progress: replace setitimer() with alarm()

Makefile

@@ -142,11 +142,6 @@ include shared.mak
 # Define NO_PREAD if you have a problem with pread() system call (e.g.
 # cygwin1.dll before v1.5.22).
 #
-# Define NO_SETITIMER if you don't have setitimer()
-#
-# Define NO_STRUCT_ITIMERVAL if you don't have struct itimerval
-# This also implies NO_SETITIMER
-#
 # Define NO_FAST_WORKING_DIRECTORY if accessing objects in pack files is
 # generally faster on your platform than accessing the working directory.
 #
@@ -1888,13 +1883,6 @@ endif
 ifdef OBJECT_CREATION_USES_RENAMES
 	COMPAT_CFLAGS += -DOBJECT_CREATION_MODE=1
 endif
-ifdef NO_STRUCT_ITIMERVAL
-	COMPAT_CFLAGS += -DNO_STRUCT_ITIMERVAL
-	NO_SETITIMER = YesPlease
-endif
-ifdef NO_SETITIMER
-	COMPAT_CFLAGS += -DNO_SETITIMER
-endif
 ifdef NO_PREAD
 	COMPAT_CFLAGS += -DNO_PREAD
 	COMPAT_OBJS += compat/pread.o

compat/mingw-posix.h

@@ -98,11 +98,6 @@ struct sigaction {
 #define SA_RESTART 0
 #define SA_NOCLDSTOP 1
 
-struct itimerval {
-	struct timeval it_value, it_interval;
-};
-#define ITIMER_REAL 0
-
 struct utsname {
 	char sysname[16];
 	char nodename[1];
@@ -131,8 +126,6 @@ static inline int fchmod(int fildes UNUSED, mode_t mode UNUSED)
 static inline pid_t fork(void)
 { errno = ENOSYS; return -1; }
 #endif
-static inline unsigned int alarm(unsigned int seconds UNUSED)
-{ return 0; }
 static inline int fsync(int fd)
 { return _commit(fd); }
 static inline void sync(void)
@@ -183,6 +176,7 @@ char *mingw_locate_in_PATH(const char *cmd);
  * implementations of missing functions
  */
 
+unsigned alarm(unsigned seconds);
 int pipe(int filedes[2]);
 unsigned int sleep (unsigned int seconds);
 int mkstemp(char *template);
@@ -193,7 +187,6 @@ struct tm *localtime_r(const time_t *timep, struct tm *result);
 #endif
 int getpagesize(void);	/* defined in MinGW's libgcc.a */
 struct passwd *getpwuid(uid_t uid);
-int setitimer(int type, struct itimerval *in, struct itimerval *out);
 int sigaction(int sig, struct sigaction *in, struct sigaction *out);
 int link(const char *oldpath, const char *newpath);
 int uname(struct utsname *buf);

compat/mingw.c

@@ -2432,15 +2432,17 @@ static sig_handler_t timer_fn = SIG_DFL, sigint_fn = SIG_DFL;
  * the thread to terminate by setting the timer_event to the signalled
  * state.
  * But ticktack() interrupts the wait state after the timer's interval
- * length to call the signal handler.
+ * length to call the signal handler if it still set.
  */
 
 static unsigned __stdcall ticktack(void *dummy UNUSED)
 {
+	sig_handler_t fn = timer_fn;
+
 	while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
-		mingw_raise(SIGALRM);
-		if (one_shot)
+		if (one_shot || timer_fn != fn)
 			break;
+		mingw_raise(SIGALRM);
 	}
 	return 0;
 }
@@ -2478,37 +2480,23 @@ static void stop_timer_thread(void)
 	timer_thread = NULL;
 }
 
-static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
+unsigned alarm(unsigned seconds)
 {
-	return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
-}
-
-int setitimer(int type UNUSED, struct itimerval *in, struct itimerval *out)
-{
-	static const struct timeval zero;
-	static int atexit_done;
-
-	if (out)
-		return errno = EINVAL,
-			error("setitimer param 3 != NULL not implemented");
-	if (!is_timeval_eq(&in->it_interval, &zero) &&
-	    !is_timeval_eq(&in->it_interval, &in->it_value))
-		return errno = EINVAL,
-			error("setitimer: it_interval must be zero or eq it_value");
-
-	if (timer_thread)
-		stop_timer_thread();
+	static bool atexit_done;
 
-	if (is_timeval_eq(&in->it_value, &zero) &&
-	    is_timeval_eq(&in->it_interval, &zero))
-		return 0;
-
-	timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
-	one_shot = is_timeval_eq(&in->it_interval, &zero);
 	if (!atexit_done) {
 		atexit(stop_timer_thread);
-		atexit_done = 1;
+		atexit_done = true;
 	}
+
+	timer_interval = seconds * 1000;
+	one_shot = !seconds;
+	if (timer_thread) {
+		if (!seconds)
+			stop_timer_thread();
+		return 0;
+	}
+
 	return start_timer_thread();
 }
 

compat/posix.h

@@ -198,23 +198,6 @@ static inline time_t git_time(time_t *tloc)
 }
 #define time git_time
 
-#ifdef NO_STRUCT_ITIMERVAL
-struct itimerval {
-	struct timeval it_interval;
-	struct timeval it_value;
-};
-#endif
-
-#ifdef NO_SETITIMER
-static inline int git_setitimer(int which UNUSED,
-				const struct itimerval *value UNUSED,
-				struct itimerval *newvalue UNUSED) {
-	return 0; /* pretend success */
-}
-#undef setitimer
-#define setitimer(which,value,ovalue) git_setitimer(which,value,ovalue)
-#endif
-
 #ifndef NO_LIBGEN_H
 #include <libgen.h>
 #else

configure.ac

@@ -872,13 +872,6 @@ case $ac_cv_type_socklen_t in
 esac
 GIT_CONF_SUBST([SOCKLEN_T])
 
