Speed up filter subscription processing by using a thread pool

sitescripts/subscriptions/combineSubscriptions.py

Index: sitescripts/subscriptions/combineSubscriptions.py
===================================================================
--- a/sitescripts/subscriptions/combineSubscriptions.py
+++ b/sitescripts/subscriptions/combineSubscriptions.py
@@ -11,77 +11,91 @@
 # 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
+import sys, os, re, subprocess, urllib2, time, traceback, codecs, hashlib, base64, multiprocessing, functools
 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 getFiles(sourceDirs):
+  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)):
+        continue
+
+      if file in verbatim:
+        yield (sourceName, sourceDir, file, 'verbatim')
+      elif not os.path.splitext(file)[1] in acceptedExtensions:
+        continue
+      else:
+        yield (sourceName, sourceDir, file, 'subscription')
+
 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)):
-        continue
-      if file in verbatim:
-        processVerbatimFile(sourceDir, targetDir, file)
-      elif not os.path.splitext(file)[1] in acceptedExtensions:
-        continue
-      else:
-        try:
-          processSubscriptionFile(sourceName, sourceDirs, targetDir, file, timeout)
-        except:
-          print >>sys.stderr, 'Error processing subscription file "%s"' % file
-          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
+  pool = multiprocessing.Pool()
+  processor = functools.partial(processFile, sourceDirs, targetDir, timeout)
+  for file, type in pool.imap(processor, getFiles(sourceDirs)):
+    known[file] = True
+    known[file + '.gz'] = True
+    if type == "subscription":
+      known[os.path.splitext(file)[0] + '.tpl'] = True
+      known[os.path.splitext(file)[0] + '.tpl.gz'] = True
 
   for file in os.listdir(targetDir):
     if file[0] == '.':
       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')
   handle.write(data)
   handle.close()
   try:
     subprocess.check_output(['7za', 'a', '-tgzip', '-mx=9', '-bd', '-mpass=15', filePath + '.gz', filePath])
   except:
     print >>sys.stderr, 'Failed to compress file %s. Please ensure that p7zip is installed on the system.' % filePath
 
+def processFile(sourceDirs, targetDir, timeout, (sourceName, sourceDir, file, type)):
+  if type == "verbatim":
+    processVerbatimFile(sourceDir, targetDir, file)
+  else:
+    try:
+      processSubscriptionFile(sourceName, sourceDirs, targetDir, file, timeout)
+    except:
+      print >>sys.stderr, 'Error processing subscription file "%s"' % file
+      traceback.print_exc()
+      print >>sys.stderr
+  return (file, type)
+
 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)