Py2/3: Unify handling of StringIO

This helps with our coverage numbers.

Under Python 2, we also start using the C implementation, and avoid
some unnecessary encode/decode cycles, so we might be a tiny bit
faster.

ZConfig/__init__.py

@@ -39,11 +39,7 @@
 from ZConfig.loader import loadConfig, loadConfigFile
 from ZConfig.loader import loadSchema, loadSchemaFile
 
-try:
-    import StringIO as StringIO
-except ImportError:
-    # Python 3 support.
-    import io as StringIO
+from ZConfig._compat import TextIO
 
 
 class ConfigurationError(Exception):
@@ -218,11 +214,12 @@ def __init__(self, source, name, url=None, lineno=None):
 
 def configureLoggers(text):
     """Configure one or more loggers from configuration text."""
-    schema = loadSchemaFile(StringIO.StringIO("""
+    schema = loadSchemaFile(TextIO("""
     <schema>
     <import package='ZConfig.components.logger'/>
     <multisection type='logger' name='*' attribute='loggers'/>
     </schema>
     """))
-    for factory in loadConfigFile(schema, StringIO.StringIO(text))[0].loggers:
+
+    for factory in loadConfigFile(schema, TextIO(text))[0].loggers:
         factory()

ZConfig/_compat.py

@@ -0,0 +1,68 @@
+##############################################################################
+#
+# Copyright (c) 2016 Zope Foundation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+import sys
+
+PY3 = sys.version_info[0] >= 3
+
+# Native string object IO
+if str is not bytes:
+    from io import StringIO as _NStringIO
+else:
+    # Python 2
+    from io import BytesIO as _NStringIO
+
+NStringIO = _NStringIO
+
+from io import StringIO
+from io import BytesIO
+
+def TextIO(text):
+    "Return StringIO or BytesIO as appropriate"
+    return BytesIO(text) if isinstance(text, bytes) else StringIO(text)
+
+try:
+    import urllib2
+except ImportError:
+    # Python 3 support.
+    import urllib.request as urllib2
+
+urllib2 = urllib2
+
+if PY3: # pragma: no cover
+    import builtins
+    exec_ = getattr(builtins, "exec")
+
+
+    def reraise(tp, value, tb=None): #pragma NO COVER
+        if value.__traceback__ is not tb:
+            raise value.with_traceback(tb)
+        raise value
+
+else: # pragma: no cover
+    def exec_(code, globs=None, locs=None): #pragma NO COVER
+        """Execute code in a namespace."""
+        if globs is None:
+            frame = sys._getframe(1)
+            globs = frame.f_globals
+            if locs is None:
+                locs = frame.f_locals
+            del frame
+        elif locs is None:
+            locs = globs
+        exec("""exec code in globs, locs""")
+
+    exec_("""def reraise(tp, value, tb=None):
+    raise tp, value, tb
+""")

ZConfig/components/logger/tests/test_logger.py

@@ -27,11 +27,7 @@
 from ZConfig.components.logger import handlers
 from ZConfig.components.logger import loghandler
 
-try:
-    import StringIO as StringIO
-except ImportError:
-    # Python 3 support.
-    import io as StringIO
+from ZConfig._compat import NStringIO as StringIO
 
 class CustomFormatter(logging.Formatter):
     def formatException(self, ei):
@@ -40,7 +36,7 @@ def formatException(self, ei):
         This adds helpful advice to the end of the traceback.
         """
         import traceback
-        sio = StringIO.StringIO()
+        sio = StringIO()
         traceback.print_exception(ei[0], ei[1], ei[2], file=sio)
         return sio.getvalue() + "... Don't panic!"
 
@@ -101,13 +97,13 @@ def move(self, fn):
 
     def get_schema(self):
         if self._schema is None:
-            sio = StringIO.StringIO(self._schematext)
+            sio = StringIO(self._schematext)
             self.__class__._schema = ZConfig.loadSchemaFile(sio)
         return self._schema
 
     def get_config(self, text):
         conf, handler = ZConfig.loadConfigFile(self.get_schema(),
-                                               StringIO.StringIO(text))
+                                               StringIO(text))
         self.assertTrue(not handler)
         return conf
 
