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LibPDF: Make Filter::decode() return ErrorOr

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This commit is contained in:
Sam Atkins 2022-01-20 17:26:37 +00:00 • committed by Andreas Kling
parent c388a879d7
commit fa3c61cf5a
3 changed files with 33 additions and 41 deletions
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47
Userland/Libraries/LibPDF/Filter.cpp
View file

@ -11,7 +11,7 @@
namespace PDF { namespace PDF {
Optional<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encoding_type) ErrorOr<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encoding_type)
{ {
if (encoding_type == CommonNames::ASCIIHexDecode) if (encoding_type == CommonNames::ASCIIHexDecode)
return decode_ascii_hex(bytes); return decode_ascii_hex(bytes);
@ -34,34 +34,26 @@ Optional<ByteBuffer> Filter::decode(ReadonlyBytes bytes, FlyString const& encodi
if (encoding_type == CommonNames::Crypt) if (encoding_type == CommonNames::Crypt)
return decode_crypt(bytes); return decode_crypt(bytes);
return {}; return Error::from_string_literal("Unrecognized filter encoding");
} }
Optional<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes) ErrorOr<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes)
{ {
if (bytes.size() % 2 == 0) { if (bytes.size() % 2 == 0)
auto decode_result = decode_hex(bytes); return decode_hex(bytes);
if (decode_result.is_error())
return {};
return decode_result.release_value();
}
// FIXME: Integrate this padding into AK/Hex? // FIXME: Integrate this padding into AK/Hex?
auto output_result = ByteBuffer::create_zeroed(bytes.size() / 2 + 1); auto output = TRY(ByteBuffer::create_zeroed(bytes.size() / 2 + 1));
if (output_result.is_error())
return {};
auto output = output_result.release_value();
for (size_t i = 0; i < bytes.size() / 2; ++i) { for (size_t i = 0; i < bytes.size() / 2; ++i) {
const auto c1 = decode_hex_digit(static_cast<char>(bytes[i * 2])); const auto c1 = decode_hex_digit(static_cast<char>(bytes[i * 2]));
if (c1 >= 16) if (c1 >= 16)
return {}; return Error::from_string_literal("Hex string contains invalid digit");
const auto c2 = decode_hex_digit(static_cast<char>(bytes[i * 2 + 1])); const auto c2 = decode_hex_digit(static_cast<char>(bytes[i * 2 + 1]));
if (c2 >= 16) if (c2 >= 16)
return {}; return Error::from_string_literal("Hex string contains invalid digit");
output[i] = (c1 << 4) + c2; output[i] = (c1 << 4) + c2;
} }
@ -72,7 +64,7 @@ Optional<ByteBuffer> Filter::decode_ascii_hex(ReadonlyBytes bytes)
return { move(output) }; return { move(output) };
}; };
Optional<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes) ErrorOr<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes)
{ {
Vector<u8> buff; Vector<u8> buff;
buff.ensure_capacity(bytes.size()); buff.ensure_capacity(bytes.size());
@ -124,19 +116,16 @@ Optional<ByteBuffer> Filter::decode_ascii85(ReadonlyBytes bytes)
buff.append(reinterpret_cast<u8*>(&number)[3 - i]); buff.append(reinterpret_cast<u8*>(&number)[3 - i]);
} }
auto result = ByteBuffer::copy(buff.span()); return ByteBuffer::copy(buff.span());
if (result.is_error())
return {};
return result.release_value();
}; };
Optional<ByteBuffer> Filter::decode_lzw(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_lzw(ReadonlyBytes)
{ {
dbgln("LZW decoding is not supported"); dbgln("LZW decoding is not supported");
VERIFY_NOT_REACHED(); VERIFY_NOT_REACHED();
}; };
Optional<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes) ErrorOr<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes)
{ {
// FIXME: The spec says Flate decoding is "based on" zlib, does that mean they // FIXME: The spec says Flate decoding is "based on" zlib, does that mean they
// aren't exactly the same? // aren't exactly the same?
@ -146,37 +135,37 @@ Optional<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes)
return buff.value(); return buff.value();
}; };
Optional<ByteBuffer> Filter::decode_run_length(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_run_length(ReadonlyBytes)
{ {
// FIXME: Support RunLength decoding // FIXME: Support RunLength decoding
TODO(); TODO();
}; };
Optional<ByteBuffer> Filter::decode_ccitt(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_ccitt(ReadonlyBytes)
{ {
// FIXME: Support CCITT decoding // FIXME: Support CCITT decoding
TODO(); TODO();
}; };
Optional<ByteBuffer> Filter::decode_jbig2(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_jbig2(ReadonlyBytes)
{ {
// FIXME: Support JBIG2 decoding // FIXME: Support JBIG2 decoding
TODO(); TODO();
}; };
Optional<ByteBuffer> Filter::decode_dct(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_dct(ReadonlyBytes)
{ {
// FIXME: Support dct decoding // FIXME: Support dct decoding
TODO(); TODO();
}; };
Optional<ByteBuffer> Filter::decode_jpx(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_jpx(ReadonlyBytes)
{ {
// FIXME: Support JPX decoding // FIXME: Support JPX decoding
TODO(); TODO();
}; };
Optional<ByteBuffer> Filter::decode_crypt(ReadonlyBytes) ErrorOr<ByteBuffer> Filter::decode_crypt(ReadonlyBytes)
{ {
// FIXME: Support Crypt decoding // FIXME: Support Crypt decoding
TODO(); TODO();

23
Userland/Libraries/LibPDF/Filter.h
View file

@ -7,25 +7,26 @@
#pragma once #pragma once
#include <AK/ByteBuffer.h> #include <AK/ByteBuffer.h>
#include <AK/Error.h>
#include <AK/FlyString.h> #include <AK/FlyString.h>
namespace PDF { namespace PDF {
class Filter { class Filter {
public: public:
static Optional<ByteBuffer> decode(ReadonlyBytes bytes, FlyString const& encoding_type); static ErrorOr<ByteBuffer> decode(ReadonlyBytes bytes, FlyString const& encoding_type);
private: private:
static Optional<ByteBuffer> decode_ascii_hex(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_ascii_hex(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_ascii85(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_ascii85(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_lzw(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_lzw(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_flate(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_flate(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_run_length(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_run_length(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_ccitt(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_ccitt(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_jbig2(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_jbig2(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_dct(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_dct(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_jpx(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_jpx(ReadonlyBytes bytes);
static Optional<ByteBuffer> decode_crypt(ReadonlyBytes bytes); static ErrorOr<ByteBuffer> decode_crypt(ReadonlyBytes bytes);
}; };
} }

4
Userland/Libraries/LibPDF/Parser.cpp
View file

@ -1071,8 +1071,10 @@ RefPtr<StreamObject> Parser::parse_stream(NonnullRefPtr<DictObject> dict)
if (dict->contains(CommonNames::Filter)) { if (dict->contains(CommonNames::Filter)) {
auto filter_type = dict->get_name(m_document, CommonNames::Filter)->name(); auto filter_type = dict->get_name(m_document, CommonNames::Filter)->name();
auto maybe_bytes = Filter::decode(bytes, filter_type); auto maybe_bytes = Filter::decode(bytes, filter_type);
if (!maybe_bytes.has_value()) if (maybe_bytes.is_error()) {
warnln("Failed to decode filter: {}", maybe_bytes.error().string_literal());
return {}; return {};
}
return make_object<EncodedStreamObject>(dict, move(maybe_bytes.value())); return make_object<EncodedStreamObject>(dict, move(maybe_bytes.value()));
} }