1 files changed, 298 insertions, 233 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 552ef1face..a286692e46 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -11,18 +11,16 @@
 #include "tree-walk.h"
 #include "builtin.h"
 #include "parse-options.h"
+#include "string-list.h"
+#include "run-command.h"
 #include "userdiff.h"
 #include "grep.h"
 #include "quote.h"
 #include "dir.h"
-
-#ifndef NO_PTHREADS
 #include "thread-utils.h"
-#include <pthread.h>
-#endif
 
 static char const * const grep_usage[] = {
-	"git grep [options] [-e] <pattern> [<rev>...] [[--] path...]",
+	"git grep [options] [-e] <pattern> [<rev>...] [[--] <path>...]",
 	NULL
 };
 
@@ -42,8 +40,7 @@ enum work_type {WORK_SHA1, WORK_FILE};
  * threads. The producer adds struct work_items to 'todo' and the
  * consumers pick work items from the same array.
  */
-struct work_item
-{
+struct work_item {
 	enum work_type type;
 	char *name;
 
@@ -96,6 +93,8 @@ static pthread_cond_t cond_write;
 /* Signalled when we are finished with everything. */
 static pthread_cond_t cond_result;
 
+static int skip_first_line;
+
 static void add_work(enum work_type type, char *name, void *id)
 {
 	grep_lock();
@@ -159,7 +158,22 @@ static void work_done(struct work_item *w)
 	for(; todo[todo_done].done && todo_done != todo_start;
 	    todo_done = (todo_done+1) % ARRAY_SIZE(todo)) {
 		w = &todo[todo_done];
-		write_or_die(1, w->out.buf, w->out.len);
+		if (w->out.len) {
+			const char *p = w->out.buf;
+			size_t len = w->out.len;
+
+			/* Skip the leading hunk mark of the first file. */
+			if (skip_first_line) {
+				while (len) {
+					len--;
+					if (*p++ == '\n')
+						break;
+				}
+				skip_first_line = 0;
+			}
+
+			write_or_die(1, p, len);
+		}
 		free(w->name);
 		free(w->identifier);
 	}
@@ -239,7 +253,7 @@ static void start_threads(struct grep_opt *opt)
 		err = pthread_create(&threads[i], NULL, run, o);
 
 		if (err)
-			die("grep: failed to create thread: %s",
+			die(_("grep: failed to create thread: %s"),
 			    strerror(err));
 	}
 }
@@ -289,6 +303,7 @@ static int wait_all(void)
 static int grep_config(const char *var, const char *value, void *cb)
 {
 	struct grep_opt *opt = cb;
+	char *color = NULL;
 
 	switch (userdiff_config(var, value)) {
 	case 0: break;
@@ -296,115 +311,41 @@ static int grep_config(const char *var, const char *value, void *cb)
 	default: return 0;
 	}
 
-	if (!strcmp(var, "color.grep")) {
-		opt->color = git_config_colorbool(var, value, -1);
-		return 0;
-	}
-	if (!strcmp(var, "color.grep.match")) {
-		if (!value)
-			return config_error_nonbool(var);
-		color_parse(value, var, opt->color_match);
+	if (!strcmp(var, "grep.extendedregexp")) {
+		if (git_config_bool(var, value))
+			opt->regflags |= REG_EXTENDED;
+		else
+			opt->regflags &= ~REG_EXTENDED;
 		return 0;
 	}
-	return git_color_default_config(var, value, cb);
-}
 
-/*
- * Return non-zero if max_depth is negative or path has no more then max_depth
- * slashes.
- */
-static int accept_subdir(const char *path, int max_depth)
-{
-	if (max_depth < 0)
-		return 1;
-
-	while ((path = strchr(path, '/')) != NULL) {
-		max_depth--;
-		if (max_depth < 0)
-			return 0;
-		path++;
-	}
-	return 1;
-}
-
-/*
- * Return non-zero if name is a subdirectory of match and is not too deep.
- */
-static int is_subdir(const char *name, int namelen,
-		const char *match, int matchlen, int max_depth)
-{
-	if (matchlen > namelen || strncmp(name, match, matchlen))
+	if (!strcmp(var, "grep.linenumber")) {
+		opt->linenum = git_config_bool(var, value);
 		return 0;
+	}
 
