Improved generation of filter subscription files

sitescripts/subscriptions/combineSubscriptions.py

 #!/usr/bin/env python
 # coding: utf-8
 
 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-2013 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 
 import sys, os, re, subprocess, urllib2, time, traceback, codecs, hashlib, base64
 from getopt import getopt, GetoptError
 
-acceptedExtensions = {
-  '.txt': True,
-}
-ignore = {
-  'Apache.txt': True,
-  'CC-BY-SA.txt': True,
-  'GPL.txt': True,
-  'MPL.txt': True,
-}
-verbatim = {
-  'COPYING': True,
-}
-
-def combineSubscriptions(sourceDirs, targetDir, timeout=30):
-  global acceptedExtensions, ignore, verbatim
-
-  if isinstance(sourceDirs, basestring):
-    sourceDirs = {'': sourceDirs}
-
-  if not os.path.exists(targetDir):
-    os.makedirs(targetDir, 0755)
-
-  known = {}
-  for sourceName, sourceDir in sourceDirs.iteritems():
-    for file in os.listdir(sourceDir):
-      if file in ignore or file[0] == '.' or not os.path.isfile(os.path.join(sourceDir, file)):
+accepted_extensions = set([".txt"])
+ignore = set(["Apache.txt", "CC-BY-SA.txt", "GPL.txt", "MPL.txt"])
+verbatim = set(["COPYING"])
+
+def combine_subscriptions(sources, target_dir, timeout=30):
+  if not os.path.exists(target_dir):
+    os.makedirs(target_dir, 0755)
+
+  known = set()
+  for source_name, source in sources.iteritems():
+    for filename in source.list_top_level_files():
+      if filename in ignore or filename.startswith("."):
         continue
-      if file in verbatim:
-        processVerbatimFile(sourceDir, targetDir, file)
-      elif not os.path.splitext(file)[1] in acceptedExtensions:
+      if filename in verbatim:
+        process_verbatim_file(source, target_dir, filename)
+      elif not os.path.splitext(filename)[1] in accepted_extensions:
         continue
       else:
         try:
-          processSubscriptionFile(sourceName, sourceDirs, targetDir, file, timeout)
+          process_subscription_file(source_name, sources, target_dir, filename, timeout)
         except:
-          print >>sys.stderr, 'Error processing subscription file "%s"' % file
+          print >>sys.stderr, 'Error processing subscription file "%s"' % filename
           traceback.print_exc()
           print >>sys.stderr
-        known[os.path.splitext(file)[0] + '.tpl'] = True
-        known[os.path.splitext(file)[0] + '.tpl.gz'] = True
-      known[file] = True
-      known[file + '.gz'] = True
-
-  for file in os.listdir(targetDir):
-    if file[0] == '.':
+        known.add(os.path.splitext(filename)[0] + ".tpl")
+        known.add(os.path.splitext(filename)[0] + ".tpl.gz")
+      known.add(filename)
+      known.add(filename + ".gz")
+
+  for filename in os.listdir(target_dir):
+    if filename.startswith("."):
       continue
-    if not file in known:
-      os.remove(os.path.join(targetDir, file))
-
-def saveFile(filePath, data):
-  handle = codecs.open(filePath, 'wb', encoding='utf-8')
+    if not filename in known:
+      os.remove(os.path.join(target_dir, filename))
+
+def save_file(path, data):
+  handle = codecs.open(path, "wb", encoding="utf-8")
   handle.write(data)
   handle.close()
   try:
-    subprocess.check_output(['7za', 'a', '-tgzip', '-mx=9', '-bd', '-mpass=5', filePath + '.gz', filePath])
+    subprocess.check_output(["7za", "a", "-tgzip", "-mx=9", "-bd", "-mpass=5", path + ".gz", path])
   except:
-    print >>sys.stderr, 'Failed to compress file %s. Please ensure that p7zip is installed on the system.' % filePath
-
-def processVerbatimFile(sourceDir, targetDir, file):
-  handle = codecs.open(os.path.join(sourceDir, file), 'rb', encoding='utf-8')
-  saveFile(os.path.join(targetDir, file), handle.read())
-  handle.close()
-
-def processSubscriptionFile(sourceName, sourceDirs, targetDir, file, timeout):
-  sourceDir = sourceDirs[sourceName]
-  filePath = os.path.join(sourceDir, file)
-  handle = codecs.open(filePath, 'rb', encoding='utf-8')
-  lines = map(lambda l: re.sub(r'[\r\n]', '', l), handle.readlines())
-  handle.close()
-
-  header = ''
+    print >>sys.stderr, "Failed to compress file %s. Please ensure that p7zip is installed on the system." % path
+
+def process_verbatim_file(source, target_dir, filename):
+  save_file(os.path.join(target_dir, filename), source.read_file(filename))
+
+def process_subscription_file(source_name, sources, target_dir, filename, timeout):
+  source = sources[source_name]
+  lines = source.read_file(filename).splitlines()
+
+  header = ""
   if len(lines) > 0:
-    header = lines[0]
-    del lines[0]
-  if not re.search(r'\[Adblock(?:\s*Plus\s*([\d\.]+)?)?\]', header, re.I):
-    raise Exception('This is not a valid Adblock Plus subscription file.')
-
-  lines = resolveIncludes(sourceName, sourceDirs, filePath, lines, timeout)
-  seen = set(['checksum', 'version'])
-  def checkLine(line):
-    if line == '':
+    header = lines.pop(0)
+  if not re.search(r"\[Adblock(?:\s*Plus\s*([\d\.]+)?)?\]", header, re.I):
+    raise Exception("This is not a valid Adblock Plus subscription file.")
+
+  lines = resolve_includes(source_name, sources, lines, timeout)
+  seen = set(["checksum", "version"])
+  def check_line(line):
+    if line == "":
       return False
-    match = re.search(r'^\s*!\s*(Redirect|Homepage|Title|Checksum|Version)\s*:', line, re.M | re.I)
+    match = re.search(r"^\s*!\s*(Redirect|Homepage|Title|Checksum|Version)\s*:", line, re.M | re.I)
     if not match:
       return True
     key = match.group(1).lower()
     if key in seen:
       return False
     seen.add(key)
     return True
-  lines = filter(checkLine, lines)
-
-  writeTPL(os.path.join(targetDir, os.path.splitext(file)[0] + '.tpl'), lines)
-
-  lines.insert(0, '! Version: %s' % time.strftime('%Y%m%d%H%M', time.gmtime()))
+  lines = filter(check_line, lines)
+
+  write_tpl(os.path.join(target_dir, os.path.splitext(filename)[0] + ".tpl"), lines)
+
+  lines.insert(0, "! Version: %s" % time.strftime("%Y%m%d%H%M", time.gmtime()))
 
