clock millis, time: now use monotonic raw time if possible

Instead of using all time, these commands now use a monotonically
increasing system timer so that they are not affected by time (e.g. ntp) adjustments.
(But not on Windows since it doesn't work reliably)

Fixes #240

Signed-off-by: Steve Bennett <steveb@workware.net.au>

5 files changed, 60 insertions, 58 deletions

diff --git a/auto.def b/auto.def
index 5d751f1..2cd63c5 100644
--- a/auto.def
+++ b/auto.def
@@ -251,7 +251,7 @@ cc-check-functions geteuid mkstemp isatty
 cc-check-functions regcomp waitpid sigaction sys_signame sys_siglist isascii
 cc-check-functions syslog opendir readlink sleep usleep pipe getaddrinfo utimes
 cc-check-functions shutdown socketpair link symlink fsync dup umask
-cc-check-functions localtime gmtime strptime clock_gettime
+cc-check-functions localtime gmtime strptime
 if {![cc-check-functions realpath]} {
 	cc-check-functions _fullpath
 }
@@ -534,6 +534,9 @@ if {[have-feature windows]} {
             set buildjimext 0
         }
     }
+} else {
+    # We don't trust any version of clock_gettime on windows
+    cc-check-functions clock_gettime
 }
 if {[have-feature termios.h]} {
     lappend extra_objs jim-tty.o
diff --git a/jim-clock.c b/jim-clock.c
index 0ca3e7b..43d7f74 100644
--- a/jim-clock.c
+++ b/jim-clock.c
@@ -151,37 +151,32 @@ static int clock_cmd_scan(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 
 static int clock_cmd_seconds(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
-    Jim_SetResultInt(interp, time(NULL));
+    Jim_SetResultInt(interp, Jim_GetTimeUsec(CLOCK_REALTIME) / 1000000);
+    return JIM_OK;
+}
 
+static int clock_cmd_clicks(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
+{
+    Jim_SetResultInt(interp, Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW));
     return JIM_OK;
 }
 
 static int clock_cmd_micros(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
-    struct timeval tv;
-
-    gettimeofday(&tv, NULL);
-
-    Jim_SetResultInt(interp, (jim_wide) tv.tv_sec * 1000000 + tv.tv_usec);
-
+    Jim_SetResultInt(interp, Jim_GetTimeUsec(CLOCK_REALTIME));
     return JIM_OK;
 }
 
 static int clock_cmd_millis(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
-    struct timeval tv;
-
-    gettimeofday(&tv, NULL);
-
-    Jim_SetResultInt(interp, (jim_wide) tv.tv_sec * 1000 + tv.tv_usec / 1000);
-
+    Jim_SetResultInt(interp, Jim_GetTimeUsec(CLOCK_REALTIME) / 1000);
     return JIM_OK;
 }
 
 static const jim_subcmd_type clock_command_table[] = {
     {   "clicks",
         NULL,
-        clock_cmd_micros,
+        clock_cmd_clicks,
         0,
         0,
         /* Description: Returns the current time in 'clicks' */
diff --git a/jim-eventloop.c b/jim-eventloop.c
index 782d5dd..b9e0e97 100644
--- a/jim-eventloop.c
+++ b/jim-eventloop.c
@@ -237,32 +237,6 @@ void Jim_DeleteFileHandler(Jim_Interp *interp, int fd, int mask)
     }
 }
 
-/**
- * Returns the time of day in microseconds.
- * (the time base is not relevant here)
- */
-static jim_wide JimGetTimeUsec(Jim_EventLoop *eventLoop)
-{
-    long long now;
-    struct timeval tv;
-
-#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC_RAW)
-    struct timespec ts;
-
-    if (clock_gettime(CLOCK_MONOTONIC_RAW, &ts) == 0) {
-        now = ts.tv_sec * 1000000LL + ts.tv_nsec / 1000;
-    }
-    else
-#endif
-    {
-        gettimeofday(&tv, NULL);
-
-        now = tv.tv_sec * 1000000LL + tv.tv_usec;
-    }
-
-    return now;
-}
-
 jim_wide Jim_CreateTimeHandler(Jim_Interp *interp, jim_wide us,
     Jim_TimeProc * proc, void *clientData, Jim_EventFinalizerProc * finalizerProc)
 {
@@ -273,7 +247,7 @@ jim_wide Jim_CreateTimeHandler(Jim_Interp *interp, jim_wide us,
     te = Jim_Alloc(sizeof(*te));
     te->id = id;
     te->initialus = us;
-    te->when = JimGetTimeUsec(eventLoop) + us;
+    te->when = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) + us;
     te->timeProc = proc;
     te->finalizerProc = finalizerProc;
     te->clientData = clientData;
@@ -374,7 +348,7 @@ jim_wide Jim_DeleteTimeHandler(Jim_Interp *interp, jim_wide id)
     if (te) {
         jim_wide remain;
 
-        remain = te->when - JimGetTimeUsec(eventLoop);
+        remain = te->when - Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
         remain = (remain < 0) ? 0 : remain;
 
         Jim_FreeTimeHandler(interp, te);
@@ -432,7 +406,7 @@ int Jim_ProcessEvents(Jim_Interp *interp, int flags)
 
