wp on monitor

src/monitor.d

@@ -0,0 +1,148 @@
+import core.stdc.errno: errno;
+import core.stdc.string: strerror;
+import core.sys.linux.sys.inotify;
+import core.sys.posix.poll;
+import core.sys.posix.unistd;
+import std.file, std.stdio, std.string;
+
+// relevant inotify events
+private immutable uint32_t mask = IN_ATTRIB | IN_CLOSE_WRITE | IN_CREATE |
+	IN_DELETE | IN_MOVE_SELF | IN_MOVE | IN_IGNORED | IN_Q_OVERFLOW;
+
+class MonitorException: Exception
+{
+    this(string msg, string file = __FILE__, size_t line = __LINE__, Throwable next = null)
+    {
+        super(makeErrorMsg(msg), file, line, next);
+    }
+
+    this(string msg, Throwable next, string file = __FILE__, size_t line = __LINE__)
+    {
+        super(makeErrorMsg(msg), file, line, next);
+    }
+
+	private string makeErrorMsg(string msg)
+	{
+		return msg ~ " :" ~ fromStringz(strerror(errno())).idup;
+	}
+}
+
+struct Monitor
+{
+	// inotify file descriptor
+	private int fd;
+	// map every watch descriptor to their dir
+	private string[int] dirs;
+	// map the inotify cookies of move_from events to their path
+	private string[int] moveFromPaths;
+	// buffer to receive the inotify events
+	private void[] buffer;
+
+	void function(string path) onDirCreated;
+	void function(string path) onDirDeleted;
+	void function(string path) onFileChanged;
+	void function(string path) onFileDeleted;
+
+	@disable this(this);
+
+	void init()
+	{
+		fd = inotify_init();
+		if (fd == -1) throw new MonitorException("inotify_init failed");
+		buffer = new void[10000];
+	}
+
+	void shutdown()
+	{
+		if (fd > 0) close(fd);
+	}
+
+	void add(string path)
+	{
+		int wd = inotify_add_watch(fd, toStringz(path), mask);
+		if (wd == -1) throw new MonitorException("inotify_add_watch failed");
+		dirs[wd] = path ~ "/";
+		writeln("Monitor directory: ", path);
+	}
+
+	void addRecursive(string path)
+	{
+		add(path);
+		foreach(DirEntry entry; dirEntries(path, SpanMode.breadth, false)) {
+			if (entry.isDir) add(entry.name);
+		}
+	}
+
+	// remove a watch descriptor
+	private void remove(int wd)
+	{
+		assert(wd in dirs);
+		int ret = inotify_rm_watch(fd, wd);
+		if (ret == -1) throw new MonitorException("inotify_rm_watch failed");
+		writeln("Monitored directory removed: ", dirs[wd]);
+		dirs.remove(wd);
+	}
+
+	// return the file path from an inotify event
+	private string getPath(const(inotify_event)* event)
+	{
+		string path = dirs[event.wd];
+		if (event.len > 0) path ~= fromStringz(event.name.ptr);
+		return path;
+	}
+
+	void update()
+	{
+		pollfd[1] fds;
+		fds[0].fd = fd;
+		fds[0].events = POLLIN;
+		int ret = poll(fds.ptr, 1, 15);
+		if (ret == -1) throw new MonitorException("poll failed");
+		else if (ret == 0) return; // no events available
+
+		assert(fds[0].revents & POLLIN);
+		size_t length = read(fds[0].fd, buffer.ptr, buffer.length);
+		if (length == -1) throw new MonitorException("read failed");
+
+		int i = 0;
+		while ( i < length ) {
+			inotify_event *event = cast(inotify_event*) &buffer[i];
+			if (event.mask & IN_IGNORED) {
+				writeln(dirs);
+				writeln("ignored ", event.wd);
+				// forget the path associated to the watch descriptor
+				dirs.remove(event.wd);
+			} else if (event.mask & IN_Q_OVERFLOW) {
+				writeln("Inotify overflow, events missing");
+			} else if (event.mask & IN_MOVED_FROM) {
+				string path = getPath(event);
+				moveFromPaths[event.cookie] = path;
+				writeln("moved from ", path);
+			} else if (event.mask & IN_MOVED_TO) {
+				string path = getPath(event);
+				writeln("moved to ", path);
+				if (event.mask & IN_ISDIR) addRecursive(path);
+			} else {
+				if (event.mask & IN_ISDIR) {
+					if (event.mask & IN_CREATE) {
+						string path = getPath(event);
+						writeln("Directory created: ", path);
+						add(path);
+					} else if (event.mask & IN_DELETE) {
+						string path = getPath(event);
+						writeln("Directory deleted: ", path);
+					}
+				} else {
+					if (event.mask & IN_ATTRIB || event.mask & IN_CLOSE_WRITE) {
+						string path = getPath(event);
+						writeln("File changed: ", path);
+					} else if (event.mask & IN_DELETE) {
+						string path = getPath(event);
+						writeln("File deleted: ", path);
+					}
+				}
+			}
+			i += inotify_event.sizeof + event.len;
+		}
+	}
+}