Mercurial > hg > svcore
view data/fileio/FileSource.h @ 353:1c6816220185
* more handy functions
author | Chris Cannam |
---|---|
date | Mon, 10 Dec 2007 17:37:13 +0000 |
parents | 1d656dcda8ef |
children | b92513201610 |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This file copyright 2007 QMUL. 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. See the file COPYING included with this distribution for more information. */ #ifndef _REMOTE_FILE_H_ #define _REMOTE_FILE_H_ #include <QUrl> #include <QMutex> #include <QString> #include <QTimer> #include <map> class QFtp; class QHttp; class QFile; class QProgressDialog; class QHttpResponseHeader; /** * FileSource is a class used to refer to the contents of a file that * may be either local or at a remote location such as a HTTP URL. * * When a FileSource object is constructed, the file or URL passed to * its constructor is tested for validity, and if it refers to a * remote HTTP or FTP location it is retrieved asynchronously (the Qt * event loop must be running) and cached locally. You can then query * a local path for the file and refer to that as a normal filename. * * Use isAvailable() to test whether the file or remote URL exists, * and isOK() to test for internal validity or transmission errors. * Call waitForStatus() to block until the availability and validity * of the URL have been established so that isAvailable may be called, * and waitForData() to block until the entire file has been cached. * * FileSource handles reference counting for cache files. You can * construct many FileSource objects with the same URL and you will * receive the same cached file for each; it is also reasonable to * pass FileSource objects by value. FileSource only makes sense for * stateless URLs that result in the same data on each request. * * Cached files share a lifetime with their "owning" FileSource * objects; when the last FileSource referring to a given URL is * deleted or goes out of scope, its cached file (if any) is also * removed. */ class FileSource : public QObject { Q_OBJECT public: /** * Construct a FileSource using the given local file path or URL. * The URL may be raw or encoded. If showProgress is true, a * progress dialog will be shown for any network transfers. */ FileSource(QString fileOrUrl, bool showProgress = false); /** * Construct a FileSource using the given remote URL. If * showProgress is true, a progress dialog will be shown for any * network transfers. */ FileSource(QUrl url, bool showProgress = false); FileSource(const FileSource &); virtual ~FileSource(); /** * Block on a sub-event-loop until the availability of the file or * remote URL is known. */ void waitForStatus(); /** * Block on a sub-event-loop until the whole of the data has been * retrieved (if it is remote). */ void waitForData(); /** * Return true if the FileSource object is valid and no error * occurred in looking up the file or remote URL. Non-existence * of the file or URL is not an error -- call isAvailable() to * test for that. */ bool isOK() const; /** * Return true if the file or remote URL exists. This may block * on a sub-event-loop (calling waitForStatus) if the status is * not yet available. */ bool isAvailable(); /** * Return true if the entire file has been retrieved and is * available. */ bool isDone() const; /** * Return true if this FileSource is referring to a remote URL. */ bool isRemote() const; /** * Return the location filename or URL as passed to the * constructor. */ QString getLocation() const; /** * Return the name of the local file this FileSource refers to. * This is the filename that should be used when reading normally * from the FileSource. If the filename passed to the constructor * was a local file, this will return the same filename; otherwise * this will be the name of the temporary cache file owned by the * FileSource. */ QString getLocalFilename() const; /** * Return the MIME content type of this file, if known. */ QString getContentType() const; /** * Return the file extension for this file, if any. */ QString getExtension() const; /** * Return an error message, if isOK() is false. */ QString getErrorString() const; /** * Specify whether any local, cached file should remain on disc * after this FileSource has been destroyed. The default is false * (cached files share their FileSource owners' lifespans). */ void setLeaveLocalFile(bool leave); /** * Return true if the given filename or URL refers to a remote * URL. */ static bool isRemote(QString fileOrUrl); /** * Return true if FileSource can handle the retrieval scheme for * the given URL (or if the URL is for a local file). */ static bool canHandleScheme(QUrl url); signals: /** * Emitted during URL retrieval, when the retrieval progress * notches up to a new percentage. */ void progress(int percent); /** * Emitted when the file's existence has been tested and/or * response header received. Calls to isAvailable() after this * has been emitted will not block. */ void statusAvailable(); /** * Emitted when the entire file data has been retrieved and the * local file is complete (if no error has occurred). */ void ready(); protected slots: void dataReadProgress(int done, int total); void httpResponseHeaderReceived(const QHttpResponseHeader &resp); void ftpCommandFinished(int, bool); void dataTransferProgress(qint64 done, qint64 total); void done(bool error); void showProgressDialog(); void cancelled(); protected: FileSource &operator=(const FileSource &); // not provided QUrl m_url; QFtp *m_ftp; QHttp *m_http; QFile *m_localFile; QString m_localFilename; QString m_errorString; QString m_contentType; bool m_ok; int m_lastStatus; bool m_remote; bool m_done; bool m_leaveLocalFile; QProgressDialog *m_progressDialog; QTimer m_progressShowTimer; typedef std::map<QUrl, int> RemoteRefCountMap; typedef std::map<QUrl, QString> RemoteLocalMap; static RemoteRefCountMap m_refCountMap; static RemoteLocalMap m_remoteLocalMap; static QMutex m_mapMutex; bool m_refCounted; void init(bool showProgress); void initHttp(); void initFtp(); void cleanup(); // Create a local file for m_url. If it already existed, return true. // The local filename is stored in m_localFilename. bool createCacheFile(); void deleteCacheFile(); static QMutex m_fileCreationMutex; static int m_count; }; class FileSourceProgressPrinter : public QObject { Q_OBJECT public: FileSourceProgressPrinter(); virtual ~FileSourceProgressPrinter(); public slots: void progress(int); protected: int m_lastProgress; }; #endif