More tests. Add flags= argument to memoryview

JelleZijlstra · May 4, 2023 · Oct 2, 2022 · Oct 3, 2022 · Oct 4, 2022 · Oct 4, 2022
commit 6c863bcf3560563a736ebcefba12c9155a6f7869
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
@@ -17,6 +17,7 @@
 import unittest
 from test import support
 from test.support import os_helper
+import inspect
 from itertools import permutations, product
 from random import randrange, sample, choice
 import warnings
@@ -4502,6 +4503,40 @@ def __release_buffer__(self, buffer):
             self.assertEqual(mv.tobytes(), b"hello")
         self.assertFalse(wr.held)
 
+    def test_buffer_flags(self):
+        class PossiblyMutable:
+            def __init__(self, data, mutable) -> None:
+                self._data = bytearray(data)
+                self._mutable = mutable
+
+            def __buffer__(self, flags):
+                if flags & inspect.BufferFlags.WRITABLE:
+                    if not self._mutable:
+                        raise RuntimeError("not mutable")
+                    return memoryview(self._data)
+                else:
+                    return memoryview(bytes(self._data))
+
+        mutable = PossiblyMutable(b"hello", True)
+        immutable = PossiblyMutable(b"hello", False)
+        with memoryview(mutable, flags=inspect.BufferFlags.WRITABLE) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"xello")
+        with memoryview(immutable, flags=inspect.BufferFlags.SIMPLE) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            with self.assertRaises(TypeError):
+                mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"hello")
+
+        with self.assertRaises(RuntimeError):
+            memoryview(immutable, flags=inspect.BufferFlags.WRITABLE)
+        with memoryview(immutable) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            with self.assertRaises(TypeError):
+                mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"hello")
+
     def test_call_builtins(self):
         ba = bytearray(b"hello")
         mv = ba.__buffer__(0)

@@ -169,7 +169,7 @@
 @MODULE__XXTESTFUZZ_TRUE@_xxtestfuzz _xxtestfuzz/_xxtestfuzz.c _xxtestfuzz/fuzzer.c
 @MODULE__TESTBUFFER_TRUE@_testbuffer _testbuffer.c
 @MODULE__TESTINTERNALCAPI_TRUE@_testinternalcapi _testinternalcapi.c
-@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c
+@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c _testcapi/buffer.c
 @MODULE__TESTCLINIC_TRUE@_testclinic _testclinic.c
 
 # Some testing modules MUST be built as shared libraries.

diff --git a/Modules/_testcapi/buffer.c b/Modules/_testcapi/buffer.c
@@ -0,0 +1,97 @@
+/* Test PEP 688 - Buffers */
+
+#include "parts.h"
+
+#include "structmember.h"           // PyMemberDef
+#include <stddef.h>                 // offsetof
+
+typedef struct {
+    PyObject_HEAD
+    PyObject *obj;
+    long references;
+} testBufObject;
+
+static PyObject *
+testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
+    if (self == NULL) {
+        return NULL;
+    }
+    self->obj = PyBytes_FromString("test");
+    self->references = 0;
+    return (PyObject *)self;
+}
+
+static int
+testbuf_traverse(testBufObject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->obj);
+    return 0;
+}
+
+static int
+testbuf_clear(testBufObject *self)
+{
+    Py_CLEAR(self->obj);
+    return 0;
+}
+
+static void
+testbuf_dealloc(testBufObject *self)
+{
+    PyObject_GC_UnTrack(self);
+    Py_XDECREF(self->obj);
+    Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static int
+testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
+{
+    int buf = PyObject_GetBuffer(self->obj, view, flags);
+    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
+    self->references++;
+    return buf;
+}
+
+static void
+testbuf_releasebuf(testBufObject *self, Py_buffer *view)
+{
+    self->references--;
+    assert(self->references >= 0);
+}
+
+static PyBufferProcs testbuf_as_buffer = {
+    .bf_getbuffer = (getbufferproc) testbuf_getbuf,
+    .bf_releasebuffer = (releasebufferproc) testbuf_releasebuf,
+};
+
+static struct PyMemberDef testbuf_members[] = {
+    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
+    {NULL},
+};
+
+static PyTypeObject testBufType = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    .tp_name = "testBufType",
+    .tp_basicsize = sizeof(testBufObject),
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+    .tp_new = testbuf_new,
+    .tp_dealloc = (destructor) testbuf_dealloc,
+    .tp_traverse = (traverseproc) testbuf_traverse,
+    .tp_clear = (inquiry) testbuf_clear,
+    .tp_as_buffer = &testbuf_as_buffer,
+    .tp_members = testbuf_members
+};
+
+int
+_PyTestCapi_Init_Buffer(PyObject *m) {
+    if (PyType_Ready(&testBufType) < 0) {
+        return -1;
+    }
+    if (PyModule_AddObjectRef(m, "testBuf", (PyObject *)&testBufType)) {
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
@@ -38,6 +38,7 @@ int _PyTestCapi_Init_Float(PyObject *module);
 int _PyTestCapi_Init_Structmember(PyObject *module);
 int _PyTestCapi_Init_Exceptions(PyObject *module);
 int _PyTestCapi_Init_Code(PyObject *module);
+int _PyTestCapi_Init_Buffer(PyObject *module);
 
