Revert of Revert "Revert 237280 "Remove TraceController""

content/browser/tracing/trace_subscriber_stdio.cc

Index: content/browser/tracing/trace_subscriber_stdio.cc
diff --git a/content/browser/tracing/trace_subscriber_stdio.cc b/content/browser/tracing/trace_subscriber_stdio.cc
new file mode 100644
index 0000000000000000000000000000000000000000..da816609391b34dd76c659b9e49fc15571216634
--- /dev/null
+++ b/content/browser/tracing/trace_subscriber_stdio.cc
@@ -0,0 +1,201 @@
+// 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/tracing/trace_subscriber_stdio.h"
+
+#include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+
+// All method calls on this class are done on a SequencedWorkerPool thread.
+class TraceSubscriberStdio::TraceSubscriberStdioWorker
+    : public base::RefCountedThreadSafe<TraceSubscriberStdioWorker> {
+ public:
+  TraceSubscriberStdioWorker(const base::FilePath& path,
+                             FileType file_type,
+                             bool has_system_trace)
+      : path_(path),
+        file_type_(file_type),
+        has_system_trace_(has_system_trace),
+        file_(0),
+        needs_comma_(false),
+        wrote_trace_(false),
+        has_pending_system_trace_(false),
+        wrote_system_trace_(false) {}
+
+  void OnTraceStart() {
+    DCHECK(!file_);
+    file_ = file_util::OpenFile(path_, "w+");
+    if (!IsValid()) {
+      LOG(ERROR) << "Failed to open performance trace file: " << path_.value();
+      return;
+    }
+
+    VLOG(0) << "Logging performance trace to file: " << path_.value();
+    if (file_type_ == FILE_TYPE_PROPERTY_LIST)
+      WriteString("{\"traceEvents\":");
+    WriteString("[");
+  }
+
+  void OnTraceData(const scoped_refptr<base::RefCountedString>& data_ptr) {
+    if (!IsValid())
+      return;
+    DCHECK(!data_ptr->data().empty());
+    if (needs_comma_)
+      WriteString(",");
+    WriteString(data_ptr->data());
+    needs_comma_ = true;
+  }
+
+  void OnSystemTraceData(
+      const scoped_refptr<base::RefCountedString>& data_ptr) {
+    if (wrote_trace_) {
+      WriteSystemTrace(data_ptr);
+      End();
+    } else {
+      pending_system_trace_ = data_ptr;
+      has_pending_system_trace_ = true;
+    }
+  }
+
+  void OnTraceEnd() {
+    if (!IsValid())
+      return;
+    WriteString("]");
+
+    wrote_trace_ = true;
+
+    if (!has_system_trace_ || wrote_system_trace_) {
+      End();
+      return;
+    }
+
+    WriteString(",");
+    if (has_pending_system_trace_) {
+      WriteSystemTrace(pending_system_trace_);
+      End();
+    }
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<TraceSubscriberStdioWorker>;
+
+  ~TraceSubscriberStdioWorker() {
+    CloseFile();
+  }
+
+  bool IsValid() const {
+    return file_ && (0 == ferror(file_));
+  }
+
+  void CloseFile() {
+    if (file_) {
+      fclose(file_);
+      file_ = 0;
+
+    }
+  }
+
+  void End() {
+    if (file_type_ == FILE_TYPE_PROPERTY_LIST)
+      WriteString("}");
+    CloseFile();
+  }
+
+  void WriteSystemTrace(const scoped_refptr<base::RefCountedString>& data_ptr) {
+    // Newlines need to be replaced with the string "\n" to be parsed correctly.
+    // Double quotes need to be replaced with the string "\"".
+    // System logs are ASCII.
+    const std::string& data = data_ptr->data();
+    const char* chars = data.c_str();
+    WriteString("\"systemTraceEvents\":\"");
+    size_t old_index = 0;
+    for (size_t new_index = data.find_first_of("\n\"");
+         std::string::npos != new_index;
+         old_index = new_index + 1,
+         new_index = data.find_first_of("\n\"", old_index)) {
+      WriteChars(chars + old_index, new_index - old_index);
+      if (chars[new_index] == '\n')
+        WriteChars("\\n", 2);
+      else
+        WriteChars("\\\"", 2);
+    }
+    WriteChars(chars + old_index, data.size() - old_index);
+    WriteString("\"");
+    wrote_system_trace_ = true;
+  }
+
+  void WriteChars(const char* output_chars, size_t size) {
+    if (size == 0)
+      return;
+
+    if (IsValid()) {
+      size_t written = fwrite(output_chars, 1, size, file_);
+      if (written != size) {
+        LOG(ERROR) << "Error " << ferror(file_) << " in fwrite() to trace file";
+        CloseFile();
+      }
+    }
+  }
+
+  void WriteString(const std::string& output_str) {
+    WriteChars(output_str.data(), output_str.size());
+  }
+
+  base::FilePath path_;
+  const FileType file_type_;
+  const bool has_system_trace_;
+  FILE* file_;
+  bool needs_comma_;
+  bool wrote_trace_;
+  bool has_pending_system_trace_;
+  bool wrote_system_trace_;
+  scoped_refptr<base::RefCountedString> pending_system_trace_;
+  DISALLOW_COPY_AND_ASSIGN(TraceSubscriberStdioWorker);
+};
+
+TraceSubscriberStdio::TraceSubscriberStdio(const base::FilePath& path,
+                                           FileType file_type,
+                                           bool has_system_trace)
+    : worker_(new TraceSubscriberStdioWorker(path,
+                                             file_type,
+                                             has_system_trace)) {
+  if (has_system_trace)
+    CHECK_EQ(FILE_TYPE_PROPERTY_LIST, file_type);
+  BrowserThread::PostBlockingPoolSequencedTask(
+      __FILE__, FROM_HERE,
+      base::Bind(&TraceSubscriberStdioWorker::OnTraceStart, worker_));
+}
+
+TraceSubscriberStdio::~TraceSubscriberStdio() {
+}
+
+void TraceSubscriberStdio::OnEndTracingComplete() {
+  BrowserThread::PostBlockingPoolSequencedTask(
+      __FILE__, FROM_HERE,
+      base::Bind(&TraceSubscriberStdioWorker::OnTraceEnd, worker_));
+}
+
+void TraceSubscriberStdio::OnTraceDataCollected(
+    const scoped_refptr<base::RefCountedString>& data_ptr) {
+  BrowserThread::PostBlockingPoolSequencedTask(
+      __FILE__, FROM_HERE,
+      base::Bind(&TraceSubscriberStdioWorker::OnTraceData, worker_, data_ptr));
+}
+
+void TraceSubscriberStdio::OnEndSystemTracing(
+    const scoped_refptr<base::RefCountedString>& events_str_ptr) {
+  BrowserThread::PostBlockingPoolSequencedTask(
+      __FILE__, FROM_HERE,
+      base::Bind(&TraceSubscriberStdioWorker::OnSystemTraceData,
+                 worker_,
+                 events_str_ptr));
+}
+
+}  // namespace content