Introduce usagef() that takes a printf-style format
[gitweb.git] / builtin-grep.c
index 3f12ba382690699d96580c3ddb1a61c79520e694..01be9bf7ff74731969384cc91dad2e20d08d81bc 100644 (file)
 #include "tag.h"
 #include "tree-walk.h"
 #include "builtin.h"
+#include "parse-options.h"
+#include "userdiff.h"
 #include "grep.h"
+#include "quote.h"
 
 #ifndef NO_EXTERNAL_GREP
 #ifdef __unix__
 #endif
 #endif
 
-static int builtin_grep;
+static char const * const grep_usage[] = {
+       "git grep [options] [-e] <pattern> [<rev>...] [[--] path...]",
+       NULL
+};
+
+static int grep_config(const char *var, const char *value, void *cb)
+{
+       struct grep_opt *opt = cb;
+
+       switch (userdiff_config(var, value)) {
+       case 0: break;
+       case -1: return -1;
+       default: return 0;
+       }
+
+       if (!strcmp(var, "color.grep")) {
+               opt->color = git_config_colorbool(var, value, -1);
+               return 0;
+       }
+       if (!strcmp(var, "color.grep.external"))
+               return git_config_string(&(opt->color_external), var, value);
+       if (!strcmp(var, "color.grep.match")) {
+               if (!value)
+                       return config_error_nonbool(var);
+               color_parse(value, var, opt->color_match);
+               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))
+               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)
+static int pathspec_matches(const char **paths, const char *name, int max_depth)
 {
        int namelen, i;
        if (!paths || !*paths)
-               return 1;
+               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 (!matchlen ||
-                   ((matchlen <= namelen) &&
-                    !strncmp(name, match, matchlen) &&
-                    (match[matchlen-1] == '/' ||
-                     name[matchlen] == '\0' || name[matchlen] == '/')))
+               if (is_subdir(name, namelen, match, matchlen, max_depth))
                        return 1;
                if (!fnmatch(match, name, 0))
                        return 1;
@@ -95,8 +158,8 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char
        unsigned long size;
        char *data;
        enum object_type type;
-       char *to_free = NULL;
        int hit;
+       struct strbuf pathbuf = STRBUF_INIT;
 
        data = read_sha1_file(sha1, &type, &size);
        if (!data) {
@@ -104,26 +167,13 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char
                return 0;
        }
        if (opt->relative && opt->prefix_length) {
-               static char name_buf[PATH_MAX];
-               char *cp;
-               int name_len = strlen(name) - opt->prefix_length + 1;
-
-               if (!tree_name_len)
-                       name += opt->prefix_length;
-               else {
-                       if (ARRAY_SIZE(name_buf) <= name_len)
-                               cp = to_free = xmalloc(name_len);
-                       else
-                               cp = name_buf;
-                       memcpy(cp, name, tree_name_len);
-                       strcpy(cp + tree_name_len,
-                              name + tree_name_len + opt->prefix_length);
-                       name = cp;
-               }
+               quote_path_relative(name + tree_name_len, -1, &pathbuf, opt->prefix);
+               strbuf_insert(&pathbuf, 0, name, tree_name_len);
+               name = pathbuf.buf;
        }
        hit = grep_buffer(opt, name, data, size);
+       strbuf_release(&pathbuf);
        free(data);
-       free(to_free);
        return hit;
 }
 
@@ -133,6 +183,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
        int i;
        char *data;
        size_t sz;
+       struct strbuf buf = STRBUF_INIT;
 
        if (lstat(filename, &st) < 0) {
        err_ret:
@@ -157,8 +208,9 @@ static int grep_file(struct grep_opt *opt, const char *filename)
        }
        close(i);
        if (opt->relative && opt->prefix_length)
-               filename += opt->prefix_length;
+               filename = quote_path_relative(filename, -1, &buf, opt->prefix);
        i = grep_buffer(opt, filename, data, sz);
+       strbuf_release(&buf);
        free(data);
        return i;
 }
@@ -255,6 +307,17 @@ static int flush_grep(struct grep_opt *opt,
                argc -= 2;
        }
 
