merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 158 insertions, 0 deletions

diff --git a/third_party/git/preload-index.c b/third_party/git/preload-index.c
new file mode 100644
index 000000000000..ed6eaa47388a
--- /dev/null
+++ b/third_party/git/preload-index.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2008 Linus Torvalds
+ */
+#include "cache.h"
+#include "pathspec.h"
+#include "dir.h"
+#include "fsmonitor.h"
+#include "config.h"
+#include "progress.h"
+#include "thread-utils.h"
+#include "repository.h"
+
+/*
+ * Mostly randomly chosen maximum thread counts: we
+ * cap the parallelism to 20 threads, and we want
+ * to have at least 500 lstat's per thread for it to
+ * be worth starting a thread.
+ */
+#define MAX_PARALLEL (20)
+#define THREAD_COST (500)
+
+struct progress_data {
+	unsigned long n;
+	struct progress *progress;
+	pthread_mutex_t mutex;
+};
+
+struct thread_data {
+	pthread_t pthread;
+	struct index_state *index;
+	struct pathspec pathspec;
+	struct progress_data *progress;
+	int offset, nr;
+};
+
+static void *preload_thread(void *_data)
+{
+	int nr, last_nr;
+	struct thread_data *p = _data;
+	struct index_state *index = p->index;
+	struct cache_entry **cep = index->cache + p->offset;
+	struct cache_def cache = CACHE_DEF_INIT;
+
+	nr = p->nr;
+	if (nr + p->offset > index->cache_nr)
+		nr = index->cache_nr - p->offset;
+	last_nr = nr;
+
+	do {
+		struct cache_entry *ce = *cep++;
+		struct stat st;
+
+		if (ce_stage(ce))
+			continue;
+		if (S_ISGITLINK(ce->ce_mode))
+			continue;
+		if (ce_uptodate(ce))
+			continue;
+		if (ce_skip_worktree(ce))
+			continue;
+		if (ce->ce_flags & CE_FSMONITOR_VALID)
+			continue;
+		if (p->progress && !(nr & 31)) {
+			struct progress_data *pd = p->progress;
+
+			pthread_mutex_lock(&pd->mutex);
+			pd->n += last_nr - nr;
+			display_progress(pd->progress, pd->n);
+			pthread_mutex_unlock(&pd->mutex);
+			last_nr = nr;
+		}
+		if (!ce_path_match(index, ce, &p->pathspec, NULL))
+			continue;
+		if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
+			continue;
+		if (lstat(ce->name, &st))
+			continue;
+		if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
+			continue;
+		ce_mark_uptodate(ce);
+		mark_fsmonitor_valid(index, ce);
+	} while (--nr > 0);
+	if (p->progress) {
+		struct progress_data *pd = p->progress;
+
+		pthread_mutex_lock(&pd->mutex);
+		display_progress(pd->progress, pd->n + last_nr);
+		pthread_mutex_unlock(&pd->mutex);
+	}
+	cache_def_clear(&cache);
+	return NULL;
+}
+
+void preload_index(struct index_state *index,
+		   const struct pathspec *pathspec,
+		   unsigned int refresh_flags)
+{
+	int threads, i, work, offset;
+	struct thread_data data[MAX_PARALLEL];
+	struct progress_data pd;
+
+	if (!HAVE_THREADS || !core_preload_index)
+		return;
+
+	threads = index->cache_nr / THREAD_COST;
+	if ((index->cache_nr > 1) && (threads < 2) && git_env_bool("GIT_TEST_PRELOAD_INDEX", 0))
+		threads = 2;
+	if (threads < 2)
+		return;
+	trace_performance_enter();
+	if (threads > MAX_PARALLEL)
+		threads = MAX_PARALLEL;
+	offset = 0;
+	work = DIV_ROUND_UP(index->cache_nr, threads);
+	memset(&data, 0, sizeof(data));
+
+	memset(&pd, 0, sizeof(pd));
+	if (refresh_flags & REFRESH_PROGRESS && isatty(2)) {
+		pd.progress = start_delayed_progress(_("Refreshing index"), index->cache_nr);
+		pthread_mutex_init(&pd.mutex, NULL);
+	}
+
+	for (i = 0; i < threads; i++) {
+		struct thread_data *p = data+i;
+		int err;
+
+		p->index = index;
+		if (pathspec)
+			copy_pathspec(&p->pathspec, pathspec);
+		p->offset = offset;
+		p->nr = work;
+		if (pd.progress)
+			p->progress = &pd;
+		offset += work;
+		err = pthread_create(&p->pthread, NULL, preload_thread, p);
+
+		if (err)
+			die(_("unable to create threaded lstat: %s"), strerror(err));
+	}
+	for (i = 0; i < threads; i++) {
+		struct thread_data *p = data+i;
+		if (pthread_join(p->pthread, NULL))
+			die("unable to join threaded lstat");
+	}
+	stop_progress(&pd.progress);
+
+	trace_performance_leave("preload index");
+}
+
+int repo_read_index_preload(struct repository *repo,
+			    const struct pathspec *pathspec,
+			    unsigned int refresh_flags)
+{
+	int retval = repo_read_index(repo);
+
+	preload_index(repo->index, pathspec, refresh_flags);
+	return retval;
+}