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AK: Move ConstrainedStream from LibWasm and limit discarding

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This commit is contained in:
Tim Schumacher 2023-03-10 16:37:52 +01:00 • committed by Andreas Kling
parent 92800cff4a
commit d1f6a28ffd
6 changed files with 99 additions and 51 deletions
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5
Userland/Libraries/LibWasm/Parser/Parser.cpp
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@ -4,6 +4,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/ConstrainedStream.h>
#include <AK/Debug.h>
#include <AK/Endian.h>
#include <AK/LEB128.h>
@ -1186,7 +1187,7 @@ ParseResult<CodeSection::Code> CodeSection::Code::parse(Stream& stream)
return with_eof_check(stream, ParseError::InvalidSize);
size_t size = size_or_error.release_value();
auto constrained_stream = ConstrainedStream { stream, size };
auto constrained_stream = ConstrainedStream { MaybeOwned<Stream>(stream), size };
auto func = Func::parse(constrained_stream);
if (func.is_error())
@ -1301,7 +1302,7 @@ ParseResult<Module> Module::parse(Stream& stream)
return with_eof_check(stream, ParseError::ExpectedSize);
size_t section_size = section_size_or_error.release_value();
auto section_stream = ConstrainedStream { stream, section_size };
auto section_stream = ConstrainedStream { MaybeOwned<Stream>(stream), section_size };
switch (section_id) {
case CustomSection::section_id:

49
Userland/Libraries/LibWasm/Types.h
View file

@ -135,55 +135,6 @@ private:
Vector<u8, 8> m_buffer;
};
class ConstrainedStream : public Stream {
public:
explicit ConstrainedStream(Stream& stream, size_t size)
: m_stream(stream)
, m_bytes_left(size)
{
}
private:
ErrorOr<Bytes> read_some(Bytes bytes) override
{
auto to_read = min(m_bytes_left, bytes.size());
auto read_bytes = TRY(m_stream.read_some(bytes.slice(0, to_read)));
m_bytes_left -= read_bytes.size();
return read_bytes;
}
bool is_eof() const override
{
return m_bytes_left == 0 || m_stream.is_eof();
}
ErrorOr<void> discard(size_t count) override
{
if (count > m_bytes_left)
return Error::from_string_literal("Trying to discard more bytes than allowed");
return m_stream.discard(count);
}
virtual ErrorOr<size_t> write_some(ReadonlyBytes) override
{
return Error::from_errno(EBADF);
}
virtual bool is_open() const override
{
return m_stream.is_open();
}
virtual void close() override
{
m_stream.close();
}
Stream& m_stream;
size_t m_bytes_left { 0 };
};
// https://webassembly.github.io/spec/core/bikeshed/#value-types%E2%91%A2
class ValueType {
public: