[PATCH 7/6] Enable threaded async procedures whenever pthreads is available

[Johannes Sixt <j6t@kdbg.org>]

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
---
On Samstag, 6. März 2010, Shawn O. Pearce wrote:
> I'm in favor of that.  If we have threaded delta search enabled,
> we probably can also run these async procedures in a POSIX thread
> rather than forking off a child.

OK. The patch could look like this.

-- Hannes

 Documentation/technical/api-run-command.txt |    5 +++--
 Makefile                                    |    5 -----
 run-command.c                               |    6 +++---
 run-command.h                               |    4 ++--
 4 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt
index 44876fa..f18b4f4 100644
--- a/Documentation/technical/api-run-command.txt
+++ b/Documentation/technical/api-run-command.txt
@@ -231,8 +231,9 @@ The function pointer in .proc has the following signature:
 
 
 There are serious restrictions on what the asynchronous function can do
-because this facility is implemented by a pipe to a forked process on
-UNIX, but by a thread in the same address space on Windows:
+because this facility is implemented by a thread in the same address
+space on most platforms (when pthreads is available), but by a pipe to
+a forked process otherwise:
 
 . It cannot change the program's state (global variables, environment,
   etc.) in a way that the caller notices; in other words, .in and .out
diff --git a/Makefile b/Makefile
index 2fe52f8..52f2cc0 100644
--- a/Makefile
+++ b/Makefile
@@ -979,7 +979,6 @@ ifeq ($(uname_S),Windows)
 	NO_CURL = YesPlease
 	NO_PYTHON = YesPlease
 	BLK_SHA1 = YesPlease
-	ASYNC_AS_THREAD = YesPlease
 
 	CC = compat/vcbuild/scripts/clink.pl
 	AR = compat/vcbuild/scripts/lib.pl
@@ -1031,7 +1030,6 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_REGEX = YesPlease
 	NO_PYTHON = YesPlease
 	BLK_SHA1 = YesPlease
-	ASYNC_AS_THREAD = YesPlease
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/fnmatch -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
 	COMPAT_OBJS += compat/mingw.o compat/fnmatch/fnmatch.o compat/winansi.o \
@@ -1344,9 +1342,6 @@ ifdef NO_PTHREADS
 else
 	EXTLIBS += $(PTHREAD_LIBS)
 	LIB_OBJS += thread-utils.o
-ifdef ASYNC_AS_THREAD
-	BASIC_CFLAGS += -DASYNC_AS_THREAD
-endif
 endif
 
 ifdef DIR_HAS_BSD_GROUP_SEMANTICS
diff --git a/run-command.c b/run-command.c
index 66cc4bf..053b28f 100644
--- a/run-command.c
+++ b/run-command.c
@@ -447,7 +447,7 @@ int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const
 	return run_command(&cmd);
 }
 
-#ifdef ASYNC_AS_THREAD
+#ifndef NO_PTHREADS
 static pthread_t main_thread;
 static int main_thread_set;
 static pthread_key_t async_key;
@@ -521,7 +521,7 @@ int start_async(struct async *async)
 	else
 		proc_out = -1;
 
-#ifndef ASYNC_AS_THREAD
+#ifdef NO_PTHREADS
 	/* Flush stdio before fork() to avoid cloning buffers */
 	fflush(NULL);
 
@@ -590,7 +590,7 @@ error:
 
 int finish_async(struct async *async)
 {
-#ifndef ASYNC_AS_THREAD
+#ifdef NO_PTHREADS
 	return wait_or_whine(async->pid, "child process", 0);
 #else
 	void *ret = (void *)(intptr_t)(-1);
diff --git a/run-command.h b/run-command.h
index 40db39c..56491b9 100644
--- a/run-command.h
+++ b/run-command.h
@@ -1,7 +1,7 @@
 #ifndef RUN_COMMAND_H
 #define RUN_COMMAND_H
 
-#ifdef ASYNC_AS_THREAD
+#ifndef NO_PTHREADS
 #include <pthread.h>
 #endif
 
@@ -78,7 +78,7 @@ struct async {
 	void *data;
 	int in;		/* caller writes here and closes it */
 	int out;	/* caller reads from here and closes it */
-#ifndef ASYNC_AS_THREAD
+#ifdef NO_PTHREADS
 	pid_t pid;
 #else
 	pthread_t tid;
-- 
1.7.0.rc2.65.g7b13a