Issue #22896: Avoid to use PyObject_AsCharBuffer(), PyObject_AsReadBuffer()

and PyObject_AsWriteBuffer().

Lib/ctypes/test/test_frombuffer.py

@@ -10,7 +10,7 @@ class X(Structure):
         self._init_called = True
 
 class Test(unittest.TestCase):
-    def test_fom_buffer(self):
+    def test_from_buffer(self):
         a = array.array("i", range(16))
         x = (c_int * 16).from_buffer(a)
 
@@ -23,25 +23,37 @@ class Test(unittest.TestCase):
         a[0], a[-1] = 200, -200
         self.assertEqual(x[:], a.tolist())
 
-        self.assertIn(a, x._objects.values())
+        self.assertRaises(BufferError, a.append, 100)
+        self.assertRaises(BufferError, a.pop)
 
-        self.assertRaises(ValueError,
-                          c_int.from_buffer, a, -1)
+        del x; del y; gc.collect(); gc.collect(); gc.collect()
+        a.append(100)
+        a.pop()
+        x = (c_int * 16).from_buffer(a)
+
+        self.assertIn(a, [obj.obj if isinstance(obj, memoryview) else obj
+                          for obj in x._objects.values()])
 
         expected = x[:]
         del a; gc.collect(); gc.collect(); gc.collect()
         self.assertEqual(x[:], expected)
 
-        self.assertRaises(TypeError,
-                          (c_char * 16).from_buffer, "a" * 16)
+        with self.assertRaises(TypeError):
+            (c_char * 16).from_buffer(b"a" * 16)
+        with self.assertRaises(TypeError):
+            (c_char * 16).from_buffer("a" * 16)
 
-    def test_fom_buffer_with_offset(self):
+    def test_from_buffer_with_offset(self):
         a = array.array("i", range(16))
         x = (c_int * 15).from_buffer(a, sizeof(c_int))
 
         self.assertEqual(x[:], a.tolist()[1:])
-        self.assertRaises(ValueError, lambda: (c_int * 16).from_buffer(a, sizeof(c_int)))
-        self.assertRaises(ValueError, lambda: (c_int * 1).from_buffer(a, 16 * sizeof(c_int)))
+        with self.assertRaises(ValueError):
+            c_int.from_buffer(a, -1)
+        with self.assertRaises(ValueError):
+            (c_int * 16).from_buffer(a, sizeof(c_int))
+        with self.assertRaises(ValueError):
+            (c_int * 1).from_buffer(a, 16 * sizeof(c_int))
 
     def test_from_buffer_copy(self):
         a = array.array("i", range(16))
@@ -56,26 +68,30 @@ class Test(unittest.TestCase):
         a[0], a[-1] = 200, -200
         self.assertEqual(x[:], list(range(16)))
 
-        self.assertEqual(x._objects, None)
+        a.append(100)
+        self.assertEqual(x[:], list(range(16)))
 
-        self.assertRaises(ValueError,
-                          c_int.from_buffer, a, -1)
+        self.assertEqual(x._objects, None)
 
         del a; gc.collect(); gc.collect(); gc.collect()
         self.assertEqual(x[:], list(range(16)))
 
         x = (c_char * 16).from_buffer_copy(b"a" * 16)
         self.assertEqual(x[:], b"a" * 16)
+        with self.assertRaises(TypeError):
+            (c_char * 16).from_buffer_copy("a" * 16)
 
-    def test_fom_buffer_copy_with_offset(self):
+    def test_from_buffer_copy_with_offset(self):
         a = array.array("i", range(16))
         x = (c_int * 15).from_buffer_copy(a, sizeof(c_int))
 
         self.assertEqual(x[:], a.tolist()[1:])
-        self.assertRaises(ValueError,
-                          (c_int * 16).from_buffer_copy, a, sizeof(c_int))
-        self.assertRaises(ValueError,
-                          (c_int * 1).from_buffer_copy, a, 16 * sizeof(c_int))
+        with self.assertRaises(ValueError):
+            c_int.from_buffer_copy(a, -1)
+        with self.assertRaises(ValueError):
+            (c_int * 16).from_buffer_copy(a, sizeof(c_int))
+        with self.assertRaises(ValueError):
+            (c_int * 1).from_buffer_copy(a, 16 * sizeof(c_int))
 
 if __name__ == '__main__':
     unittest.main()

Misc/NEWS

@@ -11,6 +11,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #22896: Avoid using PyObject_AsCharBuffer(), PyObject_AsReadBuffer()
+  and PyObject_AsWriteBuffer().
+
 - Issue #21295: Revert some changes (issue #16795) to AST line numbers and
   column offsets that constituted a regression.
 

Modules/_codecsmodule.c

@@ -284,8 +284,6 @@ unicode_internal_decode(PyObject *self,
 {
     PyObject *obj;
     const char *errors = NULL;
-    const char *data;
-    Py_ssize_t size;
 
     if (!PyArg_ParseTuple(args, "O|z:unicode_internal_decode",
                           &obj, &errors))
@@ -298,11 +296,16 @@ unicode_internal_decode(PyObject *self,
         return codec_tuple(obj, PyUnicode_GET_LENGTH(obj));
     }
     else {
-        if (PyObject_AsReadBuffer(obj, (const void **)&data, &size))
+        Py_buffer view;
+        PyObject *result;
+        if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) != 0)
             return NULL;
 
-        return codec_tuple(_PyUnicode_DecodeUnicodeInternal(data, size, errors),
-                           size);
+        result = codec_tuple(
+                _PyUnicode_DecodeUnicodeInternal(view.buf, view.len, errors),
+                view.len);
+        PyBuffer_Release(&view);
+        return result;
     }
 }
 
