Add Cython.Utils to the list of compiled modules and include a faster...

Add Cython.Utils to the list of compiled modules and include a faster @contextmanager for try-finally cases.

Cython/Tests/TestCythonUtils.py

@@ -2,7 +2,7 @@ import unittest
 
 from Cython.Utils import (
     _CACHE_NAME_PATTERN, _build_cache_name, _find_cache_attributes,
-    build_hex_version, cached_method, clear_method_caches)
+    build_hex_version, cached_method, clear_method_caches, try_finally_contextmanager)
 
 METHOD_NAME = "cached_next"
 CACHE_NAME = _build_cache_name(METHOD_NAME)
@@ -94,3 +94,35 @@ class TestCythonUtils(unittest.TestCase):
 
         clear_method_caches(obj)
         self.set_of_names_equal(obj, {names})
+
+    def test_try_finally_contextmanager(self):
+        states = []
+        @try_finally_contextmanager
+        def gen(*args, **kwargs):
+            states.append("enter")
+            yield (args, kwargs)
+            states.append("exit")
+
+        with gen(1, 2, 3, x=4) as call_args:
+            assert states == ["enter"]
+            self.assertEqual(call_args, ((1, 2, 3), {'x': 4}))
+        assert states == ["enter", "exit"]
+
+        class MyException(RuntimeError):
+            pass
+
+        del states[:]
+        with self.assertRaises(MyException):
+            with gen(1, 2, y=4) as call_args:
+                assert states == ["enter"]
+                self.assertEqual(call_args, ((1, 2), {'y': 4}))
+                raise MyException("FAIL INSIDE")
+            assert states == ["enter", "exit"]
+
+        del states[:]
+        with self.assertRaises(StopIteration):
+            with gen(1, 2, y=4) as call_args:
+                assert states == ["enter"]
+                self.assertEqual(call_args, ((1, 2), {'y': 4}))
+                raise StopIteration("STOP")
+            assert states == ["enter", "exit"]

Cython/Utils.pxd

+
+cdef class _TryFinallyGeneratorContextManager:
+    cdef object _gen

Cython/Utils.py

 """
-Cython -- Things that don't belong
-          anywhere else in particular
+Cython -- Things that don't belong anywhere else in particular
 """
 
 from __future__ import absolute_import
 
+import cython
+
+cython.declare(
+    basestring=object,
+    os=object, sys=object, re=object, io=object, codecs=object, glob=object, shutil=object, tempfile=object,
+    cython_version=object,
+    _function_caches=list, _parse_file_version=object, _match_file_encoding=object,
+)
+
 try:
     from __builtin__ import basestring
 except ImportError:
@@ -23,7 +31,7 @@ import codecs
 import glob
 import shutil
 import tempfile
-from contextlib import contextmanager
+from functools import wraps
 
 from . import __version__ as cython_version
 
@@ -34,6 +42,31 @@ _CACHE_NAME_PATTERN = re.compile(r"^__(.+)_cache$")
 
 modification_time = os.path.getmtime
 
+
+class _TryFinallyGeneratorContextManager(object):
+    """
+    Fast, bare minimum @contextmanager, only for try-finally, not for exception handling.
+    """
+    def __init__(self, gen):
+        self._gen = gen
+
+    def __enter__(self):
+        return next(self._gen)
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        try:
+            next(self._gen)
+        except (StopIteration, GeneratorExit):
+            pass
+
+
+def try_finally_contextmanager(gen_func):
+    @wraps(gen_func)
+    def make_gen(*args, **kwargs):
+        return _TryFinallyGeneratorContextManager(gen_func(*args, **kwargs))
+    return make_gen
+
+
 _function_caches = []
 
 
@@ -47,6 +80,7 @@ def cached_function(f):
     _function_caches.append(cache)
     uncomputed = object()
 
+    @wraps(f)
     def wrapper(*args):
         res = cache.get(args, uncomputed)
         if res is uncomputed:
@@ -443,7 +477,7 @@ def get_cython_cache_dir():
     return os.path.expanduser(os.path.join('~', '.cython'))
 
 
-@contextmanager
+@try_finally_contextmanager
 def captured_fd(stream=2, encoding=None):
     orig_stream = os.dup(stream)  # keep copy of original stream
     try:
@@ -455,13 +489,12 @@ def captured_fd(stream=2, encoding=None):
                 return _output[0]
 
             os.dup2(temp_file.fileno(), stream)  # replace stream by copy of pipe
-            try:
             def get_output():
                 result = read_output()
                 return result.decode(encoding) if encoding else result
 
             yield get_output
-            finally:
+            # note: @contextlib.contextmanager requires try-finally here
             os.dup2(orig_stream, stream)  # restore original stream
             read_output()  # keep the output in case it's used after closing the context manager
     finally:
@@ -514,23 +547,6 @@ def print_bytes(s, header_text=None, end=b'\n', file=sys.stdout, flush=True):
         out.flush()
 
 
-class LazyStr:
-    def __init__(self, callback):
-        self.callback = callback
-
-    def __str__(self):
-        return self.callback()
-
-    def __repr__(self):
-        return self.callback()
-
-    def __add__(self, right):
-        return self.callback() + right
-
-    def __radd__(self, left):
-        return left + self.callback()
-
-
 class OrderedSet(object):
     def __init__(self, elements=()):
         self._list = []

setup.py

@@ -94,6 +94,7 @@ def compile_cython_modules(profile=False, coverage=False, compile_more=False, cy
         "Cython.Compiler.FusedNode",
         "Cython.Tempita._tempita",
         "Cython.StringIOTree",
+        "Cython.Utils",
     ]
     if compile_more:
         compiled_modules.extend([