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authorNguyễn Thái Ngọc Duy <pclouds@gmail.com>2018-11-03 08:48:44 (GMT)
committerJunio C Hamano <gitster@pobox.com>2018-11-05 04:42:11 (GMT)
commitfd6263fb733e50cfbcf857136388bf47d9c5151f (patch)
tree3a99ad14b7c732af1035e08da8c17cbd0715d4b0 /builtin/grep.c
parent4002e87cb254298fa2f44b98ee1b618bda0e8b59 (diff)
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grep: clean up num_threads handling
When NO_PTHREADS is still used in this file, we have two separate code paths for thread and no thread support. The latter will always have num_threads remain zero while the former uses num_threads zero as "default number of threads". With recent changes blur the line between thread and no-thread support, this num_threads handling becomes a bit strange so let's redefine it like this: - num_threads == 0 means default number of threads and should become positive after all configuration and option parsing is done if multithread is supported. - num_threads <= 1 runs no threads. It does not matter if the platform supports threading or not. - num_threads > 1 will run multiple threads and is invalid if HAVE_THREADS is false. pthread API is only used in this case. PS. a new warning is also added when num_threads is forced back to one because a thread-incompatible option is specified. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/grep.c')
-rw-r--r--builtin/grep.c58
1 files changed, 27 insertions, 31 deletions
diff --git a/builtin/grep.c b/builtin/grep.c
index 6dd15db..de3f568 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -69,13 +69,11 @@ static pthread_mutex_t grep_mutex;
static inline void grep_lock(void)
{
- assert(num_threads);
pthread_mutex_lock(&grep_mutex);
}
static inline void grep_unlock(void)
{
- assert(num_threads);
pthread_mutex_unlock(&grep_mutex);
}
@@ -234,7 +232,7 @@ static int wait_all(void)
int i;
if (!HAVE_THREADS)
- return 0;
+ BUG("Never call this function unless you have started threads");
grep_lock();
all_work_added = 1;
@@ -279,14 +277,14 @@ static int grep_cmd_config(const char *var, const char *value, void *cb)
if (num_threads < 0)
die(_("invalid number of threads specified (%d) for %s"),
num_threads, var);
- else if (!HAVE_THREADS && num_threads && num_threads != 1) {
+ else if (!HAVE_THREADS && num_threads > 1) {
/*
* TRANSLATORS: %s is the configuration
* variable for tweaking threads, currently
* grep.threads
*/
warning(_("no threads support, ignoring %s"), var);
- num_threads = 0;
+ num_threads = 1;
}
}
@@ -323,7 +321,7 @@ static int grep_oid(struct grep_opt *opt, const struct object_id *oid,
grep_source_init(&gs, GREP_SOURCE_OID, pathbuf.buf, path, oid);
strbuf_release(&pathbuf);
- if (HAVE_THREADS && num_threads) {
+ if (num_threads > 1) {
/*
* add_work() copies gs and thus assumes ownership of
* its fields, so do not call grep_source_clear()
@@ -353,7 +351,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
grep_source_init(&gs, GREP_SOURCE_FILE, buf.buf, filename, filename);
strbuf_release(&buf);
- if (HAVE_THREADS && num_threads) {
+ if (num_threads > 1) {
/*
* add_work() copies gs and thus assumes ownership of
* its fields, so do not call grep_source_clear()
@@ -1025,36 +1023,34 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
pathspec.recursive = 1;
pathspec.recurse_submodules = !!recurse_submodules;
- if (HAVE_THREADS) {
- if (list.nr || cached || show_in_pager)
- num_threads = 0;
- else if (num_threads == 0)
- num_threads = GREP_NUM_THREADS_DEFAULT;
- else if (num_threads < 0)
- die(_("invalid number of threads specified (%d)"), num_threads);
- if (num_threads == 1)
- num_threads = 0;
+ if (list.nr || cached || show_in_pager) {
+ if (num_threads > 1)
+ warning(_("invalid option combination, ignoring --threads"));
+ num_threads = 1;
+ } else if (!HAVE_THREADS && num_threads > 1) {
+ warning(_("no threads support, ignoring --threads"));
+ num_threads = 1;
+ } else if (num_threads < 0)
+ die(_("invalid number of threads specified (%d)"), num_threads);
+ else if (num_threads == 0)
+ num_threads = HAVE_THREADS ? GREP_NUM_THREADS_DEFAULT : 1;
+
+ if (num_threads > 1) {
+ if (!HAVE_THREADS)
+ BUG("Somebody got num_threads calculation wrong!");
+ if (!(opt.name_only || opt.unmatch_name_only || opt.count)
+ && (opt.pre_context || opt.post_context ||
+ opt.file_break || opt.funcbody))
+ skip_first_line = 1;
+ start_threads(&opt);
} else {
- if (num_threads)
- warning(_("no threads support, ignoring --threads"));
- num_threads = 0;
- }
-
- if (!num_threads)
/*
* The compiled patterns on the main path are only
* used when not using threading. Otherwise
- * start_threads() below calls compile_grep_patterns()
+ * start_threads() above calls compile_grep_patterns()
* for each thread.
*/
compile_grep_patterns(&opt);
-
- if (HAVE_THREADS && num_threads) {
- if (!(opt.name_only || opt.unmatch_name_only || opt.count)
- && (opt.pre_context || opt.post_context ||
- opt.file_break || opt.funcbody))
- skip_first_line = 1;
- start_threads(&opt);
}
if (show_in_pager && (cached || list.nr))
@@ -1106,7 +1102,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
hit = grep_objects(&opt, &pathspec, &list);
}
- if (num_threads)
+ if (num_threads > 1)
hit |= wait_all();
if (hit && show_in_pager)
run_pager(&opt, prefix);