Introduce --pretty=oneline format.

This introduces --pretty=oneline to git-rev-tree and
git-rev-list commands to show only the first line of the commit
message, without frills. 

Signed-off-by: Junio C Hamano <junkio@cox.net>

commit.c

@@ -33,6 +33,8 @@ enum cmit_fmt get_commit_format(const char *arg)
 		return CMIT_FMT_SHORT;
 	if (!strcmp(arg, "=full"))
 		return CMIT_FMT_FULL;
+	if (!strcmp(arg, "=oneline"))
+		return CMIT_FMT_ONELINE;
 	die("invalid --pretty format");
 }
 
@@ -350,6 +352,8 @@ static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const c
 	unsigned long time;
 	int tz, ret;
 
+	if (fmt == CMIT_FMT_ONELINE)
+		return 0;
 	date = strchr(line, '>');
 	if (!date)
 		return 0;
@@ -373,6 +377,9 @@ static int is_empty_line(const char *line, int len)
 static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
 {
 	int offset = 0;
+
+	if (fmt == CMIT_FMT_ONELINE)
+		return offset;
 	switch (parents) {
 	case 1:
 		break;
@@ -393,6 +400,7 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
 	int hdr = 1, body = 0;
 	unsigned long offset = 0;
 	int parents = 0;
+	int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
 
 	for (;;) {
 		const char *line = msg;
@@ -416,6 +424,7 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
 		if (hdr) {
 			if (linelen == 1) {
 				hdr = 0;
+				if (fmt != CMIT_FMT_ONELINE)
 					buf[offset++] = '\n';
 				continue;
 			}
@@ -446,13 +455,23 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
 		} else {
 			body = 1;
 		}
-		memset(buf + offset, ' ', 4);
+
-		memcpy(buf + offset + 4, line, linelen);
+		memset(buf + offset, ' ', indent);
-		offset += linelen + 4;
+		memcpy(buf + offset + indent, line, linelen);
+		offset += linelen + indent;
+		if (fmt == CMIT_FMT_ONELINE)
+			break;
 	}
+	if (fmt == CMIT_FMT_ONELINE) {
+		/* We do not want the terminating newline */
+		if (buf[offset - 1] == '\n')
+			offset--;
+	}
+	else {
 		/* Make sure there is an EOLN */
 		if (buf[offset - 1] != '\n')
 			buf[offset++] = '\n';
+	}
 	buf[offset] = '\0';
 	return offset;
 }

commit.h

@@ -40,6 +40,7 @@ enum cmit_fmt {
 	CMIT_FMT_DEFAULT = CMIT_FMT_MEDIUM,
 	CMIT_FMT_SHORT,
 	CMIT_FMT_FULL,
+	CMIT_FMT_ONELINE,
 };
 
 extern enum cmit_fmt get_commit_format(const char *arg);

rev-list.c

@@ -63,7 +63,11 @@ static void show_commit(struct commit *commit)
 			parents = parents->next;
 		}
 	}
+	if (commit_format == CMIT_FMT_ONELINE)
+		putchar(' ');
+	else
 		putchar('\n');
+
 	if (verbose_header) {
 		static char pretty_header[16384];
 		pretty_print_commit(commit_format, commit->buffer, ~0, pretty_header, sizeof(pretty_header));
@@ -503,6 +507,9 @@ int main(int argc, char **argv)
 			commit_format = get_commit_format(arg+8);
 			verbose_header = 1;
 			hdr_termination = '\n';
+			if (commit_format == CMIT_FMT_ONELINE)
+				prefix = "";
+			else
 				prefix = "commit ";
 			continue;
 		}