+       if (opt->pre_context || opt->post_context) {
+               /*
+                * grep handles hunk marks between files, but we need to
+                * do that ourselves between multiple calls.
+                */
+               if (opt->show_hunk_mark)
+                       write_or_die(1, "--\n", 3);
+               else
+                       opt->show_hunk_mark = 1;
+       }
+
        status = exec_grep(argc, argv);
 
        if (kept_0) {
@@ -269,6 +332,21 @@ static int flush_grep(struct grep_opt *opt,
        return status;
 }
 
+static void grep_add_color(struct strbuf *sb, const char *escape_seq)
+{
+       size_t orig_len = sb->len;
+
+       while (*escape_seq) {
+               if (*escape_seq == 'm')
+                       strbuf_addch(sb, ';');
+               else if (*escape_seq != '\033' && *escape_seq  != '[')
+                       strbuf_addch(sb, *escape_seq);
+               escape_seq++;
+       }
+       if (sb->len > orig_len && sb->buf[sb->len - 1] == ';')
+               strbuf_setlen(sb, sb->len - 1);
+}
+
 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 {
        int i, nr, argc, hit, len, status;
@@ -339,6 +417,23 @@ static int external_grep(struct grep_opt *opt, const char **paths, int cached)
                push_arg("-e");
                push_arg(p->pattern);
        }
+       if (opt->color) {
+               struct strbuf sb = STRBUF_INIT;
+
+               grep_add_color(&sb, opt->color_match);
+               setenv("GREP_COLOR", sb.buf, 1);
+
+               strbuf_reset(&sb);
+               strbuf_addstr(&sb, "mt=");
+               grep_add_color(&sb, opt->color_match);
+               strbuf_addstr(&sb, ":sl=:cx=:fn=:ln=:bn=:se=");
+               setenv("GREP_COLORS", sb.buf, 1);
+
+               strbuf_release(&sb);
+
+               if (opt->color_external && strlen(opt->color_external) > 0)
+                       push_arg(opt->color_external);
+       }
 
        hit = 0;
        argc = nr;
@@ -348,7 +443,7 @@ static int external_grep(struct grep_opt *opt, const char **paths, int cached)
                int kept;
                if (!S_ISREG(ce->ce_mode))
                        continue;
-               if (!pathspec_matches(paths, ce->name))
+               if (!pathspec_matches(paths, ce->name, opt->max_depth))
                        continue;
                name = ce->name;
                if (name[0] == '-') {
@@ -381,7 +476,8 @@ static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 }
 #endif
 
-static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
+static int grep_cache(struct grep_opt *opt, const char **paths, int cached,
+                     int external_grep_allowed)
 {
        int hit = 0;
        int nr;
@@ -393,10 +489,11 @@ static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
         * we grep through the checked-out files. It tends to
         * be a lot more optimized
         */
-       if (!cached && !builtin_grep) {
+       if (!cached && external_grep_allowed) {
                hit = external_grep(opt, paths, cached);
                if (hit >= 0)
                        return hit;
+               hit = 0;
        }
 #endif
 
@@ -404,7 +501,7 @@ 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))
+               if (!pathspec_matches(paths, ce->name, opt->max_depth))
                        continue;
                /*
                 * If CE_VALID is on, we assume worktree file and its cache entry
@@ -464,7 +561,7 @@ static int grep_tree(struct grep_opt *opt, const char **paths,
                        strbuf_addch(&pathbuf, '/');
 
                down = pathbuf.buf + tn_len;
-               if (!pathspec_matches(paths, down))
+               if (!pathspec_matches(paths, down, opt->max_depth))
                        ;
                else if (S_ISREG(entry.mode))
                        hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
@@ -509,32 +606,209 @@ static int grep_object(struct grep_opt *opt, const char **paths,
        die("unable to grep from object of type %s", typename(obj->type));
 }
 