@@ -268,7 +264,7 @@ def check_standard_stream(self, name):
         # The factory has already been created; make sure it picks up
         # the stderr we set here when we create the logger and
         # handlers:
-        sio = StringIO.StringIO()
+        sio = StringIO()
         setattr(sys, name, sio)
         try:
             logger = conf.eventlog()
@@ -288,7 +284,7 @@ def test_custom_formatter(self):
         </logfile>
         </eventlog>
         """)
-        sio = StringIO.StringIO()
+        sio = StringIO()
         sys.stdout = sio
         try:
             logger = conf.eventlog()

ZConfig/loader.py

@@ -17,6 +17,8 @@
 import re
 import sys
 
+from io import StringIO
+
 import ZConfig
 import ZConfig.cfgparser
 import ZConfig.datatypes
@@ -25,17 +27,8 @@
 import ZConfig.schema
 import ZConfig.url
 
-try:
-    import StringIO as StringIO
-except ImportError:
-    # Python 3 support.
-    import io as StringIO
-
-try:
-    import urllib2
-except ImportError:
-    # Python 3 support
-    import urllib.request as urllib2
+from ZConfig._compat import reraise
+from ZConfig._compat import urllib2
 
 try:
     from urllib import pathname2url
@@ -229,15 +222,18 @@ def openResource(self, url):
                 # Python 2.1 raises a different error from Python 2.2+,
                 # so we catch both to make sure we detect the situation.
                 self._raise_open_error(url, str(e))
-            if sys.version_info[0] >= 3:
-                # Python 3 support: file.read() returns bytes, so we convert it
-                # to an StringIO.  (Can't use io.TextIOWrapper because of
-                # http://bugs.python.org/issue16723 and probably other bugs)
-                try:
-                    data = file.read().decode()
-                finally:
-                    file.close()
-                file = StringIO.StringIO(data)
+
+            # Python 3 support: file.read() returns bytes, so we convert it
+            # to an StringIO.  (Can't use io.TextIOWrapper because of
+            # http://bugs.python.org/issue16723 and probably other bugs).
+            # Do this even on Python 2 to avoid keeping a network connection
+            # open for an unbounded amount of time and to catch IOErrors here,
+            # where they make sense.
+            try:
+                data = file.read().decode()
+            finally:
+                file.close()
+            file = StringIO(data)
         return self.createResource(file, url)
 
     def _raise_open_error(self, url, message):
@@ -313,13 +309,26 @@ def openPackageResource(package, path):
         url = ZConfig.url.urlnormalize(url)
         return urllib2.urlopen(url)
     else:
+        v, tb = (None, None)
         for dir in pkg.__path__:
             loadpath = os.path.join(dir, path)
             try:
-                return StringIO.StringIO(
+                return StringIO(
                     loader.get_data(loadpath).decode('utf-8'))
-            except Exception:
-                pass
+            except Exception as e:
+                v = ZConfig.SchemaResourceError(
+                    "error opening schema component: " + repr(e),
+                    filename=path,
+                    package=package,
+                    path=pkg.__path__)
+                tb = sys.exc_info()[2]
+
+        if v is not None:
+            try:
+                reraise(type(v), v, tb)
+            finally:
+                del tb
+
         raise ZConfig.SchemaResourceError("schema component not found",
                                           filename=path,
                                           package=package,

ZConfig/schemaless.txt

@@ -46,12 +46,8 @@ open for reading.  Let's take a look at this, and what it returns::
   ...
   ... '''
 
-  >>> try:
-  ...     import StringIO
-  ... except ImportError:
-  ...     import io as StringIO
-
-  >>> config = schemaless.loadConfigFile(StringIO.StringIO(config_text))
+  >>> from ZConfig._compat import NStringIO as StringIO
+  >>> config = schemaless.loadConfigFile(StringIO(config_text))
 
 The `config` object is a mapping from top-level keys to lists of
 values::
@@ -200,7 +196,7 @@ other elements of a configuration are::
   ...
   ... '''
 
-  >>> config = schemaless.loadConfigFile(StringIO.StringIO(config_text))
+  >>> config = schemaless.loadConfigFile(StringIO(config_text))
 
   >>> print(config)
   %import some.package
@@ -231,7 +227,7 @@ Multiple imports of the same name are removed::
   ...
   ... '''
 
-  >>> config = schemaless.loadConfigFile(StringIO.StringIO(config_text))
+  >>> config = schemaless.loadConfigFile(StringIO(config_text))
 