@@ -727,8 +730,6 @@ unicode_internal_encode(PyObject *self,
 {
     PyObject *obj;
     const char *errors = NULL;
-    const char *data;
-    Py_ssize_t len, size;
 
     if (PyErr_WarnEx(PyExc_DeprecationWarning,
                      "unicode_internal codec has been deprecated",
@@ -741,6 +742,7 @@ unicode_internal_encode(PyObject *self,
 
     if (PyUnicode_Check(obj)) {
         Py_UNICODE *u;
+        Py_ssize_t len, size;
 
         if (PyUnicode_READY(obj) < 0)
             return NULL;
@@ -755,9 +757,13 @@ unicode_internal_encode(PyObject *self,
                            PyUnicode_GET_LENGTH(obj));
     }
     else {
-        if (PyObject_AsReadBuffer(obj, (const void **)&data, &size))
+        Py_buffer view;
+        PyObject *result;
+        if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) != 0)
             return NULL;
-        return codec_tuple(PyBytes_FromStringAndSize(data, size), size);
+        result = codec_tuple(PyBytes_FromStringAndSize(view.buf, view.len), view.len);
+        PyBuffer_Release(&view);
+        return result;
     }
 }
 

Modules/_ctypes/_ctypes.c

@@ -463,39 +463,45 @@ KeepRef(CDataObject *target, Py_ssize_t index, PyObject *keep);
 static PyObject *
 CDataType_from_buffer(PyObject *type, PyObject *args)
 {
-    void *buffer;
-    Py_ssize_t buffer_len;
+    Py_buffer buffer;
     Py_ssize_t offset = 0;
-    PyObject *obj, *result;
+    PyObject *result, *mv;
     StgDictObject *dict = PyType_stgdict(type);
     assert (dict);
 
-    if (!PyArg_ParseTuple(args, "O|n:from_buffer", &obj, &offset))
-        return NULL;
-
-    if (-1 == PyObject_AsWriteBuffer(obj, &buffer, &buffer_len))
+    if (!PyArg_ParseTuple(args, "w*|n:from_buffer", &buffer, &offset))
         return NULL;
 
     if (offset < 0) {
         PyErr_SetString(PyExc_ValueError,
                         "offset cannot be negative");
+        PyBuffer_Release(&buffer);
         return NULL;
     }
-    if (dict->size > buffer_len - offset) {
+    if (dict->size > buffer.len - offset) {
         PyErr_Format(PyExc_ValueError,
                      "Buffer size too small (%zd instead of at least %zd bytes)",
-                     buffer_len, dict->size + offset);
+                     buffer.len, dict->size + offset);
+        PyBuffer_Release(&buffer);
         return NULL;
     }
 
-    result = PyCData_AtAddress(type, (char *)buffer + offset);
-    if (result == NULL)
+    result = PyCData_AtAddress(type, (char *)buffer.buf + offset);
+    if (result == NULL) {
+        PyBuffer_Release(&buffer);
         return NULL;
+    }
 
-    Py_INCREF(obj);
-    if (-1 == KeepRef((CDataObject *)result, -1, obj)) {
+    mv = PyMemoryView_FromBuffer(&buffer);
+    if (mv == NULL) {
+        PyBuffer_Release(&buffer);
         return NULL;
     }
+    /* Hack the memoryview so that it will release the buffer. */
+    ((PyMemoryViewObject *)mv)->mbuf->master.obj = buffer.obj;
+    ((PyMemoryViewObject *)mv)->view.obj = buffer.obj;
+    if (-1 == KeepRef((CDataObject *)result, -1, mv))
+        result = NULL;
     return result;
 }
 
@@ -508,37 +514,36 @@ GenericPyCData_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
 static PyObject *
 CDataType_from_buffer_copy(PyObject *type, PyObject *args)
 {
-    const void *buffer;
-    Py_ssize_t buffer_len;
+    Py_buffer buffer;
     Py_ssize_t offset = 0;
-    PyObject *obj, *result;
+    PyObject *result;
     StgDictObject *dict = PyType_stgdict(type);
     assert (dict);
 
-    if (!PyArg_ParseTuple(args, "O|n:from_buffer", &obj, &offset))
-        return NULL;
-
-    if (-1 == PyObject_AsReadBuffer(obj, (const void**)&buffer, &buffer_len))
+    if (!PyArg_ParseTuple(args, "y*|n:from_buffer", &buffer, &offset))
         return NULL;
 
     if (offset < 0) {
         PyErr_SetString(PyExc_ValueError,
                         "offset cannot be negative");
+        PyBuffer_Release(&buffer);
         return NULL;
     }
 
-    if (dict->size > buffer_len - offset) {
+    if (dict->size > buffer.len - offset) {
         PyErr_Format(PyExc_ValueError,
                      "Buffer size too small (%zd instead of at least %zd bytes)",
-                     buffer_len, dict->size + offset);
+                     buffer.len, dict->size + offset);
+        PyBuffer_Release(&buffer);
         return NULL;
     }
 
     result = GenericPyCData_new((PyTypeObject *)type, NULL, NULL);
-    if (result == NULL)
-        return NULL;
-    memcpy(((CDataObject *)result)->b_ptr,
-           (char *)buffer+offset, dict->size);
+    if (result != NULL) {
+        memcpy(((CDataObject *)result)->b_ptr,
+               (char *)buffer.buf + offset, dict->size);
+    }
+    PyBuffer_Release(&buffer);
     return result;
 }
 

