scripts: docs-headings: improve performance by grouping 'hg diff' invocations

With SSD, this change reduces the execution time of this script from 8 to
0.5 seconds

scripts/docs-headings.py

@@ -1,79 +1,80 b''
 #!/usr/bin/env python2
 
 """
 Consistent formatting of rst section titles
 """
 
 import re
 import subprocess
 
 spaces = [
     (0, 1), # we assume this is a over-and-underlined header
     (2, 1),
     (1, 1),
     (1, 0),
     (1, 0),
     ]
 
 # http://sphinx-doc.org/rest.html :
 #   for the Python documentation, this convention is used which you may follow:
 #   # with overline, for parts
 #   * with overline, for chapters
 #   =, for sections
 #   -, for subsections
 #   ^, for subsubsections
 #   ", for paragraphs
 pystyles = ['#', '*', '=', '-', '^', '"']
 
 # match on a header line underlined with one of the valid characters
 headermatch = re.compile(r'''\n*(.+)\n([][!"#$%&'()*+,./:;<=>?@\\^_`{|}~-])\2{2,}\n+''', flags=re.MULTILINE)
 
 
 def main():
-    for fn in subprocess.check_output(['hg', 'loc', 'set:**.rst+kallithea/i18n/how_to']).splitlines():
-        print 'processing %s:' % fn
+    filenames = subprocess.check_output(['hg', 'loc', 'set:**.rst+kallithea/i18n/how_to']).splitlines()
+    for fn in filenames:
+        print 'processing %s' % fn
         s = open(fn).read()
 
         # find levels and their styles
         lastpos = 0
         styles = []
         for markup in headermatch.findall(s):
             style = markup[1]
             if style in styles:
                 stylepos = styles.index(style)
                 if stylepos > lastpos + 1:
                     print 'bad style %r with level %s - was at %s' % (style, stylepos, lastpos)
             else:
                 stylepos = len(styles)
                 if stylepos > lastpos + 1:
                     print 'bad new style %r - expected %r' % (style, styles[lastpos + 1])
                 else:
                     styles.append(style)
             lastpos = stylepos
 
         # remove superfluous spacing (may however be restored by header spacing)
         s = re.sub(r'''(\n\n)\n*''', r'\1', s, flags=re.MULTILINE)
 
         if styles:
             newstyles = pystyles[pystyles.index(styles[0]):]
 
             def subf(m):
                 title, style = m.groups()
                 level = styles.index(style)
                 before, after = spaces[level]
                 newstyle = newstyles[level]
                 return '\n' * (before + 1) + title + '\n' + newstyle * len(title) + '\n' * (after + 1)
             s = headermatch.sub(subf, s)
 
         # remove superfluous spacing when headers are adjacent
         s = re.sub(r'''(\n.+\n([][!"#$%&'()*+,./:;<=>?@\\^_`{|}~-])\2{2,}\n\n\n)\n*''', r'\1', s, flags=re.MULTILINE)
         # fix trailing space and spacing before link sections
         s = s.strip() + '\n'
         s = re.sub(r'''\n+((?:\.\. _[^\n]*\n)+)$''', r'\n\n\n\1', s)
 
         open(fn, 'w').write(s)
-        print subprocess.check_output(['hg', 'diff', fn])
-        print
+
+    print subprocess.check_output(['hg', 'diff'] + filenames)
 
 if __name__ == '__main__':
     main()