Code

Merge branch 'jc/blame' (early part) into HEAD
[git.git] / builtin-blame.c
index b451f6c64dde8ce6358bb5c8dfccc8bad181a6bb..cf41511c798330a7e0ec02db5785747ad2b662a5 100644 (file)
@@ -43,6 +43,7 @@ static int max_orig_digits;
 static int max_digits;
 static int max_score_digits;
 static int show_root;
+static int reverse;
 static int blank_boundary;
 static int incremental;
 static int cmd_is_annotate;
@@ -91,7 +92,7 @@ struct origin {
  * Given an origin, prepare mmfile_t structure to be used by the
  * diff machinery
  */
-static char *fill_origin_blob(struct origin *o, mmfile_t *file)
+static void fill_origin_blob(struct origin *o, mmfile_t *file)
 {
        if (!o->file.ptr) {
                enum object_type type;
@@ -106,7 +107,6 @@ static char *fill_origin_blob(struct origin *o, mmfile_t *file)
        }
        else
                *file = o->file;
-       return file->ptr;
 }
 
 /*
@@ -178,7 +178,7 @@ struct blame_entry {
 struct scoreboard {
        /* the final commit (i.e. where we started digging from) */
        struct commit *final;
-
+       struct rev_info *revs;
        const char *path;
 
        /*
@@ -1192,18 +1192,48 @@ static void pass_whole_blame(struct scoreboard *sb,
        }
 }
 
-#define MAXPARENT 16
+/*
+ * We pass blame from the current commit to its parents.  We keep saying
+ * "parent" (and "porigin"), but what we mean is to find scapegoat to
+ * exonerate ourselves.
+ */
+static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
+{
+       if (!reverse)
+               return commit->parents;
+       return lookup_decoration(&revs->children, &commit->object);
+}
+
+static int num_scapegoats(struct rev_info *revs, struct commit *commit)
+{
+       int cnt;
+       struct commit_list *l = first_scapegoat(revs, commit);
+       for (cnt = 0; l; l = l->next)
+               cnt++;
+       return cnt;
+}
+
+#define MAXSG 16
 
 static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
 {
-       int i, pass;
+       struct rev_info *revs = sb->revs;
+       int i, pass, num_sg;
        struct commit *commit = origin->commit;
-       struct commit_list *parent;
-       struct origin *parent_origin[MAXPARENT], *porigin;
-
-       memset(parent_origin, 0, sizeof(parent_origin));
+       struct commit_list *sg;
+       struct origin *sg_buf[MAXSG];
+       struct origin *porigin, **sg_origin = sg_buf;
+
+       num_sg = num_scapegoats(revs, commit);
+       if (!num_sg)
+               goto finish;
+       else if (num_sg < ARRAY_SIZE(sg_buf))
+               memset(sg_buf, 0, sizeof(sg_buf));
+       else
+               sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
 
-       /* The first pass looks for unrenamed path to optimize for
+       /*
+        * The first pass looks for unrenamed path to optimize for
         * common cases, then we look for renames in the second pass.
         */
        for (pass = 0; pass < 2; pass++) {
@@ -1211,13 +1241,13 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
                                       struct commit *, struct origin *);
                find = pass ? find_rename : find_origin;
 
-               for (i = 0, parent = commit->parents;
-                    i < MAXPARENT && parent;
-                    parent = parent->next, i++) {
-                       struct commit *p = parent->item;
+               for (i = 0, sg = first_scapegoat(revs, commit);
+                    i < num_sg && sg;
+                    sg = sg->next, i++) {
+                       struct commit *p = sg->item;
                        int j, same;
 
