michael@0: // Copyright (c) 2012 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: // Time represents an absolute point in time, internally represented as
michael@0: // microseconds (s/1,000,000) since the Windows epoch (1601-01-01 00:00:00 UTC)
michael@0: // (See http://crbug.com/14734).  System-dependent clock interface routines are
michael@0: // defined in time_PLATFORM.cc.
michael@0: //
michael@0: // TimeDelta represents a duration of time, internally represented in
michael@0: // microseconds.
michael@0: //
michael@0: // TimeTicks represents an abstract time that is most of the time incrementing
michael@0: // for use in measuring time durations. It is internally represented in
michael@0: // microseconds.  It can not be converted to a human-readable time, but is
michael@0: // guaranteed not to decrease (if the user changes the computer clock,
michael@0: // Time::Now() may actually decrease or jump).  But note that TimeTicks may
michael@0: // "stand still", for example if the computer suspended.
michael@0: //
michael@0: // These classes are represented as only a 64-bit value, so they can be
michael@0: // efficiently passed by value.
michael@0: 
michael@0: #ifndef BASE_TIME_TIME_H_
michael@0: #define BASE_TIME_TIME_H_
michael@0: 
michael@0: #include <time.h>
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/basictypes.h"
michael@0: #include "build/build_config.h"
michael@0: 
michael@0: #if defined(OS_MACOSX)
michael@0: #include <CoreFoundation/CoreFoundation.h>
michael@0: // Avoid Mac system header macro leak.
michael@0: #undef TYPE_BOOL
michael@0: #endif
michael@0: 
michael@0: #if defined(OS_POSIX)
michael@0: #include <unistd.h>
michael@0: #include <sys/time.h>
michael@0: #endif
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: // For FILETIME in FromFileTime, until it moves to a new converter class.
michael@0: // See TODO(iyengar) below.
michael@0: #include <windows.h>
michael@0: #endif
michael@0: 
michael@0: #include <limits>
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: class Time;
michael@0: class TimeTicks;
michael@0: 
michael@0: // TimeDelta ------------------------------------------------------------------
michael@0: 
michael@0: class BASE_EXPORT TimeDelta {
michael@0:  public:
michael@0:   TimeDelta() : delta_(0) {
michael@0:   }
michael@0: 
michael@0:   // Converts units of time to TimeDeltas.
michael@0:   static TimeDelta FromDays(int64 days);
michael@0:   static TimeDelta FromHours(int64 hours);
michael@0:   static TimeDelta FromMinutes(int64 minutes);
michael@0:   static TimeDelta FromSeconds(int64 secs);
michael@0:   static TimeDelta FromMilliseconds(int64 ms);
michael@0:   static TimeDelta FromMicroseconds(int64 us);
michael@0: #if defined(OS_WIN)
michael@0:   static TimeDelta FromQPCValue(LONGLONG qpc_value);
michael@0: #endif
michael@0: 
michael@0:   // Converts an integer value representing TimeDelta to a class. This is used
michael@0:   // when deserializing a |TimeDelta| structure, using a value known to be
michael@0:   // compatible. It is not provided as a constructor because the integer type
michael@0:   // may be unclear from the perspective of a caller.
michael@0:   static TimeDelta FromInternalValue(int64 delta) {
michael@0:     return TimeDelta(delta);
michael@0:   }
michael@0: 
michael@0:   // Returns the internal numeric value of the TimeDelta object. Please don't
michael@0:   // use this and do arithmetic on it, as it is more error prone than using the
michael@0:   // provided operators.
michael@0:   // For serializing, use FromInternalValue to reconstitute.
michael@0:   int64 ToInternalValue() const {
michael@0:     return delta_;
michael@0:   }
michael@0: 
michael@0: #if defined(OS_POSIX)
michael@0:   struct timespec ToTimeSpec() const;
michael@0: #endif
michael@0: 
michael@0:   // Returns the time delta in some unit. The F versions return a floating
michael@0:   // point value, the "regular" versions return a rounded-down value.
michael@0:   //
michael@0:   // InMillisecondsRoundedUp() instead returns an integer that is rounded up
michael@0:   // to the next full millisecond.