Modules/_io/bytesio.c

@@ -437,17 +437,18 @@ PyDoc_STRVAR(readinto_doc,
 "is set not to block as has no data to read.");
 
 static PyObject *
-bytesio_readinto(bytesio *self, PyObject *buffer)
+bytesio_readinto(bytesio *self, PyObject *arg)
 {
-    void *raw_buffer;
+    Py_buffer buffer;
     Py_ssize_t len, n;
 
     CHECK_CLOSED(self);
 
-    if (PyObject_AsWriteBuffer(buffer, &raw_buffer, &len) == -1)
+    if (!PyArg_Parse(arg, "w*", &buffer))
         return NULL;
 
     /* adjust invalid sizes */
+    len = buffer.len;
     n = self->string_size - self->pos;
     if (len > n) {
         len = n;
@@ -455,10 +456,11 @@ bytesio_readinto(bytesio *self, PyObject *buffer)
             len = 0;
     }
 
-    memcpy(raw_buffer, self->buf + self->pos, len);
+    memcpy(buffer.buf, self->buf + self->pos, len);
     assert(self->pos + len < PY_SSIZE_T_MAX);
     assert(len >= 0);
     self->pos += len;
+    PyBuffer_Release(&buffer);
 
     return PyLong_FromSsize_t(len);
 }

Modules/_sqlite/connection.c

@@ -522,19 +522,20 @@ _pysqlite_set_result(sqlite3_context* context, PyObject* py_val)
             return -1;
         sqlite3_result_text(context, str, -1, SQLITE_TRANSIENT);
     } else if (PyObject_CheckBuffer(py_val)) {
-        const char* buffer;
-        Py_ssize_t buflen;
-        if (PyObject_AsCharBuffer(py_val, &buffer, &buflen) != 0) {
+        Py_buffer view;
+        if (PyObject_GetBuffer(py_val, &view, PyBUF_SIMPLE) != 0) {
             PyErr_SetString(PyExc_ValueError,
                             "could not convert BLOB to buffer");
             return -1;
         }
-        if (buflen > INT_MAX) {
+        if (view.len > INT_MAX) {
             PyErr_SetString(PyExc_OverflowError,
                             "BLOB longer than INT_MAX bytes");
+            PyBuffer_Release(&view);
             return -1;
         }
-        sqlite3_result_blob(context, buffer, (int)buflen, SQLITE_TRANSIENT);
+        sqlite3_result_blob(context, view.buf, (int)view.len, SQLITE_TRANSIENT);
+        PyBuffer_Release(&view);
     } else {
         return -1;
     }

Modules/_sqlite/statement.c

@@ -94,7 +94,6 @@ int pysqlite_statement_create(pysqlite_Statement* self, pysqlite_Connection* con
 int pysqlite_statement_bind_parameter(pysqlite_Statement* self, int pos, PyObject* parameter)
 {
     int rc = SQLITE_OK;
-    const char* buffer;
     char* string;
     Py_ssize_t buflen;
     parameter_type paramtype;
@@ -145,18 +144,22 @@ int pysqlite_statement_bind_parameter(pysqlite_Statement* self, int pos, PyObjec
             }
             rc = sqlite3_bind_text(self->st, pos, string, (int)buflen, SQLITE_TRANSIENT);
             break;
-        case TYPE_BUFFER:
-            if (PyObject_AsCharBuffer(parameter, &buffer, &buflen) != 0) {
+        case TYPE_BUFFER: {
+            Py_buffer view;
+            if (PyObject_GetBuffer(parameter, &view, PyBUF_SIMPLE) != 0) {
                 PyErr_SetString(PyExc_ValueError, "could not convert BLOB to buffer");
                 return -1;
             }
-            if (buflen > INT_MAX) {
+            if (view.len > INT_MAX) {
                 PyErr_SetString(PyExc_OverflowError,
                                 "BLOB longer than INT_MAX bytes");
+                PyBuffer_Release(&view);
                 return -1;
             }
-            rc = sqlite3_bind_blob(self->st, pos, buffer, buflen, SQLITE_TRANSIENT);
+            rc = sqlite3_bind_blob(self->st, pos, view.buf, (int)view.len, SQLITE_TRANSIENT);
+            PyBuffer_Release(&view);
             break;
+        }
         case TYPE_UNKNOWN:
             rc = -1;
     }

Modules/_struct.c

@@ -1842,8 +1842,8 @@ static PyObject *
 s_pack_into(PyObject *self, PyObject *args)
 {
     PyStructObject *soself;
-    char *buffer;
-    Py_ssize_t buffer_len, offset;
+    Py_buffer buffer;
+    Py_ssize_t offset;
 
     /* Validate arguments.  +1 is for the first arg as buffer. */
     soself = (PyStructObject *)self;
@@ -1868,34 +1868,37 @@ s_pack_into(PyObject *self, PyObject *args)
     }
 
     /* Extract a writable memory buffer from the first argument */
-    if ( PyObject_AsWriteBuffer(PyTuple_GET_ITEM(args, 0),
-                                                            (void**)&buffer, &buffer_len) == -1 ) {
+    if (!PyArg_Parse(PyTuple_GET_ITEM(args, 0), "w*", &buffer))
         return NULL;
-    }
-    assert( buffer_len >= 0 );
+    assert(buffer.len >= 0);
 
     /* Extract the offset from the first argument */
     offset = PyNumber_AsSsize_t(PyTuple_GET_ITEM(args, 1), PyExc_IndexError);
-    if (offset == -1 && PyErr_Occurred())
+    if (offset == -1 && PyErr_Occurred()) {
+        PyBuffer_Release(&buffer);
         return NULL;
+    }
 
     /* Support negative offsets. */
     if (offset < 0)
-        offset += buffer_len;
+        offset += buffer.len;
 