   checksum = hashlib.md5()
-  checksum.update((header + '\n' + '\n'.join(lines)).encode('utf-8'))
-  lines.insert(0, '! Checksum: %s' % re.sub(r'=', '', base64.b64encode(checksum.digest())))
+  checksum.update("\n".join([header] + lines).encode("utf-8"))
+  lines.insert(0, "! Checksum: %s" % base64.b64encode(checksum.digest()).rstrip("="))
   lines.insert(0, header)
-  saveFile(os.path.join(targetDir, file), '\n'.join(lines))
-
-def resolveIncludes(sourceName, sourceDirs, filePath, lines, timeout, level=0):
+  save_file(os.path.join(target_dir, filename), "\n".join(lines))
+
+def resolve_includes(source_name, sources, lines, timeout, level=0):
   if level > 5:
-    raise Exception('There are too many nested includes, which is probably the result of a circular reference somewhere.')
+    raise Exception("There are too many nested includes, which is probably the result of a circular reference somewhere.")
 
   result = []
   for line in lines:
-    match = re.search(r'^\s*%include\s+(.*)%\s*$', line)
+    match = re.search(r"^\s*%include\s+(.*)%\s*$", line)
     if match:
-      file = match.group(1)
-      newLines = None
-      if re.match(r'^https?://', file):
-        result.append('! *** Fetched from: %s ***' % file)
+      filename = match.group(1)
+      newlines = None
+      if re.match(r"^https?://", filename):
+        result.append("! *** Fetched from: %s ***" % filename)
 
         for i in range(3):
           try:
-            request = urllib2.urlopen(file, None, timeout)
+            request = urllib2.urlopen(filename, None, timeout)
+            data = request.read()
             error = None
             break
           except urllib2.URLError, e:
             error = e
             time.sleep(5)
         if error:
           raise error
 