-#
-# Define NO_STRUCT_ITIMERVAL if you don't have struct itimerval.
-AC_CHECK_TYPES([struct itimerval],
-[NO_STRUCT_ITIMERVAL=],
-[NO_STRUCT_ITIMERVAL=UnfortunatelyYes],
-[#include <sys/time.h>])
-GIT_CONF_SUBST([NO_STRUCT_ITIMERVAL])
 #
 # Define USE_ST_TIMESPEC=YesPlease when stat.st_mtimespec.tv_nsec exists.
 # Define NO_NSEC=YesPlease when neither stat.st_mtim.tv_nsec nor
@@ -1097,12 +1090,6 @@ GIT_CHECK_FUNC(sync_file_range,
 	[HAVE_SYNC_FILE_RANGE=])
 GIT_CONF_SUBST([HAVE_SYNC_FILE_RANGE])
 
-#
-# Define NO_SETITIMER if you don't have setitimer.
-GIT_CHECK_FUNC(setitimer,
-[NO_SETITIMER=],
-[NO_SETITIMER=YesPlease])
-GIT_CONF_SUBST([NO_SETITIMER])
 #
 # Define NO_STRCASESTR if you don't have strcasestr.
 GIT_CHECK_FUNC(strcasestr,

meson.build

@@ -1348,22 +1348,6 @@ else
     error('Native regex support requested but not found')
 endif
 
-# setitimer and friends are provided by compat/mingw.c.
-if host_machine.system() != 'windows'
-  if not compiler.compiles('''
-    #include <sys/time.h>
-    void func(void)
-    {
-      struct itimerval value;
-    }
-  ''', name: 'struct itimerval')
-    libgit_c_args += '-DNO_STRUCT_ITIMERVAL'
-    libgit_c_args += '-DNO_SETITIMER'
-  elif not compiler.has_function('setitimer')
-    libgit_c_args += '-DNO_SETITIMER'
-  endif
-endif
-
 if compiler.has_member('struct stat', 'st_mtimespec.tv_nsec', prefix: '#include <sys/stat.h>')
   libgit_c_args += '-DUSE_ST_TIMESPEC'
 elif not compiler.has_member('struct stat', 'st_mtim.tv_nsec', prefix: '#include <sys/stat.h>')

progress.c

@@ -50,6 +50,11 @@ struct progress {
 	int split;
 };
 
+/*
+ * 0: no progress to report
+ * 1: potential update for progress to report
+ * 2: no more progress to report
+ */
 static volatile sig_atomic_t progress_update;
 
 /*
@@ -66,13 +71,15 @@ void progress_test_force_update(void)
 
 static void progress_interval(int signum UNUSED)
 {
-	progress_update = 1;
+	if (progress_update != 2) {
+		alarm(1);
+		progress_update = 1;
+	}
 }
 
 static void set_progress_signal(void)
 {
 	struct sigaction sa;
-	struct itimerval v;
 
 	if (progress_testing)
 		return;
@@ -85,20 +92,16 @@ static void set_progress_signal(void)
 	sa.sa_flags = SA_RESTART;
 	sigaction(SIGALRM, &sa, NULL);
 
-	v.it_interval.tv_sec = 1;
-	v.it_interval.tv_usec = 0;
-	v.it_value = v.it_interval;
-	setitimer(ITIMER_REAL, &v, NULL);
+	alarm(1);
 }
 
 static void clear_progress_signal(void)
 {
-	struct itimerval v = {{0,},};
-
 	if (progress_testing)
 		return;
 
-	setitimer(ITIMER_REAL, &v, NULL);
+	progress_update = 2;
+	alarm(0);
 	signal(SIGALRM, SIG_IGN);
 	progress_update = 0;
 }
@@ -116,14 +119,14 @@ static void display(struct progress *progress, uint64_t n, const char *done)
 	int show_update = 0;
 	int last_count_len = counters_sb->len;
 
-	if (progress->delay && (!progress_update || --progress->delay))
+	if (progress->delay && (!(progress_update & 1) || --progress->delay))
 		return;
 
 	progress->last_value = n;
 	tp = (progress->throughput) ? progress->throughput->display.buf : "";
 	if (progress->total) {
 		unsigned percent = n * 100 / progress->total;
-		if (percent != progress->last_percent || progress_update) {
+		if (percent != progress->last_percent || (progress_update & 1)) {
 			progress->last_percent = percent;
 
 			strbuf_reset(counters_sb);
@@ -133,7 +136,7 @@ static void display(struct progress *progress, uint64_t n, const char *done)
 				    tp);
 			show_update = 1;
 		}
-	} else if (progress_update) {
+	} else if (progress_update & 1) {
 		strbuf_reset(counters_sb);
 		strbuf_addf(counters_sb, "%"PRIuMAX"%s", (uintmax_t)n, tp);
 		show_update = 1;
@@ -244,7 +247,7 @@ void display_throughput(struct progress *progress, uint64_t total)
 	tp->idx = (tp->idx + 1) % TP_IDX_MAX;
 
 	throughput_string(&tp->display, total, rate);
-	if (progress->last_value != -1 && progress_update)
+	if (progress->last_value != -1 && (progress_update & 1))
 		display(progress, progress->last_value, NULL);
 }