     /* Check boundaries */
-    if (offset < 0 || (buffer_len - offset) < soself->s_size) {
+    if (offset < 0 || (buffer.len - offset) < soself->s_size) {
         PyErr_Format(StructError,
                      "pack_into requires a buffer of at least %zd bytes",
                      soself->s_size);
+        PyBuffer_Release(&buffer);
         return NULL;
     }
 
     /* Call the guts */
-    if ( s_pack_internal(soself, args, 2, buffer + offset) != 0 ) {
+    if (s_pack_internal(soself, args, 2, (char*)buffer.buf + offset) != 0) {
+        PyBuffer_Release(&buffer);
         return NULL;
     }
 
+    PyBuffer_Release(&buffer);
     Py_RETURN_NONE;
 }
 

Objects/abstract.c

@@ -250,28 +250,7 @@ PyObject_AsCharBuffer(PyObject *obj,
                       const char **buffer,
                       Py_ssize_t *buffer_len)
 {
-    PyBufferProcs *pb;
-    Py_buffer view;
-
-    if (obj == NULL || buffer == NULL || buffer_len == NULL) {
-        null_error();
-        return -1;
-    }
-    pb = obj->ob_type->tp_as_buffer;
-    if (pb == NULL || pb->bf_getbuffer == NULL) {
-        PyErr_SetString(PyExc_TypeError,
-                        "expected bytes, bytearray "
-                        "or buffer compatible object");
-        return -1;
-    }
-    if ((*pb->bf_getbuffer)(obj, &view, PyBUF_SIMPLE)) return -1;
-
-    *buffer = view.buf;
-    *buffer_len = view.len;
-    if (pb->bf_releasebuffer != NULL)
-        (*pb->bf_releasebuffer)(obj, &view);
-    Py_XDECREF(view.obj);
-    return 0;
+    return PyObject_AsReadBuffer(obj, (const void **)buffer, buffer_len);
 }
 
 int
@@ -295,28 +274,18 @@ int PyObject_AsReadBuffer(PyObject *obj,
                           const void **buffer,
                           Py_ssize_t *buffer_len)
 {
-    PyBufferProcs *pb;
     Py_buffer view;
 
     if (obj == NULL || buffer == NULL || buffer_len == NULL) {
         null_error();
         return -1;
     }
-    pb = obj->ob_type->tp_as_buffer;
-    if (pb == NULL ||
-        pb->bf_getbuffer == NULL) {
-        PyErr_SetString(PyExc_TypeError,
-                        "expected an object with a buffer interface");
+    if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) != 0)
         return -1;
-    }
-
-    if ((*pb->bf_getbuffer)(obj, &view, PyBUF_SIMPLE)) return -1;
 
     *buffer = view.buf;
     *buffer_len = view.len;
-    if (pb->bf_releasebuffer != NULL)
-        (*pb->bf_releasebuffer)(obj, &view);
-    Py_XDECREF(view.obj);
+    PyBuffer_Release(&view);
     return 0;
 }
 
@@ -342,9 +311,7 @@ int PyObject_AsWriteBuffer(PyObject *obj,
 
     *buffer = view.buf;
     *buffer_len = view.len;
-    if (pb->bf_releasebuffer != NULL)
-        (*pb->bf_releasebuffer)(obj, &view);
-    Py_XDECREF(view.obj);
+    PyBuffer_Release(&view);
     return 0;
 }
 
@@ -353,13 +320,15 @@ int PyObject_AsWriteBuffer(PyObject *obj,
 int
 PyObject_GetBuffer(PyObject *obj, Py_buffer *view, int flags)
 {
-    if (!PyObject_CheckBuffer(obj)) {
+    PyBufferProcs *pb = obj->ob_type->tp_as_buffer;
+
+    if (pb == NULL || pb->bf_getbuffer == NULL) {
         PyErr_Format(PyExc_TypeError,
                      "'%.100s' does not support the buffer interface",
                      Py_TYPE(obj)->tp_name);
         return -1;
     }
-    return (*(obj->ob_type->tp_as_buffer->bf_getbuffer))(obj, view, flags);
+    return (*pb->bf_getbuffer)(obj, view, flags);
 }
 
 static int
@@ -652,10 +621,14 @@ void
 PyBuffer_Release(Py_buffer *view)
 {
     PyObject *obj = view->obj;
-    if (obj && Py_TYPE(obj)->tp_as_buffer && Py_TYPE(obj)->tp_as_buffer->bf_releasebuffer)
-        Py_TYPE(obj)->tp_as_buffer->bf_releasebuffer(obj, view);
-    Py_XDECREF(obj);
+    PyBufferProcs *pb;
+    if (obj == NULL)
+        return;
+    pb = Py_TYPE(obj)->tp_as_buffer;
+    if (pb && pb->bf_releasebuffer)
+        pb->bf_releasebuffer(obj, view);
     view->obj = NULL;
+    Py_DECREF(obj);
 }
 
 PyObject *
@@ -1249,8 +1222,7 @@ PyNumber_Long(PyObject *o)
 {
     PyNumberMethods *m;
     PyObject *trunc_func;
-    const char *buffer;
-    Py_ssize_t buffer_len;
+    Py_buffer view;
     _Py_IDENTIFIER(__trunc__);
 
     if (o == NULL)
@@ -1288,21 +1260,22 @@ PyNumber_Long(PyObject *o)
     if (PyErr_Occurred())
         return NULL;
 