-                       if (parent_origin[i])
+                       if (sg_origin[i])
                                continue;
                        if (parse_commit(p))
                                continue;
@@ -1230,24 +1260,24 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
                                goto finish;
                        }
                        for (j = same = 0; j < i; j++)
-                               if (parent_origin[j] &&
-                                   !hashcmp(parent_origin[j]->blob_sha1,
+                               if (sg_origin[j] &&
+                                   !hashcmp(sg_origin[j]->blob_sha1,
                                             porigin->blob_sha1)) {
                                        same = 1;
                                        break;
                                }
                        if (!same)
-                               parent_origin[i] = porigin;
+                               sg_origin[i] = porigin;
                        else
                                origin_decref(porigin);
                }
        }
 
        num_commits++;
-       for (i = 0, parent = commit->parents;
-            i < MAXPARENT && parent;
-            parent = parent->next, i++) {
-               struct origin *porigin = parent_origin[i];
+       for (i = 0, sg = first_scapegoat(revs, commit);
+            i < num_sg && sg;
+            sg = sg->next, i++) {
+               struct origin *porigin = sg_origin[i];
                if (!porigin)
                        continue;
                if (pass_blame_to_parent(sb, origin, porigin))
@@ -1258,10 +1288,10 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
         * Optionally find moves in parents' files.
         */
        if (opt & PICKAXE_BLAME_MOVE)
-               for (i = 0, parent = commit->parents;
-                    i < MAXPARENT && parent;
-                    parent = parent->next, i++) {
-                       struct origin *porigin = parent_origin[i];
+               for (i = 0, sg = first_scapegoat(revs, commit);
+                    i < num_sg && sg;
+                    sg = sg->next, i++) {
+                       struct origin *porigin = sg_origin[i];
                        if (!porigin)
                                continue;
                        if (find_move_in_parent(sb, origin, porigin))
@@ -1272,23 +1302,25 @@ static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
         * Optionally find copies from parents' files.
         */
        if (opt & PICKAXE_BLAME_COPY)
-               for (i = 0, parent = commit->parents;
-                    i < MAXPARENT && parent;
-                    parent = parent->next, i++) {
-                       struct origin *porigin = parent_origin[i];
-                       if (find_copy_in_parent(sb, origin, parent->item,
+               for (i = 0, sg = first_scapegoat(revs, commit);
+                    i < num_sg && sg;
+                    sg = sg->next, i++) {
+                       struct origin *porigin = sg_origin[i];
+                       if (find_copy_in_parent(sb, origin, sg->item,
                                                porigin, opt))
                                goto finish;
                }
 
  finish:
-       for (i = 0; i < MAXPARENT; i++) {
-               if (parent_origin[i]) {
-                       drop_origin_blob(parent_origin[i]);
-                       origin_decref(parent_origin[i]);
+       for (i = 0; i < num_sg; i++) {
+               if (sg_origin[i]) {
+                       drop_origin_blob(sg_origin[i]);
+                       origin_decref(sg_origin[i]);
                }
        }
        drop_origin_blob(origin);
+       if (sg_buf != sg_origin)
+               free(sg_origin);
 }
 
 /*
@@ -1487,8 +1519,10 @@ static void found_guilty_entry(struct blame_entry *ent)
  * is still unknown, pick one blame_entry, and allow its current
  * suspect to pass blames to its parents.
  */
-static void assign_blame(struct scoreboard *sb, struct rev_info *revs, int opt)
+static void assign_blame(struct scoreboard *sb, int opt)
 {
+       struct rev_info *revs = sb->revs;
+
        while (1) {
                struct blame_entry *ent;
                struct commit *commit;
@@ -1509,8 +1543,9 @@ static void assign_blame(struct scoreboard *sb, struct rev_info *revs, int opt)
                commit = suspect->commit;
                if (!commit->object.parsed)
                        parse_commit(commit);
-               if (!(commit->object.flags & UNINTERESTING) &&
-                   !(revs->max_age != -1 && commit->date < revs->max_age))
+               if (reverse ||
+                   (!(commit->object.flags & UNINTERESTING) &&
+                    !(revs->max_age != -1 && commit->date < revs->max_age)))
                        pass_blame(sb, suspect, opt);
                else {
                        commit->object.flags |= UNINTERESTING;
@@ -2006,6 +2041,10 @@ static int git_blame_config(const char *var, const char *value, void *cb)
        return git_default_config(var, value, cb);
 }
 
+/*
+ * Prepare a dummy commit that represents the work tree (or staged) item.
+ * Note that annotating work tree item never works in the reverse.
+ */
 static struct commit *fake_working_tree_commit(const char *path, const char *contents_from)
 {
        struct commit *commit;
@@ -2122,6 +2161,64 @@ static struct commit *fake_working_tree_commit(const char *path, const char *con
        return commit;
 }
 
