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serenity/Userland/Libraries/LibPDF/ObjectDerivatives.cpp
Rodrigo Tobar 8c79f0e0cf LibPDF: Add more utility methods to {Dict,Array}Object
Being both of them containers, these classes already offered a set of
methods to retrieve an inner element by key or index, respectively, with
different methods for the different subtypes of the PDF::Object type
returning the element cast to the correct type pointer. On top of
that, DictObject offered an additional method to obtain an element as an
Object pointer.

While these methods were useful, they have some shortcomings:

 * They always take a Document pointer to first perform an object
   resolution, in case the element is a Reference. This is not always
   necessary though, as there are values that are always meant to be
   immediate, and hence the resolution lookup adds overhead.
 * There was no easy way to get an individual Object element from an
   ArrayObject like there is in DictObject. This makes it difficult to
   obtain such values, as one first needs to call dict.get() to get a
   Value, then cast it manually to a NonnullRefPtr<Object>.

This commit fixes these two issues by:

 * Adding a new method that returns an Object for a given index.
 * Adding overloads for this new method, and all the existing methods
   described above, that do *not* take a Document, and therefore do
   *not* perform an object resolution lookup.
2023-01-06 18:06:41 +01:00

159 lines
6.2 KiB
C++

/*
* Copyright (c) 2021-2022, Matthew Olsson <mattco@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Hex.h>
#include <LibPDF/Document.h>
#include <LibPDF/ObjectDerivatives.h>
namespace PDF {
PDFErrorOr<NonnullRefPtr<Object>> ArrayObject::get_object_at(Document* document, size_t index) const
{
return document->resolve_to<Object>(at(index));
}
PDFErrorOr<NonnullRefPtr<Object>> DictObject::get_object(Document* document, FlyString const& key) const
{
return document->resolve_to<Object>(get_value(key));
}
#define DEFINE_ACCESSORS(class_name, snake_name) \
PDFErrorOr<NonnullRefPtr<class_name>> ArrayObject::get_##snake_name##_at(Document* document, size_t index) const \
{ \
if (index >= m_elements.size()) \
return Error { Error::Type::Internal, "Out of bounds array access" }; \
return document->resolve_to<class_name>(m_elements[index]); \
} \
\
NonnullRefPtr<class_name> ArrayObject::get_##snake_name##_at(size_t index) const \
{ \
VERIFY(index < m_elements.size()); \
return cast_to<class_name>(m_elements[index]); \
} \
\
PDFErrorOr<NonnullRefPtr<class_name>> DictObject::get_##snake_name(Document* document, FlyString const& key) const \
{ \
return document->resolve_to<class_name>(get_value(key)); \
} \
\
NonnullRefPtr<class_name> DictObject::get_##snake_name(FlyString const& key) const \
{ \
return cast_to<class_name>(get_value(key)); \
}
ENUMERATE_OBJECT_TYPES(DEFINE_ACCESSORS)
#undef DEFINE_INDEXER
static void append_indent(StringBuilder& builder, int indent)
{
for (int i = 0; i < indent; i++)
builder.append(" "sv);
}
DeprecatedString StringObject::to_deprecated_string(int) const
{
if (is_binary())
return DeprecatedString::formatted("<{}>", encode_hex(string().bytes()).to_uppercase());
return DeprecatedString::formatted("({})", string());
}
DeprecatedString NameObject::to_deprecated_string(int) const
{
StringBuilder builder;
builder.appendff("/{}", this->name());
return builder.to_deprecated_string();
}
Vector<float> ArrayObject::float_elements() const
{
Vector<float> values;
values.ensure_capacity(m_elements.size());
for (auto const& value : m_elements) {
values.append(value.to_float());
}
return values;
}
DeprecatedString ArrayObject::to_deprecated_string(int indent) const
{
StringBuilder builder;
builder.append("[\n"sv);
bool first = true;
for (auto& element : elements()) {
if (!first)
builder.append(",\n"sv);
first = false;
append_indent(builder, indent + 1);
builder.appendff("{}", element.to_deprecated_string(indent));
}
builder.append('\n');
append_indent(builder, indent);
builder.append(']');
return builder.to_deprecated_string();
}
DeprecatedString DictObject::to_deprecated_string(int indent) const
{
StringBuilder builder;
builder.append("<<\n"sv);
bool first = true;
for (auto& [key, value] : map()) {
if (!first)
builder.append(",\n"sv);
first = false;
append_indent(builder, indent + 1);
builder.appendff("/{} ", key);
builder.appendff("{}", value.to_deprecated_string(indent + 1));
}
builder.append('\n');
append_indent(builder, indent);
builder.append(">>"sv);
return builder.to_deprecated_string();
}
DeprecatedString StreamObject::to_deprecated_string(int indent) const
{
StringBuilder builder;
builder.append("stream\n"sv);
append_indent(builder, indent);
builder.appendff("{}\n", dict()->to_deprecated_string(indent + 1));
append_indent(builder, indent + 1);
auto string = encode_hex(bytes());
while (true) {
if (string.length() > 60) {
builder.appendff("{}\n", string.substring(0, 60));
append_indent(builder, indent);
string = string.substring(60);
continue;
}
builder.appendff("{}\n", string);
break;
}
append_indent(builder, indent);
builder.append("endstream"sv);
return builder.to_deprecated_string();
}
DeprecatedString IndirectValue::to_deprecated_string(int indent) const
{
StringBuilder builder;
builder.appendff("{} {} obj\n", index(), generation_index());
append_indent(builder, indent + 1);
builder.append(value().to_deprecated_string(indent + 1));
builder.append('\n');
append_indent(builder, indent);
builder.append("endobj"sv);
return builder.to_deprecated_string();
}
}