blackbox: move _openlogfile to a separate method

This removes several `stat` syscalls for accessing `_bbvfs` and makes `ui`
object cleaner.

Differential Revision: https://phab.mercurial-scm.org/D769

hgext/blackbox.py

@@ -1,238 +1,238 b''
 # blackbox.py - log repository events to a file for post-mortem debugging
 #
 # Copyright 2010 Nicolas Dumazet
 # Copyright 2013 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.
 
 """log repository events to a blackbox for debugging
 
 Logs event information to .hg/blackbox.log to help debug and diagnose problems.
 The events that get logged can be configured via the blackbox.track config key.
 
 Examples::
 
   [blackbox]
   track = *
   # dirty is *EXPENSIVE* (slow);
   # each log entry indicates `+` if the repository is dirty, like :hg:`id`.
   dirty = True
   # record the source of log messages
   logsource = True
 
   [blackbox]
   track = command, commandfinish, commandexception, exthook, pythonhook
 
   [blackbox]
   track = incoming
 
   [blackbox]
   # limit the size of a log file
   maxsize = 1.5 MB
   # rotate up to N log files when the current one gets too big
   maxfiles = 3
 
 """
 
 from __future__ import absolute_import
 
 import errno
 import re
 
 from mercurial.i18n import _
 from mercurial.node import hex
 
 from mercurial import (
     registrar,
     ui as uimod,
     util,
 )
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 configitem('blackbox', 'dirty',
     default=False,
 )
 configitem('blackbox', 'maxsize',
     default='1 MB',
 )
 configitem('blackbox', 'logsource',
     default=False,
 )
 
 lastui = None
 
+def _openlogfile(ui, vfs):
+    def rotate(oldpath, newpath):
+        try:
+            vfs.unlink(newpath)
+        except OSError as err:
+            if err.errno != errno.ENOENT:
+                ui.debug("warning: cannot remove '%s': %s\n" %
+                         (newpath, err.strerror))
+        try:
+            if newpath:
+                vfs.rename(oldpath, newpath)
+        except OSError as err:
+            if err.errno != errno.ENOENT:
+                ui.debug("warning: cannot rename '%s' to '%s': %s\n" %
+                         (newpath, oldpath, err.strerror))
+
+    maxsize = ui.configbytes('blackbox', 'maxsize')
+    name = 'blackbox.log'
+    if maxsize > 0:
+        try:
+            st = vfs.stat(name)
+        except OSError:
+            pass
+        else:
+            if st.st_size >= maxsize:
+                path = vfs.join(name)
+                maxfiles = ui.configint('blackbox', 'maxfiles', 7)
+                for i in xrange(maxfiles - 1, 1, -1):
+                    rotate(oldpath='%s.%d' % (path, i - 1),
+                           newpath='%s.%d' % (path, i))
+                rotate(oldpath=path,
+                       newpath=maxfiles > 0 and path + '.1')
+    return vfs(name, 'a')
+
 def wrapui(ui):
     class blackboxui(ui.__class__):
         @property
         def _bbvfs(self):
             vfs = None
             repo = getattr(self, '_bbrepo', None)
             if repo:
                 vfs = repo.vfs
                 if not vfs.isdir('.'):
                     vfs = None
             return vfs
 
         @util.propertycache
         def track(self):
             return self.configlist('blackbox', 'track', ['*'])
 
-        def _openlogfile(self):
-            def rotate(oldpath, newpath):
-                try:
-                    self._bbvfs.unlink(newpath)
-                except OSError as err:
-                    if err.errno != errno.ENOENT:
-                        self.debug("warning: cannot remove '%s': %s\n" %
-                                   (newpath, err.strerror))
-                try:
-                    if newpath:
-                        self._bbvfs.rename(oldpath, newpath)
-                except OSError as err:
-                    if err.errno != errno.ENOENT:
-                        self.debug("warning: cannot rename '%s' to '%s': %s\n" %
-                                   (newpath, oldpath, err.strerror))
-
-            maxsize = self.configbytes('blackbox', 'maxsize')
-            name = 'blackbox.log'
-            if maxsize > 0:
-                try:
-                    st = self._bbvfs.stat(name)
-                except OSError:
-                    pass
-                else:
-                    if st.st_size >= maxsize:
-                        path = self._bbvfs.join(name)
-                        maxfiles = self.configint('blackbox', 'maxfiles', 7)
-                        for i in xrange(maxfiles - 1, 1, -1):
-                            rotate(oldpath='%s.%d' % (path, i - 1),
-                                   newpath='%s.%d' % (path, i))
-                        rotate(oldpath=path,
-                               newpath=maxfiles > 0 and path + '.1')
-            return self._bbvfs(name, 'a')
-
         def log(self, event, *msg, **opts):
             global lastui
             super(blackboxui, self).log(event, *msg, **opts)
 
