XPS tweaks/fixes.

xps_parse_resource_dictionary can now warn and return NULL when reading
an empty dictionary, rather than throwing an error.

Various bits of code are therefore updated to check for a NULL return
value.

We should cope better with multiple Resource dictionaries.

Tweak to the zip file handling when looking for parts.

Again, all from (or inspired by) Zenikos patch.

3 files changed, 17 insertions, 5 deletions

diff --git a/xps/xps_resource.c b/xps/xps_resource.c
index fad60488..cfac562d 100644
--- a/xps/xps_resource.c
+++ b/xps/xps_resource.c
@@ -80,7 +80,8 @@ xps_parse_remote_resource_dictionary(xps_document *doc, char *base_uri, char *so
 		s[1] = 0;
 
 	dict = xps_parse_resource_dictionary(doc, part_uri, xml);
-	dict->base_xml = xml; /* pass on ownership */
+	if (dict)
+		dict->base_xml = xml; /* pass on ownership */
 
 	return dict;
 }
@@ -119,7 +120,7 @@ xps_parse_resource_dictionary(xps_document *doc, char *base_uri, xml_element *ro
 	if (head)
 		head->base_uri = fz_strdup(doc->ctx, base_uri);
 	else
-		fz_throw(doc->ctx, "empty resource dictionary");
+		fz_warn(doc->ctx, "empty resource dictionary");
 
 	return head;
 }
diff --git a/xps/xps_tile.c b/xps/xps_tile.c
index 04c613a4..1acdd369 100644
--- a/xps/xps_tile.c
+++ b/xps/xps_tile.c
@@ -269,11 +269,16 @@ xps_parse_canvas(xps_document *doc, fz_matrix ctm, fz_rect area, char *base_uri,
 
 	for (node = xml_down(root); node; node = xml_next(node))
 	{
+		/* FIXME: Sumatra warns of memory leak here where we have multiple
+		 * Canvas.Resources. */
 		if (!strcmp(xml_tag(node), "Canvas.Resources") && xml_down(node))
 		{
 			new_dict = xps_parse_resource_dictionary(doc, base_uri, xml_down(node));
-			new_dict->parent = dict;
-			dict = new_dict;
+			if (new_dict)
+			{
+				new_dict->parent = dict;
+				dict = new_dict;
+			}
 		}
 
 		if (!strcmp(xml_tag(node), "Canvas.RenderTransform"))
@@ -341,6 +346,8 @@ xps_parse_fixed_page(xps_document *doc, fz_matrix ctm, xps_page *page)
 
 	for (node = xml_down(page->root); node; node = xml_next(node))
 	{
+		/* FIXME: Sumatra warns of memory leak here where we have multiple
+		 * FixedPage.Resources. */
 		if (!strcmp(xml_tag(node), "FixedPage.Resources") && xml_down(node))
 			dict = xps_parse_resource_dictionary(doc, base_uri, xml_down(node));
 		xps_parse_element(doc, ctm, area, base_uri, dict, node);
diff --git a/xps/xps_zip.c b/xps/xps_zip.c
index 7bc90319..04e37f4f 100644
--- a/xps/xps_zip.c
+++ b/xps/xps_zip.c
@@ -256,6 +256,7 @@ xps_read_zip_part(xps_document *doc, char *partname)
 	xps_part *part;
 	int count, size, offset, i;
 	char *name;
+	int seen_last = 0;
 
 	name = partname;
 	if (name[0] == '/')
@@ -273,7 +274,7 @@ xps_read_zip_part(xps_document *doc, char *partname)
 	/* Count the number of pieces and their total size */
 	count = 0;
 	size = 0;
-	while (1)
+	while (!seen_last)
 	{
 		sprintf(buf, "%s/[%d].piece", name, count);
 		ent = xps_find_zip_entry(doc, buf);
@@ -281,12 +282,15 @@ xps_read_zip_part(xps_document *doc, char *partname)
 		{
 			sprintf(buf, "%s/[%d].last.piece", name, count);
 			ent = xps_find_zip_entry(doc, buf);
+			seen_last = (ent != NULL);
 		}
 		if (!ent)
 			break;
 		count ++;
 		size += ent->usize;
 	}
+	if (!seen_last)
+		fz_throw(doc->ctx, "cannot find all pieces for part '%s'", partname);
 
 	/* Inflate the pieces */
 	if (count)