michael@0:   int InDays() const;
michael@0:   int InHours() const;
michael@0:   int InMinutes() const;
michael@0:   double InSecondsF() const;
michael@0:   int64 InSeconds() const;
michael@0:   double InMillisecondsF() const;
michael@0:   int64 InMilliseconds() const;
michael@0:   int64 InMillisecondsRoundedUp() const;
michael@0:   int64 InMicroseconds() const;
michael@0: 
michael@0:   TimeDelta& operator=(TimeDelta other) {
michael@0:     delta_ = other.delta_;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   // Computations with other deltas.
michael@0:   TimeDelta operator+(TimeDelta other) const {
michael@0:     return TimeDelta(delta_ + other.delta_);
michael@0:   }
michael@0:   TimeDelta operator-(TimeDelta other) const {
michael@0:     return TimeDelta(delta_ - other.delta_);
michael@0:   }
michael@0: 
michael@0:   TimeDelta& operator+=(TimeDelta other) {
michael@0:     delta_ += other.delta_;
michael@0:     return *this;
michael@0:   }
michael@0:   TimeDelta& operator-=(TimeDelta other) {
michael@0:     delta_ -= other.delta_;
michael@0:     return *this;
michael@0:   }
michael@0:   TimeDelta operator-() const {
michael@0:     return TimeDelta(-delta_);
michael@0:   }
michael@0: 
michael@0:   // Computations with ints, note that we only allow multiplicative operations
michael@0:   // with ints, and additive operations with other deltas.
michael@0:   TimeDelta operator*(int64 a) const {
michael@0:     return TimeDelta(delta_ * a);
michael@0:   }
michael@0:   TimeDelta operator/(int64 a) const {
michael@0:     return TimeDelta(delta_ / a);
michael@0:   }
michael@0:   TimeDelta& operator*=(int64 a) {
michael@0:     delta_ *= a;
michael@0:     return *this;
michael@0:   }
michael@0:   TimeDelta& operator/=(int64 a) {
michael@0:     delta_ /= a;
michael@0:     return *this;
michael@0:   }
michael@0:   int64 operator/(TimeDelta a) const {
michael@0:     return delta_ / a.delta_;
michael@0:   }
michael@0: 
michael@0:   // Defined below because it depends on the definition of the other classes.
michael@0:   Time operator+(Time t) const;
michael@0:   TimeTicks operator+(TimeTicks t) const;
michael@0: 
michael@0:   // Comparison operators.
michael@0:   bool operator==(TimeDelta other) const {
michael@0:     return delta_ == other.delta_;
michael@0:   }
michael@0:   bool operator!=(TimeDelta other) const {
michael@0:     return delta_ != other.delta_;
michael@0:   }
michael@0:   bool operator<(TimeDelta other) const {
michael@0:     return delta_ < other.delta_;
michael@0:   }
michael@0:   bool operator<=(TimeDelta other) const {
michael@0:     return delta_ <= other.delta_;
michael@0:   }
michael@0:   bool operator>(TimeDelta other) const {
michael@0:     return delta_ > other.delta_;
michael@0:   }
michael@0:   bool operator>=(TimeDelta other) const {
michael@0:     return delta_ >= other.delta_;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   friend class Time;
michael@0:   friend class TimeTicks;
michael@0:   friend TimeDelta operator*(int64 a, TimeDelta td);
michael@0: 
michael@0:   // Constructs a delta given the duration in microseconds. This is private
michael@0:   // to avoid confusion by callers with an integer constructor. Use
michael@0:   // FromSeconds, FromMilliseconds, etc. instead.
michael@0:   explicit TimeDelta(int64 delta_us) : delta_(delta_us) {
michael@0:   }
michael@0: 
michael@0:   // Delta in microseconds.
michael@0:   int64 delta_;
michael@0: };
michael@0: 
michael@0: inline TimeDelta operator*(int64 a, TimeDelta td) {
michael@0:   return TimeDelta(a * td.delta_);
michael@0: }
michael@0: 
michael@0: // Time -----------------------------------------------------------------------
michael@0: 
michael@0: // Represents a wall clock time.