-static const char builtin_grep_usage[] =
-"git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
+static int context_callback(const struct option *opt, const char *arg,
+                           int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       int value;
+       const char *endp;
+
+       if (unset) {
+               grep_opt->pre_context = grep_opt->post_context = 0;
+               return 0;
+       }
+       value = strtol(arg, (char **)&endp, 10);
+       if (*endp) {
+               return error("switch `%c' expects a numerical value",
+                            opt->short_name);
+       }
+       grep_opt->pre_context = grep_opt->post_context = value;
+       return 0;
+}
+
+static int file_callback(const struct option *opt, const char *arg, int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       FILE *patterns;
+       int lno = 0;
+       struct strbuf sb = STRBUF_INIT;
+
+       patterns = fopen(arg, "r");
+       if (!patterns)
+               die_errno("cannot open '%s'", arg);
+       while (strbuf_getline(&sb, patterns, '\n') == 0) {
+               /* ignore empty line like grep does */
+               if (sb.len == 0)
+                       continue;
+               append_grep_pattern(grep_opt, strbuf_detach(&sb, NULL), arg,
+                                   ++lno, GREP_PATTERN);
+       }
+       fclose(patterns);
+       strbuf_release(&sb);
+       return 0;
+}
 
-static const char emsg_invalid_context_len[] =
-"%s: invalid context length argument";
-static const char emsg_missing_context_len[] =
-"missing context length argument";
-static const char emsg_missing_argument[] =
-"option requires an argument -%s";
+static int not_callback(const struct option *opt, const char *arg, int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       append_grep_pattern(grep_opt, "--not", "command line", 0, GREP_NOT);
+       return 0;
+}
+
+static int and_callback(const struct option *opt, const char *arg, int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       append_grep_pattern(grep_opt, "--and", "command line", 0, GREP_AND);
+       return 0;
+}
+
+static int open_callback(const struct option *opt, const char *arg, int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       append_grep_pattern(grep_opt, "(", "command line", 0, GREP_OPEN_PAREN);
+       return 0;
+}
+
+static int close_callback(const struct option *opt, const char *arg, int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       append_grep_pattern(grep_opt, ")", "command line", 0, GREP_CLOSE_PAREN);
+       return 0;
+}
+
+static int pattern_callback(const struct option *opt, const char *arg,
+                           int unset)
+{
+       struct grep_opt *grep_opt = opt->value;
+       append_grep_pattern(grep_opt, arg, "-e option", 0, GREP_PATTERN);
+       return 0;
+}
+
+static int help_callback(const struct option *opt, const char *arg, int unset)
+{
+       return -1;
+}
 
