Add support for pypy

Fortunately pypy provides support for a lot of the CPython API, so the
changes are minimal.

The most important changes are:

- constructors always get a keyword argument dictionary, even if no
  keyword arguments are passed

- trying to assign to a read-only attribute raises TypeError instead of
  AttributeError

Apart from that, pypy does not provide MAXPATHLEN. There is a hack in
place currently, but there is only place that's using that macro, and
there shouldn't be a need for it much longer.

This fixes #209.

src/config.c

@@ -59,7 +59,7 @@ Config_init(Config *self, PyObject *args, PyObject *kwds)
     char *path = NULL;
     int err;
 
-    if (kwds) {
+    if (kwds && PyDict_Size(kwds) > 0) {
         PyErr_SetString(PyExc_TypeError,
                         "Config takes no keyword arguments");
         return -1;

src/index.c

@@ -46,7 +46,7 @@ Index_init(Index *self, PyObject *args, PyObject *kwds)
     char *path;
     int err;
 
-    if (kwds) {
+    if (kwds && PyDict_Size(kwds) > 0) {
         PyErr_SetString(PyExc_TypeError, "Index takes no keyword arguments");
         return -1;
     }

src/pygit2.c

@@ -27,14 +27,24 @@
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
-#include <osdefs.h>
+
+/* Pypy does not provide this header */
+#ifndef PYPY_VERSION
+# include <osdefs.h>
+#endif
+
 #include <git2.h>
 #include "error.h"
 #include "types.h"
 #include "utils.h"
 #include "repository.h"
 #include "oid.h"
 
+/* FIXME: This is for pypy */
+#ifndef MAXPATHLEN
+# define MAXPATHLEN 1024
+#endif
+
 extern PyObject *GitError;
 
 extern PyTypeObject RepositoryType;

src/repository.c

@@ -77,7 +77,7 @@ Repository_init(Repository *self, PyObject *args, PyObject *kwds)
     char *path;
     int err;
 
-    if (kwds) {
+    if (kwds && PyDict_Size(kwds) > 0) {
         PyErr_SetString(PyExc_TypeError,
                         "Repository takes no keyword arguments");
         return -1;

test/test_commit.py

@@ -34,6 +34,12 @@
 from pygit2 import GIT_OBJ_COMMIT, Signature, Oid
 from . import utils
 
+# pypy raises TypeError on writing to read-only, so we need to check
+# and change the test accordingly
+try:
+    import __pypy__
+except ImportError:
+    __pypy__ = None
 
 COMMIT_SHA = '5fe808e8953c12735680c257f56600cb0de44b10'
 
@@ -131,12 +137,13 @@ def test_modify_commit(self):
         author = ('Jane Doe', 'jdoe2@example.com', 12345)
 
         commit = self.repo[COMMIT_SHA]
-        self.assertRaises(AttributeError, setattr, commit, 'message', message)
-        self.assertRaises(AttributeError, setattr, commit, 'committer',
-                          committer)
-        self.assertRaises(AttributeError, setattr, commit, 'author', author)
-        self.assertRaises(AttributeError, setattr, commit, 'tree', None)
-        self.assertRaises(AttributeError, setattr, commit, 'parents', None)
+
+        error_type = AttributeError if not __pypy__ else TypeError
+        self.assertRaises(error_type, setattr, commit, 'message', message)
+        self.assertRaises(error_type, setattr, commit, 'committer', committer)
+        self.assertRaises(error_type, setattr, commit, 'author', author)
+        self.assertRaises(error_type, setattr, commit, 'tree', None)
+        self.assertRaises(error_type, setattr, commit, 'parents', None)
 
 
 if __name__ == '__main__':

test/test_tag.py

@@ -34,6 +34,12 @@
 import pygit2
 from . import utils
 
+# pypy raises TypeError on writing to read-only, so we need to check
+# and change the test accordingly
+try:
+    import __pypy__
+except ImportError:
+    __pypy__ = None
 
 TAG_SHA = '3d2962987c695a29f1f80b6c3aa4ec046ef44369'
 
@@ -84,10 +90,11 @@ def test_modify_tag(self):
         tagger = ('John Doe', 'jdoe@example.com', 12347)
 
         tag = self.repo[TAG_SHA]
-        self.assertRaises(AttributeError, setattr, tag, 'name', name)
-        self.assertRaises(AttributeError, setattr, tag, 'target', target)
-        self.assertRaises(AttributeError, setattr, tag, 'tagger', tagger)
-        self.assertRaises(AttributeError, setattr, tag, 'message', message)
+        error_type = AttributeError if not __pypy__ else TypeError
+        self.assertRaises(error_type, setattr, tag, 'name', name)
+        self.assertRaises(error_type, setattr, tag, 'target', target)
+        self.assertRaises(error_type, setattr, tag, 'tagger', tagger)
+        self.assertRaises(error_type, setattr, tag, 'message', message)
 
     def test_get_object(self):
         repo = self.repo