refactor git_getpass into generic prompt function
[gitweb.git] / builtin / grep.c
index 552ef1face1e25c11d5f114c8d5c1265c6c3ae9b..3d7329d78c6e3ec31ed8ce03b8928c9ed24afb9e 100644 (file)
 #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;
 
@@ -77,13 +74,32 @@ static int all_work_added;
 /* This lock protects all the variables above. */
 static pthread_mutex_t grep_mutex;
 
+static inline void grep_lock(void)
+{
+       if (use_threads)
+               pthread_mutex_lock(&grep_mutex);
+}
+
+static inline void grep_unlock(void)
+{
+       if (use_threads)
+               pthread_mutex_unlock(&grep_mutex);
+}
+
 /* Used to serialize calls to read_sha1_file. */
 static pthread_mutex_t read_sha1_mutex;
 
-#define grep_lock() pthread_mutex_lock(&grep_mutex)
-#define grep_unlock() pthread_mutex_unlock(&grep_mutex)
-#define read_sha1_lock() pthread_mutex_lock(&read_sha1_mutex)
-#define read_sha1_unlock() pthread_mutex_unlock(&read_sha1_mutex)
+static inline void read_sha1_lock(void)
+{
+       if (use_threads)
+               pthread_mutex_lock(&read_sha1_mutex);
+}
+
+static inline void read_sha1_unlock(void)
+{
+       if (use_threads)
+               pthread_mutex_unlock(&read_sha1_mutex);
+}
 
 /* Signalled when a new work_item is added to todo. */
 static pthread_cond_t cond_add;
@@ -96,6 +112,8 @@ 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 +177,22 @@ 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 +272,7 @@ 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 +322,7 @@ 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 +330,41 @@ 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;
 }
@@ -413,13 +373,9 @@ static void *lock_and_read_sha1_file(const unsigned char *sha1, enum object_type
 {
        void *data;
 
-       if (use_threads) {
-               read_sha1_lock();
-               data = read_sha1_file(sha1, type, size);
-               read_sha1_unlock();
-       } else {
-               data = read_sha1_file(sha1, type, size);
-       }
+       read_sha1_lock();
+       data = read_sha1_file(sha1, type, size);
+       read_sha1_unlock();
        return data;
 }
 
@@ -430,7 +386,7 @@ 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 +437,21 @@ 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 +490,34 @@ 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 +527,7 @@ 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 +551,32 @@ 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 +585,23 @@ 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)
@@ -640,34 +610,71 @@ 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_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 char **paths)
+static int grep_directory(struct grep_opt *opt, const struct pathspec *pathspec,
+                         int exc_std)
 {
        struct dir_struct dir;
        int i, hit = 0;
 
        memset(&dir, 0, sizeof(dir));
-       setup_standard_excludes(&dir);
+       if (exc_std)
+               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 +691,7 @@ 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 +701,27 @@ 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;
 }
@@ -757,20 +770,37 @@ static int help_callback(const struct option *opt, const char *arg, int unset)
 int cmd_grep(int argc, const char **argv, const char *prefix)
 {
        int hit = 0;
-       int cached = 0;
+       int cached = 0, untracked = 0, opt_exclude = -1;
        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"),
-               OPT_BOOLEAN(0, "index", &use_index,
-                       "--no-index finds in contents not managed by git"),
+               { OPTION_BOOLEAN, 0, "index", &use_index, NULL,
+                       "finds in contents not managed by git",
+                       PARSE_OPT_NOARG | PARSE_OPT_NEGHELP },
+               OPT_BOOLEAN(0, "untracked", &untracked,
+                       "search in both tracked and untracked files"),
+               OPT_SET_INT(0, "exclude-standard", &opt_exclude,
+                           "search also in ignored files", 1),
                OPT_GROUP(""),
                OPT_BOOLEAN('v', "invert-match", &opt.invert,
                        "show non-matching lines"),
@@ -787,15 +817,20 @@ 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 +846,25 @@ 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 +882,14 @@ 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 +897,6 @@ 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 +910,19 @@ 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 +938,30 @@ 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 +983,33 @@ 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 +1024,7 @@ 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 +1042,59 @@ 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 (!use_index) {
-               int hit;
-               if (cached)
-                       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 (show_in_pager && (cached || list.nr))
+               die(_("--open-files-in-pager only works on the worktree"));
 
-       if (!list.nr) {
-               int hit;
-               if (!cached)
-                       setup_work_tree();
+       if (show_in_pager && opt.pattern_list && !opt.pattern_list->next) {
+               const char *pager = path_list.items[0].string;
+               int len = strlen(pager);
 
-               hit = grep_cache(&opt, paths, cached);
-               if (use_threads)
-                       hit |= wait_all();
-               return !hit;
+               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 (cached)
-               die("both --cached and trees are given.");
+       if (!show_in_pager)
+               setup_pager();
 
-       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;
-               }
+       if (!use_index && (untracked || cached))
+               die(_("--cached or --untracked cannot be used with --no-index."));
+
+       if (!use_index || untracked) {
+               int use_exclude = (opt_exclude < 0) ? use_index : !!opt_exclude;
+               if (list.nr)
+                       die(_("--no-index or --untracked cannot be used with revs."));
+               hit = grep_directory(&opt, &pathspec, use_exclude);
+       } else if (0 <= opt_exclude) {
+               die(_("--[no-]exclude-standard cannot be used for tracked contents."));
+       } else if (!list.nr) {
+               if (!cached)
+                       setup_work_tree();
+
+               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;
 }