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py3: check for None before comparing with integers...
py3: check for None before comparing with integers Comparing None and integers on Python 3 is not allowed and raise error. Differential Revision: https://phab.mercurial-scm.org/D3614

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decompressionreader.c
459 lines | 10.9 KiB | text/x-c | CLexer
/**
* Copyright (c) 2017-present, Gregory Szorc
* All rights reserved.
*
* This software may be modified and distributed under the terms
* of the BSD license. See the LICENSE file for details.
*/
#include "python-zstandard.h"
extern PyObject* ZstdError;
static void set_unsupported_operation(void) {
PyObject* iomod;
PyObject* exc;
iomod = PyImport_ImportModule("io");
if (NULL == iomod) {
return;
}
exc = PyObject_GetAttrString(iomod, "UnsupportedOperation");
if (NULL == exc) {
Py_DECREF(iomod);
return;
}
PyErr_SetNone(exc);
Py_DECREF(exc);
Py_DECREF(iomod);
}
static void reader_dealloc(ZstdDecompressionReader* self) {
Py_XDECREF(self->decompressor);
Py_XDECREF(self->reader);
if (self->buffer.buf) {
PyBuffer_Release(&self->buffer);
}
PyObject_Del(self);
}
static ZstdDecompressionReader* reader_enter(ZstdDecompressionReader* self) {
if (self->entered) {
PyErr_SetString(PyExc_ValueError, "cannot __enter__ multiple times");
return NULL;
}
if (ensure_dctx(self->decompressor, 1)) {
return NULL;
}
self->entered = 1;
Py_INCREF(self);
return self;
}
static PyObject* reader_exit(ZstdDecompressionReader* self, PyObject* args) {
PyObject* exc_type;
PyObject* exc_value;
PyObject* exc_tb;
if (!PyArg_ParseTuple(args, "OOO:__exit__", &exc_type, &exc_value, &exc_tb)) {
return NULL;
}
self->entered = 0;
self->closed = 1;
/* Release resources. */
Py_CLEAR(self->reader);
if (self->buffer.buf) {
PyBuffer_Release(&self->buffer);
memset(&self->buffer, 0, sizeof(self->buffer));
}
Py_CLEAR(self->decompressor);
Py_RETURN_FALSE;
}
static PyObject* reader_readable(PyObject* self) {
Py_RETURN_TRUE;
}
static PyObject* reader_writable(PyObject* self) {
Py_RETURN_FALSE;
}
static PyObject* reader_seekable(PyObject* self) {
Py_RETURN_TRUE;
}
static PyObject* reader_close(ZstdDecompressionReader* self) {
self->closed = 1;
Py_RETURN_NONE;
}
static PyObject* reader_closed(ZstdDecompressionReader* self) {
if (self->closed) {
Py_RETURN_TRUE;
}
else {
Py_RETURN_FALSE;
}
}
static PyObject* reader_flush(PyObject* self) {
Py_RETURN_NONE;
}
static PyObject* reader_isatty(PyObject* self) {
Py_RETURN_FALSE;
}
static PyObject* reader_read(ZstdDecompressionReader* self, PyObject* args, PyObject* kwargs) {
static char* kwlist[] = {
"size",
NULL
};
Py_ssize_t size = -1;
PyObject* result = NULL;
char* resultBuffer;
Py_ssize_t resultSize;
ZSTD_outBuffer output;
size_t zresult;
if (!self->entered) {
PyErr_SetString(ZstdError, "read() must be called from an active context manager");
return NULL;
}
if (self->closed) {
PyErr_SetString(PyExc_ValueError, "stream is closed");
return NULL;
}
if (self->finishedOutput) {
return PyBytes_FromStringAndSize("", 0);
}
if (!PyArg_ParseTupleAndKeywords(args, kwargs, "n", kwlist, &size)) {
return NULL;
}
if (size < 1) {
PyErr_SetString(PyExc_ValueError, "cannot read negative or size 0 amounts");
return NULL;
}
result = PyBytes_FromStringAndSize(NULL, size);
if (NULL == result) {
return NULL;
}
PyBytes_AsStringAndSize(result, &resultBuffer, &resultSize);
output.dst = resultBuffer;
output.size = resultSize;
output.pos = 0;
readinput:
/* Consume input data left over from last time. */
if (self->input.pos < self->input.size) {
Py_BEGIN_ALLOW_THREADS
zresult = ZSTD_decompress_generic(self->decompressor->dctx,
&output, &self->input);
Py_END_ALLOW_THREADS
/* Input exhausted. Clear our state tracking. */
if (self->input.pos == self->input.size) {
memset(&self->input, 0, sizeof(self->input));
Py_CLEAR(self->readResult);
if (self->buffer.buf) {
self->finishedInput = 1;
}
}
if (ZSTD_isError(zresult)) {
PyErr_Format(ZstdError, "zstd decompress error: %s", ZSTD_getErrorName(zresult));
return NULL;
}
else if (0 == zresult) {
self->finishedOutput = 1;
}
/* We fulfilled the full read request. Emit it. */
if (output.pos && output.pos == output.size) {
self->bytesDecompressed += output.size;
return result;
}
/*
* There is more room in the output. Fall through to try to collect
* more data so we can try to fill the output.
