Remove special case for file-like objects without a readinto().

Author: pitrou

Lib/test/pickletester.py

@@ -73,23 +73,6 @@ def tell(self):
         raise io.UnsupportedOperation
 
 
-class TrivialReadableIO:
-    """
-    A readable file object that doesn't support readinto().
-    """
-    def __init__(self, *args, **kwargs):
-        self._bio = io.BytesIO(*args, **kwargs)
-
-    def read(self, n):
-        return self._bio.read(n)
-
-    def readline(self, n=None):
-        return self._bio.readline(n)
-
-    def getvalue(self):
-        return self._bio.getvalue()
-
-
 # We can't very well test the extension registry without putting known stuff
 # in it, but we have to be careful to restore its original state.  Code
 # should do this:
@@ -3399,22 +3382,6 @@ def test_unpickling_buffering_readline(self):
                 unpickler = self.unpickler_class(f)
                 self.assertEqual(unpickler.load(), data)
 
-    def test_unpickling_trivial_io(self):
-        # Check unpickling with an io class that doesn't have readinto()
-        sizes = [1, 16, 1000, 2**10]
-        data = [(b"x" * size, bytearray(b"x") * size) for size in sizes]
-        for proto in protocols:
-            with self.subTest(proto=proto):
-                bio = io.BytesIO()
-                pickler = self.pickler_class(bio, protocol=proto)
-                pickler.dump(data)
-                N = 5
-                f = TrivialReadableIO(bio.getvalue() * N)
-                unpickler = self.unpickler_class(f)
-                for i in range(N):
-                    self.assertEqual(unpickler.load(), data)
-                self.assertRaises(EOFError, unpickler.load)
-
 
 # Tests for dispatch_table attribute
 

Modules/_pickle.c

@@ -1356,8 +1356,6 @@ _Unpickler_ReadInto(UnpicklerObject *self, char *buf, Py_ssize_t n)
 {
     assert(n != READ_WHOLE_LINE);
 
-    /* XXX add tests from ogrisel's use case */
-
     /* Read from available buffer data, if any */
     Py_ssize_t in_buffer = self->input_len - self->next_read_idx;
     if (in_buffer > 0) {
@@ -1373,30 +1371,21 @@ _Unpickler_ReadInto(UnpicklerObject *self, char *buf, Py_ssize_t n)
     }
 
     /* Read from file */
+    if (!self->readinto)
+        return bad_readline();
     if (_Unpickler_SkipConsumed(self) < 0)
         return -1;
 
-    Py_ssize_t read_size;
-
-    if (self->readinto == NULL) {
-        /* Call read() and memcpy */
-        /* XXX do we want this fallback? pickle.py doesn't have it */
-        char *s;
-        read_size = _Unpickler_ReadImpl(self, &s, n);
-        if (read_size < 0) {
-            return -1;
-        }
-        assert(read_size == n);
-        memcpy(buf, s, n);
-        return n;
-    }
-
     /* Call readinto() into user buffer */
     PyObject *buf_obj = PyMemoryView_FromMemory(buf, n, PyBUF_WRITE);
-    if (buf_obj == NULL)
+    if (buf_obj == NULL) {
         return -1;
+    }
     PyObject *read_size_obj = _Pickle_FastCall(self->readinto, buf_obj);
-    read_size = PyLong_AsSsize_t(read_size_obj);
+    if (read_size_obj == NULL) {
+        return -1;
+    }
+    Py_ssize_t read_size = PyLong_AsSsize_t(read_size_obj);
     Py_DECREF(read_size_obj);
 
     if (read_size < 0) {
@@ -1614,19 +1603,17 @@ _Unpickler_SetInputStream(UnpicklerObject *self, PyObject *file)
     _Py_IDENTIFIER(readinto);
     _Py_IDENTIFIER(readline);
 
-    /* Both 'peek' and 'readline' are optional, for compatibility */
     if (_PyObject_LookupAttrId(file, &PyId_peek, &self->peek) < 0) {
         return -1;
     }
-    if (_PyObject_LookupAttrId(file, &PyId_readinto, &self->readinto) < 0) {
-        return -1;
-    }
     (void)_PyObject_LookupAttrId(file, &PyId_read, &self->read);
+    (void)_PyObject_LookupAttrId(file, &PyId_readinto, &self->readinto);
     (void)_PyObject_LookupAttrId(file, &PyId_readline, &self->readline);
-    if (self->readline == NULL || self->read == NULL) {
+    if (!self->readline || !self->readinto || !self->read) {
         if (!PyErr_Occurred()) {
             PyErr_SetString(PyExc_TypeError,
-                            "file must have 'read' and 'readline' attributes");
+                            "file must have 'read', 'readinto' and "
+                            "'readline' attributes");
         }
         Py_CLEAR(self->read);
         Py_CLEAR(self->readinto);