--- a/mercurial/appendfile.py Thu Mar 22 20:10:46 2007 -0500
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,152 +0,0 @@
-# appendfile.py - special classes to make repo updates atomic
-#
-# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
-#
-# This software may be used and distributed according to the terms
-# of the GNU General Public License, incorporated herein by reference.
-
-import cStringIO, changelog, errno, manifest, os, tempfile, util
-
-# writes to metadata files are ordered. reads: changelog, manifest,
-# normal files. writes: normal files, manifest, changelog.
-
-# manifest contains pointers to offsets in normal files. changelog
-# contains pointers to offsets in manifest. if reader reads old
-# changelog while manifest or normal files are written, it has no
-# pointers into new parts of those files that are maybe not consistent
-# yet, so will not read them.
-
-# localrepo.addchangegroup thinks it writes changelog first, then
-# manifest, then normal files (this is order they are available, and
-# needed for computing linkrev fields), but uses appendfile to hide
-# updates from readers. data not written to manifest or changelog
-# until all normal files updated. write manifest first, then
-# changelog.
-
-# with this write ordering, readers cannot see inconsistent view of
-# repo during update.
-
-class appendfile(object):
- '''implement enough of file protocol to append to revlog file.
- appended data is written to temp file. reads and seeks span real
- file and temp file. readers cannot see appended data until
- writedata called.'''
-
- def __init__(self, fp, tmpname):
- if tmpname:
- self.tmpname = tmpname
- self.tmpfp = util.posixfile(self.tmpname, 'ab+')
- else:
- fd, self.tmpname = tempfile.mkstemp(prefix="hg-appendfile-")
- os.close(fd)
- self.tmpfp = util.posixfile(self.tmpname, 'ab+')
- self.realfp = fp
- self.offset = fp.tell()
- # real file is not written by anyone else. cache its size so
- # seek and read can be fast.
- self.realsize = util.fstat(fp).st_size
- self.name = fp.name
-
- def end(self):
- self.tmpfp.flush() # make sure the stat is correct
- return self.realsize + util.fstat(self.tmpfp).st_size
-
- def tell(self):
- return self.offset
-
- def flush(self):
- self.tmpfp.flush()
-
- def close(self):
- self.realfp.close()
- self.tmpfp.close()
-
- def seek(self, offset, whence=0):
- '''virtual file offset spans real file and temp file.'''
- if whence == 0:
- self.offset = offset
- elif whence == 1:
- self.offset += offset
- elif whence == 2:
- self.offset = self.end() + offset
-
- if self.offset < self.realsize:
- self.realfp.seek(self.offset)
- else:
- self.tmpfp.seek(self.offset - self.realsize)
-
- def read(self, count=-1):
- '''only trick here is reads that span real file and temp file.'''
- fp = cStringIO.StringIO()
- old_offset = self.offset
- if self.offset < self.realsize:
- s = self.realfp.read(count)
- fp.write(s)
- self.offset += len(s)
- if count > 0:
- count -= len(s)
- if count != 0:
- if old_offset != self.offset:
- self.tmpfp.seek(self.offset - self.realsize)
- s = self.tmpfp.read(count)
- fp.write(s)
- self.offset += len(s)
- return fp.getvalue()
-
- def write(self, s):
- '''append to temp file.'''
- self.tmpfp.seek(0, 2)
- self.tmpfp.write(s)
- # all writes are appends, so offset must go to end of file.
- self.offset = self.realsize + self.tmpfp.tell()
-
-class appendopener(object):
- '''special opener for files that only read or append.'''
-
- def __init__(self, opener):
- self.realopener = opener
- self.tmpname = None
-
- def __call__(self, name, mode='r'):
- '''open file.'''
- # only handle .i file
- if not name.endswith("."):
- return self.realopener(name, mode)
- assert mode in 'ra+'
- try:
- realfp = self.realopener(name, 'r')
- except IOError, err:
- if err.errno != errno.ENOENT: raise
- self.realfp = self.realopener(name, 'w+')
- fp = appendfile(realfp, self.tmpname)
- if tmpname is None:
- self.tmpname = fp.tmpname
- self.name = name
- return fp
-
- def writedata(self):
- '''copy data from temp files to real files.'''
- if not self.tmpname:
- return
- ifp = open(self.tmpname, 'rb')
- ofp = self.realopener(self.name, 'a')
- for chunk in util.filechunkiter(ifp):
- ofp.write(chunk)
- ifp.close()
- os.unlink(self.tmpname)
- ofp.close()
-
- def cleanup(self):
- '''delete temp files (this discards unwritten data!)'''
- if self.tmpname:
- os.unlink(self.tmpname)
-
-# files for changelog and manifest are in different appendopeners, so
-# not mixed up together.
-
-class appendchangelog(changelog.changelog, appendopener):
- def __init__(self, opener):
- appendopener.__init__(self, opener)
- changelog.changelog.__init__(self, self)
- def checkinlinesize(self, fp, tr):
- return