blame: accept multiple -L ranges

git-blame accepts only a single -L option or none. Clients requiring
blame information for multiple disjoint ranges are therefore forced
either to invoke git-blame multiple times, once for each range, or only
once with no -L option to cover the entire file, both of which can be
costly.  Teach git-blame to accept multiple -L ranges.  Overlapping and
out-of-order ranges are accepted.

In this patch, the X in -LX,Y is absolute (for instance, /RE/ patterns
search from line 1), and Y is relative to X. Follow-up patches provide
more flexibility over how X is anchored.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/blame.c b/builtin/blame.c
index 9db01b0172f4d2da8c79dee592f7df967ed5e407..2f4d9e2d75d475057c4aef5781c8d4a41a45cd24 100644 (file)
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -22,6 +22,7 @@
 #include "utf8.h"
 #include "userdiff.h"
 #include "line-range.h"
+#include "line-log.h"
 
 static char blame_usage[] = N_("git blame [options] [rev-opts] [rev] [--] file");
 
@@ -2233,29 +2234,18 @@ static int blame_move_callback(const struct option *option, const char *arg, int
        return 0;
 }
 
-static int blame_bottomtop_callback(const struct option *option, const char *arg, int unset)
-{
-       const char **bottomtop = option->value;
-       if (!arg)
-               return -1;
-       if (*bottomtop)
-               die("More than one '-L n,m' option given");
-       *bottomtop = arg;
-       return 0;
-}
-
 int cmd_blame(int argc, const char **argv, const char *prefix)
 {
        struct rev_info revs;
        const char *path;
        struct scoreboard sb;
        struct origin *o;
-       struct blame_entry *ent;
-       long dashdash_pos, bottom, top, lno;
+       struct blame_entry *ent = NULL;
+       long dashdash_pos, lno;
        const char *final_commit_name = NULL;
        enum object_type type;
 
-       static const char *bottomtop = NULL;
+       static struct string_list range_list;
        static int output_option = 0, opt = 0;
        static int show_stats = 0;
        static const char *revs_file = NULL;
@@ -2281,13 +2271,15 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
                OPT_STRING(0, "contents", &contents_from, N_("file"), N_("Use <file>'s contents as the final image")),
                { OPTION_CALLBACK, 'C', NULL, &opt, N_("score"), N_("Find line copies within and across files"), PARSE_OPT_OPTARG, blame_copy_callback },
                { OPTION_CALLBACK, 'M', NULL, &opt, N_("score"), N_("Find line movements within and across files"), PARSE_OPT_OPTARG, blame_move_callback },
-               OPT_CALLBACK('L', NULL, &bottomtop, N_("n,m"), N_("Process only line range n,m, counting from 1"), blame_bottomtop_callback),
+               OPT_STRING_LIST('L', NULL, &range_list, N_("n,m"), N_("Process only line range n,m, counting from 1")),
                OPT__ABBREV(&abbrev),
                OPT_END()
        };
 
        struct parse_opt_ctx_t ctx;
        int cmd_is_annotate = !strcmp(argv[0], "annotate");
+       struct range_set ranges;
+       unsigned int range_i;
 
        git_config(git_blame_config, NULL);
        init_revisions(&revs, NULL);
@@ -2480,23 +2472,46 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
        num_read_blob++;
        lno = prepare_lines(&sb);
 
-       bottom = top = 0;
-       if (bottomtop && parse_range_arg(bottomtop, nth_line_cb, &sb, lno,
-                                        &bottom, &top, sb.path))
-               usage(blame_usage);
-       if (lno < top || ((lno || bottom) && lno < bottom))
-               die("file %s has only %lu lines", path, lno);
-       if (bottom < 1)
-               bottom = 1;
-       if (top < 1)
-               top = lno;
-       bottom--;
-
-       ent = xcalloc(1, sizeof(*ent));
-       ent->lno = bottom;
-       ent->num_lines = top - bottom;
-       ent->suspect = o;
-       ent->s_lno = bottom;
+       if (lno && !range_list.nr)
+               string_list_append(&range_list, xstrdup("1"));
+
+       range_set_init(&ranges, range_list.nr);
+       for (range_i = 0; range_i < range_list.nr; ++range_i) {
+               long bottom, top;
+               if (parse_range_arg(range_list.items[range_i].string,
+                                   nth_line_cb, &sb, lno,
+                                   &bottom, &top, sb.path))
+                       usage(blame_usage);
+               if (lno < top || ((lno || bottom) && lno < bottom))
+                       die("file %s has only %lu lines", path, lno);
+               if (bottom < 1)
+                       bottom = 1;
+               if (top < 1)
+                       top = lno;
+               bottom--;
+               range_set_append_unsafe(&ranges, bottom, top);
+       }
+       sort_and_merge_range_set(&ranges);
+
+       for (range_i = ranges.nr; range_i > 0; --range_i) {
+               const struct range *r = &ranges.ranges[range_i - 1];
+               long bottom = r->start;
+               long top = r->end;
+               struct blame_entry *next = ent;
+               ent = xcalloc(1, sizeof(*ent));
+               ent->lno = bottom;
+               ent->num_lines = top - bottom;
+               ent->suspect = o;
+               ent->s_lno = bottom;
+               ent->next = next;
+               if (next)
+                       next->prev = ent;
+               origin_incref(o);
+       }
+       origin_decref(o);
+
+       range_set_release(&ranges);
+       string_list_clear(&range_list, 0);
 
        sb.ent = ent;
        sb.path = path;