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LibPDF: Extract Parser::parse_inline_image()

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Pure code move, no intended behavior change.

The motivation is just to make Parser::parse_operators() less nested
and more focused.
This commit is contained in:
Nico Weber 2023-12-21 22:01:43 -05:00 • committed by Andreas Kling
parent f972eda7ed
commit 3d07684891
2 changed files with 45 additions and 40 deletions
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79
Userland/Libraries/LibPDF/Parser.cpp
View file

@ -520,45 +520,11 @@ PDFErrorOr<NonnullRefPtr<StreamObject>> Parser::parse_stream(NonnullRefPtr<DictO
return stream_object;
}
PDFErrorOr<Vector<Operator>> Parser::parse_operators()
PDFErrorOr<NonnullRefPtr<StreamObject>> Parser::parse_inline_image()
{
Vector<Operator> operators;
Vector<Value> operator_args;
constexpr static auto is_operator_char_start = [](char ch) {
return isalpha(ch) || ch == '*' || ch == '\'' || ch == '"';
};
constexpr static auto is_operator_char_continuation = [](char ch) {
return is_operator_char_start(ch) || ch == '0' || ch == '1';
};
m_reader.consume_whitespace();
while (!m_reader.done()) {
parse_comment();
if (m_reader.done())
break;
auto ch = m_reader.peek();
if (is_operator_char_start(ch)) {
auto operator_start = m_reader.offset();
while (is_operator_char_continuation(ch)) {
m_reader.consume();
if (m_reader.done())
break;
ch = m_reader.peek();
}
auto operator_string = StringView(m_reader.bytes().slice(operator_start, m_reader.offset() - operator_start));
m_reader.consume_whitespace();
auto operator_type = Operator::operator_type_from_symbol(operator_string);
// Inline images contain a dictionary containing arbitrary values between BI and ID,
// and then arbitrary binary data between ID and EI.
// This means they need a special code path in the parser, so that image data in there doesn't confuse the operator parser.
if (operator_type == OperatorType::InlineImageBegin) {
if (!operator_args.is_empty())
return error("operator args not empty on start of inline image");
HashMap<DeprecatedFlyString, Value> map = TRY(parse_dict_contents_until("ID"));
m_reader.consume(2); // "ID"
@ -592,10 +558,47 @@ PDFErrorOr<Vector<Operator>> Parser::parse_operators()
auto stream_bytes = m_reader.bytes().slice(stream_start, stream_end - stream_start);
Vector<Value> inline_image_args;
auto map_object = make_object<DictObject>(move(map));
inline_image_args.append(make_object<StreamObject>(move(map_object), MUST(ByteBuffer::copy(stream_bytes))));
operators.append(Operator(OperatorType::InlineImageEnd, move(inline_image_args)));
return make_object<StreamObject>(move(map_object), MUST(ByteBuffer::copy(stream_bytes)));
}
PDFErrorOr<Vector<Operator>> Parser::parse_operators()
{
Vector<Operator> operators;
Vector<Value> operator_args;
constexpr static auto is_operator_char_start = [](char ch) {
return isalpha(ch) || ch == '*' || ch == '\'' || ch == '"';
};
constexpr static auto is_operator_char_continuation = [](char ch) {
return is_operator_char_start(ch) || ch == '0' || ch == '1';
};
m_reader.consume_whitespace();
while (!m_reader.done()) {
parse_comment();
if (m_reader.done())
break;
auto ch = m_reader.peek();
if (is_operator_char_start(ch)) {
auto operator_start = m_reader.offset();
while (is_operator_char_continuation(ch)) {
m_reader.consume();
if (m_reader.done())
break;
ch = m_reader.peek();
}
auto operator_string = StringView(m_reader.bytes().slice(operator_start, m_reader.offset() - operator_start));
m_reader.consume_whitespace();
auto operator_type = Operator::operator_type_from_symbol(operator_string);
if (operator_type == OperatorType::InlineImageBegin) {
if (!operator_args.is_empty())
return error("operator args not empty on start of inline image");
operators.append(Operator(OperatorType::InlineImageEnd, { TRY(parse_inline_image()) }));
continue;
}

2
Userland/Libraries/LibPDF/Parser.h
View file

@ -73,6 +73,8 @@ public:
void pop_reference() { m_current_reference_stack.take_last(); }
protected:
PDFErrorOr<NonnullRefPtr<StreamObject>> parse_inline_image();
Error error(
ByteString const& message
#ifdef PDF_DEBUG