+static const char *prepare_final(struct scoreboard *sb)
+{
+       int i;
+       const char *final_commit_name = NULL;
+       struct rev_info *revs = sb->revs;
+
+       /*
+        * There must be one and only one positive commit in the
+        * revs->pending array.
+        */
+       for (i = 0; i < revs->pending.nr; i++) {
+               struct object *obj = revs->pending.objects[i].item;
+               if (obj->flags & UNINTERESTING)
+                       continue;
+               while (obj->type == OBJ_TAG)
+                       obj = deref_tag(obj, NULL, 0);
+               if (obj->type != OBJ_COMMIT)
+                       die("Non commit %s?", revs->pending.objects[i].name);
+               if (sb->final)
+                       die("More than one commit to dig from %s and %s?",
+                           revs->pending.objects[i].name,
+                           final_commit_name);
+               sb->final = (struct commit *) obj;
+               final_commit_name = revs->pending.objects[i].name;
+       }
+       return final_commit_name;
+}
+
+static const char *prepare_initial(struct scoreboard *sb)
+{
+       int i;
+       const char *final_commit_name = NULL;
+       struct rev_info *revs = sb->revs;
+
+       /*
+        * There must be one and only one negative commit, and it must be
+        * the boundary.
+        */
+       for (i = 0; i < revs->pending.nr; i++) {
+               struct object *obj = revs->pending.objects[i].item;
+               if (!(obj->flags & UNINTERESTING))
+                       continue;
+               while (obj->type == OBJ_TAG)
+                       obj = deref_tag(obj, NULL, 0);
+               if (obj->type != OBJ_COMMIT)
+                       die("Non commit %s?", revs->pending.objects[i].name);
+               if (sb->final)
+                       die("More than one commit to dig down to %s and %s?",
+                           revs->pending.objects[i].name,
+                           final_commit_name);
+               sb->final = (struct commit *) obj;
+               final_commit_name = revs->pending.objects[i].name;
+       }
+       if (!final_commit_name)
+               die("No commit to dig down to?");
+       return final_commit_name;
+}
+
 int cmd_blame(int argc, const char **argv, const char *prefix)
 {
        struct rev_info revs;
@@ -2154,6 +2251,10 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
                        blank_boundary = 1;
                else if (!strcmp("--root", arg))
                        show_root = 1;
+               else if (!strcmp("--reverse", arg)) {
+                       argv[unk++] = "--children";
+                       reverse = 1;
+               }
                else if (!strcmp(arg, "--show-stats"))
                        show_stats = 1;
                else if (!strcmp("-c", arg))
@@ -2327,26 +2428,13 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
        setup_revisions(unk, argv, &revs, NULL);
        memset(&sb, 0, sizeof(sb));
 
-       /*
-        * There must be one and only one positive commit in the
-        * revs->pending array.
-        */
-       for (i = 0; i < revs.pending.nr; i++) {
-               struct object *obj = revs.pending.objects[i].item;
-               if (obj->flags & UNINTERESTING)
-                       continue;
-               while (obj->type == OBJ_TAG)
-                       obj = deref_tag(obj, NULL, 0);
-               if (obj->type != OBJ_COMMIT)
-                       die("Non commit %s?",
-                           revs.pending.objects[i].name);
-               if (sb.final)
-                       die("More than one commit to dig from %s and %s?",
-                           revs.pending.objects[i].name,
-                           final_commit_name);
-               sb.final = (struct commit *) obj;
-               final_commit_name = revs.pending.objects[i].name;
-       }
+       sb.revs = &revs;
+       if (!reverse)
+               final_commit_name = prepare_final(&sb);
+       else if (contents_from)
+               die("--contents and --children do not blend well.");
+       else
+               final_commit_name = prepare_initial(&sb);
 
        if (!sb.final) {
                /*
@@ -2425,7 +2513,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
        if (!incremental)
                setup_pager();
 
-       assign_blame(&sb, &revs, opt);
+       assign_blame(&sb, opt);
 
        if (incremental)
                return 0;