-	if (name[matchlen] == '\0') /* exact match */
-		return 1;
-
-	if (!matchlen || match[matchlen-1] == '/' || name[matchlen] == '/')
-		return accept_subdir(name + matchlen + 1, max_depth);
-
-	return 0;
-}
-
-/*
- * git grep pathspecs are somewhat different from diff-tree pathspecs;
- * pathname wildcards are allowed.
- */
-static int pathspec_matches(const char **paths, const char *name, int max_depth)
-{
-	int namelen, i;
-	if (!paths || !*paths)
-		return accept_subdir(name, max_depth);
-	namelen = strlen(name);
-	for (i = 0; paths[i]; i++) {
-		const char *match = paths[i];
-		int matchlen = strlen(match);
-		const char *cp, *meta;
-
-		if (is_subdir(name, namelen, match, matchlen, max_depth))
-			return 1;
-		if (!fnmatch(match, name, 0))
-			return 1;
-		if (name[namelen-1] != '/')
-			continue;
-
-		/* We are being asked if the directory ("name") is worth
-		 * descending into.
-		 *
-		 * Find the longest leading directory name that does
-		 * not have metacharacter in the pathspec; the name
-		 * we are looking at must overlap with that directory.
-		 */
-		for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
-			char ch = *cp;
-			if (ch == '*' || ch == '[' || ch == '?') {
-				meta = cp;
-				break;
-			}
-		}
-		if (!meta)
-			meta = cp; /* fully literal */
-
-		if (namelen <= meta - match) {
-			/* Looking at "Documentation/" and
-			 * the pattern says "Documentation/howto/", or
-			 * "Documentation/diff*.txt".  The name we
-			 * have should match prefix.
-			 */
-			if (!memcmp(match, name, namelen))
-				return 1;
-			continue;
-		}
-
-		if (meta - match < namelen) {
-			/* Looking at "Documentation/howto/" and
-			 * the pattern says "Documentation/h*";
-			 * match up to "Do.../h"; this avoids descending
-			 * into "Documentation/technical/".
-			 */
-			if (!memcmp(match, name, meta - match))
-				return 1;
-			continue;
-		}
+	if (!strcmp(var, "color.grep"))
+		opt->color = git_config_colorbool(var, value);
+	else if (!strcmp(var, "color.grep.context"))
+		color = opt->color_context;
+	else if (!strcmp(var, "color.grep.filename"))
+		color = opt->color_filename;
+	else if (!strcmp(var, "color.grep.function"))
+		color = opt->color_function;
+	else if (!strcmp(var, "color.grep.linenumber"))
+		color = opt->color_lineno;
+	else if (!strcmp(var, "color.grep.match"))
+		color = opt->color_match;
+	else if (!strcmp(var, "color.grep.selected"))
+		color = opt->color_selected;
+	else if (!strcmp(var, "color.grep.separator"))
+		color = opt->color_sep;
+	else
+		return git_color_default_config(var, value, cb);
+	if (color) {
+		if (!value)
+			return config_error_nonbool(var);
+		color_parse(value, var, color);
 	}
 	return 0;
 }
@@ -430,7 +371,7 @@ static void *load_sha1(const unsigned char *sha1, unsigned long *size,
 	void *data = lock_and_read_sha1_file(sha1, &type, size);
 
 	if (!data)
-		error("'%s': unable to read %s", name, sha1_to_hex(sha1));
+		error(_("'%s': unable to read %s"), name, sha1_to_hex(sha1));
 
 	return data;
 }
@@ -481,21 +422,21 @@ static void *load_file(const char *filename, size_t *sz)
 	if (lstat(filename, &st) < 0) {
 	err_ret:
 		if (errno != ENOENT)
-			error("'%s': %s", filename, strerror(errno));
-		return 0;
+			error(_("'%s': %s"), filename, strerror(errno));
+		return NULL;
 	}
 	if (!S_ISREG(st.st_mode))
-		return 0;
+		return NULL;
 	*sz = xsize_t(st.st_size);
 	i = open(filename, O_RDONLY);
 	if (i < 0)
 		goto err_ret;
 	data = xmalloc(*sz + 1);
 	if (st.st_size != read_in_full(i, data, *sz)) {
-		error("'%s': short read %s", filename, strerror(errno));
+		error(_("'%s': short read %s"), filename, strerror(errno));
 		close(i);
 		free(data);
-		return 0;
+		return NULL;
 	}
 	close(i);
 	data[*sz] = 0;
@@ -534,7 +475,34 @@ static int grep_file(struct grep_opt *opt, const char *filename)
 	}
 }
 