*/
}
if (!self->finishedInput) {
if (self->reader) {
Py_buffer buffer;
assert(self->readResult == NULL);
self->readResult = PyObject_CallMethod(self->reader, "read",
"k", self->readSize);
if (NULL == self->readResult) {
return NULL;
}
memset(&buffer, 0, sizeof(buffer));
if (0 != PyObject_GetBuffer(self->readResult, &buffer, PyBUF_CONTIG_RO)) {
return NULL;
}
/* EOF */
if (0 == buffer.len) {
self->finishedInput = 1;
Py_CLEAR(self->readResult);
}
else {
self->input.src = buffer.buf;
self->input.size = buffer.len;
self->input.pos = 0;
}
PyBuffer_Release(&buffer);
}
else {
assert(self->buffer.buf);
/*
* We should only get here once since above block will exhaust
* source buffer until finishedInput is set.
*/
assert(self->input.src == NULL);
self->input.src = self->buffer.buf;
self->input.size = self->buffer.len;
self->input.pos = 0;
}
}
if (self->input.size) {
goto readinput;
}
/* EOF */
self->bytesDecompressed += output.pos;
if (safe_pybytes_resize(&result, output.pos)) {
Py_XDECREF(result);
return NULL;
}
return result;
}
static PyObject* reader_readall(PyObject* self) {
PyErr_SetNone(PyExc_NotImplementedError);
return NULL;
}
static PyObject* reader_readline(PyObject* self) {
PyErr_SetNone(PyExc_NotImplementedError);
return NULL;
}
static PyObject* reader_readlines(PyObject* self) {
PyErr_SetNone(PyExc_NotImplementedError);
return NULL;
}
static PyObject* reader_seek(ZstdDecompressionReader* self, PyObject* args) {
Py_ssize_t pos;
int whence = 0;
unsigned long long readAmount = 0;
size_t defaultOutSize = ZSTD_DStreamOutSize();
if (!self->entered) {
PyErr_SetString(ZstdError, "seek() must be called from an active context manager");
return NULL;
}
if (self->closed) {
PyErr_SetString(PyExc_ValueError, "stream is closed");
return NULL;
}
if (!PyArg_ParseTuple(args, "n|i:seek", &pos, &whence)) {
return NULL;
}
if (whence == SEEK_SET) {
if (pos < 0) {
PyErr_SetString(PyExc_ValueError,
"cannot seek to negative position with SEEK_SET");
return NULL;
}
if ((unsigned long long)pos < self->bytesDecompressed) {
PyErr_SetString(PyExc_ValueError,
"cannot seek zstd decompression stream backwards");
return NULL;
}
readAmount = pos - self->bytesDecompressed;
}
else if (whence == SEEK_CUR) {
if (pos < 0) {
PyErr_SetString(PyExc_ValueError,
"cannot seek zstd decompression stream backwards");
return NULL;
}
readAmount = pos;
}
else if (whence == SEEK_END) {
/* We /could/ support this with pos==0. But let's not do that until someone
needs it. */
PyErr_SetString(PyExc_ValueError,
"zstd decompression streams cannot be seeked with SEEK_END");
return NULL;
}
/* It is a bit inefficient to do this via the Python API. But since there
is a bit of state tracking involved to read from this type, it is the
easiest to implement. */
while (readAmount) {
Py_ssize_t readSize;
PyObject* readResult = PyObject_CallMethod((PyObject*)self, "read", "K",
readAmount < defaultOutSize ? readAmount : defaultOutSize);
if (!readResult) {
return NULL;
}
readSize = PyBytes_GET_SIZE(readResult);
/* Empty read means EOF. */
if (!readSize) {
break;
}
readAmount -= readSize;
}
