oops upstream/downstream typo

TODO

@@ -1,24 +1,3 @@
-- add a dependency on the icc-profiles package
- 
-  the vips load/save ops need to search the icc-profile dir 
-
-  where is it? is there a pkg-config for it?
-
-  no, just dumps profiles into /usr/share/color/icc
-
-  configure should test for the dir? what's the equivalent dir on Windows? we
-  also have nip2's dir
-
-  Windows:
-
-  	C:\Windows\System32\spool\drivers\color
-
-  OS X
-
-  	/Library/ColorSync/Profiles
-
-  added VIPS_ICC_DIR to configure.in, need to search this in format operations
-
 - doing im_create_fmask() and friends
 
 - how about im_invalidate_area()? we currently repaint the whole window on

libvips/include/vips/debug.h

@@ -59,6 +59,7 @@ im_demand_type im_char2dhint( const char *str );
 
 void im_printdesc( IMAGE *image );
 int im_image_sanity( IMAGE *im );
+void im_image_sanity_all( void );
 
 #ifdef __cplusplus
 }

libvips/iofuncs/debug.c

@@ -446,6 +446,22 @@ im__print_one( int n )
 	im_printdesc( im );
 }
 
+static void *
+sanity_upstream( IMAGE *im_up, IMAGE *im_down )
+{
+	if( !g_slist_find( im_up->downstream, im_down ) ||
+		!g_slist_find( im_down->upstream, im_up ) )
+		return( im_up );
+
+	return( NULL );
+}
+
+static void *
+sanity_downstream( IMAGE *im_down, IMAGE *im_up )
+{
+	return( sanity_upstream( im_up, im_down ) );
+}
+
 /* Test an image for sanity. We could add many more tests here.
  */
 static const char *
@@ -463,20 +479,34 @@ image_sanity( IMAGE *im )
 	}
 	g_mutex_unlock( im__global_lock );
 
-	if( im->Xsize <= 0 || im->Ysize <= 0 || im->Bands <= 0 ) 
-		return( "bad dimensions" );
-	if( im->BandFmt < -1 || im->BandFmt > IM_BANDFMT_DPCOMPLEX ||
-		(im->Coding != -1 &&
-			im->Coding != IM_CODING_NONE && 
-			im->Coding != IM_CODING_LABQ &&
-			im->Coding != IM_CODING_RAD) ||
-		im->Type > IM_TYPE_GREY16 )
-		return( "bad enum value" );
-	if( im->dtype > IM_PARTIAL || 
-		im->dhint > IM_ANY ) 
-		return( "bad enum value" );
-	if( im->Xres < 0 || im->Xres < 0 ) 
-		return( "bad resolution" );
+	/* All -1 means im has been inited but never used.
+	 */
+	if( im->Xsize != -1 ||
+		im->Ysize != -1 ||
+		im->Bands != -1 ||
+		im->BandFmt != -1 ) {
+		if( im->Xsize <= 0 || im->Ysize <= 0 || im->Bands <= 0 ) 
+			return( "bad dimensions" );
+		if( im->BandFmt < -1 || im->BandFmt > IM_BANDFMT_DPCOMPLEX ||
+			(im->Coding != -1 &&
+				im->Coding != IM_CODING_NONE && 
+				im->Coding != IM_CODING_LABQ &&
+				im->Coding != IM_CODING_RAD) ||
+			im->Type > IM_TYPE_GREY16 )
+			return( "bad enum value" );
+		if( im->dtype > IM_PARTIAL || 
+			im->dhint > IM_ANY ) 
+			return( "bad enum value" );
+		if( im->Xres < 0 || im->Xres < 0 ) 
+			return( "bad resolution" );
+	}
+
+	if( im_slist_map2( im->upstream, 
+		(VSListMap2Fn) sanity_upstream, im, NULL ) )
+		return( "upstream broken" );
+	if( im_slist_map2( im->downstream, 
+		(VSListMap2Fn) sanity_downstream, im, NULL ) )
+		return( "downstream broken" );
 
 	return( NULL );
 }
@@ -498,3 +528,10 @@ im_image_sanity( IMAGE *im )
 
 	return( 0 );
 }
+
+void
+im_image_sanity_all( void )
+{
+	g_assert( im_slist_map2( im__open_images, 
+		(VSListMap2Fn) im_image_sanity, NULL, NULL ) == 0 );
+}

libvips/iofuncs/im_demand_hint.c

@@ -59,6 +59,7 @@
 
 #include <vips/vips.h>
 #include <vips/internal.h>
+#include <vips/debug.h>
 
 #ifdef WITH_DMALLOC
 #include <dmalloc.h>
@@ -77,7 +78,7 @@ im__link_make( IMAGE *im_up, IMAGE *im_down )
 	g_assert( im_down );
 
 	im_up->downstream = g_slist_prepend( im_up->downstream, im_down );
-	im_down->upstream = g_slist_prepend( im_down->downstream, im_up );
+	im_down->upstream = g_slist_prepend( im_down->upstream, im_up );
 
 	/* Propogate the progress indicator.
 	 */
@@ -119,6 +120,9 @@ im__link_break_all( IMAGE *im )
 		(VSListMap2Fn) im__link_break, im, NULL );
 	im_slist_map2( im->downstream, 
 		(VSListMap2Fn) im__link_break_rev, im, NULL );
+
+	g_assert( !im->upstream );
+	g_assert( !im->downstream );
 }
 
 static void *