grep: support newline separated pattern list

Currently, patterns that contain newline characters don't match anything
when given to git grep.  Regular grep(1) interprets patterns as lists of
newline separated search strings instead.

Implement this functionality by creating and inserting extra grep_pat
structures for patterns consisting of multiple lines when appending to
the pattern lists.  For simplicity, all pattern strings are duplicated.
The original pattern is truncated in place to make it contain only the
first line.

Requested-by: Torne (Richard Coles) <torne@google.com>
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 32 insertions, 1 deletions

diff --git a/grep.c b/grep.c
index c35a7ce57..02258039d 100644
--- a/grep.c
+++ b/grep.c
@@ -9,7 +9,7 @@ static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 					enum grep_header_field field)
 {
 	struct grep_pat *p = xcalloc(1, sizeof(*p));
-	p->pattern = pat;
+	p->pattern = xmemdupz(pat, patlen);
 	p->patternlen = patlen;
 	p->origin = origin;
 	p->no = no;
@@ -23,6 +23,36 @@ static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
 	**tail = p;
 	*tail = &p->next;
 	p->next = NULL;
+
+	switch (p->token) {
+	case GREP_PATTERN: /* atom */
+	case GREP_PATTERN_HEAD:
+	case GREP_PATTERN_BODY:
+		for (;;) {
+			struct grep_pat *new_pat;
+			size_t len = 0;
+			char *cp = p->pattern + p->patternlen, *nl = NULL;
+			while (++len <= p->patternlen) {
+				if (*(--cp) == '\n') {
+					nl = cp;
+					break;
+				}
+			}
+			if (!nl)
+				break;
+			new_pat = create_grep_pat(nl + 1, len - 1, p->origin,
+						  p->no, p->token, p->field);
+			new_pat->next = p->next;
+			if (!p->next)
+				*tail = &new_pat->next;
+			p->next = new_pat;
+			*nl = '\0';
+			p->patternlen -= len;
+		}
+		break;
+	default:
+		break;
+	}
 }
 
 void append_header_grep_pattern(struct grep_opt *opt,
@@ -408,6 +438,7 @@ void free_grep_patterns(struct grep_opt *opt)
 				free_pcre_regexp(p);
 			else
 				regfree(&p->regexp);
+			free(p->pattern);
 			break;
 		default:
 			break;