michael@0: class BASE_EXPORT Time {
michael@0:  public:
michael@0:   static const int64 kMillisecondsPerSecond = 1000;
michael@0:   static const int64 kMicrosecondsPerMillisecond = 1000;
michael@0:   static const int64 kMicrosecondsPerSecond = kMicrosecondsPerMillisecond *
michael@0:                                               kMillisecondsPerSecond;
michael@0:   static const int64 kMicrosecondsPerMinute = kMicrosecondsPerSecond * 60;
michael@0:   static const int64 kMicrosecondsPerHour = kMicrosecondsPerMinute * 60;
michael@0:   static const int64 kMicrosecondsPerDay = kMicrosecondsPerHour * 24;
michael@0:   static const int64 kMicrosecondsPerWeek = kMicrosecondsPerDay * 7;
michael@0:   static const int64 kNanosecondsPerMicrosecond = 1000;
michael@0:   static const int64 kNanosecondsPerSecond = kNanosecondsPerMicrosecond *
michael@0:                                              kMicrosecondsPerSecond;
michael@0: 
michael@0: #if !defined(OS_WIN)
michael@0:   // On Mac & Linux, this value is the delta from the Windows epoch of 1601 to
michael@0:   // the Posix delta of 1970. This is used for migrating between the old
michael@0:   // 1970-based epochs to the new 1601-based ones. It should be removed from
michael@0:   // this global header and put in the platform-specific ones when we remove the
michael@0:   // migration code.
michael@0:   static const int64 kWindowsEpochDeltaMicroseconds;
michael@0: #endif
michael@0: 
michael@0:   // Represents an exploded time that can be formatted nicely. This is kind of
michael@0:   // like the Win32 SYSTEMTIME structure or the Unix "struct tm" with a few
michael@0:   // additions and changes to prevent errors.
michael@0:   struct BASE_EXPORT Exploded {
michael@0:     int year;          // Four digit year "2007"
michael@0:     int month;         // 1-based month (values 1 = January, etc.)
michael@0:     int day_of_week;   // 0-based day of week (0 = Sunday, etc.)
michael@0:     int day_of_month;  // 1-based day of month (1-31)
michael@0:     int hour;          // Hour within the current day (0-23)
michael@0:     int minute;        // Minute within the current hour (0-59)
michael@0:     int second;        // Second within the current minute (0-59 plus leap
michael@0:                        //   seconds which may take it up to 60).
michael@0:     int millisecond;   // Milliseconds within the current second (0-999)
michael@0: 
michael@0:     // A cursory test for whether the data members are within their
michael@0:     // respective ranges. A 'true' return value does not guarantee the
michael@0:     // Exploded value can be successfully converted to a Time value.
michael@0:     bool HasValidValues() const;
michael@0:   };
michael@0: 
michael@0:   // Contains the NULL time. Use Time::Now() to get the current time.
michael@0:   Time() : us_(0) {
michael@0:   }
michael@0: 
michael@0:   // Returns true if the time object has not been initialized.
michael@0:   bool is_null() const {
michael@0:     return us_ == 0;
michael@0:   }
michael@0: 
michael@0:   // Returns true if the time object is the maximum time.
michael@0:   bool is_max() const {
michael@0:     return us_ == std::numeric_limits<int64>::max();
michael@0:   }
michael@0: 
michael@0:   // Returns the time for epoch in Unix-like system (Jan 1, 1970).
michael@0:   static Time UnixEpoch();
michael@0: 
michael@0:   // Returns the current time. Watch out, the system might adjust its clock
michael@0:   // in which case time will actually go backwards. We don't guarantee that
michael@0:   // times are increasing, or that two calls to Now() won't be the same.
michael@0:   static Time Now();
michael@0: 
michael@0:   // Returns the maximum time, which should be greater than any reasonable time
michael@0:   // with which we might compare it.
michael@0:   static Time Max();
michael@0: 
michael@0:   // Returns the current time. Same as Now() except that this function always
michael@0:   // uses system time so that there are no discrepancies between the returned
michael@0:   // time and system time even on virtual environments including our test bot.
michael@0:   // For timing sensitive unittests, this function should be used.
michael@0:   static Time NowFromSystemTime();
michael@0: 
michael@0:   // Converts to/from time_t in UTC and a Time class.
michael@0:   // TODO(brettw) this should be removed once everybody starts using the |Time|
michael@0:   // class.
michael@0:   static Time FromTimeT(time_t tt);
michael@0:   time_t ToTimeT() const;
michael@0: 
michael@0:   // Converts time to/from a double which is the number of seconds since epoch
michael@0:   // (Jan 1, 1970).  Webkit uses this format to represent time.
michael@0:   // Because WebKit initializes double time value to 0 to indicate "not
michael@0:   // initialized", we map it to empty Time object that also means "not
michael@0:   // initialized".
