Add --avoid-stdio option to not pass FILE pointers from Python to libcurl on Windows (issue #117)

3 files changed, 27 insertions, 5 deletions

diff --git a/INSTALL.rst b/INSTALL.rst
index f96fa55..5ca73d6 100644
--- a/INSTALL.rst
+++ b/INSTALL.rst
@@ -92,12 +92,23 @@ and compiled libraries.
 
 Additional Windows setup.py options:
 
-- ``--use-libcurl-dll`` - build against libcurl DLL, if not given PycURL will
+- ``--use-libcurl-dll``: build against libcurl DLL, if not given PycURL will
   be built against libcurl statically.
-- ``--libcurl-lib-name=libcurl_imp.lib`` - specify a different name for libcurl
+- ``--libcurl-lib-name=libcurl_imp.lib``: specify a different name for libcurl
   import library. The default is ``libcurl.lib`` which is appropriate for
   static linking and is sometimes the correct choice for dynamic linking as
   well. The other possibility for dynamic linking is ``libcurl_imp.lib``.
+- ``--avoid-stdio``: on windows, a process and each library it is using
+  may be linked to its own version of the C runtime (msvcrt).
+  FILE pointers from one C runtime may not be passed to another C runtime.
+  This option prevents direct passing of FILE pointers from Python to libcurl,
+  thus permitting Python and libcurl to be linked against different C runtimes.
+  This option may carry a performance penalty when Python file objects are
+  given directly to PycURL in CURLOPT_READDATA, CURLOPT_WRITEDATA or
+  CURLOPT_WRITEHEADER options. This option applies only on Python 2; on
+  Python 3, file objects no longer expose C library FILE pointers and the
+  C runtime issue does not exist. On Python 3, this option is recognized but
+  does nothing.
 
 A good ``setup.py`` target to use is ``bdist_wininst`` which produces an
 executable installer that you can run to install PycURL.
diff --git a/setup.py b/setup.py
index da627ae..5adc91d 100644
--- a/setup.py
+++ b/setup.py
@@ -240,9 +240,14 @@ class ExtensionConfiguration(object):
             self.define_macros.append(('HAVE_CURL_SSL', 1))
         if not self.libraries:
             self.libraries.append("curl")
+        
         # Add extra compile flag for MacOS X
         if sys.platform[:-1] == "darwin":
             self.extra_link_args.append("-flat_namespace")
+        
+        # Recognize --avoid-stdio on Unix so that it can be tested
+        if scan_argv('--avoid-stdio') is not None:
+            self.extra_compile_args.append("-DAVOID_STDIO")
 
 
     def configure_windows(self):
@@ -279,6 +284,9 @@ class ExtensionConfiguration(object):
             fail("libcurl.lib does not exist at %s.\nCurl directory must point to compiled libcurl (bin/include/lib subdirectories): %s" %(libcurl_lib_path, curl_dir))
         self.extra_objects.append(libcurl_lib_path)
         
+        if scan_argv('--avoid-stdio') is not None:
+            self.extra_compile_args.append("-DAVOID_STDIO")
+        
         # make pycurl binary work on windows xp.
         # we use inet_ntop which was added in vista and implement a fallback.
         # our implementation will not be compiled with _WIN32_WINNT targeting
@@ -339,9 +347,12 @@ def get_bdist_msi_version_hack():
 
 def strip_pycurl_options():
     if sys.platform == 'win32':
-        options = ['--curl-dir=', '--curl-lib-name=', '--use-libcurl-dll']
+        options = [
+            '--curl-dir=', '--curl-lib-name=', '--use-libcurl-dll',
+            '--avoid-stdio',
+        ]
     else:
-        options = ['--openssl-dir=', '--curl-config=']
+        options = ['--openssl-dir=', '--curl-config=', '--avoid-stdio']
     for option in options:
         scan_argv(option)
 
diff --git a/src/pycurl.c b/src/pycurl.c
index 6e347d9..5f6afaa 100644
--- a/src/pycurl.c
+++ b/src/pycurl.c
@@ -2244,7 +2244,7 @@ do_curl_setopt(CurlObject *self, PyObject *args)
 #undef IS_LONG_OPTION
 #undef IS_OFF_T_OPTION
 
-#if PY_MAJOR_VERSION < 3
+#if PY_MAJOR_VERSION < 3 && !defined(PYCURL_AVOID_STDIO)
     /* Handle the case of file objects */
     if (PyFile_Check(obj)) {
         FILE *fp;