Fixes Python C extensions for Python 3 compatibility.

These are necessary, but not sufficient, changes to make the C
extensions work "polyglot".  These are believed to be complete as far
as the C code is concerned, and don't break Python 2 compatibility.

This puts all the stuff that needs to differ between Python 2 and
Python 3 into conditionally-defined macros in a new header file
python_compatibility.h.  The definitions assume Python 2.6 or later.

In addition to the things requiring conditionals, the Lexer object was
using the deprecated tp_getattr entry, with a function based on
Py_FindMethod, which is gone in Python 3.  However, the newer
tp_getattro entry can be pointed directly to PyObject_GenericGetAttr,
which works in Python 2 and 3.

Packet data returned by the Lexer is now 'bytes' in Python 3, which is
appropriate given that it may contain binary data.  However, it means
that packet data can't be passed directly to anything expecting a
'str'.  In Python 2, the data is just a 'str' as usual.

TESTED:
Ran "scons build-all check" and xgps (using Python 2.7).  Also ran the
daemon and maidenhead-locator tests with Python 2.6.

1 files changed, 9 insertions, 4 deletions

diff --git a/gpsclient.c b/gpsclient.c
index 276900e3..7b04ddc0 100644
--- a/gpsclient.c
+++ b/gpsclient.c
@@ -10,6 +10,7 @@
 #include "gps.h"
 #include "gpsdclient.h"
 #include "compiler.h"	/* for UNUSED */
+#include "python_compatibility.h"
 
 /*
  * Client utility functions
@@ -83,13 +84,16 @@ PyDoc_STRVAR(module_doc,
 /* banishes a pointless compiler warning */
 extern PyMODINIT_FUNC initclienthelpers(void);
 
-PyMODINIT_FUNC
 // cppcheck-suppress unusedFunction
-initclienthelpers(void)
+GPSD_PY_MODULE_INIT(clienthelpers)
 {
     PyObject *m;
 
-    m = Py_InitModule3("gps.clienthelpers", gpsclient_methods, module_doc);
+    /* Create the module and add the functions */
+    GPSD_PY_MODULE_DEF(m, "clienthelpers", module_doc, gpsclient_methods)
+
+    if (m == NULL)
+	return GPSD_PY_MODULE_ERROR_VAL;
 
     PyModule_AddIntConstant(m, "deg_dd", deg_dd);
     PyModule_AddIntConstant(m, "deg_ddmm", deg_ddmm);
@@ -99,5 +103,6 @@ initclienthelpers(void)
     PyModule_AddIntConstant(m, "imperial", imperial);
     PyModule_AddIntConstant(m, "nautical", nautical);
     PyModule_AddIntConstant(m, "metric", metric);
-}
 
+    return GPSD_PY_MODULE_SUCCESS_VAL(m);
+}