Added requirements.txt hook

pre_commit_hooks/requirements_txt_fixer.py

@@ -0,0 +1,82 @@
+from __future__ import print_function
+
+import argparse
+
+from pre_commit_hooks.util import entry
+
+
+class Requirement(object):
+
+    def __init__(self):
+        super(Requirement, self).__init__()
+        self.value = None
+        self.comments = []
+
+    def __lt__(self, requirement):
+        # \n means top of file comment, so always return True,
+        # otherwise just do a string comparison with value.
+        if self.value == b'\n':
+            return True
+        elif requirement.value == b'\n':
+            return False
+        else:
+            return self.value < requirement.value
+
+
+def fix_requirements(f):
+    requirements = []
+    before = []
+    after = []
+
+    for line in f:
+        before.append(line)
+
+        # If the most recent requirement object has a value, then it's time to
+        # start building the next requirement object.
+        if not len(requirements) or requirements[-1].value is not None:
+            requirements.append(Requirement())
+
+        requirement = requirements[-1]
+
+        # If we see a newline before any requirements, then this is a top of
+        # file comment.
+        if len(requirements) == 1 and line.strip() == b'':
+            if len(requirement.comments) and requirement.comments[0].startswith(b'#'):
+                requirement.value = b'\n'
+            else:
+                requirement.comments.append(line)
+        elif line.startswith(b'#') or line.strip() == b'':
+            requirement.comments.append(line)
+        else:
+            requirement.value = line
+
+    for requirement in sorted(requirements):
+        for comment in requirement.comments:
+            after.append(comment)
+        after.append(requirement.value)
+
+    before_string = b''.join(before)
+    after_string = b''.join(after)
+
+    if before_string == after_string:
+        return 0
+    else:
+        f.seek(0)
+        f.write(after_string)
+        f.truncate()
+        return 1
+
+
+@entry
+def fix_requirements_txt(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filenames', nargs='*', help='Filenames to fix')
+    args = parser.parse_args(argv)
+
+    retv = 0
+
+    for arg in args.filenames:
+        with open(arg, 'rb+') as f:
+            retv |= fix_requirements(f)
+
+    return retv