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-rw-r--r--builtin-log.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/builtin-log.c b/builtin-log.c
index 197f6eec03..e1f1cf6714 100644
--- 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) {