             /* Calculate the time missing for the nearest
              * timer to fire. */
-            sleep_us = shortest->when - JimGetTimeUsec(eventLoop);
+            sleep_us = shortest->when - Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
             if (sleep_us < 0) {
                 sleep_us = 0;
             }
@@ -534,7 +508,7 @@ int Jim_ProcessEvents(Jim_Interp *interp, int flags)
             te = te->next;
             continue;
         }
-        if (JimGetTimeUsec(eventLoop) >= te->when) {
+        if (Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) >= te->when) {
             id = te->id;
             /* Remove from the list before executing */
             Jim_RemoveTimeHandler(eventLoop, id);
diff --git a/jim.c b/jim.c
index fe1aa03..ac78fda 100644
--- a/jim.c
+++ b/jim.c
@@ -694,15 +694,35 @@ char *Jim_StrDupLen(const char *s, int l)
  * Time related functions
  * ---------------------------------------------------------------------------*/
 
-/* Returns current time in microseconds */
-static jim_wide JimClock(void)
+/* Returns current time in microseconds
+ * CLOCK_MONOTONIC (monotonic clock that is affected by time adjustments)
+ * CLOCK_MONOTONIC_RAW (monotonic clock that is not affected by time adjustments)
+ * CLOCK_REALTIME (wall time)
+ */
+jim_wide Jim_GetTimeUsec(unsigned type)
 {
+    long long now;
     struct timeval tv;
 
-    gettimeofday(&tv, NULL);
-    return (jim_wide) tv.tv_sec * 1000000 + tv.tv_usec;
+#if defined(HAVE_CLOCK_GETTIME)
+    struct timespec ts;
+
+    if (clock_gettime(type, &ts) == 0) {
+        now = ts.tv_sec * 1000000LL + ts.tv_nsec / 1000;
+    }
+    else
+#endif
+    {
+        gettimeofday(&tv, NULL);
+
+        now = tv.tv_sec * 1000000LL + tv.tv_usec;
+    }
+
+    return now;
 }
 
+
+
 /* -----------------------------------------------------------------------------
  * Hash Tables
  * ---------------------------------------------------------------------------*/
@@ -5614,7 +5634,7 @@ int Jim_Collect(Jim_Interp *interp)
     }
     Jim_FreeHashTable(&marks);
     interp->lastCollectId = interp->referenceNextId;
-    interp->lastCollectTime = JimClock();
+    interp->lastCollectTime = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
     return collected;
 }
 
@@ -5627,7 +5647,7 @@ void Jim_CollectIfNeeded(Jim_Interp *interp)
     jim_wide elapsedTime;
 
     elapsedId = interp->referenceNextId - interp->lastCollectId;
-    elapsedTime = JimClock() - interp->lastCollectTime;
+    elapsedTime = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) - interp->lastCollectTime;
 
 
     if (elapsedId > JIM_COLLECT_ID_PERIOD || elapsedTime > JIM_COLLECT_TIME_PERIOD) {
@@ -5658,7 +5678,7 @@ Jim_Interp *Jim_CreateInterp(void)
 
     i->maxCallFrameDepth = JIM_MAX_CALLFRAME_DEPTH;
     i->maxEvalDepth = JIM_MAX_EVAL_DEPTH;
-    i->lastCollectTime = JimClock();
+    i->lastCollectTime = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
 
     /* Note that we can create objects only after the
      * interpreter liveList and freeList pointers are
@@ -14592,7 +14612,7 @@ static int Jim_TimeCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *arg
     if (count < 0)
         return JIM_OK;
     i = count;
-    start = JimClock();
+    start = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
     while (i-- > 0) {
         int retval;
 
@@ -14601,7 +14621,7 @@ static int Jim_TimeCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const *arg
             return retval;
         }
     }
-    elapsed = JimClock() - start;
+    elapsed = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) - start;
     if (elapsed < count * 10) {
         Jim_SetResult(interp, Jim_NewDoubleObj(interp, elapsed * 1.0 / count));
     }
@@ -14637,11 +14657,11 @@ static int Jim_TimeRateCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const
     }
 
     /* Run until we exceed the time limit */
-    start = JimClock();
+    start = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
     count = 0;
     do {
         int retval = Jim_EvalObj(interp, argv[1]);
-        delta = JimClock() - start;
+        delta = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) - start;
         if (retval != JIM_OK) {
             return retval;
         }
@@ -14649,11 +14669,11 @@ static int Jim_TimeRateCoreCommand(Jim_Interp *interp, int argc, Jim_Obj *const
     } while (delta < us);
 
     /* Now try to account for the loop and eval overhead */
-    start = JimClock();
+    start = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW);
     n = 0;
     do {
         int retval = Jim_EvalObj(interp, interp->nullScriptObj);
-        overhead = JimClock() - start;
+        overhead = Jim_GetTimeUsec(CLOCK_MONOTONIC_RAW) - start;
         if (retval != JIM_OK) {
             return retval;
         }
diff --git a/jim.h b/jim.h
index 07dfbeb..4162e5e 100644
--- a/jim.h
+++ b/jim.h
@@ -665,6 +665,16 @@ JIM_EXPORT char *Jim_StrDupLen(const char *s, int l);
 JIM_EXPORT char **Jim_GetEnviron(void);
 JIM_EXPORT void Jim_SetEnviron(char **env);
 JIM_EXPORT int Jim_MakeTempFile(Jim_Interp *interp, const char *filename_template, int unlink_file);
+#ifndef CLOCK_REALTIME
+#  define CLOCK_REALTIME 0
+#endif
+#ifndef CLOCK_MONOTONIC
+#  define CLOCK_MONOTONIC 1
+#endif
+#ifndef CLOCK_MONOTONIC_RAW
+#  define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC
+#endif
+JIM_EXPORT jim_wide Jim_GetTimeUsec(unsigned type);
 
 /* evaluation */
 JIM_EXPORT int Jim_Eval(Jim_Interp *interp, const char *script);