[PATCH v3 0/2] grep: add --max-count command line option

This patch adds a command line option analogous to that of GNU grep(1)'s -m / --max-count, which users might already be used to. This makes it possible to limit the amount of matches shown in the output while keeping the functionality of other options such as -C (show code context) or -p (show containing function), which would be difficult to do with a shell pipeline (e.g. head(1)).

Signed-off-by: Carlos López 00xc@protonmail.com

Carlos López (2):
  grep: add --max-count command line option
  tests: add tests for grep --max-count

 Documentation/git-grep.txt |  9 +++++
 builtin/grep.c             |  9 +++++
 grep.c                     |  2 +-
 grep.h                     |  2 +
 t/t7810-grep.sh            | 83 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 104 insertions(+), 1 deletion(-)

base-commit: 5b71c59bc3b9365075e2a175aa7b6f2b0c84ce44
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1278%2F00xc%2Fmaster-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1278/00xc/master-v3
Pull-Request: https://github.com/git/git/pull/1278

Range-diff vs v2:

 1:  ee7eb298854 ! 1:  5bf7244437e grep: add --max-count command line option
     @@ Documentation/git-grep.txt: providing this option will cause it to die.
      +	Limit the amount of matches per file. When using the `-v` or
      +	`--invert-match` option, the search stops after the specified
      +	number of non-matches. A value of -1 will return unlimited
     -+	results (the default).
     ++	results (the default). A value of 0 will exit immediately with
     ++	a non-zero status.
      +
       --threads <num>::
       	Number of grep worker threads to use.
     @@ builtin/grep.c: int cmd_grep(int argc, const char **argv, const char *prefix)
      +	 * We do this to keep results consistent with GNU grep(1).
      +	 */
      +	if (opt.max_count == 0)
     -+		exit(EXIT_FAILURE);
     ++		return 1;
      +
       	if (show_in_pager) {
       		if (num_threads > 1)
     @@ builtin/grep.c: int cmd_grep(int argc, const char **argv, const char *prefix)
      
       ## grep.c ##
      @@ grep.c: static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
     - 		bol = eol + 1;
     - 		if (!left)
     - 			break;
     -+		if (opt->max_count != -1 && count == opt->max_count)
     -+			break;
     - 		left--;
     - 		lno++;
     - 	}
     + 				return 0;
     + 			goto next_line;
     + 		}
     +-		if (hit) {
     ++		if (hit && (opt->max_count < 0 || count < opt->max_count)) {
     + 			count++;
     + 			if (opt->status_only)
     + 				return 1;
      
       ## grep.h ##
      @@ grep.h: struct grep_opt {
 -:  ----------- > 2:  525958af877 tests: add tests for grep --max-count