Implement annotation deletion, with necessary changes to partial update

4 files changed, 110 insertions, 0 deletions

diff --git a/pdf/mupdf-internal.h b/pdf/mupdf-internal.h
index 0a468939..4b58f911 100644
--- a/pdf/mupdf-internal.h
+++ b/pdf/mupdf-internal.h
@@ -548,6 +548,8 @@ struct pdf_page_s
 	fz_link *links;
 	pdf_annot *annots;
 	pdf_annot *changed_annots;
+	pdf_annot *deleted_annots;
+	pdf_annot *tmp_annots;
 	pdf_obj *me;
 	float duration;
 	int transition_present;
@@ -586,6 +588,7 @@ int pdf_choice_widget_is_multiselect(pdf_document *doc, fz_widget *tw);
 int pdf_choice_widget_value(pdf_document *doc, fz_widget *tw, char *opts[]);
 void pdf_choice_widget_set_value(pdf_document *doc, fz_widget *tw, int n, char *opts[]);
 pdf_annot *pdf_create_annot(pdf_document *doc, pdf_page *page, fz_annot_type type);
+void pdf_delete_annot(pdf_document *doc, pdf_page *page, pdf_annot *annot);
 void pdf_set_annot_appearance(pdf_document *doc, pdf_annot *annot, fz_display_list *disp_list);
 void pdf_set_doc_event_callback(pdf_document *doc, fz_doc_event_cb *event_cb, void *data);
 
diff --git a/pdf/pdf_annot.c b/pdf/pdf_annot.c
index 7201045f..aa56e056 100644
--- a/pdf/pdf_annot.c
+++ b/pdf/pdf_annot.c
@@ -671,6 +671,76 @@ pdf_create_annot(pdf_document *doc, pdf_page *page, fz_annot_type type)
 }
 
 void
+pdf_delete_annot(pdf_document *doc, pdf_page *page, pdf_annot *annot)
+{
+	fz_context *ctx = doc->ctx;
+	pdf_annot **annotptr;
+	pdf_obj *old_annot_arr;
+	pdf_obj *annot_arr;
+
+	if (annot == NULL)
+		return;
+
+	/* Remove annot from page's list */
+	for (annotptr = &page->annots; *annotptr; annotptr = &(*annotptr)->next)
+	{
+		if (*annotptr == annot)
+			break;
+	}
+
+	/* Check the passed annotation was of this page */
+	if (*annotptr == NULL)
+		return;
+
+	*annotptr = annot->next;
+
+	/* Stick it in the deleted list */
+	annot->next = page->deleted_annots;
+	page->deleted_annots = annot;
+
+	pdf_drop_xobject(ctx, annot->ap);
+	annot->ap = NULL;
+
+	/* Recreate the "Annots" array with this annot removed */
+	old_annot_arr = pdf_dict_gets(page->me, "Annots");
+
+	if (old_annot_arr)
+	{
+		int i, n = pdf_array_len(old_annot_arr);
+		annot_arr = pdf_new_array(ctx, n?(n-1):0);
+
+		fz_try(ctx)
+		{
+			for (i = 0; i < n; i++)
+			{
+				pdf_obj *obj = pdf_array_get(old_annot_arr, i);
+
+				if (obj != annot->obj)
+					pdf_array_push(annot_arr, obj);
+			}
+
+			/*
+			Overwrite "Annots" in the page dictionary, which has the
+			side-effect of releasing the last reference to old_annot_arr
+			*/
+			pdf_dict_puts(page->me, "Annots", annot_arr);
+		}
+		fz_always(ctx)
+		{
+			pdf_drop_obj(annot_arr);
+		}
+		fz_catch(ctx)
+		{
+			fz_rethrow(ctx);
+		}
+	}
+
+	pdf_drop_obj(annot->obj);
+	annot->obj = NULL;
+	doc->dirty = 1;
+}
+
+void
 pdf_set_annot_appearance(pdf_document *doc, pdf_annot *annot, fz_display_list *disp_list)
 {
 	fz_context *ctx = doc->ctx;
diff --git a/pdf/pdf_form.c b/pdf/pdf_form.c
index eddf2326..5ad5e845 100644
--- a/pdf/pdf_form.c
+++ b/pdf/pdf_form.c
@@ -2160,7 +2160,20 @@ void pdf_update_page(pdf_document *doc, pdf_page *page)
 	fz_context *ctx = doc->ctx;
 	pdf_annot *annot;
 
+	/* Reset changed_annots to empty */
 	page->changed_annots = NULL;
+
+	/*
+		Free all annots in tmp_annots, since these were
+		referenced only from changed_annots.
+	*/
+	if (page->tmp_annots)
+	{
+		pdf_free_annot(ctx, page->tmp_annots);
+		page->tmp_annots = NULL;
+	}
+
+	/* Add all changed annots to the list */
 	for (annot = page->annots; annot; annot = annot->next)
 	{
 		pdf_xobject *ap = pdf_keep_xobject(ctx, annot->ap);
@@ -2185,6 +2198,24 @@ void pdf_update_page(pdf_document *doc, pdf_page *page)
 			fz_rethrow(ctx);
 		}
 	}
+
+	/*
+		Add all deleted annots to the list, since these also
+		warrant a screen update
+	*/
+	for (annot = page->deleted_annots; annot; annot = annot->next)
+	{
+		annot->next_changed = page->changed_annots;
+		page->changed_annots = annot;
+	}
+
+	/*
+		Move deleted_annots to tmp_annots to keep them separate
+		from any future deleted ones. They cannot yet be freed
+		since they are linked into changed_annots
+	*/
+	page->tmp_annots = page->deleted_annots;
+	page->deleted_annots = NULL;
 }
 
 pdf_annot *pdf_poll_changed_annot(pdf_document *idoc, pdf_page *page)
diff --git a/pdf/pdf_page.c b/pdf/pdf_page.c
index a3627176..5d6d6bca 100644
--- a/pdf/pdf_page.c
+++ b/pdf/pdf_page.c
@@ -355,6 +355,8 @@ pdf_load_page(pdf_document *xref, int number)
 	page->transparency = 0;
 	page->links = NULL;
 	page->annots = NULL;
+	page->deleted_annots = NULL;
+	page->tmp_annots = NULL;
 	page->me = pdf_keep_obj(pageobj);
 
 	obj = pdf_dict_gets(pageobj, "UserUnit");
@@ -472,6 +474,10 @@ pdf_free_page(pdf_document *xref, pdf_page *page)
 		fz_drop_link(xref->ctx, page->links);
 	if (page->annots)
 		pdf_free_annot(xref->ctx, page->annots);
+	if (page->deleted_annots)
+		pdf_free_annot(xref->ctx, page->deleted_annots);
+	if (page->tmp_annots)
+		pdf_free_annot(xref->ctx, page->tmp_annots);
 	/* xref->focus, when not NULL, refers to one of
 	 * the annotations and must be NULLed when the
 	 * annotations are destroyed. xref->focus_obj