-    if (PyBytes_Check(o))
+    if (PyUnicode_Check(o))
+        /* The below check is done in PyLong_FromUnicode(). */
+        return PyLong_FromUnicodeObject(o, 10);
+
+    if (PyObject_GetBuffer(o, &view, PyBUF_SIMPLE) == 0) {
         /* need to do extra error checking that PyLong_FromString()
          * doesn't do.  In particular int('9\x005') must raise an
          * exception, not truncate at the null.
          */
-        return _PyLong_FromBytes(PyBytes_AS_STRING(o),
-                                 PyBytes_GET_SIZE(o), 10);
-    if (PyUnicode_Check(o))
-        /* The above check is done in PyLong_FromUnicode(). */
-        return PyLong_FromUnicodeObject(o, 10);
-    if (!PyObject_AsCharBuffer(o, &buffer, &buffer_len))
-        return _PyLong_FromBytes(buffer, buffer_len, 10);
+        PyObject *result = _PyLong_FromBytes(view.buf, view.len, 10);
+        PyBuffer_Release(&view);
+        return result;
+    }
 
-    return type_error("int() argument must be a string or a "
-                      "number, not '%.200s'", o);
+    return type_error("int() argument must be a string, a bytes-like object "
+                      "or a number, not '%.200s'", o);
 }
 
 PyObject *

Objects/bytearrayobject.c

@@ -74,24 +74,6 @@ bytearray_releasebuffer(PyByteArrayObject *obj, Py_buffer *view)
     obj->ob_exports--;
 }
 
-static Py_ssize_t
-_getbuffer(PyObject *obj, Py_buffer *view)
-{
-    PyBufferProcs *buffer = Py_TYPE(obj)->tp_as_buffer;
-
-    if (buffer == NULL || buffer->bf_getbuffer == NULL)
-    {
-        PyErr_Format(PyExc_TypeError,
-                     "Type %.100s doesn't support the buffer API",
-                     Py_TYPE(obj)->tp_name);
-        return -1;
-    }
-
-    if (buffer->bf_getbuffer(obj, view, PyBUF_SIMPLE) < 0)
-            return -1;
-    return view->len;
-}
-
 static int
 _canresize(PyByteArrayObject *self)
 {
@@ -262,8 +244,8 @@ PyByteArray_Concat(PyObject *a, PyObject *b)
 
     va.len = -1;
     vb.len = -1;
-    if (_getbuffer(a, &va) < 0  ||
-        _getbuffer(b, &vb) < 0) {
+    if (PyObject_GetBuffer(a, &va, PyBUF_SIMPLE) != 0 ||
+        PyObject_GetBuffer(b, &vb, PyBUF_SIMPLE) != 0) {
             PyErr_Format(PyExc_TypeError, "can't concat %.100s to %.100s",
                          Py_TYPE(a)->tp_name, Py_TYPE(b)->tp_name);
             goto done;
@@ -304,7 +286,7 @@ bytearray_iconcat(PyByteArrayObject *self, PyObject *other)
     Py_ssize_t size;
     Py_buffer vo;
 
-    if (_getbuffer(other, &vo) < 0) {
+    if (PyObject_GetBuffer(other, &vo, PyBUF_SIMPLE) != 0) {
         PyErr_Format(PyExc_TypeError, "can't concat %.100s to %.100s",
                      Py_TYPE(other)->tp_name, Py_TYPE(self)->tp_name);
         return NULL;
@@ -562,14 +544,14 @@ bytearray_setslice(PyByteArrayObject *self, Py_ssize_t lo, Py_ssize_t hi,
         needed = 0;
     }
     else {
-            if (_getbuffer(values, &vbytes) < 0) {
-                    PyErr_Format(PyExc_TypeError,
-                                 "can't set bytearray slice from %.100s",
-                                 Py_TYPE(values)->tp_name);
-                    return -1;
-            }
-            needed = vbytes.len;
-            bytes = vbytes.buf;
+        if (PyObject_GetBuffer(values, &vbytes, PyBUF_SIMPLE) != 0) {
+            PyErr_Format(PyExc_TypeError,
+                         "can't set bytearray slice from %.100s",
+                         Py_TYPE(values)->tp_name);
+            return -1;
+        }
+        needed = vbytes.len;
+        bytes = vbytes.buf;
     }
 
     if (lo < 0)
@@ -1012,18 +994,18 @@ bytearray_richcompare(PyObject *self, PyObject *other, int op)
         Py_RETURN_NOTIMPLEMENTED;
     }
 
-    self_size = _getbuffer(self, &self_bytes);
-    if (self_size < 0) {
+    if (PyObject_GetBuffer(self, &self_bytes, PyBUF_SIMPLE) != 0) {
         PyErr_Clear();
         Py_RETURN_NOTIMPLEMENTED;
     }
+    self_size = self_bytes.len;
 
-    other_size = _getbuffer(other, &other_bytes);
-    if (other_size < 0) {
+    if (PyObject_GetBuffer(other, &other_bytes, PyBUF_SIMPLE) != 0) {
         PyErr_Clear();
         PyBuffer_Release(&self_bytes);
         Py_RETURN_NOTIMPLEMENTED;
     }
+    other_size = other_bytes.len;
 
     if (self_size != other_size && (op == Py_EQ || op == Py_NE)) {
         /* Shortcut: if the lengths differ, the objects differ */
@@ -1135,7 +1117,7 @@ bytearray_find_internal(PyByteArrayObject *self, PyObject *args, int dir)
         return -2;
 
     if (subobj) {
-        if (_getbuffer(subobj, &subbuf) < 0)
+        if (PyObject_GetBuffer(subobj, &subbuf, PyBUF_SIMPLE) != 0)
             return -2;
 
         sub = subbuf.buf;
@@ -1203,7 +1185,7 @@ bytearray_count(PyByteArrayObject *self, PyObject *args)
         return NULL;
 
     if (sub_obj) {
-        if (_getbuffer(sub_obj, &vsub) < 0)
+        if (PyObject_GetBuffer(sub_obj, &vsub, PyBUF_SIMPLE) != 0)
             return NULL;
 
         sub = vsub.buf;
@@ -1318,7 +1300,7 @@ bytearray_contains(PyObject *self, PyObject *arg)
         Py_buffer varg;
         Py_ssize_t pos;
         PyErr_Clear();
-        if (_getbuffer(arg, &varg) < 0)
+        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
             return -1;
         pos = stringlib_find(PyByteArray_AS_STRING(self), Py_SIZE(self),
                              varg.buf, varg.len, 0);
@@ -1349,7 +1331,7 @@ _bytearray_tailmatch(PyByteArrayObject *self, PyObject *substr, Py_ssize_t start
 
     str = PyByteArray_AS_STRING(self);
 
