Forms: improve cpp/c interface regarding exceptions

Three alterations:
We were previously being careful to avoid throwing exceptions in
the DOM-implementation callbacks because these were being called
directly from C++. This commit adds three veneers that turn exceptions
into warnings, hence allowing the callbacks to be written in usual
mupdf style.

Protect the "field" callbacks from executing with a NULL field.

Ensure that the event object is set up before executing A actions

1 files changed, 6 insertions, 2 deletions

diff --git a/pdf/pdf_form.c b/pdf/pdf_form.c
index 2fb8114c..76e28058 100644
--- a/pdf/pdf_form.c
+++ b/pdf/pdf_form.c
@@ -1737,9 +1737,13 @@ void pdf_update_appearance(pdf_document *doc, pdf_obj *obj)
 
 static void execute_action_chain(pdf_document *doc, pdf_obj *obj)
 {
-	pdf_obj *a;
+	pdf_obj *a = pdf_dict_gets(obj, "A");
+	pdf_js_event e;
+
+	e.target = obj;
+	e.value = "";
+	pdf_js_setup_event(doc->js, &e);
 
-	a = pdf_dict_gets(obj, "A");
 	while (a)
 	{
 		execute_action(doc, obj, a);