             if not '*' in self.track and not event in self.track:
                 return
 
             if self._bbvfs:
                 ui = self
             else:
                 # certain ui instances exist outside the context of
                 # a repo, so just default to the last blackbox that
                 # was seen.
                 ui = lastui
 
             if not ui:
                 return
             vfs = ui._bbvfs
             if not vfs:
                 return
 
             repo = getattr(ui, '_bbrepo', None)
             if not lastui or repo:
                 lastui = ui
             if getattr(ui, '_bbinlog', False):
                 # recursion and failure guard
                 return
             ui._bbinlog = True
             default = self.configdate('devel', 'default-date')
             date = util.datestr(default, '%Y/%m/%d %H:%M:%S')
             user = util.getuser()
             pid = '%d' % util.getpid()
             formattedmsg = msg[0] % msg[1:]
             rev = '(unknown)'
             changed = ''
             if repo:
                 ctx = repo[None]
                 parents = ctx.parents()
                 rev = ('+'.join([hex(p.node()) for p in parents]))
                 if (ui.configbool('blackbox', 'dirty') and
                     ctx.dirty(missing=True, merge=False, branch=False)):
                     changed = '+'
             if ui.configbool('blackbox', 'logsource'):
                 src = ' [%s]' % event
             else:
                 src = ''
             try:
                 fmt = '%s %s @%s%s (%s)%s> %s'
                 args = (date, user, rev, changed, pid, src, formattedmsg)
-                with ui._openlogfile() as fp:
+                with _openlogfile(ui, vfs) as fp:
                     fp.write(fmt % args)
             except (IOError, OSError) as err:
                 self.debug('warning: cannot write to blackbox.log: %s\n' %
                            err.strerror)
                 # do not restore _bbinlog intentionally to avoid failed
                 # logging again
             else:
                 ui._bbinlog = False
 
         def setrepo(self, repo):
             self._bbrepo = repo
 
     ui.__class__ = blackboxui
     uimod.ui = blackboxui
 
 def uisetup(ui):
     wrapui(ui)
 
 def reposetup(ui, repo):
     # During 'hg pull' a httppeer repo is created to represent the remote repo.
     # It doesn't have a .hg directory to put a blackbox in, so we don't do
     # the blackbox setup for it.
     if not repo.local():
         return
 
     if util.safehasattr(ui, 'setrepo'):
         ui.setrepo(repo)
 
         # Set lastui even if ui.log is not called. This gives blackbox a
         # fallback place to log.
         global lastui
         if lastui is None:
             lastui = ui
 
     repo._wlockfreeprefix.add('blackbox.log')
 
 @command('^blackbox',
     [('l', 'limit', 10, _('the number of events to show')),
     ],
     _('hg blackbox [OPTION]...'))
 def blackbox(ui, repo, *revs, **opts):
     '''view the recent repository events
     '''
 
     if not repo.vfs.exists('blackbox.log'):
         return
 
     limit = opts.get('limit')
     fp = repo.vfs('blackbox.log', 'r')
     lines = fp.read().split('\n')
 
     count = 0
     output = []
     for line in reversed(lines):
         if count >= limit:
             break
 
         # count the commands by matching lines like: 2013/01/23 19:13:36 root>
         if re.match('^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2} .*> .*', line):
             count += 1
         output.append(line)
 
     ui.status('\n'.join(reversed(output)))