michael@0:   static Time FromDoubleT(double dt);
michael@0:   double ToDoubleT() const;
michael@0: 
michael@0: #if defined(OS_POSIX)
michael@0:   // Converts the timespec structure to time. MacOS X 10.8.3 (and tentatively,
michael@0:   // earlier versions) will have the |ts|'s tv_nsec component zeroed out,
michael@0:   // having a 1 second resolution, which agrees with
michael@0:   // https://developer.apple.com/legacy/library/#technotes/tn/tn1150.html#HFSPlusDates.
michael@0:   static Time FromTimeSpec(const timespec& ts);
michael@0: #endif
michael@0: 
michael@0:   // Converts to/from the Javascript convention for times, a number of
michael@0:   // milliseconds since the epoch:
michael@0:   // https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date/getTime.
michael@0:   static Time FromJsTime(double ms_since_epoch);
michael@0:   double ToJsTime() const;
michael@0: 
michael@0:   // Converts to Java convention for times, a number of
michael@0:   // milliseconds since the epoch.
michael@0:   int64 ToJavaTime() const;
michael@0: 
michael@0: #if defined(OS_POSIX)
michael@0:   static Time FromTimeVal(struct timeval t);
michael@0:   struct timeval ToTimeVal() const;
michael@0: #endif
michael@0: 
michael@0: #if defined(OS_MACOSX)
michael@0:   static Time FromCFAbsoluteTime(CFAbsoluteTime t);
michael@0:   CFAbsoluteTime ToCFAbsoluteTime() const;
michael@0: #endif
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0:   static Time FromFileTime(FILETIME ft);
michael@0:   FILETIME ToFileTime() const;
michael@0: 
michael@0:   // The minimum time of a low resolution timer.  This is basically a windows
michael@0:   // constant of ~15.6ms.  While it does vary on some older OS versions, we'll
michael@0:   // treat it as static across all windows versions.
michael@0:   static const int kMinLowResolutionThresholdMs = 16;
michael@0: 
michael@0:   // Enable or disable Windows high resolution timer. If the high resolution
michael@0:   // timer is not enabled, calls to ActivateHighResolutionTimer will fail.
michael@0:   // When disabling the high resolution timer, this function will not cause
michael@0:   // the high resolution timer to be deactivated, but will prevent future
michael@0:   // activations.
michael@0:   // Must be called from the main thread.
michael@0:   // For more details see comments in time_win.cc.
michael@0:   static void EnableHighResolutionTimer(bool enable);
michael@0: 
michael@0:   // Activates or deactivates the high resolution timer based on the |activate|
michael@0:   // flag.  If the HighResolutionTimer is not Enabled (see
michael@0:   // EnableHighResolutionTimer), this function will return false.  Otherwise
michael@0:   // returns true.  Each successful activate call must be paired with a
michael@0:   // subsequent deactivate call.
michael@0:   // All callers to activate the high resolution timer must eventually call
michael@0:   // this function to deactivate the high resolution timer.
michael@0:   static bool ActivateHighResolutionTimer(bool activate);
michael@0: 
michael@0:   // Returns true if the high resolution timer is both enabled and activated.
michael@0:   // This is provided for testing only, and is not tracked in a thread-safe
michael@0:   // way.
michael@0:   static bool IsHighResolutionTimerInUse();
michael@0: #endif
michael@0: 
michael@0:   // Converts an exploded structure representing either the local time or UTC
michael@0:   // into a Time class.
michael@0:   static Time FromUTCExploded(const Exploded& exploded) {
michael@0:     return FromExploded(false, exploded);
michael@0:   }
michael@0:   static Time FromLocalExploded(const Exploded& exploded) {
michael@0:     return FromExploded(true, exploded);
michael@0:   }
michael@0: 
michael@0:   // Converts an integer value representing Time to a class. This is used
michael@0:   // when deserializing a |Time| structure, using a value known to be
michael@0:   // compatible. It is not provided as a constructor because the integer type
michael@0:   // may be unclear from the perspective of a caller.
michael@0:   static Time FromInternalValue(int64 us) {
michael@0:     return Time(us);
michael@0:   }
michael@0: 
michael@0:   // Converts a string representation of time to a Time object.
michael@0:   // An example of a time string which is converted is as below:-
michael@0:   // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
michael@0:   // in the input string, FromString assumes local time and FromUTCString
michael@0:   // assumes UTC. A timezone that cannot be parsed (e.g. "UTC" which is not
michael@0:   // specified in RFC822) is treated as if the timezone is not specified.
