lint fix

Add --open-on-demand: open the capture device only when someone is watching

.github/FUNDING.yml

@@ -1,4 +1,4 @@
 # These are supported funding model platforms
 
 patreon: pikvm
-custom: https://paypal.me/pikvm
+ko_fi: pikvm

man/ustreamer.1

@@ -112,6 +112,9 @@ It doesn't do anything. Still here for compatibility.
 .BR \-l ", " \-\-slowdown
 Slowdown capturing to 1 FPS or less when no stream or sink clients are connected. Useful to reduce CPU consumption. Default: disabled.
 .TP
+.BR \-\-open\-on\-demand \fIsec
+Don't open the capture device until at least one stream or sink client is connected, and close it again after a specified timeout since the last one disconnects. Clients see a blank screen while the device is closed. Default: disabled.
+.TP
 .BR \-\-device\-timeout\ \fIsec
 Timeout for device querying. Default: 1.
 .TP

src/ustreamer/http/path.c

@@ -120,8 +120,8 @@ char *us_simplify_request_path(const char *str) {
 #ifdef TEST_HTTP_PATH
 
 int test_simplify_request_path(const char *sample, const char *expected) {
-	char *result = us_simplify_request_path(sample);
+	const char *result = us_simplify_request_path(sample);
-	int retval = -!!strcmp(result, expected);
+	const int retval = -(!!strcmp(result, expected));
 
 	printf("Testing '%s' -> '%s' ... ", sample, expected);
 	if (retval == 0) {

src/ustreamer/options.c

@@ -89,7 +89,8 @@ enum _US_OPT_VALUES {
 
 	// Longs only
 
-	_O_DEVICE_TIMEOUT = 10000,
+	_O_OPEN_ON_DEMAND = 10000,
+	_O_DEVICE_TIMEOUT,
 	_O_DEVICE_ERROR_DELAY,
 	_O_FORMAT_SWAP_RGB,
 	_O_M2M_DEVICE,
@@ -190,6 +191,7 @@ static const struct option _LONG_OPTS[] = {
 	{"blank",					required_argument,	NULL,	_O_BLANK},
 	{"last-as-blank",			required_argument,	NULL,	_O_LAST_AS_BLANK},
 	{"slowdown",				no_argument,		NULL,	_O_SLOWDOWN},
+	{"open-on-demand",			required_argument,	NULL,	_O_OPEN_ON_DEMAND},
 	{"device-timeout",			required_argument,	NULL,	_O_DEVICE_TIMEOUT},
 	{"device-error-delay",		required_argument,	NULL,	_O_DEVICE_ERROR_DELAY},
 	{"m2m-device",				required_argument,	NULL,	_O_M2M_DEVICE},
@@ -453,6 +455,7 @@ int us_options_parse(
 			case _O_BLANK:				break; // Deprecated
 			case _O_LAST_AS_BLANK:		break; // Deprecated
 			case _O_SLOWDOWN:			OPT_SET(stream->slowdown, true);
+			case _O_OPEN_ON_DEMAND:		OPT_NUMBER("--open-on-demand", stream->open_on_demand, 1, 60, 0);
 			case _O_DEVICE_TIMEOUT:		OPT_NUMBER("--device-timeout", cap->timeout, 1, 60, 0);
 			case _O_DEVICE_ERROR_DELAY:	OPT_NUMBER("--device-error-delay", stream->error_delay, 1, 60, 0);
 			case _O_M2M_DEVICE:			OPT_SET(enc->m2m_path, optarg);
@@ -749,6 +752,10 @@ static void _help(
 	SAY("    -K|--last-as-blank <sec>  ──────────── It doesn't do anything. Still here for compatibility.\n");
 	SAY("    -l|--slowdown  ─────────────────────── Slowdown capturing to 1 FPS or less when no stream or sink clients");
 	SAY("                                           are connected. Useful to reduce CPU consumption. Default: disabled.\n");
+	SAY("    --open-on-demand <sec>  ────────────── Don't open the capture device until at least one stream");
+	SAY("                                           or sink client is connected, and close it again");
+	SAY("                                           after a specified timeout since the last one disconnects.");
+	SAY("                                           Clients see a blank screen while the device is closed. Default: disabled.\n");
 	SAY("    --device-timeout <sec>  ────────────── Timeout for device querying. Default: %u.\n", cap->timeout);
 	SAY("    --device-error-delay <sec>  ────────── Delay before trying to connect to the device again");
 	SAY("                                           after an error (timeout for example). Default: %u.\n", stream->error_delay);

