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LibPDF: Add method to Document to dump a Page and all related objects

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...except for the /Parent object, else we'd print all pages :)
This commit is contained in:
Nico Weber 2023-07-12 12:21:41 -04:00 • committed by Andreas Kling
parent b4c5a7d1a0
commit ca433befa0
2 changed files with 62 additions and 0 deletions
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61
Userland/Libraries/LibPDF/Document.cpp
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@ -136,6 +136,67 @@ u32 Document::get_page_count() const
return m_page_object_indices.size();
}
static ErrorOr<void> collect_referenced_indices(Value const& value, Vector<int>& referenced_indices)
{
TRY(value.visit(
[&](Empty const&) -> ErrorOr<void> { return {}; },
[&](nullptr_t const&) -> ErrorOr<void> { return {}; },
[&](bool const&) -> ErrorOr<void> { return {}; },
[&](int const&) -> ErrorOr<void> { return {}; },
[&](float const&) -> ErrorOr<void> { return {}; },
[&](Reference const& ref) -> ErrorOr<void> {
TRY(referenced_indices.try_append(ref.as_ref_index()));
return {};
},
[&](NonnullRefPtr<Object> const& object) -> ErrorOr<void> {
if (object->is<ArrayObject>()) {
for (auto& element : object->cast<ArrayObject>()->elements())
TRY(collect_referenced_indices(element, referenced_indices));
} else if (object->is<DictObject>()) {
for (auto& [key, value] : object->cast<DictObject>()->map()) {
if (key != CommonNames::Parent)
TRY(collect_referenced_indices(value, referenced_indices));
}
} else if (object->is<StreamObject>()) {
for (auto& [key, value] : object->cast<StreamObject>()->dict()->map()) {
if (key != CommonNames::Parent)
TRY(collect_referenced_indices(value, referenced_indices));
}
}
return {};
}));
return {};
}
static PDFErrorOr<void> dump_tree(Document& document, size_t index, HashTable<int>& seen)
{
if (seen.contains(index))
return {};
seen.set(index);
auto const& value = TRY(document.get_or_load_value(index));
outln("obj {} 0", index);
outln("{}", value.to_deprecated_string(0));
outln("endobj");
Vector<int> referenced_indices;
TRY(collect_referenced_indices(value, referenced_indices));
for (auto index : referenced_indices)
TRY(dump_tree(document, index, seen));
return {};
}
PDFErrorOr<void> Document::dump_page(u32 index)
{
VERIFY(index < m_page_object_indices.size());
auto page_object_index = m_page_object_indices[index];
HashTable<int> seen;
TRY(dump_tree(*this, page_object_index, seen));
return {};
}
PDFErrorOr<Page> Document::get_page(u32 index)
{
VERIFY(index < m_page_object_indices.size());