-    if (_getbuffer(substr, &vsubstr) < 0)
+    if (PyObject_GetBuffer(substr, &vsubstr, PyBUF_SIMPLE) != 0)
         return -1;
 
     ADJUST_INDICES(start, end, len);
@@ -1493,7 +1475,7 @@ bytearray_translate(PyByteArrayObject *self, PyObject *args)
     if (tableobj == Py_None) {
         table = NULL;
         tableobj = NULL;
-    } else if (_getbuffer(tableobj, &vtable) < 0) {
+    } else if (PyObject_GetBuffer(tableobj, &vtable, PyBUF_SIMPLE) != 0) {
         return NULL;
     } else {
         if (vtable.len != 256) {
@@ -1506,7 +1488,7 @@ bytearray_translate(PyByteArrayObject *self, PyObject *args)
     }
 
     if (delobj != NULL) {
-        if (_getbuffer(delobj, &vdel) < 0) {
+        if (PyObject_GetBuffer(delobj, &vdel, PyBUF_SIMPLE) != 0) {
             if (tableobj != NULL)
                 PyBuffer_Release(&vtable);
             return NULL;
@@ -2070,26 +2052,20 @@ given, only the first count occurrences are replaced.");
 static PyObject *
 bytearray_replace(PyByteArrayObject *self, PyObject *args)
 {
+    PyObject *res;
+    Py_buffer old = {NULL, NULL};
+    Py_buffer new = {NULL, NULL};
     Py_ssize_t count = -1;
-    PyObject *from, *to, *res;
-    Py_buffer vfrom, vto;
 
-    if (!PyArg_ParseTuple(args, "OO|n:replace", &from, &to, &count))
+    if (!PyArg_ParseTuple(args, "y*y*|n:replace", &old, &new, &count))
         return NULL;
 
-    if (_getbuffer(from, &vfrom) < 0)
-        return NULL;
-    if (_getbuffer(to, &vto) < 0) {
-        PyBuffer_Release(&vfrom);
-        return NULL;
-    }
-
     res = (PyObject *)replace((PyByteArrayObject *) self,
-                              vfrom.buf, vfrom.len,
-                              vto.buf, vto.len, count);
+                              (const char *)old.buf, old.len,
+                              (const char *)new.buf, new.len, count);
 
-    PyBuffer_Release(&vfrom);
-    PyBuffer_Release(&vto);
+    PyBuffer_Release(&old);
+    PyBuffer_Release(&new);
     return res;
 }
 
@@ -2120,7 +2096,7 @@ bytearray_split(PyByteArrayObject *self, PyObject *args, PyObject *kwds)
     if (subobj == Py_None)
         return stringlib_split_whitespace((PyObject*) self, s, len, maxsplit);
 
-    if (_getbuffer(subobj, &vsub) < 0)
+    if (PyObject_GetBuffer(subobj, &vsub, PyBUF_SIMPLE) != 0)
         return NULL;
     sub = vsub.buf;
     n = vsub.len;
@@ -2215,7 +2191,7 @@ bytearray_rsplit(PyByteArrayObject *self, PyObject *args, PyObject *kwds)
     if (subobj == Py_None)
         return stringlib_rsplit_whitespace((PyObject*) self, s, len, maxsplit);
 
-    if (_getbuffer(subobj, &vsub) < 0)
+    if (PyObject_GetBuffer(subobj, &vsub, PyBUF_SIMPLE) != 0)
         return NULL;
     sub = vsub.buf;
     n = vsub.len;
@@ -2503,7 +2479,7 @@ bytearray_strip(PyByteArrayObject *self, PyObject *args)
         argsize = 6;
     }
     else {
-        if (_getbuffer(arg, &varg) < 0)
+        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
             return NULL;
         argptr = (char *) varg.buf;
         argsize = varg.len;
@@ -2540,7 +2516,7 @@ bytearray_lstrip(PyByteArrayObject *self, PyObject *args)
         argsize = 6;
     }
     else {
-        if (_getbuffer(arg, &varg) < 0)
+        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
             return NULL;
         argptr = (char *) varg.buf;
         argsize = varg.len;
@@ -2574,7 +2550,7 @@ bytearray_rstrip(PyByteArrayObject *self, PyObject *args)
         argsize = 6;
     }
     else {
-        if (_getbuffer(arg, &varg) < 0)
+        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
             return NULL;
         argptr = (char *) varg.buf;
         argsize = varg.len;

Objects/bytes_methods.c

@@ -363,41 +363,20 @@ for use in the bytes or bytearray translate method where each byte\n\
 in frm is mapped to the byte at the same position in to.\n\
 The bytes objects frm and to must be of the same length.");
 
