mingw: make fgetc raise SIGINT if apropriate

Set a control-handler to prevent the process from terminating, and
simulate SIGINT so it can be handled by a signal-handler as usual.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/mingw.c

@@ -319,6 +319,31 @@ ssize_t mingw_write(int fd, const void *buf, size_t count)
 	return write(fd, buf, min(count, 31 * 1024 * 1024));
 }
 
+static BOOL WINAPI ctrl_ignore(DWORD type)
+{
+	return TRUE;
+}
+
+#undef fgetc
+int mingw_fgetc(FILE *stream)
+{
+	int ch;
+	if (!isatty(_fileno(stream)))
+		return fgetc(stream);
+
+	SetConsoleCtrlHandler(ctrl_ignore, TRUE);
+	while (1) {
+		ch = fgetc(stream);
+		if (ch != EOF || GetLastError() != ERROR_OPERATION_ABORTED)
+			break;
+
+		/* Ctrl+C was pressed, simulate SIGINT and retry */
+		mingw_raise(SIGINT);
+	}
+	SetConsoleCtrlHandler(ctrl_ignore, FALSE);
+	return ch;
+}
+
 #undef fopen
 FILE *mingw_fopen (const char *filename, const char *otype)
 {
@@ -1546,7 +1571,7 @@ static HANDLE timer_event;
 static HANDLE timer_thread;
 static int timer_interval;
 static int one_shot;
-static sig_handler_t timer_fn = SIG_DFL;
+static sig_handler_t timer_fn = SIG_DFL, sigint_fn = SIG_DFL;
 
 /* The timer works like this:
  * The thread, ticktack(), is a trivial routine that most of the time
@@ -1560,13 +1585,7 @@ static sig_handler_t timer_fn = SIG_DFL;
 static unsigned __stdcall ticktack(void *dummy)
 {
 	while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
-		if (timer_fn == SIG_DFL) {
-			if (isatty(STDERR_FILENO))
-				fputs("Alarm clock\n", stderr);
-			exit(128 + SIGALRM);
-		}
-		if (timer_fn != SIG_IGN)
-			timer_fn(SIGALRM);
+		mingw_raise(SIGALRM);
 		if (one_shot)
 			break;
 	}
@@ -1657,12 +1676,49 @@ int sigaction(int sig, struct sigaction *in, struct sigaction *out)
 sig_handler_t mingw_signal(int sig, sig_handler_t handler)
 {
 	sig_handler_t old = timer_fn;
-	if (sig != SIGALRM)
+
+	switch (sig) {
+	case SIGALRM:
+		timer_fn = handler;
+		break;
+
+	case SIGINT:
+		sigint_fn = handler;
+		break;
+
+	default:
 		return signal(sig, handler);
-	timer_fn = handler;
+	}
+
 	return old;
 }
 
+#undef raise
+int mingw_raise(int sig)
+{
+	switch (sig) {
+	case SIGALRM:
+		if (timer_fn == SIG_DFL) {
+			if (isatty(STDERR_FILENO))
+				fputs("Alarm clock\n", stderr);
+			exit(128 + SIGALRM);
+		} else if (timer_fn != SIG_IGN)
+			timer_fn(SIGALRM);
+		return 0;
+
+	case SIGINT:
+		if (sigint_fn == SIG_DFL)
+			exit(128 + SIGINT);
+		else if (sigint_fn != SIG_IGN)
+			sigint_fn(SIGINT);
+		return 0;
+
+	default:
+		return raise(sig);
+	}
+}
+
+
 static const char *make_backslash_path(const char *path)
 {
 	static char buf[PATH_MAX + 1];

compat/mingw.h

@@ -179,6 +179,9 @@ int mingw_open (const char *filename, int oflags, ...);
 ssize_t mingw_write(int fd, const void *buf, size_t count);
 #define write mingw_write
 
+int mingw_fgetc(FILE *stream);
+#define fgetc mingw_fgetc
+
 FILE *mingw_fopen (const char *filename, const char *otype);
 #define fopen mingw_fopen
 
@@ -290,6 +293,9 @@ static inline unsigned int git_ntohl(unsigned int x)
 sig_handler_t mingw_signal(int sig, sig_handler_t handler);
 #define signal mingw_signal
 
+int mingw_raise(int sig);
+#define raise mingw_raise
+
 /*
  * ANSI emulation wrappers
  */