Split up trace_event.h into trace_event_impl.h and add webkitplatform support.

base/debug/trace_event_impl.h

+// 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.
+
+
+#ifndef BASE_DEBUG_TRACE_EVENT_IMPL_H_
+#define BASE_DEBUG_TRACE_EVENT_IMPL_H_
+#pragma once
+
+#include "build/build_config.h"
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/hash_tables.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/string_util.h"
+#include "base/synchronization/lock.h"
+#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
+#include "base/timer.h"
+
+// Older style trace macros with explicit id and extra data
+// Only these macros result in publishing data to ETW as currently implemented.
+#define TRACE_EVENT_BEGIN_ETW(name, id, extra) \
+    base::debug::TraceLog::AddTraceEventEtw( \
+        TRACE_EVENT_PHASE_BEGIN, \
+        name, reinterpret_cast<const void*>(id), extra)
+
+#define TRACE_EVENT_END_ETW(name, id, extra) \
+    base::debug::TraceLog::AddTraceEventEtw( \
+        TRACE_EVENT_PHASE_END, \
+        name, reinterpret_cast<const void*>(id), extra)
+
+#define TRACE_EVENT_INSTANT_ETW(name, id, extra) \
+    base::debug::TraceLog::AddTraceEventEtw( \
+        TRACE_EVENT_PHASE_INSTANT, \
+        name, reinterpret_cast<const void*>(id), extra)
+
+template <typename Type>
+struct StaticMemorySingletonTraits;
+
+namespace base {
+
+class RefCountedString;
+
+namespace debug {
+
+const int kTraceMaxNumArgs = 2;
+
+// Output records are "Events" and can be obtained via the
+// OutputCallback whenever the tracing system decides to flush. This
+// can happen at any time, on any thread, or you can programatically
+// force it to happen.
+class BASE_EXPORT TraceEvent {
+ public:
+  union TraceValue {
+    bool as_bool;
+    unsigned long long as_uint;
+    long long as_int;
+    double as_double;
+    const void* as_pointer;
+    const char* as_string;
+  };
+
+  TraceEvent();
+  TraceEvent(int thread_id,
+             TimeTicks timestamp,
+             char phase,
+             const unsigned char* category_enabled,
+             const char* name,
+             unsigned long long id,
+             int num_args,
+             const char** arg_names,
+             const unsigned char* arg_types,
+             const unsigned long long* arg_values,
+             unsigned char flags);
+  ~TraceEvent();
+
+  // Serialize event data to JSON
+  static void AppendEventsAsJSON(const std::vector<TraceEvent>& events,
+                                 size_t start,
+                                 size_t count,
+                                 std::string* out);
+  void AppendAsJSON(std::string* out) const;
+
+  TimeTicks timestamp() const { return timestamp_; }
+
+  // Exposed for unittesting:
+
+  const base::RefCountedString* parameter_copy_storage() const {
+    return parameter_copy_storage_.get();
+  }
+
+  const char* name() const { return name_; }
+
+ private:
+  // Note: these are ordered by size (largest first) for optimal packing.
+  TimeTicks timestamp_;
+  // id_ can be used to store phase-specific data.
+  unsigned long long id_;
+  TraceValue arg_values_[kTraceMaxNumArgs];
+  const char* arg_names_[kTraceMaxNumArgs];
+  const unsigned char* category_enabled_;
+  const char* name_;
+  scoped_refptr<base::RefCountedString> parameter_copy_storage_;
+  int thread_id_;
+  char phase_;
+  unsigned char flags_;
+  unsigned char arg_types_[kTraceMaxNumArgs];
+};
+
+
+// TraceResultBuffer collects and converts trace fragments returned by TraceLog
+// to JSON output.
+class BASE_EXPORT TraceResultBuffer {
+ public:
+  typedef base::Callback<void(const std::string&)> OutputCallback;
+
+  // If you don't need to stream JSON chunks out efficiently, and just want to
+  // get a complete JSON string after calling Finish, use this struct to collect
+  // JSON trace output.
+  struct BASE_EXPORT SimpleOutput {
+    OutputCallback GetCallback();
+    void Append(const std::string& json_string);
+
+    // Do what you want with the json_output_ string after calling
+    // TraceResultBuffer::Finish.
+    std::string json_output;
+  };
+
+  TraceResultBuffer();
+  ~TraceResultBuffer();
+
+  // Set callback. The callback will be called during Start with the initial
+  // JSON output and during AddFragment and Finish with following JSON output
+  // chunks. The callback target must live past the last calls to
+  // TraceResultBuffer::Start/AddFragment/Finish.
+  void SetOutputCallback(const OutputCallback& json_chunk_callback);
+
+  // Start JSON output. This resets all internal state, so you can reuse
+  // the TraceResultBuffer by calling Start.
+  void Start();
+
+  // Call AddFragment 0 or more times to add trace fragments from TraceLog.
+  void AddFragment(const std::string& trace_fragment);
+
+  // When all fragments have been added, call Finish to complete the JSON
+  // formatted output.
+  void Finish();
+
+ private:
+  OutputCallback output_callback_;
+  bool append_comma_;
+};
+
+
+class BASE_EXPORT TraceLog {
+ public:
+  static TraceLog* GetInstance();
+
+  // Get set of known categories. This can change as new code paths are reached.
+  // The known categories are inserted into |categories|.
+  void GetKnownCategories(std::vector<std::string>* categories);
+
+  // Enable tracing for provided list of categories. If tracing is already
+  // enabled, this method does nothing -- changing categories during trace is
+  // not supported.
+  // If both included_categories and excluded_categories are empty,
+  //   all categories are traced.
