tools: rewrite check-install.sh in python

As it is, check-install.sh does not show more helpful error messages,
and supporting various shells could be a problem. This patch rewrites
the same in Python.

This patch also enables check-imports.py in the linting process

PR-URL: #6105
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Makefile

@@ -639,6 +639,7 @@ CPPLINT_FILES = $(filter-out $(CPPLINT_EXCLUDE), $(wildcard \
 
 cpplint:
 	@$(PYTHON) tools/cpplint.py $(CPPLINT_FILES)
+	@$(PYTHON) tools/check-imports.py
 
 ifneq ("","$(wildcard tools/eslint/bin/eslint.js)")
 lint: jslint cpplint

tools/check-imports.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+from __future__ import print_function
+import glob
+import re
+import sys
+
+
+def do_exist(file_name, lines, imported):
+  if not any(not re.match('using \w+::{0};'.format(imported), line) and
+             re.search(imported, line) for line in lines):
+    print('File "{0}" does not use "{1}"'.format(file_name, imported))
+    return False
+  return True
+
+
+def is_valid(file_name):
+  with open(file_name) as source_file:
+    lines = [line.strip() for line in source_file]
+
+  usings, importeds, line_numbers, valid = [], [], [], True
+  for idx, line in enumerate(lines, 1):
+    matches = re.search(r'^using (\w+::(\w+));$', line)
+    if matches:
+      line_numbers.append(idx)
+      usings.append(matches.group(1))
+      importeds.append(matches.group(2))
+
+  valid = all([do_exist(file_name, lines, imported) for imported in importeds])
+
+  sorted_usings = sorted(usings, key=lambda x: x.lower())
+  if sorted_usings != usings:
+    print("using statements aren't sorted in '{0}'.".format(file_name))
+    for num, actual, expected in zip(line_numbers, usings, sorted_usings):
+      if actual != expected:
+        print('\tLine {0}: Actual: {1}, Expected: {2}'
+            .format(num, actual, expected))
+    return False
+  else:
+    return valid
+
+sys.exit(0 if all(map(is_valid, glob.iglob('src/*.cc'))) else 1)