view mercurial/httprangereader.py @ 2735:07026da25ed8

hbisect.py: don't rely on __del__ to write the current state.

This is yet another page of the "Thou shalt not do too much inside
__del__ methods" book, in the "demandload and __del__ don't go well
together" chapter.

The bisect extension is broken in 0.9.1:

$ hg bisect init
$ hg bisect bad
Fatal Python error: Interpreter not initialized (version mismatch?)
Aborted

(yes, I tripled checked my instalation to make sure the problem is not
there)

It's been broken since revision fe1689273f84 moved the import of the
binascii module into a demandload.

(In details: the first time that "hg bisect bad" (or good) is called,
there are still no revisions saved in .hg/bisect/*, so bisect.__init__
doesn't call hg.bin on anything.  So, when we reach __del__, the
binascii module still hasn't been imported and we get that "nice"
message above.)

# httprangereader.py - just what it says
#
# Copyright 2005 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import byterange, urllib2

class httprangereader(object):
    def __init__(self, url):
        self.url = url
        self.pos = 0
    def seek(self, pos):
        self.pos = pos
    def read(self, bytes=None):
        opener = urllib2.build_opener(byterange.HTTPRangeHandler())
        urllib2.install_opener(opener)
        req = urllib2.Request(self.url)
        end = ''
        if bytes:
            end = self.pos + bytes - 1
        req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))
        f = urllib2.urlopen(req)
        data = f.read()
        if bytes:
            data = data[:bytes]
        return data