update g_cond_*() usage

ChangeLog

@@ -4,7 +4,7 @@
 - openslide2vips gets underlying tile size from openslide
 - embed has 'background' option
 - dzsave --layout google has a @background option
-- use vips_mutex_new()/_free() over g_mutex_new()/_free()
+- update for new glib threading API
 - remove no threads option
 
 2/10/12 started 7.30.4

configure.in

@@ -318,9 +318,10 @@ AC_CHECK_LIB(m,hypot,[AC_DEFINE(HAVE_HYPOT,1,[have hypot() in libm.])])
 PKG_CHECK_MODULES(REQUIRED, glib-2.0 >= 2.6 gmodule-2.0 >= 2.4 libxml-2.0 gobject-2.0)
 PACKAGES_USED="$PACKAGES_USED glib-2.0 gmodule-2.0 libxml-2.0 gobject-2.0"
 
-# after 2.32 g_mutex_new() becomes g_mutex_init(), annoyingly
+# after 2.32 there are a new set of thread functions, annoyingly
 PKG_CHECK_MODULES(THREADS, glib-2.0 >= 2.32,[
   AC_DEFINE(HAVE_MUTEX_INIT,1,[define if your glib has g_mutex_init().])
+  AC_DEFINE(HAVE_COND_INIT,1,[define if your glib has g_cond_init().])
 ])
 
 # check for gtk-doc

libvips/conversion/sequential.c

@@ -101,7 +101,7 @@ vips_sequential_dispose( GObject *gobject )
 	VipsSequential *sequential = (VipsSequential *) gobject;
 
 	VIPS_FREEF( vips_mutex_free, sequential->lock );
-	VIPS_FREEF( g_cond_free, sequential->ready );
+	VIPS_FREEF( vips_cond_free, sequential->ready );
 
 	G_OBJECT_CLASS( vips_sequential_parent_class )->dispose( gobject );
 }
@@ -135,18 +135,16 @@ vips_sequential_generate( VipsRegion *or,
 
 	if( r->top > sequential->y_pos && 
 		sequential->y_pos > 0 ) {
-		GTimeVal time;
-
 		/* We have started reading (y_pos > 0) and this request is for 
 		 * stuff beyond that, stall for a short while to give other
 		 * threads time to catch up.
+		 *
+		 * The stall can be cancelled by a signal on @ready.
 		 */
 		VIPS_DEBUG_MSG( "thread %p stalling for up to %gs ...\n", 
 			STALL_TIME, g_thread_self() ); 
-		g_get_current_time( &time );
-		g_time_val_add( &time, STALL_TIME * 1000000 );
-		g_cond_timed_wait( sequential->ready, 
-			sequential->lock, &time );
+		vips_cond_timed_wait( sequential->ready, 
+			sequential->lock, STALL_TIME * 1000000 );
 		VIPS_DEBUG_MSG( "thread %p awake again ...\n", 
 			g_thread_self() ); 
 	}
@@ -156,7 +154,8 @@ vips_sequential_generate( VipsRegion *or,
 	 * above. 
 	 *
 	 * Probably the operation is something like extract_area and we should 
-	 * skip the initial part of the image. In fact, we read to cache.
+	 * skip the initial part of the image. In fact, we read to cache,
+	 * since it may be useful.
 	 */
 	if( r->top > sequential->y_pos ) {
 		VipsRect area;
@@ -294,7 +293,7 @@ vips_sequential_init( VipsSequential *sequential )
 {
 	sequential->trace = FALSE;
 	sequential->lock = vips_mutex_new();
-	sequential->ready = g_cond_new();
+	sequential->ready = vips_cond_new();
 	sequential->tile_height = 1;
 	sequential->error = 0;
 }

libvips/conversion/tilecache.c

@@ -145,7 +145,7 @@ vips_block_cache_dispose( GObject *gobject )
 
 	vips_block_cache_drop_all( cache );
 	VIPS_FREEF( vips_mutex_free, cache->lock );
-	VIPS_FREEF( g_cond_free, cache->new_tile );
+	VIPS_FREEF( vips_cond_free, cache->new_tile );
 
 	G_OBJECT_CLASS( vips_block_cache_parent_class )->dispose( gobject );
 }
@@ -490,7 +490,7 @@ vips_block_cache_init( VipsBlockCache *cache )
 	cache->time = 0;
 	cache->ntiles = 0;
 	cache->lock = vips_mutex_new();
-	cache->new_tile = g_cond_new();
+	cache->new_tile = vips_cond_new();
 	cache->tiles = g_hash_table_new_full( 
 		(GHashFunc) vips_rect_hash, 
 		(GEqualFunc) vips_rect_equal,

libvips/include/vips/thread.h

@@ -49,6 +49,12 @@ extern "C" {
 GMutex *vips_mutex_new( void );
 void vips_mutex_free( GMutex * );
 
+/* Same for GCond. And we need a wrapper for waiting too.
+ */
+GCond *vips_cond_new( void );
+void vips_cond_free( GCond * );
+void vips_cond_timed_wait( GCond *, GMutex *, gint64 );
+
 #ifdef __cplusplus
 }
 #endif /*__cplusplus*/

libvips/iofuncs/semaphore.c

@@ -59,14 +59,14 @@ vips_semaphore_init( VipsSemaphore *s, int v, char *name )
 	s->v = v;
 	s->name = name;
 	s->mutex = vips_mutex_new();
-	s->cond = g_cond_new();
+	s->cond = vips_cond_new();
 }
 
 void
 vips_semaphore_destroy( VipsSemaphore *s )
 {
 	VIPS_FREEF( vips_mutex_free, s->mutex );
-	VIPS_FREEF( g_cond_free, s->cond );
+	VIPS_FREEF( vips_cond_free, s->cond );
 }
 
 /* Add n to the semaphore and signal any threads that are blocked waiting 

libvips/iofuncs/threadpool.c

@@ -130,6 +130,52 @@ vips_mutex_free( GMutex *mutex )
 #endif
 }
 
+GCond *
+vips_cond_new( void )
+{
+	GCond *cond;
+
+#ifdef HAVE_COND_INIT
+	cond = g_new( GCond, 1 );
+	g_cond_init( cond );
+#else
+	cond = g_cond_new();
+#endif
+
+	return( cond );
+}
+
+void
+vips_cond_free( GCond *cond )
+{
+#ifdef HAVE_COND_INIT
+	g_cond_clear( cond );
+	g_free( cond );
+#else
+	g_cond_free( cond );
+#endif
+}
+
+/* Wait until cond is signalled, or timeout us have passed. 
+ *
+ * You can get spurious wakeups, use this in a loop.
+ */
+void 
+vips_cond_timed_wait( GCond *cond, GMutex *mutex, gint64 timeout )
+{
+#ifdef HAVE_COND_INIT
+	gint64 end_time = g_get_monotonic_time() + timeout;
+
+	g_cond_wait_until( cond, mutex, end_time );
+#else
+	GTimeVal time;
+
+	g_get_current_time( &time );
+	g_time_val_add( &time, timeout );
+	g_cond_timed_wait( cond, mutex, &time );
+#endif
+}
+
 /**
  * vips_concurrency_set:
  * @concurrency: number of threads to run