Services: Rename ProtocolServer to RequestServer

The current ProtocolServer was really only used for requests, and with
the recent introduction of the WebSocket service, long-lasting
connections with another server are not part of it. To better reflect
this, this commit renames it to RequestServer.

This commit also changes the existing 'protocol' portal to 'request',
the existing 'protocol' user and group to 'request', and most mentions
of the 'download' aspect of the request to 'request' when relevant, to
make everything consistent across the system.

Note that LibProtocol still exists as-is, but the more generic Client
class and the more specific Download class have both been renamed to a
more accurate RequestClient and Request to match the new names.

This commit only change names, not behaviors.

Userland/Libraries/LibProtocol/Request.cpp

@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibProtocol/Request.h>
+#include <LibProtocol/RequestClient.h>
+
+namespace Protocol {
+
+Request::Request(RequestClient& client, i32 request_id)
+    : m_client(client)
+    , m_request_id(request_id)
+{
+}
+
+bool Request::stop()
+{
+    return m_client->stop_request({}, *this);
+}
+
+void Request::stream_into(OutputStream& stream)
+{
+    VERIFY(!m_internal_stream_data);
+
+    auto notifier = Core::Notifier::construct(fd(), Core::Notifier::Read);
+
+    m_internal_stream_data = make<InternalStreamData>(fd());
+    m_internal_stream_data->read_notifier = notifier;
+
+    auto user_on_finish = move(on_finish);
+    on_finish = [this](auto success, auto total_size) {
+        m_internal_stream_data->success = success;
+        m_internal_stream_data->total_size = total_size;
+        m_internal_stream_data->request_done = true;
+    };
+
+    notifier->on_ready_to_read = [this, &stream, user_on_finish = move(user_on_finish)] {
+        constexpr size_t buffer_size = PAGE_SIZE;
+        static char buf[buffer_size];
+        auto nread = m_internal_stream_data->read_stream.read({ buf, buffer_size });
+        if (!stream.write_or_error({ buf, nread })) {
+            // FIXME: What do we do here?
+            TODO();
+        }
+
+        if (m_internal_stream_data->read_stream.eof() && m_internal_stream_data->request_done) {
+            m_internal_stream_data->read_notifier->close();
+            user_on_finish(m_internal_stream_data->success, m_internal_stream_data->total_size);
+        } else {
+            m_internal_stream_data->read_stream.handle_any_error();
+        }
+    };
+}
+
+void Request::set_should_buffer_all_input(bool value)
+{
+    if (m_should_buffer_all_input == value)
+        return;
+
+    if (m_internal_buffered_data && !value) {
+        m_internal_buffered_data = nullptr;
+        m_should_buffer_all_input = false;
+        return;
+    }
+
+    VERIFY(!m_internal_stream_data);
+    VERIFY(!m_internal_buffered_data);
+    VERIFY(on_buffered_request_finish); // Not having this set makes no sense.
+    m_internal_buffered_data = make<InternalBufferedData>(fd());
+    m_should_buffer_all_input = true;
+
+    on_headers_received = [this](auto& headers, auto response_code) {
+        m_internal_buffered_data->response_headers = headers;
+        m_internal_buffered_data->response_code = move(response_code);
+    };
+
+    on_finish = [this](auto success, u32 total_size) {
+        auto output_buffer = m_internal_buffered_data->payload_stream.copy_into_contiguous_buffer();
+        on_buffered_request_finish(
+            success,
+            total_size,
+            m_internal_buffered_data->response_headers,
+            m_internal_buffered_data->response_code,
+            output_buffer);
+    };
+
+    stream_into(m_internal_buffered_data->payload_stream);
+}
+
+void Request::did_finish(Badge<RequestClient>, bool success, u32 total_size)
+{
+    if (!on_finish)
+        return;
+
+    on_finish(success, total_size);
+}
+
+void Request::did_progress(Badge<RequestClient>, Optional<u32> total_size, u32 downloaded_size)
+{
+    if (on_progress)
+        on_progress(total_size, downloaded_size);
+}
+
+void Request::did_receive_headers(Badge<RequestClient>, const HashMap<String, String, CaseInsensitiveStringTraits>& response_headers, Optional<u32> response_code)
+{
+    if (on_headers_received)
+        on_headers_received(response_headers, response_code);
+}
+
+void Request::did_request_certificates(Badge<RequestClient>)
+{
+    if (on_certificate_requested) {
+        auto result = on_certificate_requested();
+        if (!m_client->set_certificate({}, *this, result.certificate, result.key)) {
+            dbgln("Request: set_certificate failed");
+        }
+    }
+}
+}