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Diffstat (limited to 'backends/networking/curl/request.h')
-rw-r--r-- | backends/networking/curl/request.h | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/backends/networking/curl/request.h b/backends/networking/curl/request.h new file mode 100644 index 0000000000..b1261f23ee --- /dev/null +++ b/backends/networking/curl/request.h @@ -0,0 +1,203 @@ +/* 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 |