[Patch v2] notmuch-restore: handle empty input file, leading blank lines and comments.

[david at tethera.net]

From: David Bremner <bremner at debian.org>

This patch corrects several undesirable behaviours:

1) Empty files were not detected, leading to buffer read overrun.

2) An initial blank line cause restore to silently abort

3) Initial comment line caused format detection to fail
---
 notmuch-restore.c |   18 +++++++++++++-----
 test/dump-restore |    3 ---
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/notmuch-restore.c b/notmuch-restore.c
index d43546d..f436989 100644
--- a/notmuch-restore.c
+++ b/notmuch-restore.c
@@ -181,11 +181,6 @@ notmuch_restore_command (unused (void *ctx), int argc, char *argv[])
 		 argv[opt_index]);
 	return 1;
     }
-    char *p;
-
-    line_len = getline (&line, &line_size, input);
-    if (line_len == 0)
-	return 0;
 
     tag_ops = tag_op_list_create (ctx);
     if (tag_ops == NULL) {
@@ -193,6 +188,19 @@ notmuch_restore_command (unused (void *ctx), int argc, char *argv[])
 	return 1;
     }
 
+    do {
+	line_len = getline (&line, &line_size, input);
+
+	/* empty input file not considered an error */
+	if (line_len < 0)
+	    return 0;
+
+    } while ((line_len == 0) ||
+	     (line[0] == '#') ||
+	     /* the cast is safe because we checked about for line_len < 0 */
+	     (strspn (line, " \t\n") == (unsigned)line_len));
+
+    char *p;
     for (p = line; (input_format == DUMP_FORMAT_AUTO) && *p; p++) {
 	if (*p == '(')
 	    input_format = DUMP_FORMAT_SUP;
diff --git a/test/dump-restore b/test/dump-restore
index c2ddb92..ae30cd1 100755
--- a/test/dump-restore
+++ b/test/dump-restore
@@ -146,13 +146,11 @@ cat <<EOF > comments-and-blanks
 EOF
 
 test_begin_subtest 'restoring empty file is not an error'
-test_subtest_known_broken
 notmuch restore < /dev/null 2>OUTPUT.$test_count
 cp /dev/null EXPECTED
 test_expect_equal_file EXPECTED OUTPUT.$test_count
 
 test_begin_subtest 'file of comments and blank lines is not an error'
-test_subtest_known_broken
 notmuch restore --input=comments-and-blanks
 ret_val=$?
 test_expect_equal "$ret_val" "0"
@@ -172,7 +170,6 @@ echo "yun1vjwegii.fsf at aiko.keithp.com (another_tag)" \
     >> leading-comments-blanks-sup
 
 test_begin_subtest 'detect format=sup with leading comments and blanks'
-test_subtest_known_broken
 notmuch restore --input=leading-comments-blanks-sup
 notmuch search --output=tags id:yun1vjwegii.fsf at aiko.keithp.com > OUTPUT.$test_count
 echo "another_tag" > EXPECTED
-- 
1.7.10.4