1 files changed, 102 insertions, 0 deletions
diff --git a/buildbot/buildbot/dnotify.py b/buildbot/buildbot/dnotify.py
new file mode 100644
index 0000000..d23d600
--- /dev/null
+++ b/buildbot/buildbot/dnotify.py
@@ -0,0 +1,102 @@
+
+# spiv wants this
+
+import fcntl, signal
+
+class DNotify_Handler:
+    def __init__(self):
+        self.watchers = {}
+        self.installed = 0
+    def install(self):
+        if self.installed:
+            return
+        signal.signal(signal.SIGIO, self.fire)
+        self.installed = 1
+    def uninstall(self):
+        if not self.installed:
+            return
+        signal.signal(signal.SIGIO, signal.SIG_DFL)
+        self.installed = 0
+    def add(self, watcher):
+        self.watchers[watcher.fd.fileno()] = watcher
+        self.install()
+    def remove(self, watcher):
+        if self.watchers.has_key(watcher.fd.fileno()):
+            del(self.watchers[watcher.fd.fileno()])
+            if not self.watchers:
+                self.uninstall()
+    def fire(self, signum, frame):
+        # this is the signal handler
+        # without siginfo_t, we must fire them all
+        for watcher in self.watchers.values():
+            watcher.callback()
+            
+class DNotify:
+    DN_ACCESS = fcntl.DN_ACCESS  # a file in the directory was read
+    DN_MODIFY = fcntl.DN_MODIFY  # a file was modified (write,truncate)
+    DN_CREATE = fcntl.DN_CREATE  # a file was created
+    DN_DELETE = fcntl.DN_DELETE  # a file was unlinked
+    DN_RENAME = fcntl.DN_RENAME  # a file was renamed
+    DN_ATTRIB = fcntl.DN_ATTRIB  # a file had attributes changed (chmod,chown)
+
+    handler = [None]
+    
+    def __init__(self, dirname, callback=None,
+                 flags=[DN_MODIFY,DN_CREATE,DN_DELETE,DN_RENAME]):
+
+        """This object watches a directory for changes. The .callback
+        attribute should be set to a function to be run every time something
+        happens to it. Be aware that it will be called more times than you
+        expect."""
+
+        if callback:
+            self.callback = callback
+        else:
+            self.callback = self.fire
+        self.dirname = dirname
+        self.flags = reduce(lambda x, y: x | y, flags) | fcntl.DN_MULTISHOT
+        self.fd = open(dirname, "r")
+        # ideally we would move the notification to something like SIGRTMIN,
+        # (to free up SIGIO) and use sigaction to have the signal handler
+        # receive a structure with the fd number. But python doesn't offer
+        # either.
+        if not self.handler[0]:
+            self.handler[0] = DNotify_Handler()
+        self.handler[0].add(self)
+        fcntl.fcntl(self.fd, fcntl.F_NOTIFY, self.flags)
+    def remove(self):
+        self.handler[0].remove(self)
+        self.fd.close()
+    def fire(self):
+        print self.dirname, "changed!"
+
+def test_dnotify1():
+    d = DNotify(".")
+    while 1:
+        signal.pause()
+
+def test_dnotify2():
+    # create ./foo/, create/delete files in ./ and ./foo/ while this is
+    # running. Notice how both notifiers are fired when anything changes;
+    # this is an unfortunate side-effect of the lack of extended sigaction
+    # support in Python.
+    count = [0]
+    d1 = DNotify(".")
+    def fire1(count=count, d1=d1):
+        print "./ changed!", count[0]
+        count[0] += 1
+        if count[0] > 5:
+            d1.remove()
+            del(d1)
+    # change the callback, since we can't define it until after we have the
+    # dnotify object. Hmm, unless we give the dnotify to the callback.
+    d1.callback = fire1
+    def fire2(): print "foo/ changed!"
+    d2 = DNotify("foo", fire2)
+    while 1:
+        signal.pause()
+        
+    
+if __name__ == '__main__':
+    test_dnotify2()
+