view contrib/python-zstandard/c-ext/decompressobj.c @ 40121:73fef626dae3

zstandard: vendor python-zstandard 0.10.1

This was just released.

The upstream source distribution from PyPI was extracted. Unwanted
files were removed.

The clang-format ignore list was updated to reflect the new source
of files.

setup.py was updated to pass a new argument to python-zstandard's
function for returning an Extension instance. Upstream had to change
to use relative paths because Python 3.7's packaging doesn't
seem to like absolute paths when defining sources, includes, etc.
The default relative path calculation is relative to setup_zstd.py
which is different from the directory of Mercurial's setup.py.

The project contains a vendored copy of zstandard 1.3.6. The old
version was 1.3.4.

The API should be backwards compatible and nothing in core should
need adjusted. However, there is a new "chunker" API that we
may find useful in places where we want to emit compressed chunks
of a fixed size.

There are a pair of bug fixes in 0.10.0 with regards to
compressobj() and decompressobj() when block flushing is used. I
actually found these bugs when introducing these APIs in Mercurial!
But existing Mercurial code is not affected because we don't
perform block flushing.

# no-check-commit because 3rd party code has different style guidelines

Differential Revision: https://phab.mercurial-scm.org/D4911

/**
* Copyright (c) 2016-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;

PyDoc_STRVAR(DecompressionObj__doc__,
"Perform decompression using a standard library compatible API.\n"
);

static void DecompressionObj_dealloc(ZstdDecompressionObj* self) {
	Py_XDECREF(self->decompressor);

	PyObject_Del(self);
}

static PyObject* DecompressionObj_decompress(ZstdDecompressionObj* self, PyObject* args, PyObject* kwargs) {
	static char* kwlist[] = {
		"data",
		NULL
	};

	Py_buffer source;
	size_t zresult;
	ZSTD_inBuffer input;
	ZSTD_outBuffer output;
	PyObject* result = NULL;
	Py_ssize_t resultSize = 0;

	output.dst = NULL;

	if (self->finished) {
		PyErr_SetString(ZstdError, "cannot use a decompressobj multiple times");
		return NULL;
	}

#if PY_MAJOR_VERSION >= 3
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*:decompress",
#else
	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s*:decompress",
#endif
		kwlist, &source)) {
		return NULL;
	}

	if (!PyBuffer_IsContiguous(&source, 'C') || source.ndim > 1) {
		PyErr_SetString(PyExc_ValueError,
			"data buffer should be contiguous and have at most one dimension");
		goto finally;
	}

	/* Special case of empty input. Output will always be empty. */
	if (source.len == 0) {
		result = PyBytes_FromString("");
		goto finally;
	}

	input.src = source.buf;
	input.size = source.len;
	input.pos = 0;

	output.dst = PyMem_Malloc(self->outSize);
	if (!output.dst) {
		PyErr_NoMemory();
		goto except;
	}
	output.size = self->outSize;
	output.pos = 0;

	while (1) {
		Py_BEGIN_ALLOW_THREADS
		zresult = ZSTD_decompress_generic(self->decompressor->dctx, &output, &input);
		Py_END_ALLOW_THREADS

		if (ZSTD_isError(zresult)) {
			PyErr_Format(ZstdError, "zstd decompressor error: %s",
				ZSTD_getErrorName(zresult));
			goto except;
		}

		if (0 == zresult) {
			self->finished = 1;
		}

		if (output.pos) {
			if (result) {
				resultSize = PyBytes_GET_SIZE(result);
				if (-1 == safe_pybytes_resize(&result, resultSize + output.pos)) {
					Py_XDECREF(result);
					goto except;
				}

				memcpy(PyBytes_AS_STRING(result) + resultSize,
					output.dst, output.pos);
			}
			else {
				result = PyBytes_FromStringAndSize(output.dst, output.pos);
				if (!result) {
					goto except;
				}
			}
		}

		if (zresult == 0 || (input.pos == input.size && output.pos == 0)) {
			break;
		}

		output.pos = 0;
	}

	if (!result) {
		result = PyBytes_FromString("");
	}

	goto finally;

except:
	Py_CLEAR(result);

finally:
	PyMem_Free(output.dst);
	PyBuffer_Release(&source);

	return result;
}

static PyMethodDef DecompressionObj_methods[] = {
	{ "decompress", (PyCFunction)DecompressionObj_decompress,
	  METH_VARARGS | METH_KEYWORDS, PyDoc_STR("decompress data") },
	{ NULL, NULL }
};

PyTypeObject ZstdDecompressionObjType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.ZstdDecompressionObj",    /* tp_name */
	sizeof(ZstdDecompressionObj),   /* tp_basicsize */
	0,                              /* tp_itemsize */
	(destructor)DecompressionObj_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 | Py_TPFLAGS_BASETYPE, /* tp_flags */
	DecompressionObj__doc__,        /* tp_doc */
	0,                              /* tp_traverse */
	0,                              /* tp_clear */
	0,                              /* tp_richcompare */
	0,                              /* tp_weaklistoffset */
	0,                              /* tp_iter */
	0,                              /* tp_iternext */
	DecompressionObj_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 decompressobj_module_init(PyObject* module) {
	Py_TYPE(&ZstdDecompressionObjType) = &PyType_Type;
	if (PyType_Ready(&ZstdDecompressionObjType) < 0) {
		return;
	}
}