michael@0:   // TODO(iyengar) Move the FromString/FromTimeT/ToTimeT/FromFileTime to
michael@0:   // a new time converter class.
michael@0:   static bool FromString(const char* time_string, Time* parsed_time) {
michael@0:     return FromStringInternal(time_string, true, parsed_time);
michael@0:   }
michael@0:   static bool FromUTCString(const char* time_string, Time* parsed_time) {
michael@0:     return FromStringInternal(time_string, false, parsed_time);
michael@0:   }
michael@0: 
michael@0:   // For serializing, use FromInternalValue to reconstitute. Please don't use
michael@0:   // this and do arithmetic on it, as it is more error prone than using the
michael@0:   // provided operators.
michael@0:   int64 ToInternalValue() const {
michael@0:     return us_;
michael@0:   }
michael@0: 
michael@0:   // Fills the given exploded structure with either the local time or UTC from
michael@0:   // this time structure (containing UTC).
michael@0:   void UTCExplode(Exploded* exploded) const {
michael@0:     return Explode(false, exploded);
michael@0:   }
michael@0:   void LocalExplode(Exploded* exploded) const {
michael@0:     return Explode(true, exploded);
michael@0:   }
michael@0: 
michael@0:   // Rounds this time down to the nearest day in local time. It will represent
michael@0:   // midnight on that day.
michael@0:   Time LocalMidnight() const;
michael@0: 
michael@0:   Time& operator=(Time other) {
michael@0:     us_ = other.us_;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   // Compute the difference between two times.
michael@0:   TimeDelta operator-(Time other) const {
michael@0:     return TimeDelta(us_ - other.us_);
michael@0:   }
michael@0: 
michael@0:   // Modify by some time delta.
michael@0:   Time& operator+=(TimeDelta delta) {
michael@0:     us_ += delta.delta_;
michael@0:     return *this;
michael@0:   }
michael@0:   Time& operator-=(TimeDelta delta) {
michael@0:     us_ -= delta.delta_;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   // Return a new time modified by some delta.
michael@0:   Time operator+(TimeDelta delta) const {
michael@0:     return Time(us_ + delta.delta_);
michael@0:   }
michael@0:   Time operator-(TimeDelta delta) const {
michael@0:     return Time(us_ - delta.delta_);
michael@0:   }
michael@0: 
michael@0:   // Comparison operators
michael@0:   bool operator==(Time other) const {
michael@0:     return us_ == other.us_;
michael@0:   }
michael@0:   bool operator!=(Time other) const {
michael@0:     return us_ != other.us_;
michael@0:   }
michael@0:   bool operator<(Time other) const {
michael@0:     return us_ < other.us_;
michael@0:   }
michael@0:   bool operator<=(Time other) const {
michael@0:     return us_ <= other.us_;
michael@0:   }
michael@0:   bool operator>(Time other) const {
michael@0:     return us_ > other.us_;
michael@0:   }
michael@0:   bool operator>=(Time other) const {
michael@0:     return us_ >= other.us_;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   friend class TimeDelta;
michael@0: 
michael@0:   explicit Time(int64 us) : us_(us) {
michael@0:   }
michael@0: 
michael@0:   // Explodes the given time to either local time |is_local = true| or UTC
michael@0:   // |is_local = false|.
michael@0:   void Explode(bool is_local, Exploded* exploded) const;
michael@0: 
michael@0:   // Unexplodes a given time assuming the source is either local time
michael@0:   // |is_local = true| or UTC |is_local = false|.
michael@0:   static Time FromExploded(bool is_local, const Exploded& exploded);
michael@0: 
michael@0:   // Converts a string representation of time to a Time object.
michael@0:   // An example of a time string which is converted is as below:-
michael@0:   // "Tue, 15 Nov 1994 12:45:26 GMT". If the timezone is not specified
michael@0:   // in the input string, local time |is_local = true| or
michael@0:   // UTC |is_local = false| is assumed. A timezone that cannot be parsed
michael@0:   // (e.g. "UTC" which is not specified in RFC822) is treated as if the
michael@0:   // timezone is not specified.
michael@0:   static bool FromStringInternal(const char* time_string,
michael@0:                                  bool is_local,
michael@0:                                  Time* parsed_time);
michael@0: 
michael@0:   // The representation of Jan 1, 1970 UTC in microseconds since the
michael@0:   // platform-dependent epoch.
