From a5620fd41f1ecb79eb1d14056cb1a8028aa56969 Mon Sep 17 00:00:00 2001
From: Rodrigo Tobar <rtobarc@gmail.com>
Date: Fri, 6 Jan 2023 00:41:44 +0800
Subject: [PATCH] LibPDF: Load destinations from Catalogue -> Names -> Dests
 name tree

PDF allows for named destinations to be provided as string. These can be
either found in the Dests dictionary in the document catalogue (as
already implemented), or in the Name Tree specified by the Dests key in
the Names dictionary of the document catalogue (missing).

This commit adds this missing case. Once the named destination is found
in the name tree, its value is interpreted just like in the first case,
so a new utility method encapsulates the common behavior.
---
 Userland/Libraries/LibPDF/Document.cpp | 34 ++++++++++++++++++--------
 Userland/Libraries/LibPDF/Document.h   |  1 +
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/Userland/Libraries/LibPDF/Document.cpp b/Userland/Libraries/LibPDF/Document.cpp
index acc43ef192..6097122ffc 100644
--- a/Userland/Libraries/LibPDF/Document.cpp
+++ b/Userland/Libraries/LibPDF/Document.cpp
@@ -315,6 +315,17 @@ PDFErrorOr<NonnullRefPtr<Object>> Document::get_inheritable_object(FlyString con
     return object->get_object(this, name);
 }
 
+PDFErrorOr<Destination> Document::create_destination_from_dictionary_entry(NonnullRefPtr<Object> const& entry, HashMap<u32, u32> const& page_number_by_index_ref)
+{
+    if (entry->is<ArrayObject>()) {
+        auto entry_array = entry->cast<ArrayObject>();
+        return create_destination_from_parameters(entry_array, page_number_by_index_ref);
+    }
+    auto entry_dictionary = entry->cast<DictObject>();
+    auto d_array = MUST(entry_dictionary->get_array(this, CommonNames::D));
+    return create_destination_from_parameters(d_array, page_number_by_index_ref);
+}
+
 PDFErrorOr<NonnullRefPtr<OutlineItem>> Document::build_outline_item(NonnullRefPtr<DictObject> const& outline_item_dict, HashMap<u32, u32> const& page_number_by_index_ref)
 {
     auto outline_item = adopt_ref(*new OutlineItem {});
@@ -340,19 +351,22 @@ PDFErrorOr<NonnullRefPtr<OutlineItem>> Document::build_outline_item(NonnullRefPt
         if (dest_obj->is<ArrayObject>()) {
             auto dest_arr = dest_obj->cast<ArrayObject>();
             outline_item->dest = TRY(create_destination_from_parameters(dest_arr, page_number_by_index_ref));
-        } else if (dest_obj->is<NameObject>()) {
-            auto dest_name = dest_obj->cast<NameObject>()->name();
+        } else if (dest_obj->is<NameObject>() || dest_obj->is<StringObject>()) {
+            FlyString dest_name;
+            if (dest_obj->is<NameObject>())
+                dest_name = dest_obj->cast<NameObject>()->name();
+            else
+                dest_name = dest_obj->cast<StringObject>()->string();
             if (auto dests_value = m_catalog->get(CommonNames::Dests); dests_value.has_value()) {
                 auto dests = dests_value.value().get<NonnullRefPtr<Object>>()->cast<DictObject>();
                 auto entry = MUST(dests->get_object(this, dest_name));
-                if (entry->is<ArrayObject>()) {
-                    auto entry_array = entry->cast<ArrayObject>();
-                    outline_item->dest = TRY(create_destination_from_parameters(entry_array, page_number_by_index_ref));
-                } else {
-                    auto entry_dictionary = entry->cast<DictObject>();
-                    auto d_array = MUST(entry_dictionary->get_array(this, CommonNames::D));
-                    outline_item->dest = TRY(create_destination_from_parameters(d_array, page_number_by_index_ref));
-                }
+                outline_item->dest = TRY(create_destination_from_dictionary_entry(entry, page_number_by_index_ref));
+            } else if (auto names_value = m_catalog->get(CommonNames::Names); names_value.has_value()) {
+                auto names = TRY(resolve(names_value.release_value())).get<NonnullRefPtr<Object>>()->cast<DictObject>();
+                if (!names->contains(CommonNames::Dests))
+                    return Error { Error::Type::MalformedPDF, "Missing Dests key in document catalogue's Names dictionary" };
+                auto dest_obj = TRY(find_in_name_tree(TRY(names->get_dict(this, CommonNames::Dests)), dest_name));
+                outline_item->dest = TRY(create_destination_from_dictionary_entry(dest_obj, page_number_by_index_ref));
             } else {
                 return Error { Error::Type::MalformedPDF, "Malformed outline destination" };
             }
diff --git a/Userland/Libraries/LibPDF/Document.h b/Userland/Libraries/LibPDF/Document.h
index 3b183ceab9..2074af9455 100644
--- a/Userland/Libraries/LibPDF/Document.h
+++ b/Userland/Libraries/LibPDF/Document.h
@@ -136,6 +136,7 @@ private:
     PDFErrorOr<NonnullRefPtrVector<OutlineItem>> build_outline_item_chain(Value const& first_ref, HashMap<u32, u32> const&);
 
     PDFErrorOr<Destination> create_destination_from_parameters(NonnullRefPtr<ArrayObject>, HashMap<u32, u32> const&);
+    PDFErrorOr<Destination> create_destination_from_dictionary_entry(NonnullRefPtr<Object> const& entry, HashMap<u32, u32> const& page_number_by_index_ref);
 
     PDFErrorOr<NonnullRefPtr<Object>> get_inheritable_object(FlyString const& name, NonnullRefPtr<DictObject>);