 int cmd_grep(int argc, const char **argv, const char *prefix)
 {
        int hit = 0;
        int cached = 0;
+       int external_grep_allowed = 1;
        int seen_dashdash = 0;
        struct grep_opt opt;
        struct object_array list = { 0, 0, NULL };
        const char **paths = NULL;
        int i;
+       int dummy;
+       struct option options[] = {
+               OPT_BOOLEAN(0, "cached", &cached,
+                       "search in index instead of in the work tree"),
+               OPT_GROUP(""),
+               OPT_BOOLEAN('v', "invert-match", &opt.invert,
+                       "show non-matching lines"),
+               OPT_BIT('i', "ignore-case", &opt.regflags,
+                       "case insensitive matching", REG_ICASE),
+               OPT_BOOLEAN('w', "word-regexp", &opt.word_regexp,
+                       "match patterns only at word boundaries"),
+               OPT_SET_INT('a', "text", &opt.binary,
+                       "process binary files as text", GREP_BINARY_TEXT),
+               OPT_SET_INT('I', NULL, &opt.binary,
+                       "don't match patterns in binary files",
+                       GREP_BINARY_NOMATCH),
+               { OPTION_INTEGER, 0, "max-depth", &opt.max_depth, "depth",
+                       "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_GROUP(""),
+               OPT_BOOLEAN('n', NULL, &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,
+                       "show filenames relative to top directory", 1),
+               OPT_BOOLEAN('l', "files-with-matches", &opt.name_only,
+                       "show only filenames instead of matching lines"),
+               OPT_BOOLEAN(0, "name-only", &opt.name_only,
+                       "synonym for --files-with-matches"),
+               OPT_BOOLEAN('L', "files-without-match",
+                       &opt.unmatch_name_only,
+                       "show only the names of files without match"),
+               OPT_BOOLEAN('z', "null", &opt.null_following_name,
+                       "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_GROUP(""),
+               OPT_CALLBACK('C', NULL, &opt, "n",
+                       "show <n> context lines before and after matches",
+                       context_callback),
+               OPT_INTEGER('B', NULL, &opt.pre_context,
+                       "show <n> context lines before matches"),
+               OPT_INTEGER('A', NULL, &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_GROUP(""),
+               OPT_CALLBACK('f', NULL, &opt, "file",
+                       "read patterns from file", file_callback),
+               { OPTION_CALLBACK, 'e', NULL, &opt, "pattern",
+                       "match <pattern>", PARSE_OPT_NONEG, pattern_callback },
+               { OPTION_CALLBACK, 0, "and", &opt, NULL,
+                 "combine patterns specified with -e",
+                 PARSE_OPT_NOARG | PARSE_OPT_NONEG, and_callback },
+               OPT_BOOLEAN(0, "or", &dummy, ""),
+               { OPTION_CALLBACK, 0, "not", &opt, NULL, "",
+                 PARSE_OPT_NOARG | PARSE_OPT_NONEG, not_callback },
+               { OPTION_CALLBACK, '(', NULL, &opt, NULL, "",
+                 PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
+                 open_callback },
+               { OPTION_CALLBACK, ')', NULL, &opt, NULL, "",
+                 PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH,
+                 close_callback },
+               OPT_BOOLEAN(0, "all-match", &opt.all_match,
+                       "show only matches from files that match all patterns"),
+               OPT_GROUP(""),
+#if NO_EXTERNAL_GREP
+               OPT_BOOLEAN(0, "ext-grep", &external_grep_allowed,
+                       "allow calling of grep(1) (ignored by this build)"),
+#else
+               OPT_BOOLEAN(0, "ext-grep", &external_grep_allowed,
+                       "allow calling of grep(1) (default)"),
+#endif
+               { OPTION_CALLBACK, 0, "help-all", &options, NULL, "show usage",
+                 PARSE_OPT_HIDDEN | PARSE_OPT_NOARG, help_callback },
+               OPT_END()
+       };
+
+       /*
+        * 'git grep -h', unlike 'git grep -h <pattern>', is a request
+        * to show usage information and exit.
+        */
+       if (argc == 2 && !strcmp(argv[1], "-h"))
+               usage_with_options(grep_usage, options);
 
        memset(&opt, 0, sizeof(opt));
+       opt.prefix = prefix;
        opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
        opt.relative = 1;
        opt.pathname = 1;
        opt.pattern_tail = &opt.pattern_list;
        opt.regflags = REG_NEWLINE;
+       opt.max_depth = -1;
+
+       strcpy(opt.color_match, GIT_COLOR_RED GIT_COLOR_BOLD);
+       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
@@ -546,217 +820,21 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
         * unrecognized non option is the beginning of the refs list
         * that continues up to the -- (if exists), and then paths.
         */
-
-       while (1 < argc) {
-               const char *arg = argv[1];
-               argc--; argv++;
-               if (!strcmp("--cached", arg)) {
-                       cached = 1;
-                       continue;
-               }
-               if (!strcmp("--no-ext-grep", arg)) {
-                       builtin_grep = 1;
-                       continue;
-               }
-               if (!strcmp("-a", arg) ||
-                   !strcmp("--text", arg)) {
-                       opt.binary = GREP_BINARY_TEXT;
-                       continue;
-               }
-               if (!strcmp("-i", arg) ||
-                   !strcmp("--ignore-case", arg)) {
-                       opt.regflags |= REG_ICASE;
-                       continue;
-               }
-               if (!strcmp("-I", arg)) {
-                       opt.binary = GREP_BINARY_NOMATCH;
-                       continue;
-               }
-               if (!strcmp("-v", arg) ||
-                   !strcmp("--invert-match", arg)) {
-                       opt.invert = 1;
-                       continue;
-               }
-               if (!strcmp("-E", arg) ||
-                   !strcmp("--extended-regexp", arg)) {
-                       opt.regflags |= REG_EXTENDED;
-                       continue;
-               }
-               if (!strcmp("-F", arg) ||
-                   !strcmp("--fixed-strings", arg)) {
-                       opt.fixed = 1;
-                       continue;
-               }
-               if (!strcmp("-G", arg) ||
-                   !strcmp("--basic-regexp", arg)) {
-                       opt.regflags &= ~REG_EXTENDED;
-                       continue;
-               }
-               if (!strcmp("-n", arg)) {
-                       opt.linenum = 1;
-                       continue;
-               }
-               if (!strcmp("-h", arg)) {
-                       opt.pathname = 0;
-                       continue;
-               }
-               if (!strcmp("-H", arg)) {
-                       opt.pathname = 1;
-                       continue;
-               }
-               if (!strcmp("-l", arg) ||
-                   !strcmp("--name-only", arg) ||
-                   !strcmp("--files-with-matches", arg)) {
-                       opt.name_only = 1;
-                       continue;
-               }
-               if (!strcmp("-L", arg) ||
-                   !strcmp("--files-without-match", arg)) {
-                       opt.unmatch_name_only = 1;
-                       continue;
-               }
-               if (!strcmp("-z", arg) ||
-                   !strcmp("--null", arg)) {
-                       opt.null_following_name = 1;
-                       continue;
-               }
-               if (!strcmp("-c", arg) ||
-                   !strcmp("--count", arg)) {
-                       opt.count = 1;
-                       continue;
-               }
-               if (!strcmp("-w", arg) ||
-                   !strcmp("--word-regexp", arg)) {
-                       opt.word_regexp = 1;
-                       continue;
-               }
-               if (!prefixcmp(arg, "-A") ||
-                   !prefixcmp(arg, "-B") ||
-                   !prefixcmp(arg, "-C") ||
-                   (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
-                       unsigned num;
-                       const char *scan;
-                       switch (arg[1]) {
-                       case 'A': case 'B': case 'C':
-                               if (!arg[2]) {
-                                       if (argc <= 1)
-                                               die(emsg_missing_context_len);
-                                       scan = *++argv;
-                                       argc--;
-                               }
-                               else
-                                       scan = arg + 2;
-                               break;
-                       default:
-                               scan = arg + 1;
-                               break;
-                       }
-                       if (strtoul_ui(scan, 10, &num))
-                               die(emsg_invalid_context_len, scan);
-                       switch (arg[1]) {
-                       case 'A':
-                               opt.post_context = num;
-                               break;
-                       default:
-                       case 'C':
-                               opt.post_context = num;
-                       case 'B':
-                               opt.pre_context = num;
-                               break;
-                       }
-                       continue;
-               }
-               if (!strcmp("-f", arg)) {
-                       FILE *patterns;
-                       int lno = 0;
-                       char buf[1024];
-                       if (argc <= 1)
-                               die(emsg_missing_argument, arg);
-                       patterns = fopen(argv[1], "r");
-                       if (!patterns)
-                               die("'%s': %s", argv[1], strerror(errno));
-                       while (fgets(buf, sizeof(buf), patterns)) {
-                               int len = strlen(buf);
-                               if (len && buf[len-1] == '\n')
-                                       buf[len-1] = 0;
-                               /* ignore empty line like grep does */
-                               if (!buf[0])
-                                       continue;
-                               append_grep_pattern(&opt, xstrdup(buf),
-                                                   argv[1], ++lno,
-                                                   GREP_PATTERN);
-                       }
-                       fclose(patterns);
-                       argv++;
-                       argc--;
-                       continue;
-               }
-               if (!strcmp("--not", arg)) {
-                       append_grep_pattern(&opt, arg, "command line", 0,
-                                           GREP_NOT);
-                       continue;
-               }
-               if (!strcmp("--and", arg)) {
-                       append_grep_pattern(&opt, arg, "command line", 0,
-                                           GREP_AND);
-                       continue;
-               }
-               if (!strcmp("--or", arg))
-                       continue; /* no-op */
-               if (!strcmp("(", arg)) {
-                       append_grep_pattern(&opt, arg, "command line", 0,
-                                           GREP_OPEN_PAREN);
-                       continue;
-               }
-               if (!strcmp(")", arg)) {
-                       append_grep_pattern(&opt, arg, "command line", 0,
-                                           GREP_CLOSE_PAREN);
-                       continue;
-               }
-               if (!strcmp("--all-match", arg)) {
-                       opt.all_match = 1;
-                       continue;
-               }
-               if (!strcmp("-e", arg)) {
-                       if (1 < argc) {
-                               append_grep_pattern(&opt, argv[1],
-                                                   "-e option", 0,
-                                                   GREP_PATTERN);
-                               argv++;
-                               argc--;
-                               continue;
-                       }
-                       die(emsg_missing_argument, arg);
-               }
-               if (!strcmp("--full-name", arg)) {
-                       opt.relative = 0;
-                       continue;
-               }
-               if (!strcmp("--", arg)) {
-                       /* later processing wants to have this at argv[1] */
-                       argv--;
-                       argc++;
-                       break;
-               }
-               if (*arg == '-')
-                       usage(builtin_grep_usage);
-
-               /* First unrecognized non-option token */
-               if (!opt.pattern_list) {
-                       append_grep_pattern(&opt, arg, "command line", 0,
-                                           GREP_PATTERN);
-                       break;
-               }
-               else {
-                       /* We are looking at the first path or rev;
-                        * it is found at argv[1] after leaving the
-                        * loop.
-                        */
-                       argc++; argv--;
-                       break;
-               }
+       argc = parse_options(argc, argv, prefix, options, grep_usage,
+                            PARSE_OPT_KEEP_DASHDASH |
+                            PARSE_OPT_STOP_AT_NON_OPTION |
+                            PARSE_OPT_NO_INTERNAL_HELP);
+
+       /* First unrecognized non-option token */
+       if (argc > 0 && !opt.pattern_list) {
+               append_grep_pattern(&opt, argv[0], "command line", 0,
+                                   GREP_PATTERN);
+               argv++;
+               argc--;
        }
 
