4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
7 * \author Angus Leeming
8 * \author Guillaume Munch
10 * Full author contact details are available in file CREDITS.
12 * FileMonitor monitors a file and informs a listener when that file has
19 #include "support/FileName.h"
20 #include "support/signals.h"
24 #include <QFileSystemWatcher>
33 /// FileMonitor, a file monitor based on QFileSystemWatcher
37 class ActiveFileMonitor;
38 class FileMonitorGuard;
39 typedef std::unique_ptr<FileMonitor> FileMonitorPtr;
40 typedef std::unique_ptr<ActiveFileMonitor> ActiveFileMonitorPtr;
44 /// FileMonitorPtr monitor = FileSystemWatcher::monitor(file_with_path);
45 /// monitor.connect(...); //(using boost::signals2), or:
46 /// connect(monitor, SIGNAL(fileChanged()),...); // (using Qt)
48 /// Remember that a unique_ptr is automatically deleted at the end of a scope if
49 /// it has not been moved, or when assigned. When that happens, the signal
50 /// object is deleted and therefore all the connections are closed. The file
51 /// ceases being tracked when all the monitors for a file have been deleted.
54 /// * as determined statically by the scope, or
55 /// * dynamically, using:
56 /// monitor = nullptr;
58 /// Watch a different file:
59 /// monitor = FileSystemWatcher::monitor(file_with_path2);
60 /// monitor.connect(...);
61 /// (stops watching the first)
63 class FileSystemWatcher
66 /// as described above
67 static FileMonitorPtr monitor(FileName const & filename);
68 /// same but with an ActiveFileMonitor
69 static ActiveFileMonitorPtr activeMonitor(FileName const & filename,
70 int interval = 10000);
71 /// Output whether the paths tracked by qwatcher_ and the active
72 /// FileMonitorGuards are in correspondence.
76 /// A global instance is created automatically on first call
77 static FileSystemWatcher & instance();
79 std::shared_ptr<FileMonitorGuard> getGuard(FileName const & filename);
80 /// Caches the monitor guards but allow them to be destroyed
81 std::map<std::string, std::weak_ptr<FileMonitorGuard>> store_;
82 /// This class is a wrapper for QFileSystemWatcher
83 std::unique_ptr<QFileSystemWatcher> const qwatcher_;
87 /// Must be unique per path
88 /// Ends the watch when deleted
89 class FileMonitorGuard : public QObject
95 FileMonitorGuard(std::string const & filename,
96 QFileSystemWatcher * qwatcher);
99 /// absolute path being tracked
100 std::string const & filename() { return filename_; }
103 /// Make sure it is being monitored, after e.g. a deletion. See
104 /// <https://bugreports.qt.io/browse/QTBUG-46483>. This is called
106 void refresh(bool emit = true);
109 /// Connect to this to be notified when the file changes
110 void fileChanged(bool exists) const;
113 /// Receive notifications from the QFileSystemWatcher
114 void notifyChange(QString const & path);
117 std::string const filename_;
118 QFileSystemWatcher * qwatcher_;
119 /// for emitting fileChanged() when the file is created or deleted
125 class FileMonitor : public QObject
130 FileMonitor(std::shared_ptr<FileMonitorGuard> monitor);
132 typedef signals2::signal<void(bool)> sig;
133 typedef sig::slot_type slot;
134 /// Connect and you'll be informed when the file has changed.
135 signals2::connection connect(slot const &);
136 /// absolute path being tracked
137 std::string const & filename() { return monitor_->filename(); }
138 /// Make sure the good file is being monitored, after e.g. a move or a
139 /// deletion. See <https://bugreports.qt.io/browse/QTBUG-46483>. This is
140 /// called automatically.
141 void refresh() { monitor_->refresh(); }
144 /// Connect to this to be notified when the file changes
145 void fileChanged(bool exists) const;
148 /// Receive notifications from the FileMonitorGuard
149 void changed(bool exists);
151 void connectToFileMonitorGuard();
156 /// the unique watch for our file
157 std::shared_ptr<FileMonitorGuard> const monitor_;
161 /// When a more active monitoring style is needed.
162 /// For instance because QFileSystemWatcher does not work for remote file
164 class ActiveFileMonitor : public FileMonitor
168 ActiveFileMonitor(std::shared_ptr<FileMonitorGuard> monitor,
169 FileName const & filename, int interval);
170 /// call checkModified asynchronously
171 void checkModifiedAsync();
174 /// Check explicitly for a modification, but not more than once every
176 void checkModified();
179 void setCooldown() { cooldown_ = true; }
180 void clearCooldown() { cooldown_ = false; }
183 FileName const filename_;
189 unsigned long checksum_;
195 } // namespace support
198 #endif // FILEMONITOR_H