belaran@966: #!/usr/bin/env python
belaran@966: #
belaran@966: # save as .hg/check_whitespace.py and make executable
belaran@966: 
belaran@966: import re
belaran@966: 
belaran@966: def trailing_whitespace(difflines):
belaran@966:     # 
belaran@966:     linenum, header = 0, False
belaran@966: 
belaran@966:     for line in difflines:
belaran@966:         if header:
belaran@966:             # remember the name of the file that this diff affects
belaran@966:             m = re.match(r'(?:---|\+\+\+) ([^\t]+)', line)
belaran@966:             if m and m.group(1) != '/dev/null':
belaran@966:                 filename = m.group(1).split('/', 1)[-1]
belaran@966:             if line.startswith('+++ '):
belaran@966:                 header = False
belaran@966:             continue
belaran@966:         if line.startswith('diff '):
belaran@966:             header = True
belaran@966:             continue
belaran@966:         # hunk header - save the line number
belaran@966:         m = re.match(r'@@ -\d+,\d+ \+(\d+),', line)
belaran@966:         if m:
belaran@966:             linenum = int(m.group(1))
belaran@966:             continue
belaran@966:         # hunk body - check for an added line with trailing whitespace
belaran@966:         m = re.match(r'\+.*\s$', line)
belaran@966:         if m:
belaran@966:             yield filename, linenum
belaran@966:         if line and line[0] in ' +':
belaran@966:             linenum += 1
belaran@966: 
belaran@966: if __name__ == '__main__':
belaran@966:     import os, sys
belaran@966:     
belaran@966:     added = 0
belaran@966:     for filename, linenum in trailing_whitespace(os.popen('hg export tip')):
belaran@966:         print >> sys.stderr, ('%s, line %d: trailing whitespace added' %
belaran@966:                               (filename, linenum))
belaran@966:         added += 1
belaran@966:     if added:
belaran@966:         # save the commit message so we don't need to retype it
belaran@966:         os.system('hg tip --template "{desc}" > .hg/commit.save')
belaran@966:         print >> sys.stderr, 'commit message saved to .hg/commit.save'
belaran@966:         sys.exit(1)