ladybird/Userland/Libraries/LibPDF/Document.h
Ali Mohammad Pur 78c04cb8b2 AK+LibPDF: Make Format print floats in a roundtrip-safe way by default
Previously we assumed a default precision of 6, which made the printed
values quite odd in some cases.
This commit changes that default to print them with just enough
precision to produce the exact same float when roundtripped.

This commit adds some new tests that assert exact format outputs, which
have to be modified if we decide to change the default behaviour.
2023-10-31 09:12:35 +03:30

268 lines
9.4 KiB
C++

/*
* Copyright (c) 2021-2022, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Format.h>
#include <AK/HashMap.h>
#include <AK/RefCounted.h>
#include <AK/Weakable.h>
#include <LibGfx/Color.h>
#include <LibPDF/DocumentParser.h>
#include <LibPDF/Encryption.h>
#include <LibPDF/Error.h>
#include <LibPDF/ObjectDerivatives.h>
#include <LibPDF/Page.h>
namespace PDF {
struct Destination {
enum class Type {
XYZ,
Fit,
FitH,
FitV,
FitR,
FitB,
FitBH,
FitBV,
};
Type type;
Optional<u32> page;
Vector<Optional<float>> parameters;
};
struct OutlineItem final : public RefCounted<OutlineItem> {
RefPtr<OutlineItem> parent;
Vector<NonnullRefPtr<OutlineItem>> children;
DeprecatedString title;
i32 count { 0 };
Destination dest;
Gfx::Color color { Color::NamedColor::Black }; // 'C' in the PDF spec
bool italic { false }; // bit 0 of 'F' in the PDF spec
bool bold { false }; // bit 0 of 'F' in the PDF spec
OutlineItem() = default;
DeprecatedString to_deprecated_string(int indent) const;
};
struct OutlineDict final : public RefCounted<OutlineDict> {
Vector<NonnullRefPtr<OutlineItem>> children;
u32 count { 0 };
OutlineDict() = default;
};
class InfoDict {
public:
InfoDict(Document* document, NonnullRefPtr<DictObject> dict)
: m_document(document)
, m_info_dict(move(dict))
{
}
PDFErrorOr<Optional<DeprecatedString>> title() const;
PDFErrorOr<Optional<DeprecatedString>> author() const;
PDFErrorOr<Optional<DeprecatedString>> subject() const;
PDFErrorOr<Optional<DeprecatedString>> keywords() const;
// Name of the program that created the original, non-PDF file.
PDFErrorOr<Optional<DeprecatedString>> creator() const;
// Name of the program that converted the file to PDF.
PDFErrorOr<Optional<DeprecatedString>> producer() const;
// FIXME: Provide some helper for parsing the date strings returned by these two methods.
PDFErrorOr<Optional<DeprecatedString>> creation_date() const;
PDFErrorOr<Optional<DeprecatedString>> modification_date() const;
private:
PDFErrorOr<Optional<DeprecatedString>> get(DeprecatedFlyString const& name) const
{
if (!m_info_dict->contains(name))
return OptionalNone {};
return TRY(m_info_dict->get_string(m_document, name))->string();
}
WeakPtr<Document> m_document;
NonnullRefPtr<DictObject> m_info_dict;
};
class Document final
: public RefCounted<Document>
, public Weakable<Document> {
public:
static PDFErrorOr<NonnullRefPtr<Document>> create(ReadonlyBytes bytes);
// If a security handler is present, it is the caller's responsibility to ensure
// this document is unencrypted before calling this function. The user does not
// need to handle the case where the user password is the empty string.
PDFErrorOr<void> initialize();
Version version() const { return m_version; }
ALWAYS_INLINE RefPtr<SecurityHandler> const& security_handler() const { return m_security_handler; }
ALWAYS_INLINE RefPtr<OutlineDict> const& outline() const { return m_outline; }
ALWAYS_INLINE RefPtr<DictObject> const& trailer() const { return m_trailer; }
[[nodiscard]] PDFErrorOr<Value> get_or_load_value(u32 index);
[[nodiscard]] u32 get_first_page_index() const;
[[nodiscard]] u32 get_page_count() const;
PDFErrorOr<void> dump_page(u32 index);
[[nodiscard]] PDFErrorOr<Page> get_page(u32 index);
ALWAYS_INLINE Value get_value(u32 index) const
{
return m_values.get(index).value_or({});
}
// Strips away the layer of indirection by turning indirect value
// refs into the value they reference, and indirect values into
// the value being wrapped.
PDFErrorOr<Value> resolve(Value const& value);
// Like resolve, but unwraps the Value into the given type. Accepts
