hgweb: allow symbolic revisions with forward slashes in urls

It's possible to have a branch/tag/bookmark with all kinds of special
characters, such as {}/\!?. While not very conveniently, symbolic revisions
with such characters work from command line if user correctly quotes the
characters. These characters also work in hgweb, when they are properly
encoded, with one exception: '/' (forward slash, urlencoded as '%2F'), which
was getting decoded before hgweb could parse it as a part of PATH_INFO.
Because of that, hgweb was seeing it as any other forward slash, that is, as
just another url parts separator.

For example, if user wanted to see the content of dir/file at bookmark
'feature/eggs', url could be: '/file/feature%2Feggs/dir/file'. But hgweb tried
to find a revision 'feature' and get contents of 'eggs/dir/file'.

To fix this, let's assume forward slashes are doubly-urlencoded (%252F), so
CGI/WSGI server decodes it into %2F. Then we can decode %2F in the revision
part of the url into an actual '/' character.

Making hgweb produce such urls will be done in the next 2 patches.

mercurial/hgweb/hgweb_mod.py

@@ -235,7 +235,7 b' class hgweb(object):'
                 req.form['file'] = ['/'.join(args)]
             else:
                 if args and args[0]:
-                    node = args.pop(0)
+                    node = args.pop(0).replace('%2F', '/')
                     req.form['node'] = [node]
                 if args:
                     req.form['file'] = args

tests/test-hgweb.t

@@ -10,6 +10,9 b' Some tests for hgweb. Tests static files'
   $ hg ci -Ambase
   adding da/foo
   adding foo
+  $ hg bookmark -r0 '@'
+  $ hg bookmark -r0 'a b c'
+  $ hg bookmark -r0 'd/e/f'
   $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
   $ cat hg.pid >> $DAEMON_PIDS
 
@@ -264,7 +267,7 b' try bad style'
   <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2>
   <h3>
    directory / @ 0:<a href="/rev/2ef0ac749a14">2ef0ac749a14</a>
-   <span class="tag">tip</span> 
+   <span class="tag">tip</span> <span class="tag">@</span> <span class="tag">a b c</span> <span class="tag">d/e/f</span> 
   </h3>
   
   <form class="search" action="/log">
@@ -557,6 +560,9 b' phase changes are refreshed (issue4061)'
   summary:     base
   branch:      default
   tag:         tip
+  bookmark:    @
+  bookmark:    a b c
+  bookmark:    d/e/f
   
   
   $ hg phase --draft tip
@@ -580,8 +586,29 b' phase changes are refreshed (issue4061)'
   user:        test
   date:        Thu, 01 Jan 1970 00:00:00 +0000
   summary:     base
+  bookmark:    @
+  bookmark:    a b c
+  bookmark:    d/e/f
+  
   
   
+access bookmarks
+
+  $ get-with-headers.py localhost:$HGPORT 'rev/@?style=paper' | egrep '^200|changeset 0:'
+  200 Script output follows
+   changeset 0:<a href="/rev/2ef0ac749a14?style=paper">2ef0ac749a14</a>
+
+  $ get-with-headers.py localhost:$HGPORT 'rev/%40?style=paper' | egrep '^200|changeset 0:'
+  200 Script output follows
+   changeset 0:<a href="/rev/2ef0ac749a14?style=paper">2ef0ac749a14</a>
+
+  $ get-with-headers.py localhost:$HGPORT 'rev/a%20b%20c?style=paper' | egrep '^200|changeset 0:'
+  200 Script output follows
+   changeset 0:<a href="/rev/2ef0ac749a14?style=paper">2ef0ac749a14</a>
+
+  $ get-with-headers.py localhost:$HGPORT 'rev/d%252Fe%252Ff?style=paper' | egrep '^200|changeset 0:'
+  200 Script output follows
+   changeset 0:<a href="/rev/2ef0ac749a14?style=paper">2ef0ac749a14</a>
 
 no style can be loaded from directories other than the specified paths