try to stop vips-n-xxx.v files being left in tmp

On Windows, set _O_TEMPORARY. On *nix, unlink after rewind.

ChangeLog

@@ -43,6 +43,8 @@
 - VipsStats tracks minpos/maxpos as well
 - moved mask/ to deprecated
 - use atexit() to call vips_shutdown()
+- set _O_TEMPORARY on delete-on-close temp images if possible
+- unlink temps on rewind on *nix, less likely to leave temps on a crash
 
 12/10/11 started 7.26.6
 - NOCACHE was not being set correctly on OS X causing performance 

TODO

@@ -17,6 +17,9 @@
 
 
 
+- test _O_TEMPORARY thing on Windows
+
+
 
 - avg/dev etc. should uncode images? eg. labq2lab etc.
 

libvips/iofuncs/image.c

@@ -167,6 +167,20 @@ static guint vips_image_signals[SIG_LAST] = { 0 };
 
 G_DEFINE_TYPE( VipsImage, vips_image, VIPS_TYPE_OBJECT );
 
+static void
+vips_image_delete( VipsImage *image )
+{
+	if( image->delete_on_close ) {
+		g_assert( image->delete_on_close_filename );
+
+		VIPS_DEBUG_MSG( "vips_image_delete: removing temp %s\n", 
+				image->delete_on_close_filename );
+		g_unlink( image->delete_on_close_filename );
+		VIPS_FREE( image->delete_on_close_filename );
+		image->delete_on_close = FALSE;
+	}
+}
+
 static void
 vips_image_finalize( GObject *gobject )
 {
@@ -215,15 +229,9 @@ vips_image_finalize( GObject *gobject )
 		image->data = NULL;
 	}
 
-	if( image->delete_on_close ) {
-		g_assert( image->delete_on_close_filename );
-
-		VIPS_DEBUG_MSG( "vips_image_finalize: removing temp %s\n", 
-				image->delete_on_close_filename );
-		g_unlink( image->delete_on_close_filename );
-		VIPS_FREE( image->delete_on_close_filename );
-		image->delete_on_close = FALSE;
-	}
+	/* If this is a temp, delete it.
+	 */
+	vips_image_delete( image );
 
 	VIPS_FREEF( g_mutex_free, image->sslock );
 
@@ -2003,6 +2011,19 @@ vips_image_rewind_output( VipsImage *image )
 		return( -1 );
 	}
 
+	/* Now we've finished writing and reopened as read, we can
+	 * delete-on-close. 
+	 *
+	 * On *nix-like systems, this will unlink the file
+	 * from the filesystem and when we exit, for whatever reason, the file
+	 * we be reclaimed. 
+	 *
+	 * On Windows this will fail because the file is open and you can't
+	 * delete open files. However, on Windows we set O_TEMP, so the file
+	 * will be deleted anyway on exit.
+	 */
+	vips_image_delete( image );
+
 	return( 0 );
 }
 

libvips/iofuncs/vips.c

@@ -952,9 +952,21 @@ vips_image_open_output( VipsImage *image )
 		 * writing a VIPS image anyway.
 		 */
 		unsigned char header[VIPS_SIZEOF_HEADER];
+		int flags;
+
+		flags = MODE_WRITE;
+
+		/* On Windows, setting O_TEMP gets the file automatically
+		 * deleted on process exit, even if the processes crashes. See
+		 * vips_image_rewind() for what we do to help on *nix.
+		 */
+#ifdef _O_TEMPORARY
+		if( image->delete_on_close )
+			flags |= _O_TEMPORARY;
+#endif /*_O_TEMPORARY*/
 
 		if( (image->fd = vips_tracked_open( image->filename, 
-			MODE_WRITE, 0666 )) < 0 ) {
+			flags, 0666 )) < 0 ) {
 			vips_error_system( errno, "VipsImage", 
 				_( "unable to write to \"%s\"" ), 
 				image->filename );