integration of pthread_workqueue as a git submodule

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "libpwq"]
+	path = libpwq
+	url = https://github.com/dgrove-oss/libpwq.git

INSTALL

@@ -109,7 +109,13 @@ Prepare your system
  2. Install dtrace (to generate provider.h)
     sudo apt-get install systemtap-sdt-dev
  3. Install libdispatch pre-reqs
-    sudo apt-get install libblocksruntime-dev libkqueue-dev libpthread-workqueue-dev libbsd-dev
+    sudo apt-get install libblocksruntime-dev libkqueue-dev libbsd-dev
+
+Initialize git submodules:
+  We are using git submodules to incorporate a specific revision of the
+  upstream pthread_workqueue library into the build.
+    git submodule init
+    git submodule update
 
 Build:
 	sh autogen.sh

Makefile.am

@@ -4,13 +4,24 @@
 
 ACLOCAL_AMFLAGS = -I m4
 
+if BUILD_OWN_PTHREAD_WORKQUEUES
 SUBDIRS=					\
 	dispatch				\
+	libpwq					\
 	man						\
 	os						\
 	private					\
 	src						\
 	tests
+else
+SUBDIRS=					\
+	dispatch				\
+	man						\
+	os						\
+	private					\
+	src						\
+	tests
+endif
 
 EXTRA_DIST=					\
 	README.md				\

configure.ac

@@ -166,12 +166,25 @@ AS_IF([test -n "$apple_libpthread_source_path" -a -n "$apple_xnu_source_osfmk_pa
   mkdir -p mach && ln -fsh "$apple_xnu_source_osfmk_path"/mach/coalition.h mach
 ])
 AC_CHECK_HEADERS([pthread_machdep.h pthread/qos.h])
-AC_CHECK_HEADERS([pthread/workqueue_private.h pthread_workqueue.h],
-  [AC_DEFINE(HAVE_PTHREAD_WORKQUEUES, 1, [Define if pthread work queues are present])
+
+# pthread_workqueues.
+# Look for own version first, then system version.
+AS_IF([test -f libpwq/configure.ac],
+  [AC_DEFINE(BUILD_OWN_PTHREAD_WORKQUEUES, 1, [Define if building pthread work queues from source])
+   AC_CONFIG_SUBDIRS([libpwq])
+   build_own_pthread_workqueue=true,
+   AC_DEFINE(HAVE_PTHREAD_WORKQUEUES, 1, [Define if pthread work queues are present])
    have_pthread_workqueues=true],
-  [have_pthread_workqueues=false]
+  [build_own_pthread_workqueue=false
+   AC_CHECK_HEADERS([pthread/workqueue_private.h pthread_workqueue.h],
+     [AC_DEFINE(HAVE_PTHREAD_WORKQUEUES, 1, [Define if pthread work queues are present])
+      have_pthread_workqueues=true],
+     [have_pthread_workqueues=false]
+   )]
 )
+AM_CONDITIONAL(BUILD_OWN_PTHREAD_WORKQUEUES, $build_own_pthread_workqueues)
 AM_CONDITIONAL(HAVE_PTHREAD_WORKQUEUES, $have_pthread_workqueues)
+
 AC_CHECK_HEADERS([libproc_internal.h], [], [], [#include <mach/mach.h>])
 AC_CHECK_FUNCS([pthread_workqueue_setdispatch_np _pthread_workqueue_init])
 AS_IF([test -n "$apple_libpthread_source_path" -a -n "$apple_xnu_source_osfmk_path"], [

src/Makefile.am

@@ -51,13 +51,18 @@ AM_CPPFLAGS=-I$(top_builddir) -I$(top_srcdir) \
 
 DISPATCH_CFLAGS=-Wall $(VISIBILITY_FLAGS) $(OMIT_LEAF_FP_FLAGS) \
 	$(MARCH_FLAGS) $(KQUEUE_CFLAGS) $(BSD_OVERLAY_CFLAGS)
-AM_CFLAGS=$(DISPATCH_CFLAGS) $(CBLOCKS_FLAGS)
+AM_CFLAGS= $(PTHREAD_WORKQUEUE_CFLAGS) $(DISPATCH_CFLAGS) $(CBLOCKS_FLAGS)
 AM_OBJCFLAGS=$(DISPATCH_CFLAGS) $(CBLOCKS_FLAGS)
 AM_CXXFLAGS=$(DISPATCH_CFLAGS) $(CXXBLOCKS_FLAGS)
 AM_OBJCXXFLAGS=$(DISPATCH_CFLAGS) $(CXXBLOCKS_FLAGS)
 
-if HAVE_PTHREAD_WORKQUEUES
-PTHREAD_WORKQUEUE_LIBS=-lpthread_workqueue
+if BUILD_OWN_PTHREAD_WORKQUEUES
+  PTHREAD_WORKQUEUE_LIBS=../libpwq/libpthread_workqueue.la
+  PTHREAD_WORKQUEUE_CFLAGS=-I../libpwq/include
+else
+  if HAVE_PTHREAD_WORKQUEUES
+    PTHREAD_WORKQUEUE_LIBS=-lpthread_workqueue
+  endif
 endif
 
 libdispatch_la_LDFLAGS=-avoid-version

src/queue.c

@@ -200,12 +200,11 @@ struct dispatch_root_queue_context_s {
 typedef struct dispatch_root_queue_context_s *dispatch_root_queue_context_t;
 
 #define WORKQ_PRIO_INVALID (-1)
-#ifdef __linux__
+#ifndef WORKQ_BG_PRIOQUEUE_CONDITIONAL
 #define WORKQ_BG_PRIOQUEUE_CONDITIONAL WORKQ_PRIO_INVALID
+#endif
+#ifndef WORKQ_HIGH_PRIOQUEUE_CONDITIONAL
 #define WORKQ_HIGH_PRIOQUEUE_CONDITIONAL WORKQ_PRIO_INVALID
-#else
-#define WORKQ_BG_PRIOQUEUE_CONDITIONAL WORKQ_BG_PRIOQUEUE
-#define WORKQ_HIGH_PRIOQUEUE_CONDITIONAL WORKQ_HIGH_PRIOQUEUE
 #endif
 
 DISPATCH_CACHELINE_ALIGN

tests/Makefile.am

@@ -114,8 +114,10 @@ AM_OBJCFLAGS=$(DISPATCH_TESTS_CFLAGS) $(CBLOCKS_FLAGS)
 AM_CXXFLAGS=$(DISPATCH_TESTS_CFLAGS) $(CXXBLOCKS_FLAGS) $(BSD_OVERLAY_CFLAGS)
 AM_OBJCXXFLAGS=$(DISPATCH_TESTS_CFLAGS) $(CXXBLOCKS_FLAGS)
 
-if HAVE_PTHREAD_WORKQUEUES
-PTHREAD_WORKQUEUE_LIBS=-lpthread_workqueue
+if !BUILD_OWN_PTHREAD_WORKQUEUES
+  if HAVE_PTHREAD_WORKQUEUES
+    PTHREAD_WORKQUEUE_LIBS=-lpthread_workqueue
+  endif
 endif
 
 LDADD=libbsdtests.la ../src/libdispatch.la $(KQUEUE_LIBS) $(PTHREAD_WORKQUEUE_LIBS) $(BSD_OVERLAY_LIBS)