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AK+LibCore: Make output buffered stream seekable

Just like with input buffered streams, we don't currently have a use
case for output buffered streams which aren't seekable, since the main
application are files.
This commit is contained in:
kleines Filmröllchen 2023-07-04 17:47:23 +02:00 committed by Andrew Kaster
parent c2d9d0277f
commit 001ea22917
3 changed files with 46 additions and 10 deletions

View file

@ -310,10 +310,10 @@ private:
BufferedHelper<T> m_helper;
};
template<StreamLike T>
class OutputBufferedStream final : public Stream {
template<SeekableStreamLike T>
class OutputBufferedSeekable : public SeekableStream {
public:
static ErrorOr<NonnullOwnPtr<OutputBufferedStream<T>>> create(NonnullOwnPtr<T> stream, size_t buffer_size = 16 * KiB)
static ErrorOr<NonnullOwnPtr<OutputBufferedSeekable<T>>> create(NonnullOwnPtr<T> stream, size_t buffer_size = 16 * KiB)
{
if (buffer_size == 0)
return Error::from_errno(EINVAL);
@ -322,11 +322,11 @@ public:
auto buffer = TRY(CircularBuffer::create_empty(buffer_size));
return adopt_nonnull_own_or_enomem(new OutputBufferedStream<T>(move(stream), move(buffer)));
return adopt_nonnull_own_or_enomem(new OutputBufferedSeekable<T>(move(stream), move(buffer)));
}
OutputBufferedStream(OutputBufferedStream&& other) = default;
OutputBufferedStream& operator=(OutputBufferedStream&& other) = default;
OutputBufferedSeekable(OutputBufferedSeekable&& other) = default;
OutputBufferedSeekable& operator=(OutputBufferedSeekable&& other) = default;
virtual ErrorOr<Bytes> read_some(Bytes buffer) override
{
@ -368,13 +368,31 @@ public:
return {};
}
virtual ~OutputBufferedStream() override
// Since tell() doesn't involve moving the write offset, we can skip flushing the buffer here.
virtual ErrorOr<size_t> tell() const override
{
return TRY(m_stream->tell()) + m_buffer.used_space();
}
virtual ErrorOr<size_t> seek(i64 offset, SeekMode mode) override
{
TRY(flush_buffer());
return m_stream->seek(offset, mode);
}
virtual ErrorOr<void> truncate(size_t length) override
{
TRY(flush_buffer());
return m_stream->truncate(length);
}
virtual ~OutputBufferedSeekable() override
{
MUST(flush_buffer());
}
private:
OutputBufferedStream(NonnullOwnPtr<T> stream, CircularBuffer buffer)
OutputBufferedSeekable(NonnullOwnPtr<T> stream, CircularBuffer buffer)
: m_stream(move(stream))
, m_buffer(move(buffer))
{
@ -389,5 +407,5 @@ private:
#if USING_AK_GLOBALLY
using AK::BufferedHelper;
using AK::InputBufferedSeekable;
using AK::OutputBufferedStream;
using AK::OutputBufferedSeekable;
#endif