+       if ((opt.color && !opt.color_external) || opt.funcname)
+               external_grep_allowed = 0;
        if (!opt.pattern_list)
                die("no pattern given.");
        if ((opt.regflags != REG_NEWLINE) && opt.fixed)
@@ -764,7 +842,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
        compile_grep_patterns(&opt);
 
        /* Check revs and then paths */
-       for (i = 1; i < argc; i++) {
+       for (i = 0; i < argc; i++) {
                const char *arg = argv[i];
                unsigned char sha1[20];
                /* Is it a rev? */
@@ -789,15 +867,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
                        verify_filename(prefix, argv[j]);
        }
 
-       if (i < argc) {
+       if (i < argc)
                paths = get_pathspec(prefix, argv + i);
-               if (opt.prefix_length && opt.relative) {
-                       /* Make sure we do not get outside of paths */
-                       for (i = 0; paths[i]; i++)
-                               if (strncmp(prefix, paths[i], opt.prefix_length))
-                                       die("git grep: cannot generate relative filenames containing '..'");
-               }
-       }
        else if (prefix) {
                paths = xcalloc(2, sizeof(const char *));
                paths[0] = prefix;
@@ -807,7 +878,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
        if (!list.nr) {
                if (!cached)
                        setup_work_tree();
-               return !grep_cache(&opt, paths, cached);
+               return !grep_cache(&opt, paths, cached, external_grep_allowed);
        }
 
        if (cached)