   >>> print(config)
   %import some.package
@@ -280,7 +276,7 @@ raised when loading the configuration::
   ...
   ... '''
 
-  >>> schemaless.loadConfigFile(StringIO.StringIO(config_text))
+  >>> schemaless.loadConfigFile(StringIO(config_text))
   Traceback (most recent call last):
   NotImplementedError: defines are not supported
 
@@ -292,6 +288,6 @@ A similar exception is raised for %include::
   ...
   ... '''
 
-  >>> schemaless.loadConfigFile(StringIO.StringIO(config_text))
+  >>> schemaless.loadConfigFile(StringIO(config_text))
   Traceback (most recent call last):
   NotImplementedError: includes are not supported

ZConfig/tests/support.py

@@ -21,11 +21,7 @@
 from ZConfig.loader import ConfigLoader
 from ZConfig.url import urljoin
 
-try:
-    import StringIO
-except ImportError:
-    # Python 3 support.
-    import io as StringIO
+from ZConfig._compat import NStringIO as StringIO
 
 try:
     from urllib import pathname2url
@@ -61,7 +57,7 @@ def load_schema(self, relurl):
         return self.schema
 
     def load_schema_text(self, text, url=None):
-        sio = StringIO.StringIO(text)
+        sio = StringIO(text)
         self.schema = ZConfig.loadSchemaFile(sio, url)
         return self.schema
 
@@ -73,7 +69,7 @@ def load_config(self, schema, conf_url, num_handlers=0):
         return self.conf
 
     def load_config_text(self, schema, text, num_handlers=0, url=None):
-        sio = StringIO.StringIO(text)
+        sio = StringIO(text)
         loader = self.create_config_loader(schema)
         self.conf, self.handlers = loader.loadFile(sio, url)
         self.assertEqual(len(self.handlers), num_handlers)

ZConfig/tests/test_cfgimports.py

@@ -18,12 +18,7 @@
 import ZConfig
 import ZConfig.tests.support
 
-try:
-    from StringIO import StringIO
-except ImportError:
-    # Python 3 support.
-    from io import StringIO
-
+from ZConfig._compat import NStringIO as StringIO
 
 class TestImportFromConfiguration(
     ZConfig.tests.support.TestHelper, unittest.TestCase):

ZConfig/tests/test_config.py

@@ -20,11 +20,7 @@
 
 from ZConfig.tests.support import CONFIG_BASE
 
-try:
-    import StringIO as StringIO
-except ImportError:
-    # Python 3 support.
-    import io as StringIO
+from ZConfig._compat import NStringIO as StringIO
 
 class ConfigurationTestCase(unittest.TestCase):
 
@@ -47,7 +43,7 @@ def load(self, relurl, context=None):
         return conf
 
     def loadtext(self, text):
-        sio = StringIO.StringIO(text)
+        sio = StringIO(text)
         return self.loadfile(sio)
 
     def loadfile(self, file):
@@ -112,7 +108,7 @@ def test_include(self):
         self.assertEqual(conf.var4, "value")
 
     def test_includes_with_defines(self):
-        self.schema = ZConfig.loadSchemaFile(StringIO.StringIO("""\
+        self.schema = ZConfig.loadSchemaFile(StringIO("""\
             <schema>
               <key name='refinner' />
               <key name='refouter' />
@@ -145,8 +141,8 @@ def test_fragment_ident_disallowed(self):
                           self.load, "simplesections.conf#another")
 
     def test_load_from_fileobj(self):
-        sio = StringIO.StringIO("%define name value\n"
-                                "getname x $name y \n")
+        sio = StringIO("%define name value\n"
+                       "getname x $name y \n")
         cf = self.loadfile(sio)
         self.assertEqual(cf.getname, "x value y")
 

ZConfig/tests/test_loader.py

@@ -22,19 +22,10 @@
 import ZConfig.loader
 import ZConfig.url
 
-from ZConfig.tests.support import CONFIG_BASE, TestHelper
-
-try:
-    import urllib2
-except ImportError:
-    # Python 3 support.
-    import urllib.request as urllib2
+from ZConfig._compat import NStringIO as StringIO
+from ZConfig._compat import urllib2
 
-try:
-    from StringIO import StringIO
-except ImportError:
-    # Python 3 support.
-    from io import StringIO
+from ZConfig.tests.support import CONFIG_BASE, TestHelper
 
 
 try: