SpiceAgent: Implement FileTransferData messages

Userland/Services/SpiceAgent/Message.cpp

@@ -267,4 +267,25 @@ ErrorOr<String> FileTransferStatusMessage::debug_description()
     return builder.to_string();
 }
 
+ErrorOr<FileTransferDataMessage> FileTransferDataMessage::read_from_stream(AK::Stream& stream)
+{
+    auto id = TRY(stream.read_value<u32>());
+    auto size = TRY(stream.read_value<u64>());
+
+    auto contents = TRY(ByteBuffer::create_uninitialized(size));
+    TRY(stream.read_until_filled(contents));
+
+    return FileTransferDataMessage(id, contents);
+}
+
+ErrorOr<String> FileTransferDataMessage::debug_description()
+{
+    StringBuilder builder;
+    TRY(builder.try_append("FileTransferData { "sv));
+    TRY(builder.try_appendff("id = {}, ", id()));
+    TRY(builder.try_appendff("contents.size() = {}", contents().size()));
+    TRY(builder.try_append(" }"sv));
+    return builder.to_string();
+}
+
 }

Userland/Services/SpiceAgent/Message.h

@@ -242,6 +242,28 @@ private:
     FileTransferStatus m_status;
 };
 
+// Contains the file data sent from a file transfer request after it has been approved.
+class FileTransferDataMessage : public Message {
+public:
+    static ErrorOr<FileTransferDataMessage> read_from_stream(AK::Stream& stream);
+
+    ErrorOr<String> debug_description() override;
+
+    u32 id() const { return m_id; }
+    ByteBuffer const& contents() { return m_contents; }
+
+private:
+    FileTransferDataMessage(u32 id, ByteBuffer const& contents)
+        : Message(Type::FileTransferData)
+        , m_id(id)
+        , m_contents(contents)
+    {
+    }
+
+    u32 m_id { 0 };
+    ByteBuffer m_contents;
+};
+
 }
 
 namespace AK {