statichttprepo: don't send Range header when requesting entire file

When requesting files using statichttprepo.httprangereader, a request for the
entire file is sent with a Range: bytes=0- header. This causes problems with
web servers such as Cherokee that return an HTTP 416 when an empty file is
requested in this way, which in turn cause some repository clone attempts to
fail. This patch omits the Range header when the entire file is being
requested, which fixes the problem.

mercurial/statichttprepo.py

@@ -1,139 +1,140 b''
 # statichttprepo.py - simple http repository class for mercurial
 #
 # This provides read-only repo access to repositories exported via static http
 #
 # 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 or any later version.
 
 from i18n import _
 import changelog, byterange, url, error
 import localrepo, manifest, util, scmutil, store
 import urllib, urllib2, errno
 
 class httprangereader(object):
     def __init__(self, url, opener):
         # we assume opener has HTTPRangeHandler
         self.url = url
         self.pos = 0
         self.opener = opener
         self.name = url
     def seek(self, pos):
         self.pos = pos
     def read(self, bytes=None):
         req = urllib2.Request(self.url)
         end = ''
         if bytes:
             end = self.pos + bytes - 1
-        req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))
+        if self.pos or end:
+            req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))
 
         try:
             f = self.opener.open(req)
             data = f.read()
             # Python 2.6+ defines a getcode() function, and 2.4 and
             # 2.5 appear to always have an undocumented code attribute
             # set. If we can't read either of those, fall back to 206
             # and hope for the best.
             code = getattr(f, 'getcode', lambda : getattr(f, 'code', 206))()
         except urllib2.HTTPError, inst:
             num = inst.code == 404 and errno.ENOENT or None
             raise IOError(num, inst)
         except urllib2.URLError, inst:
             raise IOError(None, inst.reason[1])
 
         if code == 200:
             # HTTPRangeHandler does nothing if remote does not support
             # Range headers and returns the full entity. Let's slice it.
             if bytes:
                 data = data[self.pos:self.pos + bytes]
             else:
                 data = data[self.pos:]
         elif bytes:
             data = data[:bytes]
         self.pos += len(data)
         return data
     def __iter__(self):
         return iter(self.read().splitlines(1))
     def close(self):
         pass
 
 def build_opener(ui, authinfo):
     # urllib cannot handle URLs with embedded user or passwd
     urlopener = url.opener(ui, authinfo)
     urlopener.add_handler(byterange.HTTPRangeHandler())
 
     class statichttpopener(scmutil.abstractopener):
         def __init__(self, base):
             self.base = base
 
         def __call__(self, path, mode="r", atomictemp=None):
             if mode not in ('r', 'rb'):
                 raise IOError('Permission denied')
             f = "/".join((self.base, urllib.quote(path)))
             return httprangereader(f, urlopener)
 
     return statichttpopener
 
 class statichttprepository(localrepo.localrepository):
     def __init__(self, ui, path):
         self._url = path
         self.ui = ui
 
         self.root = path
         u = util.url(path.rstrip('/') + "/.hg")
         self.path, authinfo = u.authinfo()
 
         opener = build_opener(ui, authinfo)
         self.opener = opener(self.path)
         self._phasedefaults = []
 
         try:
             requirements = scmutil.readrequires(self.opener, self.supported)
         except IOError, inst:
             if inst.errno != errno.ENOENT:
                 raise
             requirements = set()
 
             # check if it is a non-empty old-style repository
             try:
                 fp = self.opener("00changelog.i")
                 fp.read(1)
                 fp.close()
             except IOError, inst:
                 if inst.errno != errno.ENOENT:
                     raise
                 # we do not care about empty old-style repositories here
                 msg = _("'%s' does not appear to be an hg repository") % path
                 raise error.RepoError(msg)
 
         # setup store
         self.store = store.store(requirements, self.path, opener)
         self.spath = self.store.path
         self.sopener = self.store.opener
         self.sjoin = self.store.join
         self._filecache = {}
 
         self.manifest = manifest.manifest(self.sopener)
         self.changelog = changelog.changelog(self.sopener)
         self._tags = None
         self.nodetagscache = None
         self._branchcache = None
         self._branchcachetip = None
         self.encodepats = None
         self.decodepats = None
         self.capabilities.difference_update(["pushkey"])
 
     def url(self):
         return self._url
 
     def local(self):
         return False
 
     def lock(self, wait=True):
         raise util.Abort(_('cannot lock static-http repository'))
 
 def instance(ui, path, create):
     if create:
         raise util.Abort(_('cannot create new static-http repository'))
     return statichttprepository(ui, path[7:])