 #ifdef LIMITED_API_AVAILABLE
 int _PyTestCapi_Init_VectorcallLimited(PyObject *module);

diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
@@ -3746,86 +3746,6 @@ static PyTypeObject MyList_Type = {
     MyList_new,                                 /* tp_new */
 };
 
-typedef struct {
-    PyObject_HEAD
-    PyObject *obj;
-    long references;
-} testBufObject;
-
-static PyObject *
-testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
-{
-    testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
-    if (self == NULL) {
-        return NULL;
-    }
-    self->obj = PyBytes_FromString("test");
-    self->references = 0;
-    return (PyObject *)self;
-}
-
-static int
-testbuf_traverse(testBufObject *self, visitproc visit, void *arg)
-{
-    Py_VISIT(self->obj);
-    return 0;
-}
-
-static int
-testbuf_clear(testBufObject *self)
-{
-    Py_CLEAR(self->obj);
-    return 0;
-}
-
-static void
-testbuf_dealloc(testBufObject *self)
-{
-    PyObject_GC_UnTrack(self);
-    Py_XDECREF(self->obj);
-    Py_TYPE(self)->tp_free((PyObject *) self);
-}
-
-static int
-testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
-{
-    int buf = PyObject_GetBuffer(self->obj, view, flags);
-    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
-    self->references++;
-    return buf;
-}
-
-static void
-testbuf_releasebuf(testBufObject *self, Py_buffer *view)
-{
-    self->references--;
-    assert(self->references >= 0);
-}
-
-static PyBufferProcs testbuf_as_buffer = {
-    .bf_getbuffer = (getbufferproc) testbuf_getbuf,
-    .bf_releasebuffer = (releasebufferproc) testbuf_releasebuf,
-};
-
-static struct PyMemberDef testbuf_members[] = {
-    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
-    {NULL},
-};
-
-static PyTypeObject testBufType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    .tp_name = "testBufType",
-    .tp_basicsize = sizeof(testBufObject),
-    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
-    .tp_new = testbuf_new,
-    .tp_dealloc = (destructor) testbuf_dealloc,
-    .tp_traverse = (traverseproc) testbuf_traverse,
-    .tp_clear = (inquiry) testbuf_clear,
-    .tp_as_buffer = &testbuf_as_buffer,
-    .tp_members = testbuf_members
-};
-
-
 /* Test PEP 560 */
 
 typedef struct {
@@ -4057,13 +3977,6 @@ PyInit__testcapi(void)
     Py_INCREF(&MyList_Type);
     PyModule_AddObject(m, "MyList", (PyObject *)&MyList_Type);
 
-    if (PyType_Ready(&testBufType) < 0) {
-        return NULL;
-    }
-    if (PyModule_AddObjectRef(m, "testBuf", (PyObject *)&testBufType)) {
-        return NULL;
-    }
-
     if (PyType_Ready(&GenericAlias_Type) < 0)
         return NULL;
     Py_INCREF(&GenericAlias_Type);
@@ -4172,6 +4085,9 @@ PyInit__testcapi(void)
     if (_PyTestCapi_Init_Code(m) < 0) {
         return NULL;
     }
+    if (_PyTestCapi_Init_Buffer(m) < 0) {
+        return NULL;
+    }
 
 #ifndef LIMITED_API_AVAILABLE
     PyModule_AddObjectRef(m, "LIMITED_API_AVAILABLE", Py_False);

diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
@@ -965,15 +965,17 @@ PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)
 memoryview.__new__
 
     object: object
+    *
+    flags: int(c_default='PyBUF_FULL_RO') = PyBUF_FULL_RO
 
 Create a new memoryview object which references the given object.
 [clinic start generated code]*/
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object)
-/*[clinic end generated code: output=7de78e184ed66db8 input=f04429eb0bdf8c6e]*/
+memoryview_impl(PyTypeObject *type, PyObject *object, int flags)
+/*[clinic end generated code: output=f1c225d1ad24ec11 input=cab66ab4bb27f268]*/
 {
-    return PyMemoryView_FromObject(object);
+    return PyMemoryView_FromObjectAndFlags(object, flags);
 }
 
 

@@ -109,6 +109,7 @@
     <ClCompile Include="..\Modules\_testcapi\structmember.c" />
     <ClCompile Include="..\Modules\_testcapi\exceptions.c" />
     <ClCompile Include="..\Modules\_testcapi\code.c" />
+    <ClCompile Include="..\Modules\_testcapi\buffer.c" />
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="..\PC\python_nt.rc" />

@@ -57,6 +57,9 @@
     <ClCompile Include="..\Modules\_testcapi\code.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\Modules\_testcapi\buffer.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="..\PC\python_nt.rc">