diff hgext/fsmonitor/watchmanclient.py @ 28433:3b67f27bb908

fsmonitor: new experimental extension

Extension to plug into a Watchman daemon, speeding up hg status calls by
relying on OS events to tell us what files have changed.

Originally developed at https://bitbucket.org/facebook/hgwatchman

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/fsmonitor/watchmanclient.py	Thu Mar 03 14:29:19 2016 +0000
@@ -0,0 +1,109 @@
+# watchmanclient.py - Watchman client for the fsmonitor extension
+#
+# Copyright 2013-2016 Facebook, Inc.
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+
+from __future__ import absolute_import
+
+import getpass
+
+from mercurial import util
+
+from . import pywatchman
+
+class Unavailable(Exception):
+    def __init__(self, msg, warn=True, invalidate=False):
+        self.msg = msg
+        self.warn = warn
+        if self.msg == 'timed out waiting for response':
+            self.warn = False
+        self.invalidate = invalidate
+
+    def __str__(self):
+        if self.warn:
+            return 'warning: Watchman unavailable: %s' % self.msg
+        else:
+            return 'Watchman unavailable: %s' % self.msg
+
+class WatchmanNoRoot(Unavailable):
+    def __init__(self, root, msg):
+        self.root = root
+        super(WatchmanNoRoot, self).__init__(msg)
+
+class client(object):
+    def __init__(self, repo, timeout=1.0):
+        err = None
+        if not self._user:
+            err = "couldn't get user"
+            warn = True
+        if self._user in repo.ui.configlist('fsmonitor', 'blacklistusers'):
+            err = 'user %s in blacklist' % self._user
+            warn = False
+
+        if err:
+            raise Unavailable(err, warn)
+
+        self._timeout = timeout
+        self._watchmanclient = None
+        self._root = repo.root
+        self._ui = repo.ui
+        self._firsttime = True
+
+    def settimeout(self, timeout):
+        self._timeout = timeout
+        if self._watchmanclient is not None:
+            self._watchmanclient.setTimeout(timeout)
+
+    def getcurrentclock(self):
+        result = self.command('clock')
+        if not util.safehasattr(result, 'clock'):
+            raise Unavailable('clock result is missing clock value',
+                              invalidate=True)
+        return result.clock
+
+    def clearconnection(self):
+        self._watchmanclient = None
+
+    def available(self):
+        return self._watchmanclient is not None or self._firsttime
+
+    @util.propertycache
+    def _user(self):
+        try:
+            return getpass.getuser()
+        except KeyError:
+            # couldn't figure out our user
+            return None
+
+    def _command(self, *args):
+        watchmanargs = (args[0], self._root) + args[1:]
+        try:
+            if self._watchmanclient is None:
+                self._firsttime = False
+                self._watchmanclient = pywatchman.client(
+                    timeout=self._timeout,
+                    useImmutableBser=True)
+            return self._watchmanclient.query(*watchmanargs)
+        except pywatchman.CommandError as ex:
+            if ex.msg.startswith('unable to resolve root'):
+                raise WatchmanNoRoot(self._root, ex.msg)
+            raise Unavailable(ex.msg)
+        except pywatchman.WatchmanError as ex:
+            raise Unavailable(str(ex))
+
+    def command(self, *args):
+        try:
+            try:
+                return self._command(*args)
+            except WatchmanNoRoot:
+                # this 'watch' command can also raise a WatchmanNoRoot if
+                # watchman refuses to accept this root
+                self._command('watch')
+                return self._command(*args)
+        except Unavailable:
+            # this is in an outer scope to catch Unavailable form any of the
+            # above _command calls
+            self._watchmanclient = None
+            raise