Antoine Pitrou | 91f4380 | 2019-05-26 17:10:09 +0200 | [diff] [blame] | 1 | /* PickleBuffer object implementation */ |
| 2 | |
| 3 | #define PY_SSIZE_T_CLEAN |
| 4 | #include "Python.h" |
| 5 | #include <stddef.h> |
| 6 | |
| 7 | typedef struct { |
| 8 | PyObject_HEAD |
| 9 | /* The view exported by the original object */ |
| 10 | Py_buffer view; |
| 11 | PyObject *weakreflist; |
| 12 | } PyPickleBufferObject; |
| 13 | |
| 14 | /* C API */ |
| 15 | |
| 16 | PyObject * |
| 17 | PyPickleBuffer_FromObject(PyObject *base) |
| 18 | { |
| 19 | PyTypeObject *type = &PyPickleBuffer_Type; |
| 20 | PyPickleBufferObject *self; |
| 21 | |
| 22 | self = (PyPickleBufferObject *) type->tp_alloc(type, 0); |
| 23 | if (self == NULL) { |
| 24 | return NULL; |
| 25 | } |
| 26 | self->view.obj = NULL; |
| 27 | self->weakreflist = NULL; |
| 28 | if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) { |
| 29 | Py_DECREF(self); |
| 30 | return NULL; |
| 31 | } |
| 32 | return (PyObject *) self; |
| 33 | } |
| 34 | |
| 35 | const Py_buffer * |
| 36 | PyPickleBuffer_GetBuffer(PyObject *obj) |
| 37 | { |
| 38 | PyPickleBufferObject *self = (PyPickleBufferObject *) obj; |
| 39 | |
| 40 | if (!PyPickleBuffer_Check(obj)) { |
| 41 | PyErr_Format(PyExc_TypeError, |
| 42 | "expected PickleBuffer, %.200s found", |
| 43 | Py_TYPE(obj)->tp_name); |
| 44 | return NULL; |
| 45 | } |
| 46 | if (self->view.obj == NULL) { |
| 47 | PyErr_SetString(PyExc_ValueError, |
| 48 | "operation forbidden on released PickleBuffer object"); |
| 49 | return NULL; |
| 50 | } |
| 51 | return &self->view; |
| 52 | } |
| 53 | |
| 54 | int |
| 55 | PyPickleBuffer_Release(PyObject *obj) |
| 56 | { |
| 57 | PyPickleBufferObject *self = (PyPickleBufferObject *) obj; |
| 58 | |
| 59 | if (!PyPickleBuffer_Check(obj)) { |
| 60 | PyErr_Format(PyExc_TypeError, |
| 61 | "expected PickleBuffer, %.200s found", |
| 62 | Py_TYPE(obj)->tp_name); |
| 63 | return -1; |
| 64 | } |
| 65 | PyBuffer_Release(&self->view); |
| 66 | return 0; |
| 67 | } |
| 68 | |
| 69 | static PyObject * |
| 70 | picklebuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds) |
| 71 | { |
| 72 | PyPickleBufferObject *self; |
| 73 | PyObject *base; |
| 74 | char *keywords[] = {"", NULL}; |
| 75 | |
| 76 | if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:PickleBuffer", |
| 77 | keywords, &base)) { |
| 78 | return NULL; |
| 79 | } |
| 80 | |
| 81 | self = (PyPickleBufferObject *) type->tp_alloc(type, 0); |
| 82 | if (self == NULL) { |
| 83 | return NULL; |
| 84 | } |
| 85 | self->view.obj = NULL; |
| 86 | self->weakreflist = NULL; |
| 87 | if (PyObject_GetBuffer(base, &self->view, PyBUF_FULL_RO) < 0) { |
| 88 | Py_DECREF(self); |
| 89 | return NULL; |
| 90 | } |
| 91 | return (PyObject *) self; |
| 92 | } |
| 93 | |
| 94 | static int |
| 95 | picklebuf_traverse(PyPickleBufferObject *self, visitproc visit, void *arg) |
| 96 | { |
| 97 | Py_VISIT(self->view.obj); |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | static int |
| 102 | picklebuf_clear(PyPickleBufferObject *self) |
| 103 | { |
| 104 | PyBuffer_Release(&self->view); |
| 105 | return 0; |
| 106 | } |
| 107 | |
| 108 | static void |
| 109 | picklebuf_dealloc(PyPickleBufferObject *self) |
| 110 | { |
| 111 | PyObject_GC_UnTrack(self); |
| 112 | if (self->weakreflist != NULL) |
| 113 | PyObject_ClearWeakRefs((PyObject *) self); |
| 114 | PyBuffer_Release(&self->view); |
| 115 | Py_TYPE(self)->tp_free((PyObject *) self); |
| 116 | } |
| 117 | |
| 118 | /* Buffer API */ |
| 119 | |
| 120 | static int |
| 121 | picklebuf_getbuf(PyPickleBufferObject *self, Py_buffer *view, int flags) |
| 122 | { |
| 123 | if (self->view.obj == NULL) { |
| 124 | PyErr_SetString(PyExc_ValueError, |
| 125 | "operation forbidden on released PickleBuffer object"); |
