log: --author-date-order

Sometimes people would want to view the commits in parallel histories in the order of author dates, not committer dates. Teach "topo-order" sort machinery to do so, using a commit-info slab to record the author dates of each commit, and prio-queue to sort them. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: gitster

Documentation/rev-list-options.txt

@@ -617,6 +617,10 @@ By default, the commits are shown in reverse chronological order.
 Show no parents before all of its children are shown, but
 otherwise show commits in the commit timestamp order.
 
+--author-date-order::
+Show no parents before all of its children are shown, but
+otherwise show commits in the author timestamp order.
+
 --topo-order::
 Show no parents before all of its children are shown, and
 avoid showing commits on multiple lines of history

commit.c

@@ -510,6 +510,68 @@ struct commit *pop_commit(struct commit_list **stack)
 /* count number of children that have not been emitted */
 define_commit_slab(indegree_slab, int);
 
+/* record author-date for each commit object */
+define_commit_slab(author_date_slab, unsigned long);
+
+static void record_author_date(struct author_date_slab *author_date,
+ struct commit *commit)
+{
+const char *buf, *line_end;
+char *buffer = NULL;
+struct ident_split ident;
+char *date_end;
+unsigned long date;
+
+if (!commit->buffer) {
+unsigned long size;
+enum object_type type;
+buffer = read_sha1_file(commit->object.sha1, &type, &size);
+if (!buffer)
+return;
+}
+
+for (buf = commit->buffer ? commit->buffer : buffer;
+ buf;
+ buf = line_end + 1) {
+line_end = strchrnul(buf, '\n');
+if (prefixcmp(buf, "author ")) {
+if (!line_end[0] || line_end[1] == '\n')
+return; /* end of header */
+continue;
+}
+if (split_ident_line(&ident,
+ buf + strlen("author "),
+ line_end - (buf + strlen("author "))) ||
+ !ident.date_begin || !ident.date_end)
+goto fail_exit; /* malformed "author" line */
+break;
+}
+
+date = strtoul(ident.date_begin, &date_end, 10);
+if (date_end != ident.date_end)
+goto fail_exit; /* malformed date */
+*(author_date_slab_at(author_date, commit)) = date;
+
+fail_exit:
+free(buffer);
+}
+
+static int compare_commits_by_author_date(const void *a_, const void *b_,
+ void *cb_data)
+{
+const struct commit *a = a_, *b = b_;
+struct author_date_slab *author_date = cb_data;
+unsigned long a_date = *(author_date_slab_at(author_date, a));
+unsigned long b_date = *(author_date_slab_at(author_date, b));
+
+/* newer commits with larger date first */
+if (a_date < b_date)
+return 1;
+else if (a_date > b_date)
+return -1;
+return 0;
+}
+
 static int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 {
 const struct commit *a = a_, *b = b_;
@@ -531,26 +593,36 @@ void sort_in_topological_order(struct commit_list **list, enum rev_sort_order so
 struct indegree_slab indegree;
 struct prio_queue queue;
 struct commit *commit;
+struct author_date_slab author_date;
 
 if (!orig)
 return;
 *list = NULL;
 
 init_indegree_slab(&indegree);
 memset(&queue, '\0', sizeof(queue));
+
 switch (sort_order) {
 default: /* REV_SORT_IN_GRAPH_ORDER */
 queue.compare = NULL;
 break;
 case REV_SORT_BY_COMMIT_DATE:
 queue.compare = compare_commits_by_commit_date;
 break;
+case REV_SORT_BY_AUTHOR_DATE:
+init_author_date_slab(&author_date);
+queue.compare = compare_commits_by_author_date;
+queue.cb_data = &author_date;
+break;
 }
 
 /* Mark them and clear the indegree */
 for (next = orig; next; next = next->next) {
 struct commit *commit = next->item;
 *(indegree_slab_at(&indegree, commit)) = 1;
+/* also record the author dates, if needed */
+if (sort_order == REV_SORT_BY_AUTHOR_DATE)
+record_author_date(&author_date, commit);
 }
 
 /* update the indegree */
@@ -621,6 +693,8 @@ void sort_in_topological_order(struct commit_list **list, enum rev_sort_order so
 
 clear_indegree_slab(&indegree);
 clear_prio_queue(&queue);
+if (sort_order == REV_SORT_BY_AUTHOR_DATE)
+clear_author_date_slab(&author_date);
 }
 
 /* merge-base stuff */

commit.h

@@ -142,7 +142,8 @@ void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark);
 
 enum rev_sort_order {
 REV_SORT_IN_GRAPH_ORDER = 0,
-REV_SORT_BY_COMMIT_DATE
+REV_SORT_BY_COMMIT_DATE,
+REV_SORT_BY_AUTHOR_DATE
 };
 
 /*

revision.c

@@ -1393,6 +1393,9 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 } else if (!strcmp(arg, "--date-order")) {
 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
 revs->topo_order = 1;
+} else if (!strcmp(arg, "--author-date-order")) {
+revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
+revs->topo_order = 1;
 } else if (!prefixcmp(arg, "--early-output")) {
 int count = 100;
 switch (arg[14]) {