-static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
+static void append_path(struct grep_opt *opt, const void *data, size_t len)
+{
+	struct string_list *path_list = opt->output_priv;
+
+	if (len == 1 && *(const char *)data == '\0')
+		return;
+	string_list_append(path_list, xstrndup(data, len));
+}
+
+static void run_pager(struct grep_opt *opt, const char *prefix)
+{
+	struct string_list *path_list = opt->output_priv;
+	const char **argv = xmalloc(sizeof(const char *) * (path_list->nr + 1));
+	int i, status;
+
+	for (i = 0; i < path_list->nr; i++)
+		argv[i] = path_list->items[i].string;
+	argv[path_list->nr] = NULL;
+
+	if (prefix && chdir(prefix))
+		die(_("Failed to chdir: %s"), prefix);
+	status = run_command_v_opt(argv, RUN_USING_SHELL);
+	if (status)
+		exit(status);
+	free(argv);
+}
+
+static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int cached)
 {
 	int hit = 0;
 	int nr;
@@ -544,7 +512,7 @@ static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 		struct cache_entry *ce = active_cache[nr];
 		if (!S_ISREG(ce->ce_mode))
 			continue;
-		if (!pathspec_matches(paths, ce->name, opt->max_depth))
+		if (!match_pathspec_depth(pathspec, ce->name, ce_namelen(ce), 0, NULL))
 			continue;
 		/*
 		 * If CE_VALID is on, we assume worktree file and its cache entry
@@ -568,48 +536,32 @@ static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 		if (hit && opt->status_only)
 			break;
 	}
-	free_grep_patterns(opt);
 	return hit;
 }
 
-static int grep_tree(struct grep_opt *opt, const char **paths,
-		     struct tree_desc *tree,
-		     const char *tree_name, const char *base)
+static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
+		     struct tree_desc *tree, struct strbuf *base, int tn_len)
 {
-	int len;
-	int hit = 0;
+	int hit = 0, match = 0;
 	struct name_entry entry;
-	char *down;
-	int tn_len = strlen(tree_name);
-	struct strbuf pathbuf;
-
-	strbuf_init(&pathbuf, PATH_MAX + tn_len);
-
-	if (tn_len) {
-		strbuf_add(&pathbuf, tree_name, tn_len);
-		strbuf_addch(&pathbuf, ':');
-		tn_len = pathbuf.len;
-	}
-	strbuf_addstr(&pathbuf, base);
-	len = pathbuf.len;
+	int old_baselen = base->len;
 
 	while (tree_entry(tree, &entry)) {
 		int te_len = tree_entry_len(entry.path, entry.sha1);
-		pathbuf.len = len;
-		strbuf_add(&pathbuf, entry.path, te_len);
-
-		if (S_ISDIR(entry.mode))
-			/* Match "abc/" against pathspec to
-			 * decide if we want to descend into "abc"
-			 * directory.
-			 */
-			strbuf_addch(&pathbuf, '/');
-
-		down = pathbuf.buf + tn_len;
-		if (!pathspec_matches(paths, down, opt->max_depth))
-			;
-		else if (S_ISREG(entry.mode))
-			hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
+
+		if (match != 2) {
+			match = tree_entry_interesting(&entry, base, tn_len, pathspec);
+			if (match < 0)
+				break;
+			if (match == 0)
+				continue;
+		}
+
+		strbuf_add(base, entry.path, te_len);
+
+		if (S_ISREG(entry.mode)) {
+			hit |= grep_sha1(opt, entry.sha1, base->buf, tn_len);
+		}
 		else if (S_ISDIR(entry.mode)) {
 			enum object_type type;
 			struct tree_desc sub;
@@ -618,20 +570,23 @@ static int grep_tree(struct grep_opt *opt, const char **paths,
 
