Address review comments from Matt on the sort_includes.py script.

1) Teach it to handle files with #include on the first line -- these do
   actually exist in LLVM.
2) Support llvm-c and clang-c include projects.
3) Nuke some stail imports.
4) Switch to using os.path to split the file extension off.
5) Remove debugging leftovers.
6) Add docstring (a really puny one) for the sort function.

I'm continuing te avoid stripping the whitespace on the RHS to preserve
whatever newline characters happen to be in the original file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169222 91177308-0d34-0410-b5e6-96231b3b80d8

utils/sort_includes.py

@@ -10,13 +10,12 @@
 
 import argparse
 import os
-import re
-import sys
-import tempfile
 
 def sort_includes(f):
+  """Sort the #include lines of a specific file."""
   lines = f.readlines()
-  look_for_api_header = f.name[-4:] == '.cpp'
+  look_for_api_header = os.path.splitext(f.name)[1] == '.cpp'
+  found_headers = False
   headers_begin = 0
   headers_end = 0
   api_headers = []
@@ -27,8 +26,9 @@ def sort_includes(f):
     if l.strip() == '':
       continue
     if l.startswith('#include'):
-      if headers_begin == 0:
+      if not found_headers:
         headers_begin = i
+        found_headers = True
       headers_end = i
       header = l[len('#include'):].lstrip()
       if look_for_api_header and header.startswith('"'):
@@ -38,20 +38,21 @@ def sort_includes(f):
       if header.startswith('<'):
         system_headers.append(header)
         continue
-      if header.startswith('"llvm/') or header.startswith('"clang/'):
+      if (header.startswith('"llvm/') or header.startswith('"llvm-c/') or
+          header.startswith('"clang/') or header.startswith('"clang-c/')):
         project_headers.append(header)
         continue
       local_headers.append(header)
       continue
 
     # Only allow comments and #defines prior to any includes. If either are
     # mixed with includes, the order might be sensitive.
-    if headers_begin != 0:
+    if found_headers:
       break
     if l.startswith('//') or l.startswith('#define') or l.startswith('#ifndef'):
       continue
     break
-  if headers_begin == 0:
+  if not found_headers:
     return
 
   local_headers.sort()
@@ -61,8 +62,6 @@ def sort_includes(f):
   header_lines = ['#include ' + h for h in headers]
   lines = lines[:headers_begin] + header_lines + lines[headers_end + 1:]
 
-  #for l in lines[headers_begin:headers_end]:
-  #  print l.rstrip()
   f.seek(0)
   f.truncate()
   f.writelines(lines)