| 126 | return -1; |
| 127 | } |
| 128 | return PyObject_GetBuffer(self->view.obj, view, flags); |
| 129 | } |
| 130 | |
| 131 | static void |
| 132 | picklebuf_releasebuf(PyPickleBufferObject *self, Py_buffer *view) |
| 133 | { |
| 134 | /* Since our bf_getbuffer redirects to the original object, this |
| 135 | * implementation is never called. It only exists to signal that |
| 136 | * buffers exported by PickleBuffer have non-trivial releasing |
| 137 | * behaviour (see check in Python/getargs.c). |
| 138 | */ |
| 139 | } |
| 140 | |
| 141 | static PyBufferProcs picklebuf_as_buffer = { |
| 142 | .bf_getbuffer = (getbufferproc) picklebuf_getbuf, |
| 143 | .bf_releasebuffer = (releasebufferproc) picklebuf_releasebuf, |
| 144 | }; |
| 145 | |
| 146 | /* Methods */ |
| 147 | |
| 148 | static PyObject * |
| 149 | picklebuf_raw(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored)) |
| 150 | { |
| 151 | if (self->view.obj == NULL) { |
| 152 | PyErr_SetString(PyExc_ValueError, |
| 153 | "operation forbidden on released PickleBuffer object"); |
| 154 | return NULL; |
| 155 | } |
| 156 | if (self->view.suboffsets != NULL |
| 157 | || !PyBuffer_IsContiguous(&self->view, 'A')) { |
| 158 | PyErr_SetString(PyExc_BufferError, |
| 159 | "cannot extract raw buffer from non-contiguous buffer"); |
| 160 | return NULL; |
| 161 | } |
| 162 | PyObject *m = PyMemoryView_FromObject((PyObject *) self); |
| 163 | if (m == NULL) { |
| 164 | return NULL; |
| 165 | } |
| 166 | PyMemoryViewObject *mv = (PyMemoryViewObject *) m; |
| 167 | assert(mv->view.suboffsets == NULL); |
| 168 | /* Mutate memoryview instance to make it a "raw" memoryview */ |
| 169 | mv->view.format = "B"; |
| 170 | mv->view.ndim = 1; |
| 171 | mv->view.itemsize = 1; |
| 172 | /* shape = (length,) */ |
| 173 | mv->view.shape = &mv->view.len; |
| 174 | /* strides = (1,) */ |
| 175 | mv->view.strides = &mv->view.itemsize; |
| 176 | /* Fix memoryview state flags */ |
| 177 | /* XXX Expose memoryobject.c's init_flags() instead? */ |
| 178 | mv->flags = _Py_MEMORYVIEW_C | _Py_MEMORYVIEW_FORTRAN; |
| 179 | return m; |
| 180 | } |
| 181 | |
| 182 | PyDoc_STRVAR(picklebuf_raw_doc, |
| 183 | "raw($self, /)\n--\n\ |
| 184 | \n\ |
| 185 | Return a memoryview of the raw memory underlying this buffer.\n\ |
| 186 | Will raise BufferError is the buffer isn't contiguous."); |
| 187 | |
| 188 | static PyObject * |
| 189 | picklebuf_release(PyPickleBufferObject *self, PyObject *Py_UNUSED(ignored)) |
| 190 | { |
| 191 | PyBuffer_Release(&self->view); |
| 192 | Py_RETURN_NONE; |
| 193 | } |
| 194 | |
| 195 | PyDoc_STRVAR(picklebuf_release_doc, |
| 196 | "release($self, /)\n--\n\ |
| 197 | \n\ |
| 198 | Release the underlying buffer exposed by the PickleBuffer object."); |
| 199 | |
| 200 | static PyMethodDef picklebuf_methods[] = { |
| 201 | {"raw", (PyCFunction) picklebuf_raw, METH_NOARGS, picklebuf_raw_doc}, |
| 202 | {"release", (PyCFunction) picklebuf_release, METH_NOARGS, picklebuf_release_doc}, |
| 203 | {NULL, NULL} |
| 204 | }; |
| 205 | |
| 206 | PyTypeObject PyPickleBuffer_Type = { |
| 207 | PyVarObject_HEAD_INIT(NULL, 0) |
| 208 | .tp_name = "pickle.PickleBuffer", |
| 209 | .tp_doc = "Wrapper for potentially out-of-band buffers", |
| 210 | .tp_basicsize = sizeof(PyPickleBufferObject), |
| 211 | .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, |
| 212 | .tp_new = picklebuf_new, |
| 213 | .tp_dealloc = (destructor) picklebuf_dealloc, |
| 214 | .tp_traverse = (traverseproc) picklebuf_traverse, |
| 215 | .tp_clear = (inquiry) picklebuf_clear, |
| 216 | .tp_weaklistoffset = offsetof(PyPickleBufferObject, weakreflist), |
| 217 | .tp_as_buffer = &picklebuf_as_buffer, |
| 218 | .tp_methods = picklebuf_methods, |
| 219 | }; |