BuildSystem: Cleanup userspace directory layout

userspace programs are now in userspace/programs
userspace tests are now in userspace/tests

This makes listing userspace projects much cleaner. Libraries were
already separated to their own directory, so other programs should also.

userspace/programs/http-server/HTTPServer.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <BAN/ByteSpan.h>
+#include <BAN/HashMap.h>
+#include <BAN/IPv4.h>
+#include <BAN/String.h>
+#include <BAN/StringView.h>
+#include <BAN/Vector.h>
+
+struct HTTPHeader
+{
+	BAN::StringView name;
+	BAN::StringView value;
+};
+
+struct HTTPRequest
+{
+	BAN::StringView method;
+	BAN::StringView path;
+	BAN::StringView version;
+
+	BAN::Vector<HTTPHeader> headers;
+	BAN::ConstByteSpan body;
+};
+
+class HTTPServer
+{
+public:
+	HTTPServer();
+	~HTTPServer();
+
+	BAN::ErrorOr<void> initialize(BAN::StringView root, BAN::IPv4Address ip, int port);
+	void start();
+
+	BAN::StringView web_root() const { return m_web_root.sv(); }
+
+private:
+	BAN::ErrorOr<HTTPRequest> get_http_request(BAN::Vector<uint8_t>& data);
+	BAN::ErrorOr<void> send_http_response(int fd, unsigned status, BAN::ConstByteSpan, BAN::StringView mime);
+	BAN::ErrorOr<unsigned> handle_request(int fd, BAN::Vector<uint8_t>& data);
+	// Returns false if the connection should be closed
+	bool handle_all_requests(int fd, BAN::Vector<uint8_t>& data);
+
+private:
+	BAN::String m_web_root;
+
+	int m_listen_socket { -1 };
+	BAN::HashMap<int, BAN::Vector<uint8_t>> m_client_data;
+};