michael@0:   static const int64 kTimeTToMicrosecondsOffset;
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0:   // Indicates whether fast timers are usable right now.  For instance,
michael@0:   // when using battery power, we might elect to prevent high speed timers
michael@0:   // which would draw more power.
michael@0:   static bool high_resolution_timer_enabled_;
michael@0:   // Count of activations on the high resolution timer.  Only use in tests
michael@0:   // which are single threaded.
michael@0:   static int high_resolution_timer_activated_;
michael@0: #endif
michael@0: 
michael@0:   // Time in microseconds in UTC.
michael@0:   int64 us_;
michael@0: };
michael@0: 
michael@0: // Inline the TimeDelta factory methods, for fast TimeDelta construction.
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromDays(int64 days) {
michael@0:   return TimeDelta(days * Time::kMicrosecondsPerDay);
michael@0: }
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromHours(int64 hours) {
michael@0:   return TimeDelta(hours * Time::kMicrosecondsPerHour);
michael@0: }
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromMinutes(int64 minutes) {
michael@0:   return TimeDelta(minutes * Time::kMicrosecondsPerMinute);
michael@0: }
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromSeconds(int64 secs) {
michael@0:   return TimeDelta(secs * Time::kMicrosecondsPerSecond);
michael@0: }
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromMilliseconds(int64 ms) {
michael@0:   return TimeDelta(ms * Time::kMicrosecondsPerMillisecond);
michael@0: }
michael@0: 
michael@0: // static
michael@0: inline TimeDelta TimeDelta::FromMicroseconds(int64 us) {
michael@0:   return TimeDelta(us);
michael@0: }
michael@0: 
michael@0: inline Time TimeDelta::operator+(Time t) const {
michael@0:   return Time(t.us_ + delta_);
michael@0: }
michael@0: 
michael@0: // TimeTicks ------------------------------------------------------------------
michael@0: 
michael@0: class BASE_EXPORT TimeTicks {
michael@0:  public:
michael@0:   TimeTicks() : ticks_(0) {
michael@0:   }
michael@0: 
michael@0:   // Platform-dependent tick count representing "right now."
michael@0:   // The resolution of this clock is ~1-15ms.  Resolution varies depending
michael@0:   // on hardware/operating system configuration.
michael@0:   static TimeTicks Now();
michael@0: 
michael@0:   // Returns a platform-dependent high-resolution tick count. Implementation
michael@0:   // is hardware dependent and may or may not return sub-millisecond
michael@0:   // resolution.  THIS CALL IS GENERALLY MUCH MORE EXPENSIVE THAN Now() AND
michael@0:   // SHOULD ONLY BE USED WHEN IT IS REALLY NEEDED.
michael@0:   static TimeTicks HighResNow();
michael@0: 
michael@0:   // Returns true if ThreadNow() is supported on this system.
michael@0:   static bool IsThreadNowSupported() {
michael@0: #if defined(_POSIX_THREAD_CPUTIME) && (_POSIX_THREAD_CPUTIME >= 0)
michael@0:     return true;
michael@0: #else
michael@0:     return false;
michael@0: #endif
michael@0:   }
michael@0: 
michael@0:   // Returns thread-specific CPU-time on systems that support this feature.
michael@0:   // Needs to be guarded with a call to IsThreadNowSupported(). Use this timer
michael@0:   // to (approximately) measure how much time the calling thread spent doing
michael@0:   // actual work vs. being de-scheduled. May return bogus results if the thread
michael@0:   // migrates to another CPU between two calls.
michael@0:   static TimeTicks ThreadNow();
michael@0: 
michael@0:   // Returns the current system trace time or, if none is defined, the current
michael@0:   // high-res time (i.e. HighResNow()). On systems where a global trace clock
michael@0:   // is defined, timestamping TraceEvents's with this value guarantees
michael@0:   // synchronization between events collected inside chrome and events
michael@0:   // collected outside (e.g. kernel, X server).
michael@0:   static TimeTicks NowFromSystemTraceTime();
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0:   // Get the absolute value of QPC time drift. For testing.
michael@0:   static int64 GetQPCDriftMicroseconds();
michael@0: 
michael@0:   static TimeTicks FromQPCValue(LONGLONG qpc_value);
michael@0: 
michael@0:   // Returns true if the high resolution clock is working on this system.
michael@0:   // This is only for testing.
