[PATCH 1 of 3] hgweb, templates: add websub template filter

[Angel Ezquerra]

# HG changeset patch
# User Angel Ezquerra <angel.ezquerra at gmail.com>
# Date 1360343132 -3600
# Node ID d2fe4130209f6877d841926df79ba02842c83e20
# Parent  766ad3e48bdff8ee2b2a3a9276eff398dcaafa02
hgweb, templates: add websub template filter

The purpose of this new filter is to make it possible to partially replace the
functionality of the interhg extension. The idea is to be able to define regular
expression based substitutions on a new "websub" config section. hgweb will then
be able to apply these substitutions wherever the "websub" filter is used on a
template.

This first revision just adds the code necessary to load the websub expressions
and adds the websub filter, but it does not add any calls to the websub filter
itself on any of the templates. That will be done on the following revisions.

diff --git a/mercurial/hgweb/hgweb_mod.py b/mercurial/hgweb/hgweb_mod.py
--- a/mercurial/hgweb/hgweb_mod.py
+++ b/mercurial/hgweb/hgweb_mod.py
@@ -8,6 +8,7 @@
 
 import os
 from mercurial import ui, hg, hook, error, encoding, templater, util, repoview
+from mercurial import templatefilters
 from common import get_stat, ErrorResponse, permhooks, caching
 from common import HTTP_OK, HTTP_NOT_MODIFIED, HTTP_BAD_REQUEST
 from common import HTTP_NOT_FOUND, HTTP_SERVER_ERROR
@@ -49,6 +50,9 @@
         urlel = os.path.dirname(urlel)
     return reversed(breadcrumb)
 
+from mercurial.i18n import _
+import re
+websubtable = []
 
 class hgweb(object):
     def __init__(self, repo, name=None, baseui=None):
@@ -73,6 +77,7 @@
         # a repo owner may set web.templates in .hg/hgrc to get any file
         # readable by the user running the CGI script
         self.templatepath = self.config('web', 'templates')
+        self.websubtable = self.loadwebsub()
 
     # The CGI scripts are often run by a user different from the repo owner.
     # Trust the settings from the .hg/hgrc files by default.
@@ -258,6 +263,43 @@
                 return ['']
             return tmpl('error', error=inst.message)
 
+    def loadwebsub(self):
+        websubtable = []
+        for key, pattern in self.repo.ui.configitems('websub'):
+            # grab the delimiter from the character after the "s"
+            unesc = pattern[1]
+            delim = re.escape(unesc)
+
+            # identify portions of the pattern, taking care to avoid escaped
+            # delimiters. the replace format and flags are optional, but delimiters
+            # are required.
+            match = re.match(r'^s%s(.+)(?:(?<=\\\\)|(?<!\\))%s(.*)%s([ilmsux])*$'
+                             % (delim, delim, delim), pattern)
+            if not match:
+                self.repo.ui.warn(_("websub: invalid pattern for %s: %s\n")
+                                  % (key, pattern))
+                continue
+
+            # we need to unescape the delimiter for regexp and format
+            delim_re = re.compile(r'(?<!\\)\\%s' % delim)
+            regexp = delim_re.sub(unesc, match.group(1))
+            format = delim_re.sub(unesc, match.group(2))
+
+            # the pattern allows for 6 regexp flags, so set them if necessary
+            flagin = match.group(3)
+            flags = 0
+            if flagin:
+                for flag in flagin.upper():
+                    flags |= re.__dict__[flag]
+
+            try:
+                regexp = re.compile(regexp, flags)
+                websubtable.append((regexp, format))
+            except re.error:
+                self.repo.ui.warn(_("websub: invalid regexp for %s: %s\n")
+                                  % (key, regexp))
+        return websubtable
+
     def templater(self, req):
 
         # determine scheme, port and server name
@@ -312,8 +354,8 @@
                              or req.url.strip('/') or self.repo.root)
 
         # create the templater
-
         tmpl = templater.templater(mapfile,
+                                   filters={"websub": lambda text: templatefilters.websub(text, self.websubtable)},
                                    defaults={"url": req.url,
                                              "logourl": logourl,
                                              "logoimg": logoimg,
@@ -325,6 +367,7 @@
                                              "motd": motd,
                                              "sessionvars": sessionvars,
                                              "pathdef": makebreadcrumb(req.url),
+                                             "websubtable": self.websubtable,
                                             })
         return tmpl
 
diff --git a/mercurial/templatefilters.py b/mercurial/templatefilters.py
--- a/mercurial/templatefilters.py
+++ b/mercurial/templatefilters.py
@@ -391,6 +391,15 @@
     "xmlescape": xmlescape,
 }
 
+def websub(text, websubtable):
+    """:websub: Any text. Only applies to hgweb. Applies the regular
+    expression replacements defined in the websub section.
+    """
+    if websubtable:
+        for regexp, format in websubtable:
+            text = regexp.sub(format, text)
+    return text
+
 def fillfunc(context, mapping, args):
     if not (1 <= len(args) <= 2):
         raise error.ParseError(_("fill expects one or two arguments"))
@@ -418,6 +427,7 @@
 funcs = {
     "fill": fillfunc,
     "date": datefunc,
+    #"linkify": linkify,
 }
 
 # tell hggettext to extract docstrings from these functions: