Merge branch 'jc/merge-reduce-parents-early'
[gitweb.git] / builtin / fmt-merge-msg.c
index 1bc6b8b8c3a4f4ab174841f3c8507d784f237a1f..a517f1794a1c1bcc0939ad8b81d482356c20d2ba 100644 (file)
@@ -55,7 +55,48 @@ static void init_src_data(struct src_data *data)
 static struct string_list srcs = STRING_LIST_INIT_DUP;
 static struct string_list origins = STRING_LIST_INIT_DUP;
 
-static int handle_line(char *line)
+struct merge_parents {
+       int alloc, nr;
+       struct merge_parent {
+               unsigned char given[20];
+               unsigned char commit[20];
+               unsigned char used;
+       } *item;
+};
+
+/*
+ * I know, I know, this is inefficient, but you won't be pulling and merging
+ * hundreds of heads at a time anyway.
+ */
+static struct merge_parent *find_merge_parent(struct merge_parents *table,
+                                             unsigned char *given,
+                                             unsigned char *commit)
+{
+       int i;
+       for (i = 0; i < table->nr; i++) {
+               if (given && hashcmp(table->item[i].given, given))
+                       continue;
+               if (commit && hashcmp(table->item[i].commit, commit))
+                       continue;
+               return &table->item[i];
+       }
+       return NULL;
+}
+
+static void add_merge_parent(struct merge_parents *table,
+                            unsigned char *given,
+                            unsigned char *commit)
+{
+       if (table->nr && find_merge_parent(table, given, commit))
+               return;
+       ALLOC_GROW(table->item, table->nr + 1, table->alloc);
+       hashcpy(table->item[table->nr].given, given);
+       hashcpy(table->item[table->nr].commit, commit);
+       table->item[table->nr].used = 0;
+       table->nr++;
+}
+
+static int handle_line(char *line, struct merge_parents *merge_parents)
 {
        int i, len = strlen(line);
        struct origin_data *origin_data;
@@ -63,6 +104,7 @@ static int handle_line(char *line)
        struct src_data *src_data;
        struct string_list_item *item;
        int pulling_head = 0;
+       unsigned char sha1[20];
 
        if (len < 43 || line[40] != '\t')
                return 1;
@@ -73,14 +115,15 @@ static int handle_line(char *line)
        if (line[41] != '\t')
                return 2;
 
-       line[40] = 0;
-       origin_data = xcalloc(1, sizeof(struct origin_data));
-       i = get_sha1(line, origin_data->sha1);
-       line[40] = '\t';
-       if (i) {
-               free(origin_data);
+       i = get_sha1_hex(line, sha1);
+       if (i)
                return 3;
-       }
+
+       if (!find_merge_parent(merge_parents, sha1, NULL))
+               return 0; /* subsumed by other parents */
+
+       origin_data = xcalloc(1, sizeof(struct origin_data));
+       hashcpy(origin_data->sha1, sha1);
 
        if (line[len - 1] == '\n')
                line[len - 1] = 0;
@@ -472,6 +515,67 @@ static void fmt_merge_msg_sigs(struct strbuf *out)
        strbuf_release(&tagbuf);
 }
 
+static void find_merge_parents(struct merge_parents *result,
+                              struct strbuf *in, unsigned char *head)
+{
+       struct commit_list *parents, *next;
+       struct commit *head_commit;
+       int pos = 0, i, j;
+
+       parents = NULL;
+       while (pos < in->len) {
+               int len;
+               char *p = in->buf + pos;
+               char *newline = strchr(p, '\n');
+               unsigned char sha1[20];
+               struct commit *parent;
+               struct object *obj;
+
+               len = newline ? newline - p : strlen(p);
+               pos += len + !!newline;
+
+               if (len < 43 ||
+                   get_sha1_hex(p, sha1) ||
+                   p[40] != '\t' ||
+                   p[41] != '\t')
+                       continue; /* skip not-for-merge */
+               /*
+                * Do not use get_merge_parent() here; we do not have
+                * "name" here and we do not want to contaminate its
+                * util field yet.
+                */
+               obj = parse_object(sha1);
+               parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
+               if (!parent)
+                       continue;
+               commit_list_insert(parent, &parents);
+               add_merge_parent(result, obj->sha1, parent->object.sha1);
+       }
+       head_commit = lookup_commit(head);
+       if (head_commit)
+               commit_list_insert(head_commit, &parents);
+       parents = reduce_heads(parents);
+
+       while (parents) {
+               for (i = 0; i < result->nr; i++)
+                       if (!hashcmp(result->item[i].commit,
+                                    parents->item->object.sha1))
+                               result->item[i].used = 1;
+               next = parents->next;
+               free(parents);
+               parents = next;
+       }
+
+       for (i = j = 0; i < result->nr; i++) {
+               if (result->item[i].used) {
+                       if (i != j)
+                               result->item[j] = result->item[i];
+                       j++;
+               }
+       }
+       result->nr = j;
+}
+
 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
                  struct fmt_merge_msg_opts *opts)
 {
@@ -479,6 +583,9 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
        unsigned char head_sha1[20];
        const char *current_branch;
        void *current_branch_to_free;
+       struct merge_parents merge_parents;
+
+       memset(&merge_parents, 0, sizeof(merge_parents));
 
        /* get current branch */
        current_branch = current_branch_to_free =
@@ -488,6 +595,8 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
        if (!prefixcmp(current_branch, "refs/heads/"))
                current_branch += 11;
 
+       find_merge_parents(&merge_parents, in, head_sha1);
+
        /* get a line */
        while (pos < in->len) {
                int len;
@@ -498,7 +607,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
                pos += len + !!newline;
                i++;
                p[len] = 0;
-               if (handle_line(p))
+               if (handle_line(p, &merge_parents))
                        die ("Error in line %d: %.*s", i, len, p);
        }
 
@@ -529,6 +638,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
        strbuf_complete_line(out);
        free(current_branch_to_free);
+       free(merge_parents.item);
        return 0;
 }