Move read_revisions_from_stdin from builtin-rev-list.c to revision.c

Reading rev-list parameters from the command line can be reused by
commands other than rev-list.  Move this function to more "library-ish"
place to promote code reuse.

Signed-off-by: Adam Brewster <asb@bu.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 83a7b134..54b6672 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -565,23 +565,6 @@
 	return best;
 }
 
-static void read_revisions_from_stdin(struct rev_info *revs)
-{
-	char line[1000];
-
-	while (fgets(line, sizeof(line), stdin) != NULL) {
-		int len = strlen(line);
-		if (len && line[len - 1] == '\n')
-			line[--len] = 0;
-		if (!len)
-			break;
-		if (line[0] == '-')
-			die("options not supported in --stdin mode");
-		if (handle_revision_arg(line, revs, 0, 1))
-			die("bad revision '%s'", line);
-	}
-}
-
 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 {
 	struct commit_list *list;
diff --git a/revision.c b/revision.c
index fc66755..6ce6042 100644
--- a/revision.c
+++ b/revision.c
@@ -910,6 +910,23 @@
 	return 0;
 }
 
+void read_revisions_from_stdin(struct rev_info *revs)
+{
+	char line[1000];
+
+	while (fgets(line, sizeof(line), stdin) != NULL) {
+		int len = strlen(line);
+		if (len && line[len - 1] == '\n')
+			line[--len] = '\0';
+		if (!len)
+			break;
+		if (line[0] == '-')
+			die("options not supported in --stdin mode");
+		if (handle_revision_arg(line, revs, 0, 1))
+			die("bad revision '%s'", line);
+	}
+}
+
 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 {
 	if (!revs->grep_filter) {
diff --git a/revision.h b/revision.h
index abce500..83f364a 100644
--- a/revision.h
+++ b/revision.h
@@ -111,6 +111,8 @@
 #define REV_TREE_DIFFERENT	2
 
 /* revision.c */
+void read_revisions_from_stdin(struct rev_info *revs);
+
 typedef void (*show_early_output_fn_t)(struct rev_info *, struct commit_list *);
 volatile show_early_output_fn_t show_early_output;