Merge branch 'nd/pthreads'

The codebase has been cleaned up to reduce "#ifndef NO_PTHREADS".

* nd/pthreads:
  Clean up pthread_create() error handling
  read-cache.c: initialize copy_len to shut up gcc 8
  read-cache.c: reduce branching based on HAVE_THREADS
  read-cache.c: remove #ifdef NO_PTHREADS
  pack-objects: remove #ifdef NO_PTHREADS
  preload-index.c: remove #ifdef NO_PTHREADS
  grep: clean up num_threads handling
  grep: remove #ifdef NO_PTHREADS
  attr.c: remove #ifdef NO_PTHREADS
  name-hash.c: remove #ifdef NO_PTHREADS
  index-pack: remove #ifdef NO_PTHREADS
  send-pack.c: move async's #ifdef NO_PTHREADS back to run-command.c
  run-command.h: include thread-utils.h instead of pthread.h
  thread-utils: macros to unconditionally compile pthreads API

3 files changed, 46 insertions, 122 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 56e4a11..cca87cf 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -34,7 +34,6 @@ static int recurse_submodules;
 #define GREP_NUM_THREADS_DEFAULT 8
 static int num_threads;
 
-#ifndef NO_PTHREADS
 static pthread_t *threads;
 
 /* We use one producer thread and THREADS consumer
@@ -70,13 +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);
 }
 
@@ -234,6 +231,9 @@ static int wait_all(void)
 	int hit = 0;
 	int i;
 
+	if (!HAVE_THREADS)
+		BUG("Never call this function unless you have started threads");
+
 	grep_lock();
 	all_work_added = 1;
 
@@ -265,13 +265,6 @@ static int wait_all(void)
 
 	return hit;
 }
-#else /* !NO_PTHREADS */
-
-static int wait_all(void)
-{
-	return 0;
-}
-#endif
 
 static int grep_cmd_config(const char *var, const char *value, void *cb)
 {
@@ -284,17 +277,15 @@ 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);
-#ifdef NO_PTHREADS
-		else if (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;
 		}
-#endif
 	}
 
 	if (!strcmp(var, "submodule.recurse"))
@@ -330,17 +321,14 @@ 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);
 
-#ifndef NO_PTHREADS
-	if (num_threads) {
+	if (num_threads > 1) {
 		/*
 		 * add_work() copies gs and thus assumes ownership of
 		 * its fields, so do not call grep_source_clear()
 		 */
 		add_work(opt, &gs);
 		return 0;
-	} else
-#endif
-	{
+	} else {
 		int hit;
 
 		hit = grep_source(opt, &gs);
@@ -363,17 +351,14 @@ 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);
 
-#ifndef NO_PTHREADS
-	if (num_threads) {
+	if (num_threads > 1) {
 		/*
 		 * add_work() copies gs and thus assumes ownership of
 		 * its fields, so do not call grep_source_clear()
 		 */
 		add_work(opt, &gs);
 		return 0;
-	} else
-#endif
-	{
+	} else {
 		int hit;
 
 		hit = grep_source(opt, &gs);
@@ -1049,39 +1034,35 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	pathspec.recursive = 1;
 	pathspec.recurse_submodules = !!recurse_submodules;
 
-#ifndef NO_PTHREADS
-	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;
-#else
-	if (num_threads)
+	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 = 0;
-#endif
+		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)
+	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 {
 		/*
 		 * 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);
-
-#ifndef NO_PTHREADS
-	if (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);
 	}
-#endif
 
 	if (show_in_pager && (cached || list.nr))
 		die(_("--open-files-in-pager only works on the worktree"));
@@ -1132,7 +1113,7 @@ 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);
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 2004e25..6820425 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -42,9 +42,7 @@ struct base_data {
 };
 
 struct thread_local {
-#ifndef NO_PTHREADS
 	pthread_t thread;
-#endif
 	struct base_data *base_cache;
 	size_t base_cache_used;
 	int pack_fd;
@@ -98,8 +96,6 @@ static uint32_t input_crc32;
 static int input_fd, output_fd;
 static const char *curr_pack;
 
-#ifndef NO_PTHREADS
-
 static struct thread_local *thread_data;
 static int nr_dispatched;
 static int threads_active;
@@ -179,26 +175,6 @@ static void cleanup_thread(void)
 	free(thread_data);
 }
 
-#else
-
-#define read_lock()
-#define read_unlock()
-
-#define counter_lock()
-#define counter_unlock()
-
-#define work_lock()
-#define work_unlock()
-
-#define deepest_delta_lock()
-#define deepest_delta_unlock()
-
-#define type_cas_lock()
-#define type_cas_unlock()
-
-#endif
-
-
 static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
 {
 	if (!obj)
@@ -364,22 +340,20 @@ static NORETURN void bad_object(off_t offset, const char *format, ...)
 
 static inline struct thread_local *get_thread_data(void)
 {
-#ifndef NO_PTHREADS
-	if (threads_active)
-		return pthread_getspecific(key);
-	assert(!threads_active &&
-	       "This should only be reached when all threads are gone");
-#endif
+	if (HAVE_THREADS) {
+		if (threads_active)
+			return pthread_getspecific(key);
+		assert(!threads_active &&
+		       "This should only be reached when all threads are gone");
+	}
 	return &nothread_data;
 }
 