// any object type, and the three primitive Value types.
template<IsValueType T>
PDFErrorOr<UnwrappedValueType<T>> resolve_to(Value const& value)
{
return cast_to<T>(TRY(resolve(value)));
}
/// Whether this Document is ready to resolve references, which is usually
/// true, except just before the XRef table is parsed (and while the linearization
/// dict is being read).
bool can_resolve_references() { return m_parser->can_resolve_references(); }
PDFErrorOr<Optional<InfoDict>> info_dict();
PDFErrorOr<Vector<DeprecatedFlyString>> read_filters(NonnullRefPtr<DictObject>);
private:
explicit Document(NonnullRefPtr<DocumentParser> const& parser);
// FIXME: Currently, to improve performance, we don't load any pages at Document
// construction, rather we just load the page structure and populate
// m_page_object_indices. However, we can be even lazier and defer page tree node
// parsing, as good PDF writers will layout the page tree in a balanced tree to
// improve lookup time. This would reduce the initial overhead by not loading
// every page tree node of, say, a 1000+ page PDF file.
PDFErrorOr<void> build_page_tree();
PDFErrorOr<void> add_page_tree_node_to_page_tree(NonnullRefPtr<DictObject> const& page_tree);
PDFErrorOr<void> build_outline();
PDFErrorOr<NonnullRefPtr<OutlineItem>> build_outline_item(NonnullRefPtr<DictObject> const& outline_item_dict, HashMap<u32, u32> const&);
PDFErrorOr<Vector<NonnullRefPtr<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<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>);
PDFErrorOr<NonnullRefPtr<Object>> find_in_name_tree(NonnullRefPtr<DictObject> root, DeprecatedFlyString name);
PDFErrorOr<NonnullRefPtr<Object>> find_in_name_tree_nodes(NonnullRefPtr<ArrayObject> siblings, DeprecatedFlyString name);
PDFErrorOr<NonnullRefPtr<Object>> find_in_key_value_array(NonnullRefPtr<ArrayObject> key_value_array, DeprecatedFlyString name);
NonnullRefPtr<DocumentParser> m_parser;
Version m_version;
RefPtr<DictObject> m_catalog;
RefPtr<DictObject> m_trailer;
Vector<u32> m_page_object_indices;
HashMap<u32, Page> m_pages;
HashMap<u32, Value> m_values;
RefPtr<OutlineDict> m_outline;
RefPtr<SecurityHandler> m_security_handler;
};
}
namespace AK {
template<>
struct Formatter<PDF::Destination> : Formatter<FormatString> {
ErrorOr<void> format(FormatBuilder& builder, PDF::Destination const& destination)
{
StringView type_str;
switch (destination.type) {
case PDF::Destination::Type::XYZ:
type_str = "XYZ"sv;
break;
case PDF::Destination::Type::Fit:
type_str = "Fit"sv;
break;
case PDF::Destination::Type::FitH:
type_str = "FitH"sv;
break;
case PDF::Destination::Type::FitV:
type_str = "FitV"sv;
break;
case PDF::Destination::Type::FitR:
type_str = "FitR"sv;
break;
case PDF::Destination::Type::FitB:
type_str = "FitB"sv;
break;
case PDF::Destination::Type::FitBH:
type_str = "FitBH"sv;
break;
case PDF::Destination::Type::FitBV:
type_str = "FitBV"sv;
break;
}
StringBuilder param_builder;
builder.builder().appendff("{{ type={} page="sv, type_str);
if (!destination.page.has_value())
TRY(builder.put_literal("{{}}"sv));
else
TRY(builder.put_u64(destination.page.value()));
if (!destination.parameters.is_empty()) {
TRY(builder.put_literal(" parameters="sv));
for (auto const& param : destination.parameters) {
if (param.has_value())
TRY(builder.put_f32_or_f64(param.value()));
else
TRY(builder.put_literal("{{}}"sv));
TRY(builder.put_literal(" "sv));
}
}
return builder.put_literal(" }}"sv);
}
};
template<>
struct Formatter<PDF::OutlineItem> : Formatter<FormatString> {
ErrorOr<void> format(FormatBuilder& builder, PDF::OutlineItem const& item)
{
return builder.put_string(item.to_deprecated_string(0));
}
};
template<>
struct Formatter<PDF::OutlineDict> : Formatter<FormatString> {
ErrorOr<void> format(FormatBuilder& builder, PDF::OutlineDict const& dict)
{
StringBuilder child_builder;
child_builder.append('[');
for (auto& child : dict.children)
child_builder.appendff("{}\n", child->to_deprecated_string(2));
child_builder.append(" ]"sv);
return Formatter<FormatString>::format(builder,
"OutlineDict {{\n count={}\n children={}\n}}"sv, dict.count, child_builder.to_deprecated_string());
}
};
}