return PyLong_FromUnsignedLongLong(self->bytesDecompressed);
}
static PyObject* reader_tell(ZstdDecompressionReader* self) {
/* TODO should this raise OSError since stream isn't seekable? */
return PyLong_FromUnsignedLongLong(self->bytesDecompressed);
}
static PyObject* reader_write(PyObject* self, PyObject* args) {
set_unsupported_operation();
return NULL;
}
static PyObject* reader_writelines(PyObject* self, PyObject* args) {
set_unsupported_operation();
return NULL;
}
static PyObject* reader_iter(PyObject* self) {
PyErr_SetNone(PyExc_NotImplementedError);
return NULL;
}
static PyObject* reader_iternext(PyObject* self) {
PyErr_SetNone(PyExc_NotImplementedError);
return NULL;
}
static PyMethodDef reader_methods[] = {
{ "__enter__", (PyCFunction)reader_enter, METH_NOARGS,
PyDoc_STR("Enter a compression context") },
{ "__exit__", (PyCFunction)reader_exit, METH_VARARGS,
PyDoc_STR("Exit a compression context") },
{ "close", (PyCFunction)reader_close, METH_NOARGS,
PyDoc_STR("Close the stream so it cannot perform any more operations") },
{ "closed", (PyCFunction)reader_closed, METH_NOARGS,
PyDoc_STR("Whether stream is closed") },
{ "flush", (PyCFunction)reader_flush, METH_NOARGS, PyDoc_STR("no-ops") },
{ "isatty", (PyCFunction)reader_isatty, METH_NOARGS, PyDoc_STR("Returns False") },
{ "readable", (PyCFunction)reader_readable, METH_NOARGS,
PyDoc_STR("Returns True") },
{ "read", (PyCFunction)reader_read, METH_VARARGS | METH_KEYWORDS,
PyDoc_STR("read compressed data") },
{ "readall", (PyCFunction)reader_readall, METH_NOARGS, PyDoc_STR("Not implemented") },
{ "readline", (PyCFunction)reader_readline, METH_NOARGS, PyDoc_STR("Not implemented") },
{ "readlines", (PyCFunction)reader_readlines, METH_NOARGS, PyDoc_STR("Not implemented") },
{ "seek", (PyCFunction)reader_seek, METH_VARARGS, PyDoc_STR("Seek the stream") },
{ "seekable", (PyCFunction)reader_seekable, METH_NOARGS,
PyDoc_STR("Returns True") },
{ "tell", (PyCFunction)reader_tell, METH_NOARGS,
PyDoc_STR("Returns current number of bytes compressed") },
{ "writable", (PyCFunction)reader_writable, METH_NOARGS,
PyDoc_STR("Returns False") },
{ "write", (PyCFunction)reader_write, METH_VARARGS, PyDoc_STR("unsupported operation") },
{ "writelines", (PyCFunction)reader_writelines, METH_VARARGS, PyDoc_STR("unsupported operation") },
{ NULL, NULL }
};
PyTypeObject ZstdDecompressionReaderType = {
PyVarObject_HEAD_INIT(NULL, 0)
"zstd.ZstdDecompressionReader", /* tp_name */
sizeof(ZstdDecompressionReader), /* tp_basicsize */
0, /* tp_itemsize */
(destructor)reader_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
0, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT, /* tp_flags */
0, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
reader_iter, /* tp_iter */
reader_iternext, /* tp_iternext */
reader_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
PyType_GenericNew, /* tp_new */
};
void decompressionreader_module_init(PyObject* mod) {
/* TODO make reader a sub-class of io.RawIOBase */
Py_TYPE(&ZstdDecompressionReaderType) = &PyType_Type;
if (PyType_Ready(&ZstdDecompressionReaderType) < 0) {
return;
}
}