tests/test-hgweb-no-path-info.t

osutil: implement setprocname to set process title for some platforms

This patch adds a simple setprocname method to osutil. The operation is not
defined by any standard and is platform-specific, the current implementation
tries to cover some major platforms (ex. Linux, OS X, FreeBSD) that is
relatively easy to support. Other platforms (Windows [4], other BSDs, ...)
can be added in the future.

The current implementation supports two methods to change process title:
  a. setproctitle if available (works in FreeBSD).
  b. rewrite argv in place (works in Linux [1] and Mac OS X). [2] [3]

[1]: Linux has "prctl(PR_SET_NAME, ...)" but 1) it has 16-byte limit, which
is too small; 2) it is not quite equivalent to what we want - it changes
"/proc/self/comm", not "/proc/self/cmdline" - "comm" change won't show up
in "ps" output unless "-o comm" is used.

[2]: The implementation does not rewrite the **environ buffer like some
other implementations do, just to make the code simpler and safer. However,
this also means the buffer size we can rewrite is significantly shorter. If
we are really greedy and want the "environ" space, we can change the
implementation later.

[3]: It requires a CPython private API: Py_GetArgcArgv to get the original
argv. Unfortunately Python 3 makes a copy of argv and returns the wchar_t
version, so it is not supported for now. (if we really want to, we could
count backwards from "char **environ", given known argc and argv, not sure
if that's a good idea - probably not)

[4]: The feature is aimed to make it easier for forked command server
processes to show what they are doing. Since Windows does not support
fork(), despite it's a major platform, its support is not added in this
patch.

This tests if hgweb and hgwebdir still work if the REQUEST_URI variable is
no longer passed with the request. Instead, SCRIPT_NAME and PATH_INFO
should be used from d74fc8dec2b4 onward to route the request.

  $ hg init repo
  $ cd repo
  $ echo foo > bar
  $ hg add bar
  $ hg commit -m "test"
  $ hg tip
  changeset:   0:61c9426e69fe
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  
  $ cat > request.py <<EOF
  > from __future__ import absolute_import
  > import os
  > import sys
  > from mercurial.hgweb import (
  >     hgweb,
  >     hgwebdir,
  > )
  > from mercurial import (
  >     util,
  > )
  > stringio = util.stringio
  > 
  > errors = stringio()
  > input = stringio()
  > 
  > def startrsp(status, headers):
  >     print '---- STATUS'
  >     print status
  >     print '---- HEADERS'
  >     print [i for i in headers if i[0] != 'ETag']
  >     print '---- DATA'
  >     return output.write
  > 
  > env = {
  >     'wsgi.version': (1, 0),
  >     'wsgi.url_scheme': 'http',
  >     'wsgi.errors': errors,
  >     'wsgi.input': input,
  >     'wsgi.multithread': False,
  >     'wsgi.multiprocess': False,
  >     'wsgi.run_once': False,
  >     'REQUEST_METHOD': 'GET',
  >     'PATH_INFO': '/',
  >     'SCRIPT_NAME': '',
  >     'SERVER_NAME': '127.0.0.1',
  >     'SERVER_PORT': os.environ['HGPORT'],
  >     'SERVER_PROTOCOL': 'HTTP/1.0'
  > }
  > 
  > def process(app):
  >     content = app(env, startrsp)
  >     sys.stdout.write(output.getvalue())
  >     sys.stdout.write(''.join(content))
  >     getattr(content, 'close', lambda : None)()
  >     print '---- ERRORS'
  >     print errors.getvalue()
  > 
  > output = stringio()
  > env['QUERY_STRING'] = 'style=atom'
  > process(hgweb('.', name='repo'))
  > 
  > output = stringio()
  > env['QUERY_STRING'] = 'style=raw'
  > process(hgwebdir({'repo': '.'}))
  > EOF
  $ python request.py
  ---- STATUS
  200 Script output follows
  ---- HEADERS
  [('Content-Type', 'application/atom+xml; charset=ascii')]
  ---- DATA
  <?xml version="1.0" encoding="ascii"?>
  <feed xmlns="http://www.w3.org/2005/Atom">
   <!-- Changelog -->
   <id>http://127.0.0.1:$HGPORT/</id> (glob)
   <link rel="self" href="http://127.0.0.1:$HGPORT/atom-log"/> (glob)
   <link rel="alternate" href="http://127.0.0.1:$HGPORT/"/> (glob)
   <title>repo Changelog</title>
   <updated>1970-01-01T00:00:00+00:00</updated>
  
   <entry>
    <title>[default] test</title>
    <id>http://127.0.0.1:$HGPORT/#changeset-61c9426e69fef294feed5e2bbfc97d39944a5b1c</id> (glob)
    <link href="http://127.0.0.1:$HGPORT/rev/61c9426e69fe"/> (glob)
    <author>
     <name>test</name>
     <email>&#116;&#101;&#115;&#116;</email>
    </author>
    <updated>1970-01-01T00:00:00+00:00</updated>
    <published>1970-01-01T00:00:00+00:00</published>
    <content type="xhtml">
     <table xmlns="http://www.w3.org/1999/xhtml">
      <tr>
       <th style="text-align:left;">changeset</th>
       <td>61c9426e69fe</td>
      </tr>
      <tr>
       <th style="text-align:left;">branch</th>
       <td>default</td>
      </tr>
      <tr>
       <th style="text-align:left;">bookmark</th>
       <td></td>
      </tr>
      <tr>
       <th style="text-align:left;">tag</th>
       <td>tip</td>
      </tr>
      <tr>
       <th style="text-align:left;">user</th>
       <td>&#116;&#101;&#115;&#116;</td>
      </tr>
      <tr>
       <th style="text-align:left;vertical-align:top;">description</th>
       <td>test</td>
      </tr>
      <tr>
       <th style="text-align:left;vertical-align:top;">files</th>
       <td>bar<br /></td>
      </tr>
     </table>
    </content>
   </entry>
  
  </feed>
  ---- ERRORS
  
  ---- STATUS
  200 Script output follows
  ---- HEADERS
  [('Content-Type', 'text/plain; charset=ascii')]
  ---- DATA
  
  /repo/
  
  ---- ERRORS
  

  $ cd ..