Mercurial > hg > svcore
view data/fileio/FileSource.h @ 1517:925d205c39b4 import-audio-data
Handle sample range specification for CSV import
author | Chris Cannam |
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date | Sat, 08 Sep 2018 20:43:14 +0100 |
parents | 329ddaf7415d |
children | ad5f892c0c4d |
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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 _FILE_SOURCE_H_ #define _FILE_SOURCE_H_ #include <QUrl> #include <QMutex> #include <QString> #include <QTimer> #include <QNetworkReply> #include <map> #include "base/Debug.h" class QFile; class ProgressReporter; /** * 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 a ProgressReporter is provided, it will be updated with * progress status. Note that the progress() signal will also be * emitted regularly during retrieval, even if no reporter is * supplied here. Caller retains ownership of the reporter object. */ FileSource(QString fileOrUrl, ProgressReporter *reporter = 0, QString preferredContentType = ""); /** * Construct a FileSource using the given remote URL. * * If a ProgressReporter is provided, it will be updated with * progress status. Note that the progress() signal will also be * emitted regularly during retrieval, even if no reporter is * supplied here. Caller retains ownership of the reporter object. */ FileSource(QUrl url, ProgressReporter *reporter = 0); 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 neither error * nor cancellation occurred while retrieving 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 the operation was cancelled by the user through * the ProgressReporter interface. Note that the cancelled() * signal will have been emitted, and isOK() will also return * false in this case. */ bool wasCancelled() const; /** * Return true if this FileSource is referring to a QRC resource. */ bool isResource() 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 base name, i.e. the final path element (including * extension, if any) of the location. */ QString getBasename() const; /** * Return the MIME content type of this file, if known. */ QString getContentType() const; /** * Return the file extension for this file, if any. The returned * extension is always lower-case. */ 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); /** * Print some stats, if FileSource was compiled with debugging. * It's safe to leave a call to this function in release code, as * long as FileSource itself is compiled with release flags. */ static void debugReport(); 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 metaDataChanged(); void readyRead(); void replyFailed(QNetworkReply::NetworkError); void replyFinished(); void downloadProgress(qint64 done, qint64 total); void cancelled(); protected: FileSource &operator=(const FileSource &); // not provided QString m_rawFileOrUrl; QUrl m_url; QFile *m_localFile; QNetworkReply *m_reply; QString m_localFilename; QString m_errorString; QString m_contentType; QString m_preferredContentType; bool m_ok; bool m_cancelled; int m_lastStatus; bool m_resource; bool m_remote; bool m_done; bool m_leaveLocalFile; ProgressReporter *m_reporter; 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(); void initRemote(); 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; }; #endif