Merge branch 'cc/bisect'

[git.git] / builtin-log.c

diff --git a/builtin-log.c b/builtin-log.c
index 197f6eec03df49d4fac044377afd8d0c50e90c81..e1f1cf67143721933010065130adaba8723b272b 100644 (file)
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -77,11 +77,134 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
        }
 }
 
+/*
+ * This gives a rough estimate for how many commits we
+ * will print out in the list.
+ */
+static int estimate_commit_count(struct rev_info *rev, struct commit_list *list)
+{
+       int n = 0;
+
+       while (list) {
+               struct commit *commit = list->item;
+               unsigned int flags = commit->object.flags;
+               list = list->next;
+               if (!(flags & (TREESAME | UNINTERESTING)))
+                       n++;
+       }
+       return n;
+}
+
+static void show_early_header(struct rev_info *rev, const char *stage, int nr)
+{
+       if (rev->shown_one) {
+               rev->shown_one = 0;
+               if (rev->commit_format != CMIT_FMT_ONELINE)
+                       putchar(rev->diffopt.line_termination);
+       }
+       printf("Final output: %d %s\n", nr, stage);
+}
+
+struct itimerval early_output_timer;
+
+static void log_show_early(struct rev_info *revs, struct commit_list *list)
+{
+       int i = revs->early_output;
+       int show_header = 1;
+
+       sort_in_topological_order(&list, revs->lifo);
+       while (list && i) {
+               struct commit *commit = list->item;
+               switch (simplify_commit(revs, commit)) {
+               case commit_show:
+                       if (show_header) {
+                               int n = estimate_commit_count(revs, list);
+                               show_early_header(revs, "incomplete", n);
+                               show_header = 0;
+                       }
+                       log_tree_commit(revs, commit);
+                       i--;
+                       break;
+               case commit_ignore:
+                       break;
+               case commit_error:
+                       return;
+               }
+               list = list->next;
+       }
+
+       /* Did we already get enough commits for the early output? */
+       if (!i)
+               return;
+
+       /*
+        * ..if no, then repeat it twice a second until we
+        * do.
+        *
+        * NOTE! We don't use "it_interval", because if the
+        * reader isn't listening, we want our output to be
+        * throttled by the writing, and not have the timer
+        * trigger every second even if we're blocked on a
+        * reader!
+        */
+       early_output_timer.it_value.tv_sec = 0;
+       early_output_timer.it_value.tv_usec = 500000;
+       setitimer(ITIMER_REAL, &early_output_timer, NULL);
+}
+
+static void early_output(int signal)
+{
+       show_early_output = log_show_early;
+}
+
+static void setup_early_output(struct rev_info *rev)
+{
+       struct sigaction sa;
+
+       /*
+        * Set up the signal handler, minimally intrusively:
+        * we only set a single volatile integer word (not
+        * using sigatomic_t - trying to avoid unnecessary
+        * system dependencies and headers), and using
+        * SA_RESTART.
+        */
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = early_output;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       sigaction(SIGALRM, &sa, NULL);
+
+       /*
+        * If we can get the whole output in less than a
+        * tenth of a second, don't even bother doing the
+        * early-output thing..
+        *
+        * This is a one-time-only trigger.
+        */
+       early_output_timer.it_value.tv_sec = 0;
+       early_output_timer.it_value.tv_usec = 100000;
+       setitimer(ITIMER_REAL, &early_output_timer, NULL);
+}
+
+static void finish_early_output(struct rev_info *rev)
+{
+       int n = estimate_commit_count(rev, rev->commits);
+       signal(SIGALRM, SIG_IGN);
+       show_early_header(rev, "done", n);
+}
+
 static int cmd_log_walk(struct rev_info *rev)
 {
        struct commit *commit;
 
+       if (rev->early_output)
+               setup_early_output(rev);
+
        prepare_revision_walk(rev);
+
+       if (rev->early_output)
+               finish_early_output(rev);
+
        while ((commit = get_revision(rev)) != NULL) {
                log_tree_commit(rev, commit);
                if (!rev->reflog_info) {