+  // Else if included_categories is non-empty, only those are traced.
+  // Else if excluded_categories is non-empty, everything but those are traced.
+  // Wildcards * and ? are supported (see MatchPattern in string_util.h).
+  void SetEnabled(const std::vector<std::string>& included_categories,
+                  const std::vector<std::string>& excluded_categories);
+
+  // |categories| is a comma-delimited list of category wildcards.
+  // A category can have an optional '-' prefix to make it an excluded category.
+  // All the same rules apply above, so for example, having both included and
+  // excluded categories in the same list would not be supported.
+  //
+  // Example: SetEnabled("test_MyTest*");
+  // Example: SetEnabled("test_MyTest*,test_OtherStuff");
+  // Example: SetEnabled("-excluded_category1,-excluded_category2");
+  void SetEnabled(const std::string& categories);
+
+  // Retieves the categories set via a prior call to SetEnabled(). Only
+  // meaningful if |IsEnabled()| is true.
+  void GetEnabledTraceCategories(std::vector<std::string>* included_out,
+                                 std::vector<std::string>* excluded_out);
+
+  // Disable tracing for all categories.
+  void SetDisabled();
+  // Helper method to enable/disable tracing for all categories.
+  void SetEnabled(bool enabled);
+  bool IsEnabled() { return enabled_; }
+
+  float GetBufferPercentFull() const;
+
+  // When enough events are collected, they are handed (in bulk) to
+  // the output callback. If no callback is set, the output will be
+  // silently dropped. The callback must be thread safe. The string format is
+  // undefined. Use TraceResultBuffer to convert one or more trace strings to
+  // JSON.
+  typedef RefCountedData<std::string> RefCountedString;
+  typedef base::Callback<void(const scoped_refptr<RefCountedString>&)>
+      OutputCallback;
+  void SetOutputCallback(const OutputCallback& cb);
+
+  // The trace buffer does not flush dynamically, so when it fills up,
+  // subsequent trace events will be dropped. This callback is generated when
+  // the trace buffer is full. The callback must be thread safe.
+  typedef base::Callback<void(void)> BufferFullCallback;
+  void SetBufferFullCallback(const BufferFullCallback& cb);
+
+  // Flushes all logged data to the callback.
+  void Flush();
+
+  // Called by TRACE_EVENT* macros, don't call this directly.
+  static const unsigned char* GetCategoryEnabled(const char* name);
+  static const char* GetCategoryName(const unsigned char* category_enabled);
+
+  // Called by TRACE_EVENT* macros, don't call this directly.
+  // Returns the index in the internal vector of the event if it was added, or
+  //         -1 if the event was not added.
+  // On end events, the return value of the begin event can be specified along
+  // with a threshold in microseconds. If the elapsed time between begin and end
+  // is less than the threshold, the begin/end event pair is dropped.
+  // If |copy| is set, |name|, |arg_name1| and |arg_name2| will be deep copied
+  // into the event; see "Memory scoping note" and TRACE_EVENT_COPY_XXX above.
+  int AddTraceEvent(char phase,
+                    const unsigned char* category_enabled,
+                    const char* name,
+                    unsigned long long id,
+                    int num_args,
+                    const char** arg_names,
+                    const unsigned char* arg_types,
+                    const unsigned long long* arg_values,
+                    int threshold_begin_id,
+                    long long threshold,
+                    unsigned char flags);
+  static void AddTraceEventEtw(char phase,
+                               const char* name,
+                               const void* id,
+                               const char* extra);
+  static void AddTraceEventEtw(char phase,
+                               const char* name,
+                               const void* id,
+                               const std::string& extra);
+
+  // Mangle |ptr| with a hash based on the process ID so that if |ptr| occurs on
+  // more than one process, it will not collide.
+  unsigned long long GetInterProcessID(void* ptr) const {
+    return static_cast<unsigned long long>(reinterpret_cast<uintptr_t>(ptr)) ^
+           process_id_hash_;
+  }
+
+  int process_id() const { return process_id_; }
+
+  // Exposed for unittesting:
+
+  // Allows deleting our singleton instance.
+  static void DeleteForTesting();
+
+  // Allows resurrecting our singleton instance post-AtExit processing.
+  static void Resurrect();
+
+  // Allow tests to inspect TraceEvents.
+  size_t GetEventsSize() const { return logged_events_.size(); }
+  const TraceEvent& GetEventAt(size_t index) const {
+    DCHECK(index < logged_events_.size());
+    return logged_events_[index];
+  }
+
+  void SetProcessID(int process_id);
+
+ private:
+  // This allows constructor and destructor to be private and usable only
+  // by the Singleton class.
+  friend struct StaticMemorySingletonTraits<TraceLog>;
+
+  TraceLog();
+  ~TraceLog();
+  const unsigned char* GetCategoryEnabledInternal(const char* name);
+  void AddThreadNameMetadataEvents();
+  void AddClockSyncMetadataEvents();
+
+  // TODO(nduca): switch to per-thread trace buffers to reduce thread
+  // synchronization.
+  Lock lock_;
+  bool enabled_;
+  OutputCallback output_callback_;
+  BufferFullCallback buffer_full_callback_;
+  std::vector<TraceEvent> logged_events_;
+  std::vector<std::string> included_categories_;
+  std::vector<std::string> excluded_categories_;
+
+  base::hash_map<int, std::string> thread_names_;
+
+  // XORed with TraceID to make it unlikely to collide with other processes.
+  unsigned long long process_id_hash_;
+
+  int process_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(TraceLog);
+};
+
+}  // namespace debug
+}  // namespace base
+
+#endif  // BASE_DEBUG_TRACE_EVENT_IMPL_H_