src/ustreamer/stream.c

@@ -206,7 +206,23 @@ void us_stream_loop(us_stream_s *stream) {
 		US_LOG_INFO("Capturing ...");
 
 		int has_any_clients_prev = -1;
+		ldf no_clients_since_ts = 0;
 		while (!atomic_load(&run->stop) && !atomic_load(&threads_stop)) {
+			if (stream->open_on_demand > 0) {
+				if (_stream_has_any_clients_cached(stream)) {
+					no_clients_since_ts = 0;
+				} else {
+					const ldf now_ts = us_get_now_monotonic();
+					if (no_clients_since_ts == 0) {
+						no_clients_since_ts = now_ts;
+					} else if (no_clients_since_ts + stream->open_on_demand < now_ts) {
+						US_LOG_INFO("No stream or sink clients found in last %u seconds, closing the device ...",
+							stream->open_on_demand);
+						goto close;
+					}
+				}
+			}
+
 			us_capture_hwbuf_s *hw;
 			switch (us_capture_hwbuf_grab(cap, &hw)) {
 				case 0 ... INT_MAX: break; // Grabbed buffer number
@@ -578,7 +594,18 @@ static int _stream_init_loop(us_stream_s *stream) {
 		UPDATE_SINK(stream->h264_sink);
 #		undef UPDATE_SINK
 
-		_stream_check_suicide(stream, _stream_has_any_clients_cached(stream));
+		const bool has_any_clients = _stream_has_any_clients_cached(stream);
+
+		_stream_check_suicide(stream, has_any_clients);
+
+		if (stream->open_on_demand > 0 && !has_any_clients) {
+			US_ONCE({ US_LOG_INFO("Waiting for the stream or sink clients to open the device ..."); });
+			blank_reason = (
+				"< WAITING FOR CLIENTS >\n \n"
+				"   The camera is idle  "
+			);
+			goto silent_error;
+		}
 
 		stream->cap->dma_export = (
 			stream->enc->type == US_ENCODER_TYPE_M2M_VIDEO
@@ -598,7 +625,7 @@ static int _stream_init_loop(us_stream_s *stream) {
 					"  - Bad config       \n \n"
 					"  - Malfunction      "
 				);
-				goto silent_error;
+				goto silent_capture_error;
 			case US_ERROR_NO_CABLE:
 				blank_reason = (
 					"< NO VIDEO SOURCE >\n \n"
@@ -606,7 +633,7 @@ static int _stream_init_loop(us_stream_s *stream) {
 					" - Source is off   \n \n"
 					" - Cable problems  "
 				);
-				goto silent_error;
+				goto silent_capture_error;
 			case US_ERROR_NO_SIGNAL:
 				blank_reason = (
 					"< NO SIGNAL DETECTED >\n \n"
@@ -614,7 +641,7 @@ static int _stream_init_loop(us_stream_s *stream) {
                     "   - Video suspended  \n \n"
 					"   - Cable problems   "
 				);
-				goto silent_error;
+				goto silent_capture_error;
 			case US_ERROR_NO_SYNC:
 				blank_reason = (
 					"< NO SYNC WITH SIGNAL >\n \n"
@@ -622,7 +649,7 @@ static int _stream_init_loop(us_stream_s *stream) {
 					"   - Source is crazy   \n \n"
 					"   - Cable problems    "
 				);
-				goto silent_error;
+				goto silent_capture_error;
 			case US_ERROR_NO_LANES:
 				blank_reason = (
 					"< UNSUPPORTED SIGNAL TIMINGS >\n \n"
@@ -638,10 +665,12 @@ static int _stream_init_loop(us_stream_s *stream) {
 		us_encoder_open(stream->enc, stream->cap);
 		return 0;
 
-	silent_error:
+	silent_capture_error:
 		if (!stream->exit_on_device_error) {
 			US_ONCE({ US_LOG_INFO("Waiting for the capture device ..."); });
 		}
+
+	silent_error:
 		goto offline_and_retry;
 
 	verbose_error:

src/ustreamer/stream.h

@@ -83,6 +83,7 @@ typedef struct {
 	uint			desired_fps;
 	bool			notify_parent;
 	bool			slowdown;
+	uint			open_on_demand;
 	uint			error_delay;
 	bool			exit_on_device_error;
 	uint			exit_on_no_clients;