-#ifndef NO_PTHREADS
 static void set_thread_data(struct thread_local *data)
 {
 	if (threads_active)
 		pthread_setspecific(key, data);
 }
-#endif
 
 static struct base_data *alloc_base_data(void)
 {
@@ -1092,7 +1066,6 @@ static void resolve_base(struct object_entry *obj)
 	find_unresolved_deltas(base_obj);
 }
 
-#ifndef NO_PTHREADS
 static void *threaded_second_pass(void *data)
 {
 	set_thread_data(data);
@@ -1116,7 +1089,6 @@ static void *threaded_second_pass(void *data)
 	}
 	return NULL;
 }
-#endif
 
 /*
  * First pass:
@@ -1213,7 +1185,6 @@ static void resolve_deltas(void)
 		progress = start_progress(_("Resolving deltas"),
 					  nr_ref_deltas + nr_ofs_deltas);
 
-#ifndef NO_PTHREADS
 	nr_dispatched = 0;
 	if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
 		init_thread();
@@ -1229,7 +1200,6 @@ static void resolve_deltas(void)
 		cleanup_thread();
 		return;
 	}
-#endif
 
 	for (i = 0; i < nr_objects; i++) {
 		struct object_entry *obj = &objects[i];
@@ -1531,11 +1501,10 @@ static int git_index_pack_config(const char *k, const char *v, void *cb)
 		if (nr_threads < 0)
 			die(_("invalid number of threads specified (%d)"),
 			    nr_threads);
-#ifdef NO_PTHREADS
-		if (nr_threads != 1)
+		if (!HAVE_THREADS && nr_threads != 1) {
 			warning(_("no threads support, ignoring %s"), k);
-		nr_threads = 1;
-#endif
+			nr_threads = 1;
+		}
 		return 0;
 	}
 	return git_default_config(k, v, cb);
@@ -1723,12 +1692,10 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 				nr_threads = strtoul(arg+10, &end, 0);
 				if (!arg[10] || *end || nr_threads < 0)
 					usage(index_pack_usage);
-#ifdef NO_PTHREADS
-				if (nr_threads != 1)
-					warning(_("no threads support, "
-						  "ignoring %s"), arg);
-				nr_threads = 1;
-#endif
+				if (!HAVE_THREADS && nr_threads != 1) {
+					warning(_("no threads support, ignoring %s"), arg);
+					nr_threads = 1;
+				}
 			} else if (starts_with(arg, "--pack_header=")) {
 				struct pack_header *hdr;
 				char *c;
@@ -1791,14 +1758,12 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 	if (strict)
 		opts.flags |= WRITE_IDX_STRICT;
 
-#ifndef NO_PTHREADS
-	if (!nr_threads) {
+	if (HAVE_THREADS && !nr_threads) {
 		nr_threads = online_cpus();
 		/* An experiment showed that more threads does not mean faster */
 		if (nr_threads > 3)
 			nr_threads = 3;
 	}
-#endif
 
 	curr_pack = open_pack_file(pack_name);
 	parse_pack_header();
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index c99ee79..2193054 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1953,8 +1953,6 @@ static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
 	return 0;
 }
 
-#ifndef NO_PTHREADS
-
 /* Protect access to object database */
 static pthread_mutex_t read_mutex;
 #define read_lock()		pthread_mutex_lock(&read_mutex)
@@ -1979,16 +1977,6 @@ static pthread_mutex_t progress_mutex;
  * ahead in the list because they can be stolen and would need
  * progress_mutex for protection.
  */
-#else
-
-#define read_lock()		(void)0
-#define read_unlock()		(void)0
-#define cache_lock()		(void)0
-#define cache_unlock()		(void)0
-#define progress_lock()		(void)0
-#define progress_unlock()	(void)0
-
-#endif
 
 /*
  * Return the size of the object without doing any delta
@@ -2347,8 +2335,6 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
 	free(array);
 }
 
-#ifndef NO_PTHREADS
-
 static void try_to_free_from_threads(size_t size)
 {
 	read_lock();
@@ -2577,10 +2563,6 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 	free(p);
 }
 
-#else
-#define ll_find_deltas(l, s, w, d, p)	find_deltas(l, &s, w, d, p)
-#endif
-
 static void add_tag_chain(const struct object_id *oid)
 {
 	struct tag *tag;
@@ -2733,12 +2715,10 @@ static int git_pack_config(const char *k, const char *v, void *cb)
 		if (delta_search_threads < 0)
 			die(_("invalid number of threads specified (%d)"),
 			    delta_search_threads);
-#ifdef NO_PTHREADS
-		if (delta_search_threads != 1) {
+		if (!HAVE_THREADS && delta_search_threads != 1) {
 			warning(_("no threads support, ignoring %s"), k);
 			delta_search_threads = 0;
 		}
-#endif
 		return 0;
 	}
 	if (!strcmp(k, "pack.indexversion")) {
@@ -3402,10 +3382,8 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (!delta_search_threads)	/* --threads=0 means autodetect */
 		delta_search_threads = online_cpus();
 
-#ifdef NO_PTHREADS
-	if (delta_search_threads != 1)
+	if (!HAVE_THREADS && delta_search_threads != 1)
 		warning(_("no threads support, ignoring --threads"));
-#endif
 	if (!pack_to_stdout && !pack_size_limit)
 		pack_size_limit = pack_size_limit_cfg;
 	if (pack_to_stdout && pack_size_limit)