Creating a file system watcher for Mac
Archives Forums/MacOS X Discussion/Creating a file system watcher for Mac
| ||
| I'm attempting to create a file system watcher like Windows has: http://blitzmax.com/codearcs/codearcs.php?code=2747 I'm including a single .mm file in my BlitzMax project and wrapping the code up so my BlitzMax program can just call a few functions and detect file changes to a directory I am watching. http://developer.apple.com/library/mac/#documentation/Darwin/Conceptual/FSEvents_ProgGuide/UsingtheFSEventsFramework/UsingtheFSEventsFramework.html I wrote some code out to the best of my ability below, but I am completely confounded with Objective-C and the FSEventStream API: #include <CoreServices/CoreServices.h>
FSEventStreamRef fsevenrstreamref;
void Callback(ConstFSEventStreamRef streamRef,void *clientCallBackInfo,size_t numEvents,void *eventPaths,const FSEventStreamEventFlags eventFlags[],const FSEventStreamEventId eventIds[])
{
printf("File change occured!\n");
}
void InitializeFSEventStream(std::string path)
{
CFAllocatorRef allocator = NULL;
FSEventStreamCallback callback = Callback;
FSEventStreamContext *context = NULL;
CFArrayRef pathsToWatch;//???
FSEventStreamEventId sinceWhen = kFSEventStreamEventIdSinceNow;
CFTimeInterval latency = 1;
FSEventStreamCreateFlags flags = kFSEventStreamCreateFlagFileEvents;
fsevenrstreamref = FSEventStreamCreate(allocator,callback,context,pathsToWatch,sinceWhen,latency,flags);
CFRunLoopRef runLoop;//???
CFStringRef runLoopMode;//???
FSEventStreamScheduleWithRunLoop(fsevenrstreamref,runLoop,runLoopMode);
}
void UpdateFSEventStream()
{
if (fsevenrstreamref.Start())
{
fsevenrstreamref.Stop()
}
}
Are there any simple examples available that will do what I am trying to do? Thank you. |
| ||
| I'm making some progress here: https://devforums.apple.com/message/748539 |
| ||
| Here's a failed attempt that only watches a single file path: http://www.leadwerks.com/werkspace/files/file/380-failed-attempt-at-a-filesystem-watcher-for-mac/ |
| ||
| A quick google on the subject found this alternative approach. http://stackoverflow.com/questions/11556545/fsevents-c-example Sticking with an objective c solution will help you become expert in OSX which is always a good thing of course. |
| ||
I ran the code from Xcode. Had to make one small change. It detects events but does not appear to be recursive://
// main.cpp
// FileWatch
//
// Created by Josh Klint on 10/30/12.
// Copyright (c) 2012 Josh Klint. All rights reserved.
//
#include <iostream>
#include <errno.h> // for errno
#include <fcntl.h> // for O_RDONLY
#include <stdio.h> // for fprintf()
#include <stdlib.h> // for EXIT_SUCCESS
#include <string.h> // for strerror()
#include <sys/event.h> // for kqueue() etc.
#include <unistd.h> // for close()
int main (int argc, const char *argv[])
{
int kq = kqueue ();
char *dirname = "./";
// dir name is in argv[1], NO checks for errors here
int dirfd = open (dirname, O_RDONLY);
struct kevent direvent;
EV_SET (&direvent, dirfd, EVFILT_VNODE, EV_ADD | EV_CLEAR | EV_ENABLE,
NOTE_WRITE, 0, (void *)dirname);
kevent(kq, &direvent, 1, NULL, 0, NULL);
// Register interest in SIGINT with the queue. The user data
// is NULL, which is how we'll differentiate between
// a directory-modification event and a SIGINT-received event.
struct kevent sigevent;
EV_SET (&sigevent, SIGINT, EVFILT_SIGNAL, EV_ADD | EV_ENABLE, 0, 0, NULL);
// kqueue event handling happens after the legacy API, so make
// sure it doesn eat the signal before the kqueue can see it.
signal (SIGINT, SIG_IGN);
// Register the signal event.
kevent(kq, &sigevent, 1, NULL, 0, NULL);
while (1) {
// camp on kevent() until something interesting happens
struct kevent change;
if (kevent(kq, NULL, 0, &change, 1, NULL) == -1) { exit(1); }
// The signal event has NULL in the user data. Check for that first.
if (change.udata == NULL) {
break;
} else {
// udata is non-null, so it's the name of the directory
printf ("%s\n", (char*)change.udata);
}
}
close (kq);
return 0;
}Last edited 2012 |
| ||
| I figured it out. It will take extra work because the granularity of the Mac FSEvents system is not as fine as I would like, but I'm done with the Objective-C stuff. |
| ||
| I finished it: http://www.leadwerks.com/werkspace/blog/1/entry-1005-halloween-horrors-with-objective-c/ |