         # We should really get the charset from the headers rather than assuming
         # that it is UTF-8. However, some of the Google Code mirrors are
         # misconfigured and will return ISO-8859-1 as charset instead of UTF-8.
-        newLines = unicode(request.read(), 'utf-8').split('\n')
-        newLines = map(lambda l: re.sub(r'[\r\n]', '', l), newLines)
-        newLines = filter(lambda l: not re.search(r'^\s*!.*?\bExpires\s*(?::|after)\s*(\d+)\s*(h)?', l, re.M | re.I), newLines)
-        newLines = filter(lambda l: not re.search(r'^\s*!\s*(Redirect|Homepage|Title|Version)\s*:', l, re.M | re.I), newLines)
+        newlines = data.decode("utf-8").splitlines()
+        newlines = filter(lambda l: not re.search(r"^\s*!.*?\bExpires\s*(?::|after)\s*(\d+)\s*(h)?", l, re.M | re.I), newlines)
+        newlines = filter(lambda l: not re.search(r"^\s*!\s*(Redirect|Homepage|Title|Version)\s*:", l, re.M | re.I), newlines)
       else:
-        result.append('! *** %s ***' % file)
-
-        includeSource = sourceName
-        if file.find(':') >= 0:
-          includeSource, file = file.split(':', 1)
-        if not includeSource in sourceDirs:
-          raise Exception('Cannot include file from repository "%s", this repository is unknown' % includeSource)
-
-        parentDir = sourceDirs[includeSource]
-        includePath = os.path.join(parentDir, file)
-        relPath = os.path.relpath(includePath, parentDir)
-        if len(relPath) == 0 or relPath[0] == '.':
-          raise Exception('Invalid include "%s", needs to be an HTTP/HTTPS URL or a relative file path' % file)
-
-        handle = codecs.open(includePath, 'rb', encoding='utf-8')
-        newLines = map(lambda l: re.sub(r'[\r\n]', '', l), handle.readlines())
-        newLines = resolveIncludes(includeSource, sourceDirs, includePath, newLines, timeout, level + 1)
-        handle.close()
-
-      if len(newLines) and re.search(r'\[Adblock(?:\s*Plus\s*([\d\.]+)?)?\]', newLines[0], re.I):
-        del newLines[0]
-      result.extend(newLines)
+        result.append("! *** %s ***" % filename)
+
+        include_source = source_name
+        if ":" in filename:
+          include_source, filename = filename.split(":", 1)
+        if not include_source in sources:
+          raise Exception('Cannot include file from repository "%s", this repository is unknown' % include_source)
+
+        source = sources[include_source]
+        newlines = source.read_file(filename).splitlines()
+        newlines = resolve_includes(include_source, sources, newlines, timeout, level + 1)
+
+      if len(newlines) and re.search(r"\[Adblock(?:\s*Plus\s*([\d\.]+)?)?\]", newlines[0], re.I):
+        del newlines[0]
+      result.extend(newlines)
     else:
-      if line.find('%timestamp%') >= 0:
+      if line.find("%timestamp%") >= 0:
         if level == 0:
-          line = line.replace('%timestamp%', time.strftime('%d %b %Y %H:%M UTC', time.gmtime()))
+          line = line.replace("%timestamp%", time.strftime("%d %b %Y %H:%M UTC", time.gmtime()))
         else:
-          line = ''
+          line = ""
       result.append(line)
   return result
 