 			data = lock_and_read_sha1_file(entry.sha1, &type, &size);
 			if (!data)
-				die("unable to read tree (%s)",
+				die(_("unable to read tree (%s)"),
 				    sha1_to_hex(entry.sha1));
+
+			strbuf_addch(base, '/');
 			init_tree_desc(&sub, data, size);
-			hit |= grep_tree(opt, paths, &sub, tree_name, down);
+			hit |= grep_tree(opt, pathspec, &sub, base, tn_len);
 			free(data);
 		}
+		strbuf_setlen(base, old_baselen);
+
 		if (hit && opt->status_only)
 			break;
 	}
-	strbuf_release(&pathbuf);
 	return hit;
 }
 
-static int grep_object(struct grep_opt *opt, const char **paths,
+static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		       struct object *obj, const char *name)
 {
 	if (obj->type == OBJ_BLOB)
@@ -640,20 +595,52 @@ static int grep_object(struct grep_opt *opt, const char **paths,
 		struct tree_desc tree;
 		void *data;
 		unsigned long size;
-		int hit;
+		struct strbuf base;
+		int hit, len;
+
+		read_sha1_lock();
 		data = read_object_with_reference(obj->sha1, tree_type,
 						  &size, NULL);
+		read_sha1_unlock();
+
 		if (!data)
-			die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
+			die(_("unable to read tree (%s)"), sha1_to_hex(obj->sha1));
+
+		len = name ? strlen(name) : 0;
+		strbuf_init(&base, PATH_MAX + len + 1);
+		if (len) {
+			strbuf_add(&base, name, len);
+			strbuf_addch(&base, ':');
+		}
 		init_tree_desc(&tree, data, size);
-		hit = grep_tree(opt, paths, &tree, name, "");
+		hit = grep_tree(opt, pathspec, &tree, &base, base.len);
+		strbuf_release(&base);
 		free(data);
 		return hit;
 	}
-	die("unable to grep from object of type %s", typename(obj->type));
+	die(_("unable to grep from object of type %s"), typename(obj->type));
 }
 
-static int grep_directory(struct grep_opt *opt, const char **paths)
+static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
+			const struct object_array *list)
+{
+	unsigned int i;
+	int hit = 0;
+	const unsigned int nr = list->nr;
+
+	for (i = 0; i < nr; i++) {
+		struct object *real_obj;
+		real_obj = deref_tag(list->objects[i].item, NULL, 0);
+		if (grep_object(opt, pathspec, real_obj, list->objects[i].name)) {
+			hit = 1;
+			if (opt->status_only)
+				break;
+		}
+	}
+	return hit;
+}
+
+static int grep_directory(struct grep_opt *opt, const struct pathspec *pathspec)
 {
 	struct dir_struct dir;
 	int i, hit = 0;
@@ -661,13 +648,16 @@ static int grep_directory(struct grep_opt *opt, const char **paths)
 	memset(&dir, 0, sizeof(dir));
 	setup_standard_excludes(&dir);
 
-	fill_directory(&dir, paths);
+	fill_directory(&dir, pathspec->raw);
 	for (i = 0; i < dir.nr; i++) {
+		const char *name = dir.entries[i]->name;
+		int namelen = strlen(name);
+		if (!match_pathspec_depth(pathspec, name, namelen, 0, NULL))
+			continue;
 		hit |= grep_file(opt, dir.entries[i]->name);
 		if (hit && opt->status_only)
 			break;
 	}
-	free_grep_patterns(opt);
 	return hit;
 }
 