michael@0:   static bool IsHighResClockWorking();
michael@0: 
michael@0:   // Enable high resolution time for TimeTicks::Now(). This function will
michael@0:   // test for the availability of a working implementation of
michael@0:   // QueryPerformanceCounter(). If one is not available, this function does
michael@0:   // nothing and the resolution of Now() remains 1ms. Otherwise, all future
michael@0:   // calls to TimeTicks::Now() will have the higher resolution provided by QPC.
michael@0:   // Returns true if high resolution time was successfully enabled.
michael@0:   static bool SetNowIsHighResNowIfSupported();
michael@0: 
michael@0:   // Returns a time value that is NOT rollover protected.
michael@0:   static TimeTicks UnprotectedNow();
michael@0: #endif
michael@0: 
michael@0:   // Returns true if this object has not been initialized.
michael@0:   bool is_null() const {
michael@0:     return ticks_ == 0;
michael@0:   }
michael@0: 
michael@0:   // Converts an integer value representing TimeTicks to a class. This is used
michael@0:   // when deserializing a |TimeTicks| structure, using a value known to be
michael@0:   // compatible. It is not provided as a constructor because the integer type
michael@0:   // may be unclear from the perspective of a caller.
michael@0:   static TimeTicks FromInternalValue(int64 ticks) {
michael@0:     return TimeTicks(ticks);
michael@0:   }
michael@0: 
michael@0:   // Returns the internal numeric value of the TimeTicks object.
michael@0:   // For serializing, use FromInternalValue to reconstitute.
michael@0:   int64 ToInternalValue() const {
michael@0:     return ticks_;
michael@0:   }
michael@0: 
michael@0:   TimeTicks& operator=(TimeTicks other) {
michael@0:     ticks_ = other.ticks_;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   // Compute the difference between two times.
michael@0:   TimeDelta operator-(TimeTicks other) const {
michael@0:     return TimeDelta(ticks_ - other.ticks_);
michael@0:   }
michael@0: 
michael@0:   // Modify by some time delta.
michael@0:   TimeTicks& operator+=(TimeDelta delta) {
michael@0:     ticks_ += delta.delta_;
michael@0:     return *this;
michael@0:   }
michael@0:   TimeTicks& operator-=(TimeDelta delta) {
michael@0:     ticks_ -= delta.delta_;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   // Return a new TimeTicks modified by some delta.
michael@0:   TimeTicks operator+(TimeDelta delta) const {
michael@0:     return TimeTicks(ticks_ + delta.delta_);
michael@0:   }
michael@0:   TimeTicks operator-(TimeDelta delta) const {
michael@0:     return TimeTicks(ticks_ - delta.delta_);
michael@0:   }
michael@0: 
michael@0:   // Comparison operators
michael@0:   bool operator==(TimeTicks other) const {
michael@0:     return ticks_ == other.ticks_;
michael@0:   }
michael@0:   bool operator!=(TimeTicks other) const {
michael@0:     return ticks_ != other.ticks_;
michael@0:   }
michael@0:   bool operator<(TimeTicks other) const {
michael@0:     return ticks_ < other.ticks_;
michael@0:   }
michael@0:   bool operator<=(TimeTicks other) const {
michael@0:     return ticks_ <= other.ticks_;
michael@0:   }
michael@0:   bool operator>(TimeTicks other) const {
michael@0:     return ticks_ > other.ticks_;
michael@0:   }
michael@0:   bool operator>=(TimeTicks other) const {
michael@0:     return ticks_ >= other.ticks_;
michael@0:   }
michael@0: 
michael@0:  protected:
michael@0:   friend class TimeDelta;
michael@0: 
michael@0:   // Please use Now() to create a new object. This is for internal use
michael@0:   // and testing. Ticks is in microseconds.
michael@0:   explicit TimeTicks(int64 ticks) : ticks_(ticks) {
michael@0:   }
michael@0: 
michael@0:   // Tick count in microseconds.
michael@0:   int64 ticks_;
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0:   typedef DWORD (*TickFunctionType)(void);
michael@0:   static TickFunctionType SetMockTickFunction(TickFunctionType ticker);
michael@0: #endif
michael@0: };
michael@0: 
michael@0: inline TimeTicks TimeDelta::operator+(TimeTicks t) const {
michael@0:   return TimeTicks(t.ticks_ + delta_);
michael@0: }
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_TIME_TIME_H_