::iterator it = filters_.begin(); it != filters_.end(); ++it) {
-    it->get()->SendGetTraceBufferPercentFull();
-  }
-
-  return true;
-}
-
-void TraceController::CancelSubscriber(TraceSubscriber* subscriber) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  if (subscriber == subscriber_) {
-    subscriber_ = NULL;
-    // End tracing if necessary.
-    if (is_tracing_ && pending_end_ack_count_ == 0)
-      EndTracingAsync(NULL);
-  }
-}
-
-void TraceController::AddFilter(TraceMessageFilter* filter) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::AddFilter, base::Unretained(this),
-                   make_scoped_refptr(filter)));
-    return;
-  }
-
-  filters_.insert(filter);
-  if (is_tracing_enabled()) {
-    filter->SendBeginTracing(included_categories_, excluded_categories_);
-  }
-}
-
-void TraceController::RemoveFilter(TraceMessageFilter* filter) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::RemoveFilter, base::Unretained(this),
-                   make_scoped_refptr(filter)));
-    return;
-  }
-
-  filters_.erase(filter);
-}
-
-void TraceController::OnTracingBegan(TraceSubscriber* subscriber) {
-  is_tracing_ = true;
-
-  subscriber_ = subscriber;
-
-  TraceLog::GetInstance()->GetEnabledTraceCategories(&included_categories_,
-                                                     &excluded_categories_);
-  // Notify all child processes.
-  for (FilterMap::iterator it = filters_.begin(); it != filters_.end(); ++it) {
-    it->get()->SendBeginTracing(included_categories_, excluded_categories_);
-  }
-}
-
-void TraceController::OnEndTracingAck(
-    const std::vector<std::string>& known_categories) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnEndTracingAck, base::Unretained(this),
-                   known_categories));
-    return;
-  }
-
-  // Merge known_categories with known_categories_
-  known_categories_.insert(known_categories.begin(), known_categories.end());
-
-  if (pending_end_ack_count_ == 0)
-    return;
-
-  if (--pending_end_ack_count_ == 0) {
-    // All acks have been received.
-    is_tracing_ = false;
-
-    // Disable local trace. During this call, our OnTraceDataCollected will be
-    // called with the last of the local trace data. Since we are on the UI
-    // thread, the call to OnTraceDataCollected will be synchronous, so we can
-    // immediately call OnEndTracingComplete below.
-    TraceLog::GetInstance()->SetEnabled(false);
-
-    // Trigger callback if one is set.
-    if (subscriber_) {
-      if (is_get_categories_)
-        subscriber_->OnKnownCategoriesCollected(known_categories_);
-      else
-        subscriber_->OnEndTracingComplete();
-      // Clear subscriber so that others can use TraceController.
-      subscriber_ = NULL;
-    }
-
-    is_get_categories_ = false;
-  }
-
-  if (pending_end_ack_count_ == 1) {
-    // The last ack represents local trace, so we need to ack it now. Note that
-    // this code only executes if there were child processes.
-    std::vector<std::string> categories;
-    TraceLog::GetInstance()->GetKnownCategories(&categories);
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnEndTracingAck, base::Unretained(this),
-                   categories));
-  }
-}
-
-void TraceController::OnTraceDataCollected(
-    const scoped_refptr<base::RefCountedString>& events_str_ptr) {
-  // OnTraceDataCollected may be called from any browser thread, either by the
-  // local event trace system or from child processes via TraceMessageFilter.
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnTraceDataCollected,
-                   base::Unretained(this), events_str_ptr));
-    return;
-  }
-
-  // Drop trace events if we are just getting categories.
-  if (subscriber_ && !is_get_categories_)
-    subscriber_->OnTraceDataCollected(events_str_ptr);
-}
-
-void TraceController::OnTraceBufferFull() {
-  // OnTraceBufferFull may be called from any browser thread, either by the
-  // local event trace system or from child processes via TraceMessageFilter.
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnTraceBufferFull,
-                   base::Unretained(this)));
-    return;
-  }
-
-  // EndTracingAsync may return false if tracing is already in the process of
-  // being ended. That is ok.
-  EndTracingAsync(subscriber_);
-}
-
-void TraceController::OnTraceBufferPercentFullReply(float percent_full) {
-  if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnTraceBufferPercentFullReply,
-                   base::Unretained(this), percent_full));
-    return;
-  }
-
-  if (pending_bpf_ack_count_ == 0)
-    return;
-
-  maximum_bpf_ = (maximum_bpf_ > percent_full)? maximum_bpf_ : percent_full;
-
-  if (--pending_bpf_ack_count_ == 0) {
-    // Trigger callback if one is set.
-    if (subscriber_)
-      subscriber_->OnTraceBufferPercentFullReply(maximum_bpf_);
-  }
-
-  if (pending_bpf_ack_count_ == 1) {
-    // The last ack represents local trace, so we need to ack it now. Note that
-    // this code only executes if there were child processes.
-    float bpf = TraceLog::GetInstance()->GetBufferPercentFull();
-    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-        base::Bind(&TraceController::OnTraceBufferPercentFullReply,
-                   base::Unretained(this), bpf));
-  }
-}
-