-static Py_ssize_t
-_getbuffer(PyObject *obj, Py_buffer *view)
-{
-    PyBufferProcs *buffer = Py_TYPE(obj)->tp_as_buffer;
-
-    if (buffer == NULL || buffer->bf_getbuffer == NULL)
-    {
-        PyErr_Format(PyExc_TypeError,
-                     "Type %.100s doesn't support the buffer API",
-                     Py_TYPE(obj)->tp_name);
-        return -1;
-    }
-
-    if (buffer->bf_getbuffer(obj, view, PyBUF_SIMPLE) < 0)
-        return -1;
-    return view->len;
-}
-
 PyObject *
 _Py_bytes_maketrans(PyObject *args)
 {
-    PyObject *frm, *to, *res = NULL;
-    Py_buffer bfrm, bto;
+    PyObject *res = NULL;
+    Py_buffer bfrm = {NULL, NULL};
+    Py_buffer bto = {NULL, NULL};
     Py_ssize_t i;
     char *p;
 
     bfrm.len = -1;
     bto.len = -1;
 
-    if (!PyArg_ParseTuple(args, "OO:maketrans", &frm, &to))
-        return NULL;
-    if (_getbuffer(frm, &bfrm) < 0)
+    if (!PyArg_ParseTuple(args, "y*y*:maketrans", &bfrm, &bto))
         return NULL;
-    if (_getbuffer(to, &bto) < 0)
-        goto done;
     if (bfrm.len != bto.len) {
         PyErr_Format(PyExc_ValueError,
                      "maketrans arguments must have same length");
@@ -415,9 +394,9 @@ _Py_bytes_maketrans(PyObject *args)
     }
 
 done:
-    if (bfrm.len != -1)
+    if (bfrm.obj != NULL)
         PyBuffer_Release(&bfrm);
-    if (bto.len != -1)
+    if (bfrm.obj != NULL)
         PyBuffer_Release(&bto);
     return res;
 }

Objects/complexobject.c

@@ -767,6 +767,7 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
     int got_bracket=0;
     PyObject *s_buffer = NULL;
     Py_ssize_t len;
+    Py_buffer view = {NULL, NULL};
 
     if (PyUnicode_Check(v)) {
         s_buffer = _PyUnicode_TransformDecimalAndSpaceToASCII(v);
@@ -776,7 +777,11 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
         if (s == NULL)
             goto error;
     }
-    else if (PyObject_AsCharBuffer(v, &s, &len)) {
+    else if (PyObject_GetBuffer(v, &view, PyBUF_SIMPLE) == 0) {
+        s = (const char *)view.buf;
+        len = view.len;
+    }
+    else {
         PyErr_Format(PyExc_TypeError,
             "complex() argument must be a string or a number, not '%.200s'",
             Py_TYPE(v)->tp_name);
@@ -890,6 +895,7 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
     if (s-start != len)
         goto parse_error;
 
+    PyBuffer_Release(&view);
     Py_XDECREF(s_buffer);
     return complex_subtype_from_doubles(type, x, y);
 
@@ -897,6 +903,7 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v)
     PyErr_SetString(PyExc_ValueError,
                     "complex() arg is a malformed string");
   error:
+    PyBuffer_Release(&view);
     Py_XDECREF(s_buffer);
     return NULL;
 }

Objects/exceptions.c

@@ -1922,8 +1922,6 @@ static int
 UnicodeDecodeError_init(PyObject *self, PyObject *args, PyObject *kwds)
 {
     PyUnicodeErrorObject *ude;
-    const char *data;
-    Py_ssize_t size;
 
     if (BaseException_init((PyBaseExceptionObject *)self, args, kwds) == -1)
         return -1;
@@ -1944,21 +1942,27 @@ UnicodeDecodeError_init(PyObject *self, PyObject *args, PyObject *kwds)
              return -1;
     }
 
-    if (!PyBytes_Check(ude->object)) {
-        if (PyObject_AsReadBuffer(ude->object, (const void **)&data, &size)) {
-            ude->encoding = ude->object = ude->reason = NULL;
-            return -1;
-        }
-        ude->object = PyBytes_FromStringAndSize(data, size);
-    }
-    else {
-        Py_INCREF(ude->object);
-    }
-
     Py_INCREF(ude->encoding);
+    Py_INCREF(ude->object);
     Py_INCREF(ude->reason);
 
+    if (!PyBytes_Check(ude->object)) {
+        Py_buffer view;
+        if (PyObject_GetBuffer(ude->object, &view, PyBUF_SIMPLE) != 0)
+            goto error;
+        Py_CLEAR(ude->object);
+        ude->object = PyBytes_FromStringAndSize(view.buf, view.len);
+        PyBuffer_Release(&view);
+        if (!ude->object)
+            goto error;
+    }
     return 0;
+
+error:
+    Py_CLEAR(ude->encoding);
+    Py_CLEAR(ude->object);
+    Py_CLEAR(ude->reason);
+    return -1;
 }
 
 static PyObject *

Objects/floatobject.c

@@ -131,6 +131,7 @@ PyFloat_FromString(PyObject *v)
     double x;
     PyObject *s_buffer = NULL;
     Py_ssize_t len;
+    Py_buffer view = {NULL, NULL};
     PyObject *result = NULL;
 
     if (PyUnicode_Check(v)) {
@@ -143,7 +144,11 @@ PyFloat_FromString(PyObject *v)
             return NULL;
         }
     }
-    else if (PyObject_AsCharBuffer(v, &s, &len)) {
+    else if (PyObject_GetBuffer(v, &view, PyBUF_SIMPLE) == 0) {
+        s = (const char *)view.buf;
+        len = view.len;
+    }
+    else {
         PyErr_Format(PyExc_TypeError,
             "float() argument must be a string or a number, not '%.200s'",
             Py_TYPE(v)->tp_name);
@@ -170,6 +175,7 @@ PyFloat_FromString(PyObject *v)
     else
         result = PyFloat_FromDouble(x);
 