@@ -684,7 +674,7 @@ static int context_callback(const struct option *opt, const char *arg,
 	}
 	value = strtol(arg, (char **)&endp, 10);
 	if (*endp) {
-		return error("switch `%c' expects a numerical value",
+		return error(_("switch `%c' expects a numerical value"),
 			     opt->short_name);
 	}
 	grep_opt->pre_context = grep_opt->post_context = value;
@@ -694,21 +684,27 @@ 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);
+		die_errno(_("cannot open '%s'"), arg);
 	while (strbuf_getline(&sb, patterns, '\n') == 0) {
+		char *s;
+		size_t len;
+
 		/* ignore empty line like grep does */
 		if (sb.len == 0)
 			continue;
-		append_grep_pattern(grep_opt, strbuf_detach(&sb, NULL), arg,
-				    ++lno, GREP_PATTERN);
+
+		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;
 }
@@ -760,12 +756,24 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	int cached = 0;
 	int seen_dashdash = 0;
 	int external_grep_allowed__ignored;
+	const char *show_in_pager = NULL, *default_pager = "dummy";
 	struct grep_opt opt;
-	struct object_array list = { 0, 0, NULL };
+	struct object_array list = OBJECT_ARRAY_INIT;
 	const char **paths = NULL;
+	struct pathspec pathspec;
+	struct string_list path_list = STRING_LIST_INIT_NODUP;
 	int i;
 	int dummy;
-	int nongit = 0, use_index = 1;
+	int use_index = 1;
+	enum {
+		pattern_type_unspecified = 0,
+		pattern_type_bre,
+		pattern_type_ere,
+		pattern_type_fixed,
+		pattern_type_pcre,
+	};
+	int pattern_type = pattern_type_unspecified;
+
 	struct option options[] = {
 		OPT_BOOLEAN(0, "cached", &cached,
 			"search in index instead of in the work tree"),
@@ -787,15 +795,20 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			"descend at most <depth> levels", PARSE_OPT_NONEG,
 			NULL, 1 },
 		OPT_GROUP(""),
-		OPT_BIT('E', "extended-regexp", &opt.regflags,
-			"use extended POSIX regular expressions", REG_EXTENDED),
-		OPT_NEGBIT('G', "basic-regexp", &opt.regflags,
-			"use basic POSIX regular expressions (default)",
-			REG_EXTENDED),
-		OPT_BOOLEAN('F', "fixed-strings", &opt.fixed,
-			"interpret patterns as fixed strings"),
+		OPT_SET_INT('E', "extended-regexp", &pattern_type,
+			    "use extended POSIX regular expressions",
+			    pattern_type_ere),
+		OPT_SET_INT('G', "basic-regexp", &pattern_type,
+			    "use basic POSIX regular expressions (default)",
+			    pattern_type_bre),
+		OPT_SET_INT('F', "fixed-strings", &pattern_type,
+			    "interpret patterns as fixed strings",
+			    pattern_type_fixed),
+		OPT_SET_INT('P', "perl-regexp", &pattern_type,
+			    "use Perl-compatible regular expressions",
+			    pattern_type_pcre),
 		OPT_GROUP(""),
-		OPT_BOOLEAN('n', NULL, &opt.linenum, "show line numbers"),
+		OPT_BOOLEAN('n', "line-number", &opt.linenum, "show line numbers"),
 		OPT_NEGBIT('h', NULL, &opt.pathname, "don't show filenames", 1),
 		OPT_BIT('H', NULL, &opt.pathname, "show filenames", 1),
 		OPT_NEGBIT(0, "full-name", &opt.relative,
@@ -811,19 +824,25 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			"print NUL after filenames"),
 		OPT_BOOLEAN('c', "count", &opt.count,
 			"show the number of matches instead of matching lines"),
-		OPT_SET_INT(0, "color", &opt.color, "highlight matches", 1),
+		OPT__COLOR(&opt.color, "highlight matches"),
+		OPT_BOOLEAN(0, "break", &opt.file_break,
+			"print empty line between matches from different files"),
+		OPT_BOOLEAN(0, "heading", &opt.heading,
+			"show filename only once above matches from same file"),
 		OPT_GROUP(""),
-		OPT_CALLBACK('C', NULL, &opt, "n",
+		OPT_CALLBACK('C', "context", &opt, "n",
 			"show <n> context lines before and after matches",
 			context_callback),
-		OPT_INTEGER('B', NULL, &opt.pre_context,
+		OPT_INTEGER('B', "before-context", &opt.pre_context,
 			"show <n> context lines before matches"),
-		OPT_INTEGER('A', NULL, &opt.post_context,
+		OPT_INTEGER('A', "after-context", &opt.post_context,
 			"show <n> context lines after matches"),
 		OPT_NUMBER_CALLBACK(&opt, "shortcut for -C NUM",
 			context_callback),
 		OPT_BOOLEAN('p', "show-function", &opt.funcname,
 			"show a line with the function name before matches"),
+		OPT_BOOLEAN('W', "function-context", &opt.funcbody,
+			"show the surrounding function"),
 		OPT_GROUP(""),
 		OPT_CALLBACK('f', NULL, &opt, "file",
 			"read patterns from file", file_callback),
@@ -841,11 +860,14 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		{ OPTION_CALLBACK, ')', NULL, &opt, NULL, "",
 		  PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
 		  close_callback },
-		OPT_BOOLEAN('q', "quiet", &opt.status_only,
-			    "indicate hit with exit status without output"),
+		OPT__QUIET(&opt.status_only,
+			   "indicate hit with exit status without output"),
 		OPT_BOOLEAN(0, "all-match", &opt.all_match,
 			"show only matches from files that match all patterns"),
 		OPT_GROUP(""),
+		{ OPTION_STRING, 'O', "open-files-in-pager", &show_in_pager,
+			"pager", "show matching files in the pager",
+			PARSE_OPT_OPTARG, NULL, (intptr_t)default_pager },
 		OPT_BOOLEAN(0, "ext-grep", &external_grep_allowed__ignored,
 			    "allow calling of grep(1) (ignored by this build)"),
 		{ OPTION_CALLBACK, 0, "help-all", &options, NULL, "show usage",
@@ -853,8 +875,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	prefix = setup_git_directory_gently(&nongit);
-
 	/*
 	 * 'git grep -h', unlike 'git grep -h <pattern>', is a request
 	 * to show usage information and exit.
@@ -868,14 +888,19 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	opt.relative = 1;
 	opt.pathname = 1;
 	opt.pattern_tail = &opt.pattern_list;
+	opt.header_tail = &opt.header_list;
 	opt.regflags = REG_NEWLINE;
 	opt.max_depth = -1;
 