-def writeTPL(filePath, lines):
+def write_tpl(path, lines):
   result = []
-  result.append('msFilterList')
+  result.append("msFilterList")
   for line in lines:
-    if re.search(r'^!', line):
+    if re.search(r"^\s*!", line):
       # This is a comment. Handle "Expires" comment in a special way, keep the rest.
-      match = re.search(r'\bExpires\s*(?::|after)\s*(\d+)\s*(h)?', line, re.I)
+      match = re.search(r"\bExpires\s*(?::|after)\s*(\d+)\s*(h)?", line, re.I)
       if match:
         interval = int(match.group(1))
         if match.group(2):
           interval = int(interval / 24)
-        result.append(': Expires=%i' % interval)
+        result.append(": Expires=%i" % interval)
       else:
-        result.append(re.sub(r'!', '#', re.sub(r'--!$', '--#', line)))
-    elif line.find('#') >= 0:
+        result.append(re.sub(r"^\s*!", "#", re.sub(r"--!$", "--#", line)))
+    elif line.find("#") >= 0:
       # Element hiding rules are not supported in MSIE, drop them
       pass
     else:
       # We have a blocking or exception rule, try to convert it
-      origLine = line
-
-      isException = False
-      if line[0:2] == '@@':
-        isException = True
+      origline = line
+
+      is_exception = False
+      if line.startswith("@@"):
+        is_exception = True
         line = line[2:]
 
-      hasUnsupportedOptions = False
-      requiresScript = False
-      match = re.search(r'^(.*?)\$(.*)', line)
+      has_unsupported = False
+      requires_script = False
+      match = re.search(r"^(.*?)\$(.*)", line)
       if match:
         # This rule has options, check whether any of them are important
         line = match.group(1)
-        options = match.group(2).replace('_', '-').lower().split(',')
+        options = match.group(2).replace("_", "-").lower().split(",")
 
         # Remove first-party only exceptions, we will allow an ad server everywhere otherwise
-        if isException and '~third-party' in options:
-          hasUnsupportedOptions = True
+        if is_exception and "~third-party" in options:
+          has_unsupported = True
 
         # A number of options are not supported in MSIE but can be safely ignored, remove them
-        options = filter(lambda o: not o in ('', 'third-party', '~third-party', 'match-case', '~match-case', '~other', '~donottrack'), options)
+        options = filter(lambda o: not o in ("", "third-party", "~third-party", "match-case", "~match-case", "~other", "~donottrack"), options)
 
         # Also ignore domain negation of whitelists
-        if isException:
-          options = filter(lambda o: not o.startswith('domain=~'), options)
-
-        unsupportedOptions = filter(lambda o: o in ('other', 'elemhide'), options)
-        if unsupportedOptions and len(unsupportedOptions) == len(options):
+        if is_exception:
+          options = filter(lambda o: not o.startswith("domain=~"), options)
+
+        unsupported = filter(lambda o: o in ("other", "elemhide"), options)
+        if unsupported and len(unsupported) == len(options):
           # The rule only applies to types that are not supported in MSIE
-          hasUnsupportedOptions = True
-        elif 'donottrack' in options:
+          has_unsupported = True
+        elif "donottrack" in options:
           # Do-Not-Track rules have to be removed even if $donottrack is combined with other options
-          hasUnsupportedOptions = True
-        elif 'script' in options and len(options) == len(unsupportedOptions) + 1:
+          has_unsupported = True
+        elif "script" in options and len(options) == len(unsupported) + 1:
           # Mark rules that only apply to scripts for approximate conversion
-          requiresScript = True
+          requires_script = True
         elif len(options) > 0:
           # The rule has further options that aren't available in TPLs. For
           # exception rules that aren't specific to a domain we ignore all
           # remaining options to avoid potential false positives. Other rules
           # simply aren't included in the TPL file.
-          if isException:
-            hasUnsupportedOptions = any([o.startswith('domain=') for o in options])
+          if is_exception:
+            has_unsupported = any([o.startswith("domain=") for o in options])
           else:
-            hasUnsupportedOptions = True
-
-      if hasUnsupportedOptions:
+            has_unsupported = True
+
+      if has_unsupported:
         # Do not include filters with unsupported options
-        result.append('# ' + origLine)
+        result.append("# " + origline)
       else:
-        line = line.replace('^', '/') # Assume that separator placeholders mean slashes
+        line = line.replace("^", "/") # Assume that separator placeholders mean slashes
 
