changelog: swap opener to switch delay modes

mercurial/changelog.py

@@ -1,230 +1,231
 # changelog.py - changelog class for mercurial
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 from node import bin, hex, nullid
 from i18n import _
 import util, error, revlog, encoding
 
 def _string_escape(text):
     """
     >>> d = {'nl': chr(10), 'bs': chr(92), 'cr': chr(13), 'nul': chr(0)}
     >>> s = "ab%(nl)scd%(bs)s%(bs)sn%(nul)sab%(cr)scd%(bs)s%(nl)s" % d
     >>> s
     'ab\\ncd\\\\\\\\n\\x00ab\\rcd\\\\\\n'
     >>> res = _string_escape(s)
     >>> s == res.decode('string_escape')
     True
     """
     # subset of the string_escape codec
     text = text.replace('\\', '\\\\').replace('\n', '\\n').replace('\r', '\\r')
     return text.replace('\0', '\\0')
 
 def decodeextra(text):
     extra = {}
     for l in text.split('\0'):
         if l:
             k, v = l.decode('string_escape').split(':', 1)
             extra[k] = v
     return extra
 
 def encodeextra(d):
     # keys must be sorted to produce a deterministic changelog entry
     items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)]
     return "\0".join(items)
 
 class appender(object):
     '''the changelog index must be updated last on disk, so we use this class
     to delay writes to it'''
     def __init__(self, fp, buf):
         self.data = buf
         self.fp = fp
         self.offset = fp.tell()
         self.size = util.fstat(fp).st_size
 
     def end(self):
         return self.size + len("".join(self.data))
     def tell(self):
         return self.offset
     def flush(self):
         pass
     def close(self):
         self.fp.close()
 
     def seek(self, offset, whence=0):
         '''virtual file offset spans real file and data'''
         if whence == 0:
             self.offset = offset
         elif whence == 1:
             self.offset += offset
         elif whence == 2:
             self.offset = self.end() + offset
         if self.offset < self.size:
             self.fp.seek(self.offset)
 
     def read(self, count=-1):
         '''only trick here is reads that span real file and data'''
         ret = ""
         if self.offset < self.size:
             s = self.fp.read(count)
             ret = s
             self.offset += len(s)
             if count > 0:
                 count -= len(s)
         if count != 0:
             doff = self.offset - self.size
             self.data.insert(0, "".join(self.data))
             del self.data[1:]
             s = self.data[0][doff:doff+count]
             self.offset += len(s)
             ret += s
         return ret
 
     def write(self, s):
         self.data.append(str(s))
         self.offset += len(s)
 
 class changelog(revlog.revlog):
     def __init__(self, opener):
+        revlog.revlog.__init__(self, opener, "00changelog.i")
         self._realopener = opener
         self._delayed = False
         self._divert = False
-        revlog.revlog.__init__(self, self._delayopener, "00changelog.i")
 
     def delayupdate(self):
         "delay visibility of index updates to other readers"
         self._delayed = True
         self._divert = (len(self) == 0)
         self._delaybuf = []
+        self.opener = self._delayopener
 
     def finalize(self, tr):
         "finalize index updates"
         self._delayed = False
+        self.opener = self._realopener
         # move redirected index data back into place
         if self._divert:
             n = self._realopener(self.indexfile).name
             util.rename(n + ".a", n)
         elif self._delaybuf:
             fp = self.opener(self.indexfile, 'a')
             fp.write("".join(self._delaybuf))
             fp.close()
             self._delaybuf = []
         # split when we're done
         self.checkinlinesize(tr)
 
     def _delayopener(self, name, mode='r'):
         fp = self._realopener(name, mode)
         # only divert the index
-        if not self._delayed or not name == self.indexfile:
+        if not name == self.indexfile:
             return fp
         # if we're doing an initial clone, divert to another file
         if self._divert:
             if not len(self):
                 # make sure to truncate the file
                 mode = mode.replace('a', 'w')
             return self._realopener(name + ".a", mode)
         # otherwise, divert to memory
         return appender(fp, self._delaybuf)
 
     def readpending(self, file):
         r = revlog.revlog(self.opener, file)
         self.index = r.index
         self.nodemap = r.nodemap
         self._chunkcache = r._chunkcache
 
     def writepending(self):
         "create a file containing the unfinalized state for pretxnchangegroup"
         if self._delaybuf:
             # make a temporary copy of the index
             fp1 = self._realopener(self.indexfile)
             fp2 = self._realopener(self.indexfile + ".a", "w")
             fp2.write(fp1.read())
             # add pending data
             fp2.write("".join(self._delaybuf))
             fp2.close()
             # switch modes so finalize can simply rename
             self._delaybuf = []
             self._divert = True
 
         if self._divert:
             return True
 
         return False
 
     def checkinlinesize(self, tr, fp=None):
-        if self.opener == self._delayopener:
-            return
-        return revlog.revlog.checkinlinesize(self, tr, fp)
+        if not self._delayed:
+            revlog.revlog.checkinlinesize(self, tr, fp)
 
     def read(self, node):
         """
         format used:
         nodeid\n        : manifest node in ascii
         user\n          : user, no \n or \r allowed
         time tz extra\n : date (time is int or float, timezone is int)
                         : extra is metadatas, encoded and separated by '\0'
                         : older versions ignore it
         files\n\n       : files modified by the cset, no \n or \r allowed
         (.*)            : comment (free text, ideally utf-8)
 
         changelog v0 doesn't use extra
         """
         text = self.revision(node)
         if not text:
             return (nullid, "", (0, 0), [], "", {'branch': 'default'})
         last = text.index("\n\n")
         desc = encoding.tolocal(text[last + 2:])
         l = text[:last].split('\n')
         manifest = bin(l[0])
         user = encoding.tolocal(l[1])
 
         extra_data = l[2].split(' ', 2)
         if len(extra_data) != 3:
             time = float(extra_data.pop(0))
             try:
                 # various tools did silly things with the time zone field.
                 timezone = int(extra_data[0])
             except:
                 timezone = 0
             extra = {}
         else:
             time, timezone, extra = extra_data
             time, timezone = float(time), int(timezone)
             extra = decodeextra(extra)
         if not extra.get('branch'):
             extra['branch'] = 'default'
         files = l[3:]
         return (manifest, user, (time, timezone), files, desc, extra)
 
     def add(self, manifest, files, desc, transaction, p1, p2,
                   user, date=None, extra={}):
         user = user.strip()
         # An empty username or a username with a "\n" will make the
         # revision text contain two "\n\n" sequences -> corrupt
         # repository since read cannot unpack the revision.
         if not user:
             raise error.RevlogError(_("empty username"))
         if "\n" in user:
             raise error.RevlogError(_("username %s contains a newline")
                                     % repr(user))
 
         # strip trailing whitespace and leading and trailing empty lines
         desc = '\n'.join([l.rstrip() for l in desc.splitlines()]).strip('\n')
 
         user, desc = encoding.fromlocal(user), encoding.fromlocal(desc)
 
         if date:
             parseddate = "%d %d" % util.parsedate(date)
         else:
             parseddate = "%d %d" % util.makedate()
         if extra and extra.get("branch") in ("default", ""):
             del extra["branch"]
         if extra:
             extra = encodeextra(extra)
             parseddate = "%s %s" % (parseddate, extra)
         l = [hex(manifest), user, parseddate] + sorted(files) + ["", desc]
         text = "\n".join(l)
         return self.addrevision(text, transaction, len(self), p1, p2)