-	strcpy(opt.color_match, GIT_COLOR_RED GIT_COLOR_BOLD);
+	strcpy(opt.color_context, "");
+	strcpy(opt.color_filename, "");
+	strcpy(opt.color_function, "");
+	strcpy(opt.color_lineno, "");
+	strcpy(opt.color_match, GIT_COLOR_BOLD_RED);
+	strcpy(opt.color_selected, "");
+	strcpy(opt.color_sep, GIT_COLOR_CYAN);
 	opt.color = -1;
 	git_config(grep_config, &opt);
-	if (opt.color == -1)
-		opt.color = git_use_color_default;
 
 	/*
 	 * If there is no -- then the paths must exist in the working
@@ -891,8 +916,30 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_STOP_AT_NON_OPTION |
 			     PARSE_OPT_NO_INTERNAL_HELP);
+	switch (pattern_type) {
+	case pattern_type_fixed:
+		opt.fixed = 1;
+		opt.pcre = 0;
+		break;
+	case pattern_type_bre:
+		opt.fixed = 0;
+		opt.pcre = 0;
+		opt.regflags &= ~REG_EXTENDED;
+		break;
+	case pattern_type_ere:
+		opt.fixed = 0;
+		opt.pcre = 0;
+		opt.regflags |= REG_EXTENDED;
+		break;
+	case pattern_type_pcre:
+		opt.fixed = 0;
+		opt.pcre = 1;
+		break;
+	default:
+		break; /* nothing */
+	}
 
-	if (use_index && nongit)
+	if (use_index && !startup_info->have_repository)
 		/* die the same way as if we did it at the beginning */
 		setup_git_directory();
 
@@ -914,19 +961,33 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		argc--;
 	}
 