         # Try to extract domain info
         domain = None
-        match = re.search(r'^(\|\||\|\w+://)([^*:/]+)(:\d+)?(/.*)', line)
+        match = re.search(r"^(\|\||\|\w+://)([^*:/]+)(:\d+)?(/.*)", line)
         if match:
           domain = match.group(2)
           line = match.group(4)
         else:
           # No domain info, remove anchors at the rule start
-          line = re.sub(r'^\|\|', 'http://', line)
-          line = re.sub(r'^\|', '', line)
+          line = re.sub(r"^\|\|", "http://", line)
+          line = re.sub(r"^\|", "", line)
         # Remove anchors at the rule end
-        line = re.sub(r'\|$', '', line)
+        line = re.sub(r"\|$", "", line)
         # Remove unnecessary asterisks at the ends of lines
-        line = re.sub(r'\*$', '', line)
+        line = re.sub(r"\*$", "", line)
         # Emulate $script by appending *.js to the rule
-        if requiresScript:
-          line += '*.js'
-        if line.startswith('/*'):
+        if requires_script:
+          line += "*.js"
+        if line.startswith("/*"):
           line = line[2:]
         if domain:
-          line = '%sd %s %s' % ('+' if isException else '-', domain, line)
-          line = re.sub(r'\s+/$', '', line)
+          line = "%sd %s %s" % ("+" if is_exception else "-", domain, line)
+          line = re.sub(r"\s+/$", "", line)
           result.append(line)
-        elif isException:
+        elif is_exception:
           # Exception rules without domains are unsupported
-          result.append('# ' + origLine)
+          result.append("# " + origline)
         else:
-          result.append('- ' + line)
-  saveFile(filePath, '\n'.join(result) + '\n')
+          result.append("- " + line)
+  save_file(path, "\n".join(result) + "\n")
+
+class FileSource:
+  def __init__(self, dir):
+    self._dir = dir
+    if os.path.exists(os.path.join(dir, ".hg")):
+      # This is a Mercurial repository, try updating
+      subprocess.call(["hg", "-q", "-R", dir, "pull", "--update"])
+
+  def get_path(self, filename):
+    return os.path.join(self._dir, *filename.split("/"))
+
+  def read_file(self, filename):
+    path = self.get_path(filename)
+    if os.path.relpath(path, self._dir).startswith("."):
+      raise Exception("Attempt to access a file outside the repository")
+    with codecs.open(path, "rb", encoding="utf-8") as handle:
+      return handle.read()
+
+  def list_top_level_files(self):
+    for filename in os.listdir(self._dir):
+      path = os.path.join(self._dir, filename)
+      if os.path.isfile(path):
+        yield filename
 
 def usage():
-  print '''Usage: %s [source_dir] [output_dir]
+  print """Usage: %s source_name=source_dir ... [output_dir]
 
 Options:
   -h          --help              Print this message and exit
   -t seconds  --timeout=seconds   Timeout when fetching remote subscriptions
-''' % os.path.basename(sys.argv[0])
-
-if __name__ == '__main__':
+""" % os.path.basename(sys.argv[0])
+
+if __name__ == "__main__":
   try:
-    opts, args = getopt(sys.argv[1:], 'ht:', ['help', 'timeout='])
+    opts, args = getopt(sys.argv[1:], "ht:", ["help", "timeout="])
   except GetoptError, e:
     print str(e)
     usage()
     sys.exit(2)
 
-  sourceDir, targetDir =  '.', 'subscriptions'
-  if len(args) >= 1:
-    sourceDir = args[0]
-  if len(args) >= 2:
-    targetDir = args[1]
+  target_dir = "subscriptions"
+  sources = {}
+  for arg in args:
+    if "=" in arg:
+      source_name, source_dir = arg.split("=", 1)
+      sources[source_name] = FileSource(source_dir)
+    else:
+      target_dir = arg
+  if not sources:
+    sources[""] = FileSource(".")
 
   timeout = 30
   for option, value in opts:
-    if option in ('-h', '--help'):
+    if option in ("-h", "--help"):
       usage()
       sys.exit()
-    elif option in ('-t', '--timeout'):
+    elif option in ("-t", "--timeout"):
       timeout = int(value)
 
-  if os.path.exists(os.path.join(sourceDir, '.hg')):
-    # Our source is a Mercurial repository, try updating
-    subprocess.check_call(['hg', '-q', '-R', sourceDir, 'pull', '--update'])
-
-  combineSubscriptions(sourceDir, targetDir, timeout)
+  combine_subscriptions(sources, target_dir, timeout)