michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: //------------------------------------------------------------------------------
michael@0: // Tracked is the base class for all tracked objects.  During construction, it
michael@0: // registers the fact that an instance was created, and at destruction time, it
michael@0: // records that event.  The instance may be tagged with a name, which is refered
michael@0: // to as its Location.  The Location is a file and line number, most
michael@0: // typically indicated where the object was constructed.  In some cases, as the
michael@0: // object's significance is refined (for example, a Task object is augmented to
michael@0: // do additonal things), its Location may be redefined to that later location.
michael@0: 
michael@0: // Tracking includes (for each instance) recording the birth thread, death
michael@0: // thread, and duration of life (from construction to destruction).  All this
michael@0: // data is accumulated and filtered for review at about:objects.
michael@0: 
michael@0: #ifndef BASE_TRACKED_H_
michael@0: #define BASE_TRACKED_H_
michael@0: 
michael@0: #include <string>
michael@0: 
michael@0: #include "base/time.h"
michael@0: 
michael@0: #ifndef NDEBUG
michael@0: #ifndef TRACK_ALL_TASK_OBJECTS
michael@0: #define TRACK_ALL_TASK_OBJECTS
michael@0: #endif   // TRACK_ALL_TASK_OBJECTS
michael@0: #endif  // NDEBUG
michael@0: 
michael@0: namespace tracked_objects {
michael@0: 
michael@0: //------------------------------------------------------------------------------
michael@0: // Location provides basic info where of an object was constructed, or was
michael@0: // significantly brought to life.
michael@0: 
michael@0: class Location {
michael@0:  public:
michael@0:   // Constructor should be called with a long-lived char*, such as __FILE__.
michael@0:   // It assumes the provided value will persist as a global constant, and it
michael@0:   // will not make a copy of it.
michael@0:   Location(const char* function_name, const char* file_name, int line_number)
michael@0:       : function_name_(function_name),
michael@0:         file_name_(file_name),
michael@0:         line_number_(line_number) { }
michael@0: 
michael@0:   // Provide a default constructor for easy of debugging.
michael@0:   Location()
michael@0:       : function_name_("Unknown"),
michael@0:         file_name_("Unknown"),
michael@0:         line_number_(-1) { }
michael@0: 
michael@0:   // Comparison operator for insertion into a std::map<> hash tables.
michael@0:   // All we need is *some* (any) hashing distinction.  Strings should already
michael@0:   // be unique, so we don't bother with strcmp or such.
michael@0:   // Use line number as the primary key (because it is fast, and usually gets us
michael@0:   // a difference), and then pointers as secondary keys (just to get some
michael@0:   // distinctions).
michael@0:   bool operator < (const Location& other) const {
michael@0:     if (line_number_ != other.line_number_)
michael@0:       return line_number_ < other.line_number_;
michael@0:     if (file_name_ != other.file_name_)
michael@0:       return file_name_ < other.file_name_;
michael@0:     return function_name_ < other.function_name_;
michael@0:   }
michael@0: 
michael@0:   const char* function_name() const { return function_name_; }
michael@0:   const char* file_name()     const { return file_name_; }
michael@0:   int line_number()           const { return line_number_; }
michael@0: 
michael@0:   void Write(bool display_filename, bool display_function_name,
michael@0:              std::string* output) const;
michael@0: 
michael@0:   // Write function_name_ in HTML with '<' and '>' properly encoded.
michael@0:   void WriteFunctionName(std::string* output) const;
michael@0: 
michael@0:  private:
michael@0:   const char* const function_name_;
michael@0:   const char* const file_name_;
michael@0:   const int line_number_;
michael@0: };
michael@0: 
michael@0: 
michael@0: //------------------------------------------------------------------------------
michael@0: // Define a macro to record the current source location.
michael@0: 
michael@0: #define FROM_HERE tracked_objects::Location(__FUNCTION__, __FILE__, __LINE__)
michael@0: 
michael@0: 
michael@0: //------------------------------------------------------------------------------
michael@0: 
michael@0: 
michael@0: class Births;
michael@0: 
michael@0: class Tracked {
michael@0:  public:
michael@0:   Tracked();
michael@0:   virtual ~Tracked();
michael@0: 
michael@0:   // Used to record the FROM_HERE location of a caller.
michael@0:   void SetBirthPlace(const Location& from_here);
michael@0: 
michael@0:   // When a task sits around a long time, such as in a timer, or object watcher,
michael@0:   // this method should be called when the task becomes active, and its
michael@0:   // significant lifetime begins (and its waiting to be woken up has passed).
michael@0:   void ResetBirthTime();
michael@0: 
michael@0:   bool MissingBirthplace() const;
michael@0: 
michael@0:  private:
michael@0: #ifdef TRACK_ALL_TASK_OBJECTS
michael@0: 
michael@0:   // Pointer to instance were counts of objects with the same birth location
michael@0:   // (on the same thread) are stored.
michael@0:   Births* tracked_births_;
michael@0:   // The time this object was constructed.  If its life consisted of a long
michael@0:   // waiting period, and then it became active, then this value is generally
michael@0:   // reset before the object begins it active life.
michael@0:   base::Time tracked_birth_time_;
michael@0: 
michael@0: #endif  // TRACK_ALL_TASK_OBJECTS
michael@0: 
michael@0:   DISALLOW_COPY_AND_ASSIGN(Tracked);
michael@0: };
michael@0: 
michael@0: }  // namespace tracked_objects
michael@0: 
michael@0: #endif  // BASE_TRACKED_H_