Make trailing LF following fast-import `data` commands optional

A few fast-import frontend developers have found it odd that we
require the LF following a `data` command, especially in the exact
byte count format.  Technically we don't need this LF to parse
the stream properly, but having it here does make the stream more
readable to humans.  We can easily make the LF optional by peeking
at the next byte available from the stream and pushing it back into
the buffer if its not LF.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 9 insertions, 4 deletions

diff --git a/fast-import.c b/fast-import.c
index 98ebe4770..f950cff5e 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -61,7 +61,7 @@ Format of STDIN stream:
      #
   mark ::= 'mark' sp idnum lf;
   data ::= (delimited_data | exact_data)
-    lf;
+    lf?;
 
     # note: delim may be any string but must not contain lf.
     # data_line may contain any data but must not be exactly
@@ -1470,6 +1470,13 @@ static void read_next_command(void)
 	} while (!command_buf.eof && command_buf.buf[0] == '#');
 }
 
+static void skip_optional_lf()
+{
+	int term_char = fgetc(stdin);
+	if (term_char != '\n' && term_char != EOF)
+		ungetc(term_char, stdin);
+}
+
 static void cmd_mark(void)
 {
 	if (!prefixcmp(command_buf.buf, "mark :")) {
@@ -1522,9 +1529,7 @@ static void *cmd_data (size_t *size)
 		}
 	}
 
-	if (fgetc(stdin) != '\n')
-		die("An lf did not trail the binary data as expected.");
-
+	skip_optional_lf();
 	*size = length;
 	return buffer;
 }