+    PyBuffer_Release(&view);
     Py_XDECREF(s_buffer);
     return result;
 }

Objects/stringlib/join.h

@@ -58,7 +58,14 @@ STRINGLIB(bytes_join)(PyObject *sep, PyObject *iterable)
     for (i = 0, nbufs = 0; i < seqlen; i++) {
         Py_ssize_t itemlen;
         item = PySequence_Fast_GET_ITEM(seq, i);
-        if (_getbuffer(item, &buffers[i]) < 0) {
+        if (PyBytes_CheckExact(item)) {
+            /* Fast path. */
+            Py_INCREF(item);
+            buffers[i].obj = item;
+            buffers[i].buf = PyBytes_AS_STRING(item);
+            buffers[i].len = PyBytes_GET_SIZE(item);
+        }
+        else if (PyObject_GetBuffer(item, &buffers[i], PyBUF_SIMPLE) != 0) {
             PyErr_Format(PyExc_TypeError,
                          "sequence item %zd: expected a bytes-like object, "
                          "%.80s found",

Python/bltinmodule.c

@@ -559,10 +559,10 @@ PyDoc_STRVAR(chr_doc,
 Return a Unicode string of one character with ordinal i; 0 <= i <= 0x10ffff.");
 
 
-static char *
-source_as_string(PyObject *cmd, char *funcname, char *what, PyCompilerFlags *cf)
+static const char *
+source_as_string(PyObject *cmd, const char *funcname, const char *what, PyCompilerFlags *cf, Py_buffer *view)
 {
-    char *str;
+    const char *str;
     Py_ssize_t size;
 
     if (PyUnicode_Check(cmd)) {
@@ -571,19 +571,21 @@ source_as_string(PyObject *cmd, char *funcname, char *what, PyCompilerFlags *cf)
         if (str == NULL)
             return NULL;
     }
-    else if (!PyObject_CheckReadBuffer(cmd)) {
+    else if (PyObject_GetBuffer(cmd, view, PyBUF_SIMPLE) == 0) {
+        str = (const char *)view->buf;
+        size = view->len;
+    }
+    else {
         PyErr_Format(PyExc_TypeError,
           "%s() arg 1 must be a %s object",
           funcname, what);
         return NULL;
     }
-    else if (PyObject_AsReadBuffer(cmd, (const void **)&str, &size) < 0) {
-        return NULL;
-    }
 
     if (strlen(str) != size) {
         PyErr_SetString(PyExc_TypeError,
                         "source code string cannot contain null bytes");
+        PyBuffer_Release(view);
         return NULL;
     }
     return str;
@@ -592,7 +594,8 @@ source_as_string(PyObject *cmd, char *funcname, char *what, PyCompilerFlags *cf)
 static PyObject *
 builtin_compile(PyObject *self, PyObject *args, PyObject *kwds)
 {
-    char *str;
+    Py_buffer view = {NULL, NULL};
+    const char *str;
     PyObject *filename;
     char *startstr;
     int mode = -1;
@@ -678,11 +681,12 @@ builtin_compile(PyObject *self, PyObject *args, PyObject *kwds)
         goto finally;
     }
 
-    str = source_as_string(cmd, "compile", "string, bytes or AST", &cf);
+    str = source_as_string(cmd, "compile", "string, bytes or AST", &cf, &view);
     if (str == NULL)
         goto error;
 
     result = Py_CompileStringObject(str, filename, start[mode], &cf, optimize);
+    PyBuffer_Release(&view);
     goto finally;
 
 error:
@@ -752,7 +756,8 @@ builtin_eval(PyObject *self, PyObject *args)
 {
     PyObject *cmd, *result, *tmp = NULL;
     PyObject *globals = Py_None, *locals = Py_None;
-    char *str;
+    Py_buffer view = {NULL, NULL};
+    const char *str;
     PyCompilerFlags cf;
 
     if (!PyArg_UnpackTuple(args, "eval", 1, 3, &cmd, &globals, &locals))
@@ -801,7 +806,7 @@ builtin_eval(PyObject *self, PyObject *args)
     }
 
     cf.cf_flags = PyCF_SOURCE_IS_UTF8;
-    str = source_as_string(cmd, "eval", "string, bytes or code", &cf);
+    str = source_as_string(cmd, "eval", "string, bytes or code", &cf, &view);
     if (str == NULL)
         return NULL;
 
@@ -810,6 +815,7 @@ builtin_eval(PyObject *self, PyObject *args)
 
     (void)PyEval_MergeCompilerFlags(&cf);
     result = PyRun_StringFlags(str, Py_eval_input, globals, locals, &cf);
+    PyBuffer_Release(&view);
     Py_XDECREF(tmp);
     return result;
 }
@@ -876,11 +882,12 @@ builtin_exec(PyObject *self, PyObject *args)
         v = PyEval_EvalCode(prog, globals, locals);
     }
     else {
-        char *str;
+        Py_buffer view = {NULL, NULL};
+        const char *str;
         PyCompilerFlags cf;
         cf.cf_flags = PyCF_SOURCE_IS_UTF8;
         str = source_as_string(prog, "exec",
-                                     "string, bytes or code", &cf);
+                                     "string, bytes or code", &cf, &view);
         if (str == NULL)
             return NULL;
         if (PyEval_MergeCompilerFlags(&cf))
@@ -888,6 +895,7 @@ builtin_exec(PyObject *self, PyObject *args)
                                   locals, &cf);
         else
             v = PyRun_String(str, Py_file_input, globals, locals);
+        PyBuffer_Release(&view);
     }
     if (v == NULL)
         return NULL;