From f646e47d4624260d8583ddd5c349d58250399d98 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Mon, 16 Oct 2023 21:18:01 -0400
Subject: [PATCH] LibPDF: Extract a create_destination_from_object() function

No big behavior change. The new function now produces an error
if a destination isn't in one of the supported formats.
---
 Userland/Libraries/LibPDF/Document.cpp | 56 +++++++++++++++-----------
 Userland/Libraries/LibPDF/Document.h   |  1 +
 2 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/Userland/Libraries/LibPDF/Document.cpp b/Userland/Libraries/LibPDF/Document.cpp
index d5b3c671df..1c2402780a 100644
--- a/Userland/Libraries/LibPDF/Document.cpp
+++ b/Userland/Libraries/LibPDF/Document.cpp
@@ -487,6 +487,37 @@ PDFErrorOr<Destination> Document::create_destination_from_dictionary_entry(Nonnu
     return create_destination_from_parameters(d_array, page_number_by_index_ref);
 }
 
+PDFErrorOr<Destination> Document::create_destination_from_object(NonnullRefPtr<Object> const& dest_obj, HashMap<u32, u32> const& page_number_by_index_ref)
+{
+    // PDF 1.7 spec, "8.2.1 Destinations"
+    if (dest_obj->is<ArrayObject>()) {
+        auto dest_arr = dest_obj->cast<ArrayObject>();
+        return TRY(create_destination_from_parameters(dest_arr, page_number_by_index_ref));
+    }
+
+    if (dest_obj->is<NameObject>() || dest_obj->is<StringObject>()) {
+        DeprecatedFlyString 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));
+            return TRY(create_destination_from_dictionary_entry(entry, page_number_by_index_ref));
+        }
+        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));
+            return TRY(create_destination_from_dictionary_entry(dest_obj, page_number_by_index_ref));
+        }
+    }
+
+    return Error { Error::Type::MalformedPDF, "Malformed outline destination" };
+}
+
 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 {});
@@ -508,30 +539,7 @@ PDFErrorOr<NonnullRefPtr<OutlineItem>> Document::build_outline_item(NonnullRefPt
 
     if (outline_item_dict->contains(CommonNames::Dest)) {
         auto dest_obj = TRY(outline_item_dict->get_object(this, CommonNames::Dest));
-
-        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>() || dest_obj->is<StringObject>()) {
-            DeprecatedFlyString 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));
-                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" };
-            }
-        }
+        outline_item->dest = TRY(create_destination_from_object(dest_obj, page_number_by_index_ref));
     }
 
     if (outline_item_dict->contains(CommonNames::C)) {
diff --git a/Userland/Libraries/LibPDF/Document.h b/Userland/Libraries/LibPDF/Document.h
index 0c6c7298b4..3328e40f49 100644
--- a/Userland/Libraries/LibPDF/Document.h
+++ b/Userland/Libraries/LibPDF/Document.h
@@ -166,6 +166,7 @@ private:
 
     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<Destination> create_destination_from_object(NonnullRefPtr<Object> const& dest_obj, HashMap<u32, u32> const& page_number_by_index_ref);
 
     PDFErrorOr<Optional<NonnullRefPtr<Object>>> get_inheritable_object(DeprecatedFlyString const& name, NonnullRefPtr<DictObject>);
     PDFErrorOr<Optional<Value>> get_inheritable_value(DeprecatedFlyString const& name, NonnullRefPtr<DictObject>);