+	if (show_in_pager == default_pager)
+		show_in_pager = git_pager(1);
+	if (show_in_pager) {
+		opt.color = 0;
+		opt.name_only = 1;
+		opt.null_following_name = 1;
+		opt.output_priv = &path_list;
+		opt.output = append_path;
+		string_list_append(&path_list, show_in_pager);
+		use_threads = 0;
+	}
+
 	if (!opt.pattern_list)
-		die("no pattern given.");
+		die(_("no pattern given."));
 	if (!opt.fixed && opt.ignore_case)
 		opt.regflags |= REG_ICASE;
-	if ((opt.regflags != REG_NEWLINE) && opt.fixed)
-		die("cannot mix --fixed-strings and regexp");
 
 #ifndef NO_PTHREADS
 	if (online_cpus() == 1 || !grep_threads_ok(&opt))
 		use_threads = 0;
 
-	if (use_threads)
+	if (use_threads) {
+		if (opt.pre_context || opt.post_context || opt.file_break ||
+		    opt.funcbody)
+			skip_first_line = 1;
 		start_threads(&opt);
+	}
 #else
 	use_threads = 0;
 #endif
@@ -941,7 +1002,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		if (!get_sha1(arg, sha1)) {
 			struct object *object = parse_object(sha1);
 			if (!object)
-				die("bad object %s", arg);
+				die(_("bad object %s"), arg);
 			add_object_array(object, arg, &list);
 			continue;
 		}
@@ -959,52 +1020,56 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			verify_filename(prefix, argv[j]);
 	}
 
-	if (i < argc)
-		paths = get_pathspec(prefix, argv + i);
-	else if (prefix) {
-		paths = xcalloc(2, sizeof(const char *));
-		paths[0] = prefix;
-		paths[1] = NULL;
+	paths = get_pathspec(prefix, argv + i);
+	init_pathspec(&pathspec, paths);
+	pathspec.max_depth = opt.max_depth;
+	pathspec.recursive = 1;
+
+	if (show_in_pager && (cached || list.nr))
+		die(_("--open-files-in-pager only works on the worktree"));
+
+	if (show_in_pager && opt.pattern_list && !opt.pattern_list->next) {
+		const char *pager = path_list.items[0].string;
+		int len = strlen(pager);
+
+		if (len > 4 && is_dir_sep(pager[len - 5]))
+			pager += len - 4;
+
+		if (!strcmp("less", pager) || !strcmp("vi", pager)) {
+			struct strbuf buf = STRBUF_INIT;
+			strbuf_addf(&buf, "+/%s%s",
+					strcmp("less", pager) ? "" : "*",
+					opt.pattern_list->pattern);
+			string_list_append(&path_list, buf.buf);
+			strbuf_detach(&buf, NULL);
+		}
 	}
 
+	if (!show_in_pager)
+		setup_pager();
+
+
 	if (!use_index) {
-		int hit;
 		if (cached)
-			die("--cached cannot be used with --no-index.");
+			die(_("--cached cannot be used with --no-index."));
 		if (list.nr)
-			die("--no-index cannot be used with revs.");
-		hit = grep_directory(&opt, paths);
-		if (use_threads)
-			hit |= wait_all();
-		return !hit;
-	}
-
-	if (!list.nr) {
-		int hit;
+			die(_("--no-index cannot be used with revs."));
+		hit = grep_directory(&opt, &pathspec);
+	} else if (!list.nr) {
 		if (!cached)
 			setup_work_tree();
 
-		hit = grep_cache(&opt, paths, cached);
-		if (use_threads)
-			hit |= wait_all();
-		return !hit;
-	}
-
-	if (cached)
-		die("both --cached and trees are given.");
-
-	for (i = 0; i < list.nr; i++) {
-		struct object *real_obj;
-		real_obj = deref_tag(list.objects[i].item, NULL, 0);
-		if (grep_object(&opt, paths, real_obj, list.objects[i].name)) {
-			hit = 1;
-			if (opt.status_only)
-				break;
-		}
+		hit = grep_cache(&opt, &pathspec, cached);
+	} else {
+		if (cached)
+			die(_("both --cached and trees are given."));
+		hit = grep_objects(&opt, &pathspec, &list);
 	}
 
 	if (use_threads)
 		hit |= wait_all();
+	if (hit && show_in_pager)
+		run_pager(&opt, prefix);
 	free_grep_patterns(&opt);
 	return !hit;
 }