Tweak store handling of PDF document destroy.

When we destroy a PDF document, currently we bin everything
from the store. Instead, drop just the objects that are
specifically tied to that document.

Any object tied to the document has a pdf_obj with the
required document pointer in it as the key.

3 files changed, 20 insertions, 1 deletions

diff --git a/include/mupdf/pdf/resource.h b/include/mupdf/pdf/resource.h
index f9f99da6..5c19f35a 100644
--- a/include/mupdf/pdf/resource.h
+++ b/include/mupdf/pdf/resource.h
@@ -7,6 +7,7 @@
 void pdf_store_item(fz_context *ctx, pdf_obj *key, void *val, size_t itemsize);
 void *pdf_find_item(fz_context *ctx, fz_store_drop_fn *drop, pdf_obj *key);
 void pdf_remove_item(fz_context *ctx, fz_store_drop_fn *drop, pdf_obj *key);
+void pdf_empty_store(fz_context *ctx, pdf_document *doc);
 
 /*
  * Structures used for managing resource locations and avoiding multiple
diff --git a/source/pdf/pdf-store.c b/source/pdf/pdf-store.c
index fa5cf76e..ccedbe0b 100644
--- a/source/pdf/pdf-store.c
+++ b/source/pdf/pdf-store.c
@@ -54,6 +54,8 @@ void
 pdf_store_item(fz_context *ctx, pdf_obj *key, void *val, size_t itemsize)
 {
 	void *existing;
+
+	assert(pdf_is_array(ctx, key) || pdf_is_dict(ctx, key) || pdf_is_indirect(ctx, key));
 	existing = fz_store_item(ctx, key, val, itemsize, &pdf_obj_store_type);
 	assert(existing == NULL);
 	(void)existing; /* Silence warning in release builds */
@@ -70,3 +72,19 @@ pdf_remove_item(fz_context *ctx, fz_store_drop_fn *drop, pdf_obj *key)
 {
 	fz_remove_item(ctx, drop, key, &pdf_obj_store_type);
 }
+
+static int
+pdf_filter_store(fz_context *ctx, void *doc_, void *key)
+{
+	pdf_document *doc = (pdf_document *)doc_;
+	pdf_obj *obj = (pdf_obj *)key;
+	pdf_document *key_doc = pdf_get_bound_document(ctx, obj);
+
+	return (doc == key_doc);
+}
+
+void
+pdf_empty_store(fz_context *ctx, pdf_document *doc)
+{
+	fz_filter_store(ctx, pdf_filter_store, doc, &pdf_obj_store_type);
+}
diff --git a/source/pdf/pdf-xref.c b/source/pdf/pdf-xref.c
index 30904d78..2d6bc1e0 100644
--- a/source/pdf/pdf-xref.c
+++ b/source/pdf/pdf-xref.c
@@ -1610,7 +1610,7 @@ pdf_drop_document_imp(fz_context *ctx, pdf_document *doc)
 
 	pdf_drop_ocg(ctx, doc->ocg);
 
-	fz_empty_store(ctx);
+	pdf_empty_store(ctx, doc);
 
 	pdf_lexbuf_fin(ctx, &doc->lexbuf.base);