add EOF marker functionality

since it's hard or impossible to close fifo pipes in shell scripts,
it's handy to have a way to signal jobflow when the end of input
is reached so it can terminate once everything is processed.
the shell script can now run jobflow with -eof=XXX to specify a
magic eof marker.

jobflow.c

@@ -16,7 +16,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 
-#define VERSION "1.2.2"
+#define VERSION "1.2.3"
 
 
 #undef _POSIX_C_SOURCE
@@ -86,6 +86,7 @@ typedef struct {
 	unsigned numthreads;
 	unsigned threads_running;
 	char* statefile;
+	char* eof_marker;
 	unsigned long long skip;
 	sblist* job_infos;
 	sblist* subst_entries;
@@ -319,6 +320,7 @@ static int syntax(void) {
 		"available options:\n\n"
 		"-skip=XXX -threads=XXX -resume -statefile=/tmp/state -delayedflush\n"
 		"-delayedspinup=XXX -buffered -joinoutput -limits=mem=16M,cpu=10\n"
+		"-eof=XXX\n"
 		"-exec ./mycommand {}\n"
 		"\n"
 		"-skip=XXX\n"
@@ -327,6 +329,10 @@ static int syntax(void) {
 		"    XXX=number of parallel processes to spawn\n"
 		"-resume\n"
 		"    resume from last jobnumber stored in statefile\n"
+		"-eof=XXX\n"
+		"    use XXX as the EOF marker on stdin\n"
+		"    if the marker is encountered, behave as if stdin was closed\n"
+		"    not compatible with pipe/bulk mode\n"
 		"-statefile=XXX\n"
 		"    XXX=filename\n"
 		"    saves last launched jobnumber into a file\n"
@@ -393,6 +399,9 @@ static int parse_args(int argc, char** argv) {
 	op_temp = op_get(op, SPL("statefile"));
 	prog_state.statefile = op_temp;
 
+	op_temp = op_get(op, SPL("eof"));
+	prog_state.eof_marker = op_temp;
+
 	op_temp = op_get(op, SPL("skip"));
 	prog_state.skip = op_temp ? strtoll(op_temp,0,10) : 0;
 	if(op_hasflag(op, SPL("resume"))) {
@@ -585,6 +594,13 @@ static size_t count_linefeeds(const char *buf, size_t len) {
 	}
 	return cnt;
 }
+
+static int match_eof(char* inbuf, size_t len) {
+	if(!prog_state.eof_marker) return 0;
+	size_t l = strlen(prog_state.eof_marker);
+	return l == len-1 && !memcmp(prog_state.eof_marker, inbuf, l);
+}
+
 #define MAX_SUBSTS 16
 static int dispatch_line(char* inbuf, size_t len, char** argv) {
 	char subst_buf[MAX_SUBSTS][4096];
@@ -751,13 +767,17 @@ int main(int argc, char** argv) {
 
 			if(!p) break;
 			ptrdiff_t diff = (p - in) + 1;
+			if(match_eof(in, diff)) {
+				exitcode = 0;
+				goto out;
+			}
 			if(!dispatch_line(in, diff, argv))
 				goto out;
 			left -= diff;
 			in += diff;
 		}
 		if(!n) {
-			if(left) dispatch_line(in, left, argv);
+			if(left && !match_eof(in, left)) dispatch_line(in, left, argv);
 			break;
 		}
 		if(left > chunksize) {