WIP: Lint script from stdin (#240)

test/unit/vint/linting/test_cli.py

@@ -56,5 +56,10 @@ def test_start_with_both_calid_invalid_file_paths(self):
         self.assertExitWithFailure(argv)
 
 
+    @mock.patch('sys.stdin', open('test/fixture/cli/valid1.vim'))
+    def test_passing_code_to_stdin_lints_the_code_from_stdin(self):
+        argv = ['bin/vint', '-']
+        self.assertExitWithSuccess(argv)
+
 if __name__ == '__main__':
     unittest.main()

vint/linting/cli.py

@@ -1,5 +1,6 @@
 import sys
 from argparse import ArgumentParser
+from pathlib import PosixPath
 import pkg_resources
 import logging
 
@@ -15,7 +16,6 @@
 from vint.linting.formatter.json_formatter import JSONFormatter
 from vint.linting.formatter.statistic_formatter import StatisticFormatter
 
-
 class CLI(object):
     def start(self):
         env = self._build_env(sys.argv)
@@ -44,11 +44,12 @@ def _validate(self, env):
             parser.print_help()
             parser.exit(status=1)
 
-        for path_to_lint in paths_to_lint:
-            if not path_to_lint.exists() or not path_to_lint.is_file():
-                logging.error('no such file or directory: `{path}`'.format(
-                    path=str(path_to_lint)))
-                parser.exit(status=1)
+        if not self._should_read_from_stdin(env):
+            for path_to_lint in paths_to_lint:
+                if not path_to_lint.exists() or not path_to_lint.is_file():
+                    logging.error('no such file or directory: `{path}`'.format(
+                        path=str(path_to_lint)))
+                    parser.exit(status=1)
 
 
     def _build_config_dict(self, env):
@@ -116,11 +117,17 @@ def _lint_all(self, env, config_dict):
         violations = []
         linter = self._build_linter(config_dict)
 
-        for file_path in paths_to_lint:
-            violations += linter.lint_file(file_path)
+        if self._should_read_from_stdin(env):
+            violations += linter.lint_text(sys.stdin.read())
+        else:
+            for file_path in paths_to_lint:
+                violations += linter.lint_file(file_path)
 
         return violations
 
+    def _should_read_from_stdin(self, env):
+        return len(env['file_paths']) == 1 and PosixPath('-') in env['file_paths']
+
 
     def _get_formatter(self, config_dict):
         if 'cmdargs' not in config_dict:

vint/linting/linter.py

@@ -112,11 +112,31 @@ def lint_file(self, path):
             decoding_error = self._create_decoding_error(path, str(exception))
             return [decoding_error]
 
+        self._traverse(root_ast, path)
+
+        return self._violations
+
+
+    def lint_text(self, text):
+        self._log_file_path_to_lint('stdin')
+
+        try:
+            root_ast = self._parser.parse(text)
+        except vimlparser.VimLParserException as exception:
+            parse_error = self._create_parse_error('stdin', str(exception))
+            return [parse_error]
+        except EncodingDetectionError as exception:
+            decoding_error = self._create_decoding_error('stdin', str(exception))
+            return [decoding_error]
+
+        self._traverse(root_ast, 'stdin')
+
+        return self._violations
 
-        self._violations = []
-        self._update_listeners_map()
 
-        # Given root AST to makepolicy flexibility
+    def _traverse(self, root_ast, path):
+        self._prepare_for_traversal()
+
         lint_context = {
             'path': path,
             'root_node': root_ast,
@@ -129,7 +149,10 @@ def lint_file(self, path):
                  on_enter=lambda node: self._handle_enter(node, lint_context),
                  on_leave=lambda node: self._handle_leave(node, lint_context))
 
-        return self._violations
+
+    def _prepare_for_traversal(self):
+        self._violations = []
+        self._update_listeners_map()
 
 
     def _handle_enter(self, node, lint_context):

vint/linting/policy/prohibit_missing_scriptencoding.py

@@ -1,4 +1,5 @@
 import chardet
+import sys
 
 from vint.ast.node_type import NodeType
 from vint.ast.traversing import traverse, SKIP_CHILDREN
@@ -49,6 +50,26 @@ def _check_scriptencoding(self, node):
 
 
     def _check_script_has_multibyte_char(self, lint_context):
+        if self._is_from_stdin(lint_context):
+            return self._check_stdin_has_multibyte_char()
+        else:
+            return self._check_file_has_multibyte_char(lint_context)
+
+
+    def _is_from_stdin(self, lint_context):
+        return lint_context['path'] == 'stdin'
+
+
+    def _check_stdin_has_multibyte_char(self):
+        sys.stdin.seek(0)
+
+        try:
+            sys.stdin.read().encode('ascii')
+            return False
+        except UnicodeError:
+            return True
+
+    def _check_file_has_multibyte_char(self, lint_context):
         # TODO: Use cache to make performance efficiency
         with lint_context['path'].open(mode='br') as f:
             byte_seq = f.read()