grep: read patterns from stdin with -f -

Support the well-know convention of reading standard input instead of a
named file if "-" (dash) is specified.  GNU grep does the same.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/grep.c b/builtin/grep.c
index eaf8560a520bd8aac4fa62394378b444116d6226..0bf8c0116a6a4c178a2c368f17d4103e91486624 100644 (file)
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -659,11 +659,12 @@ static int context_callback(const struct option *opt, const char *arg,
 static int file_callback(const struct option *opt, const char *arg, int unset)
 {
        struct grep_opt *grep_opt = opt->value;
+       int from_stdin = !strcmp(arg, "-");
        FILE *patterns;
        int lno = 0;
        struct strbuf sb = STRBUF_INIT;
 
-       patterns = fopen(arg, "r");
+       patterns = from_stdin ? stdin : fopen(arg, "r");
        if (!patterns)
                die_errno("cannot open '%s'", arg);
        while (strbuf_getline(&sb, patterns, '\n') == 0) {
@@ -677,7 +678,8 @@ static int file_callback(const struct option *opt, const char *arg, int unset)
                s = strbuf_detach(&sb, &len);
                append_grep_pat(grep_opt, s, len, arg, ++lno, GREP_PATTERN);
        }
-       fclose(patterns);
+       if (!from_stdin)
+               fclose(patterns);
        strbuf_release(&sb);
        return 0;
 }

diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 8a7788dc39f236b15e60912c384d835fd1db5a28..dbc6cd8a775a43efbd8fdf433958ccd090b6e3ab 100755 (executable)
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -303,6 +303,11 @@ test_expect_success 'grep -f, ignore empty lines' '
        test_cmp expected actual
 '
 
+test_expect_success 'grep -f, ignore empty lines, read patterns from stdin' '
+       git grep -f - <patterns >actual &&
+       test_cmp expected actual
+'
+
 cat >expected <<EOF
 y:y yy
 --