# HG changeset patch
# User Colin McMillen <mcmillen@cs.cmu.edu>
# Date 1146429821 -7200
# Node ID dd4ec4576cc8c72e58921bb35b53ccbd142fdce1
# Parent  d821918e3bee7e6599ce680887e14b7646c62e4f
Proper check to see if zip dest needs to be wrapped in tellable

From hgweb, calling archival.zipit fails with the error message
"Illegal seek". This happens because sys.stdout.tell() throws an
exception:

Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/mercurial/archival.py", line 99, in addfile
    self.z.writestr(i, data)
  File "/usr/lib/python2.4/zipfile.py", line 468, in writestr
    zinfo.header_offset = self.fp.tell()    # Start of header bytes

Checking whether hasattr(dest, 'tell') is insufficient, because
sys.stdout has a tell() method; you just can't call it.

This patch instead determines whether a fileobj is tellable by trying
to tell(), wrapping the fileobj if an exception is generated.



diff -r d821918e3bee -r dd4ec4576cc8 mercurial/archival.py
--- a/mercurial/archival.py	Sun Apr 30 21:11:22 2006 +0200
+++ b/mercurial/archival.py	Sun Apr 30 22:43:41 2006 +0200
@@ -80,8 +80,13 @@
 
     def __init__(self, dest, prefix, compress=True):
         self.prefix = tidyprefix(dest, prefix, ('.zip',))
-        if not isinstance(dest, str) and not hasattr(dest, 'tell'):
-            dest = tellable(dest)
+        if not isinstance(dest, str):
+            try:
+                dest.tell()
+            except AttributeError:
+                dest = tellable(dest)
+            except IOError:
+                dest = tellable(dest)
         self.z = zipfile.ZipFile(dest, 'w',
                                  compress and zipfile.ZIP_DEFLATED or
                                  zipfile.ZIP_STORED)