LibRequests: Create ReadStream abstraction for reading request data

Given the RequestServer created the request fd with socketpair() on
Windows and pipe2() on Unix, this abstraction avoids inlined ifdef soup
by hiding the details of how the AK::Stream and Core::Notifier are
created.

Author: ayeteadoe

Libraries/LibRequests/Request.cpp

@@ -9,6 +9,20 @@
 
 namespace Requests {
 
+ErrorOr<NonnullOwnPtr<ReadStream>> ReadStream::create(int reader_fd)
+{
+#if defined(AK_OS_WINDOWS)
+    auto local_socket = TRY(Core::LocalSocket::adopt_fd(reader_fd));
+    auto notifier = local_socket->notifier();
+    VERIFY(notifier);
+    return adopt_own(*new ReadStream(move(local_socket), notifier.release_nonnull()));
+#else
+    auto file = TRY(Core::File::adopt_fd(reader_fd, Core::File::OpenMode::Read));
+    auto notifier = Core::Notifier::construct(reader_fd, Core::Notifier::Type::Read);
+    return adopt_own(*new ReadStream(move(file), move(notifier)));
+#endif
+}
+
 Request::Request(RequestClient& client, i32 request_id)
     : m_client(client)
     , m_request_id(request_id)
@@ -37,11 +51,11 @@ void Request::set_request_fd(Badge<Requests::RequestClient>, int fd)
     VERIFY(m_fd == -1);
     m_fd = fd;
 
-    auto notifier = Core::Notifier::construct(fd, Core::Notifier::Type::Read);
-    auto stream = MUST(Core::File::adopt_fd(fd, Core::File::OpenMode::Read));
+    auto read_stream = MUST(ReadStream::create(fd));
+    auto notifier = read_stream->notifier();
     notifier->on_activation = move(m_internal_stream_data->read_notifier->on_activation);
-    m_internal_stream_data->read_notifier = move(notifier);
-    m_internal_stream_data->read_stream = move(stream);
+    m_internal_stream_data->read_notifier = notifier;
+    m_internal_stream_data->read_stream = move(read_stream);
 }
 
 void Request::set_buffered_request_finished_callback(BufferedRequestFinished on_buffered_request_finished)
@@ -117,7 +131,7 @@ void Request::set_up_internal_stream_data(DataReceived on_data_available)
     m_internal_stream_data = make<InternalStreamData>();
     m_internal_stream_data->read_notifier = Core::Notifier::construct(fd(), Core::Notifier::Type::Read);
     if (fd() != -1)
-        m_internal_stream_data->read_stream = MUST(Core::File::adopt_fd(fd(), Core::File::OpenMode::Read));
+        m_internal_stream_data->read_stream = MUST(ReadStream::create(fd()));
 
     auto user_on_finish = move(on_finish);
     on_finish = [this](auto total_size, auto const& timing_info, auto network_error) {

Libraries/LibRequests/Request.h

@@ -21,6 +21,27 @@ namespace Requests {
 
 class RequestClient;
 
+class ReadStream {
+public:
+    static ErrorOr<NonnullOwnPtr<ReadStream>> create(int reader_fd);
+
+    NonnullRefPtr<Core::Notifier> const& notifier() const { return m_notifier; }
+
+    bool is_eof() const { return m_stream->is_eof(); }
+
+    ErrorOr<Bytes> read_some(Bytes bytes) { return m_stream->read_some(bytes); }
+
+private:
+    ReadStream(NonnullOwnPtr<Stream> stream, NonnullRefPtr<Core::Notifier> notifier)
+        : m_stream(move(stream))
+        , m_notifier(move(notifier))
+    {
+    }
+
+    NonnullOwnPtr<Stream> m_stream;
+    NonnullRefPtr<Core::Notifier> m_notifier;
+};
+
 class Request : public RefCounted<Request> {
 public:
     struct CertificateAndKey {
@@ -90,7 +111,7 @@ class Request : public RefCounted<Request> {
     struct InternalStreamData {
         InternalStreamData() { }
 
-        OwnPtr<Stream> read_stream;
+        OwnPtr<ReadStream> read_stream;
         RefPtr<Core::Notifier> read_notifier;
         u32 total_size { 0 };
         Optional<NetworkError> network_error;