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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef BACKENDS_NETWORKING_CURL_REQUEST_H
+#define BACKENDS_NETWORKING_CURL_REQUEST_H
+
+#include "common/callback.h"
+#include "common/scummsys.h"
+#include "common/str.h"
+
+namespace Networking {
+
+class Request;
+
+/**
+ * Response<T> is a struct to be returned from Request
+ * to user's callbacks. It's a type safe way to indicate
+ * which "return value" Request has and user awaits.
+ *
+ * It just keeps a Request pointer together with
+ * some T value (which might be a pointer, a reference
+ * or a plain type (copied by value)).
+ *
+ * To make it more convenient, typedefs are used.
+ * For example, Response<void *> is called DataResponse
+ * and corresponding callback pointer is DataCallback.
+ */
+
+template<typename T> struct Response {
+ Request *request;
+ T value;
+
+ Response(Request *rq, T v) : request(rq), value(v) {}
+};
+
+/**
+ * ErrorResponse is a struct to be returned from Request
+ * to user's failure callbacks.
+ *
+ * It keeps a Request pointer together with some useful
+ * information fields, which would explain why failure
+ * callback was called.
+ *
+ * <interrupted> flag is set when Request was interrupted,
+ * i.e. finished by user with finish() call.
+ *
+ * <failed> flag is set when Request has failed because of
+ * some error (bad server response, for example).
+ *
+ * <response> contains server's original response.
+ *
+ * <httpResponseCode> contains server's HTTP response code.
+ */
+
+struct ErrorResponse {
+ Request *request;
+ bool interrupted;
+ bool failed;
+ Common::String response;
+ long httpResponseCode;
+
+ ErrorResponse(Request *rq);
+ ErrorResponse(Request *rq, bool interrupt, bool failure, Common::String resp, long httpCode);
+};
+
+typedef Response<void *> DataReponse;
+typedef Common::BaseCallback<DataReponse> *DataCallback;
+typedef Common::BaseCallback<ErrorResponse> *ErrorCallback;
+
+/**
+ * RequestState is used to indicate current Request state.
+ * ConnectionManager uses it to decide what to do with the Request.
+ *
+ * PROCESSING state indicates that Request is working.
+ * ConnectionManager calls handle() method of Requests in that state.
+ *
+ * PAUSED state indicates that Request is not working.
+ * ConnectionManager keeps Requests in that state and doesn't call any methods of those.
+ *
+ * RETRY state indicates that Request must restart after a few seconds.
+ * ConnectionManager calls handleRetry() method of Requests in that state.
+ * Default handleRetry() implementation decreases _retryInSeconds value
+ * until it reaches zero. When it does, Request's restart() method is called.
+ *
+ * FINISHED state indicates that Request did the work and might be deleted.
+ * ConnectionManager deletes Requests in that state.
+ * After this state is set, but before ConnectionManager deletes the Request,
+ * Request calls user's callback. User can ask Request to change its state
+ * by calling retry() or pause() methods and Request won't be deleted.
+ *
+ * Request get a success and failure callbacks. Request must call one
+ * (and only one!) of these callbacks when it sets FINISHED state.
+ */
+enum RequestState {
+ PROCESSING,
+ PAUSED,
+ RETRY,
+ FINISHED
+};
+
+class Request {
+protected:
+ /**
+ * Callback, which should be called when Request is finished.
+ * That's the way Requests pass the result to the code which asked to create this request.
+ *
+ * @note some Requests use their own callbacks to return something but void *.
+ * @note callback must be called in finish() or similar method.
+ */
+ DataCallback _callback;
+
+ /**
+ * Callback, which should be called when Request is failed/interrupted.
+ * That's the way Requests pass error information to the code which asked to create this request.
+ * @note callback must be called in finish() or similar method.
+ */
+ ErrorCallback _errorCallback;
+
+ /**
+ * Request state, which is used by ConnectionManager to determine
+ * whether request might be deleted or it's still working.
+ *
+ * State might be changed from outside with finish(), pause() or
+ * retry() methods. Override these if you want to react to these
+ * changes correctly.
+ */
+ RequestState _state;
+
+ /** In RETRY state this indicates whether it's time to call restart(). */
+ uint32 _retryInSeconds;
+
+ /** Sets FINISHED state and calls the _errorCallback with given error. */
+ virtual void finishError(ErrorResponse error);
+
+ /** Sets FINISHED state. Implementations might extend it if needed. */
+ virtual void finishSuccess();
+
+public:
+ Request(DataCallback cb, ErrorCallback ecb);
+ virtual ~Request();
+
+ /** Method, which does actual work. Depends on what this Request is doing. */
+ virtual void handle() = 0;
+
+ /** Method, which is called by ConnectionManager when Request's state is RETRY. */
+ virtual void handleRetry();
+
+ /** Method, which is used to restart the Request. */
+ virtual void restart() = 0;
+
+ /** Method, which is called to pause the Request. */
+ virtual void pause();
+
+ /**
+ * Method, which is called to *interrupt* the Request.
+ * When it's called, Request must stop its work and
+ * call the failure callback to notify user.
+ */
+ virtual void finish();
+
+ /** Method, which is called to retry the Request. */
+ virtual void retry(uint32 seconds);
+
+ /** Returns Request's current state. */
+ RequestState state() const;
+
+ /**
+ * Return date this Request received from server.
+ * It could be extracted from "Date" header,
+ * which is kept in NetworkReadStream.
+ *
+ * @note not all Requests do that, so "" is returned
+ * to indicate the date is unknown. That's also true
+ * if no server response available or no "Date" header
+ * was passed.
+ *
+ * @returns date from "Date" response header.
+ */
+ virtual Common::String date() const;
+};
+
+} // End of namespace Networking
+
+#endif