contrib/python-zstandard/c-ext/compressionwriter.c

paper: remove css hack that made .branchname look like .branchhead

There's a visual difference in hgweb between one changeset that is the tip of
its branch and another that simply belongs to that branch. But paper theme
ignored this difference on changeset page and used to always use "branchname"
css class, be that changeset the tip of its branch or not. That has been
recently fixed, so this piece of css is not needed anymore.

/**
* 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(ZstdCompresssionWriter__doc__,
"""A context manager used for writing compressed output to a writer.\n"
);

static void ZstdCompressionWriter_dealloc(ZstdCompressionWriter* self) {
	Py_XDECREF(self->compressor);
	Py_XDECREF(self->writer);

	PyObject_Del(self);
}

static PyObject* ZstdCompressionWriter_enter(ZstdCompressionWriter* self) {
	if (self->entered) {
		PyErr_SetString(ZstdError, "cannot __enter__ multiple times");
		return NULL;
	}

	if (self->compressor->mtcctx) {
		if (init_mtcstream(self->compressor, self->sourceSize)) {
			return NULL;
		}
	}
	else {
		if (0 != init_cstream(self->compressor, self->sourceSize)) {
			return NULL;
		}
	}

	self->entered = 1;

	Py_INCREF(self);
	return (PyObject*)self;
}

static PyObject* ZstdCompressionWriter_exit(ZstdCompressionWriter* self, PyObject* args) {
	PyObject* exc_type;
	PyObject* exc_value;
	PyObject* exc_tb;
	size_t zresult;

	ZSTD_outBuffer output;
	PyObject* res;

	if (!PyArg_ParseTuple(args, "OOO:__exit__", &exc_type, &exc_value, &exc_tb)) {
		return NULL;
	}

	self->entered = 0;

	if ((self->compressor->cstream || self->compressor->mtcctx) && exc_type == Py_None
		&& exc_value == Py_None && exc_tb == Py_None) {

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

		while (1) {
			if (self->compressor->mtcctx) {
				zresult = ZSTDMT_endStream(self->compressor->mtcctx, &output);
			}
			else {
				zresult = ZSTD_endStream(self->compressor->cstream, &output);
			}
			if (ZSTD_isError(zresult)) {
				PyErr_Format(ZstdError, "error ending compression stream: %s",
					ZSTD_getErrorName(zresult));
				PyMem_Free(output.dst);
				return NULL;
			}

			if (output.pos) {
#if PY_MAJOR_VERSION >= 3
				res = PyObject_CallMethod(self->writer, "write", "y#",
#else
				res = PyObject_CallMethod(self->writer, "write", "s#",
#endif
					output.dst, output.pos);
				Py_XDECREF(res);
			}

			if (!zresult) {
				break;
			}

			output.pos = 0;
		}

		PyMem_Free(output.dst);
	}

	Py_RETURN_FALSE;
}

static PyObject* ZstdCompressionWriter_memory_size(ZstdCompressionWriter* self) {
	if (!self->compressor->cstream) {
		PyErr_SetString(ZstdError, "cannot determine size of an inactive compressor; "
			"call when a context manager is active");
		return NULL;
	}

	return PyLong_FromSize_t(ZSTD_sizeof_CStream(self->compressor->cstream));
}

static PyObject* ZstdCompressionWriter_write(ZstdCompressionWriter* self, PyObject* args) {
	const char* source;
	Py_ssize_t sourceSize;
	size_t zresult;
	ZSTD_inBuffer input;
	ZSTD_outBuffer output;
	PyObject* res;
	Py_ssize_t totalWrite = 0;

#if PY_MAJOR_VERSION >= 3
	if (!PyArg_ParseTuple(args, "y#:write", &source, &sourceSize)) {
#else
	if (!PyArg_ParseTuple(args, "s#:write", &source, &sourceSize)) {
#endif
		return NULL;
	}

	if (!self->entered) {
		PyErr_SetString(ZstdError, "compress must be called from an active context manager");
		return NULL;
	}

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

	input.src = source;
	input.size = sourceSize;
	input.pos = 0;

	while ((ssize_t)input.pos < sourceSize) {
		Py_BEGIN_ALLOW_THREADS
		if (self->compressor->mtcctx) {
			zresult = ZSTDMT_compressStream(self->compressor->mtcctx,
				&output, &input);
		}
		else {
			zresult = ZSTD_compressStream(self->compressor->cstream, &output, &input);
		}
		Py_END_ALLOW_THREADS

		if (ZSTD_isError(zresult)) {
			PyMem_Free(output.dst);
			PyErr_Format(ZstdError, "zstd compress error: %s", ZSTD_getErrorName(zresult));
			return NULL;
		}

		/* Copy data from output buffer to writer. */
		if (output.pos) {
#if PY_MAJOR_VERSION >= 3
			res = PyObject_CallMethod(self->writer, "write", "y#",
#else
			res = PyObject_CallMethod(self->writer, "write", "s#",
#endif
				output.dst, output.pos);
			Py_XDECREF(res);
			totalWrite += output.pos;
		}
		output.pos = 0;
	}

	PyMem_Free(output.dst);

	return PyLong_FromSsize_t(totalWrite);
}

static PyObject* ZstdCompressionWriter_flush(ZstdCompressionWriter* self, PyObject* args) {
	size_t zresult;
	ZSTD_outBuffer output;
	PyObject* res;
	Py_ssize_t totalWrite = 0;

	if (!self->entered) {
		PyErr_SetString(ZstdError, "flush must be called from an active context manager");
		return NULL;
	}

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

	while (1) {
		Py_BEGIN_ALLOW_THREADS
		if (self->compressor->mtcctx) {
			zresult = ZSTDMT_flushStream(self->compressor->mtcctx, &output);
		}
		else {
			zresult = ZSTD_flushStream(self->compressor->cstream, &output);
		}
		Py_END_ALLOW_THREADS

		if (ZSTD_isError(zresult)) {
			PyMem_Free(output.dst);
			PyErr_Format(ZstdError, "zstd compress error: %s", ZSTD_getErrorName(zresult));
			return NULL;
		}

		if (!output.pos) {
			break;
		}

		/* Copy data from output buffer to writer. */
		if (output.pos) {
#if PY_MAJOR_VERSION >= 3
			res = PyObject_CallMethod(self->writer, "write", "y#",
#else
			res = PyObject_CallMethod(self->writer, "write", "s#",
#endif
				output.dst, output.pos);
			Py_XDECREF(res);
			totalWrite += output.pos;
		}
		output.pos = 0;
	}

	PyMem_Free(output.dst);

	return PyLong_FromSsize_t(totalWrite);
}

static PyMethodDef ZstdCompressionWriter_methods[] = {
	{ "__enter__", (PyCFunction)ZstdCompressionWriter_enter, METH_NOARGS,
	PyDoc_STR("Enter a compression context.") },
	{ "__exit__", (PyCFunction)ZstdCompressionWriter_exit, METH_VARARGS,
	PyDoc_STR("Exit a compression context.") },
	{ "memory_size", (PyCFunction)ZstdCompressionWriter_memory_size, METH_NOARGS,
	PyDoc_STR("Obtain the memory size of the underlying compressor") },
	{ "write", (PyCFunction)ZstdCompressionWriter_write, METH_VARARGS,
	PyDoc_STR("Compress data") },
	{ "flush", (PyCFunction)ZstdCompressionWriter_flush, METH_NOARGS,
	PyDoc_STR("Flush data and finish a zstd frame") },
	{ NULL, NULL }
};

PyTypeObject ZstdCompressionWriterType = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"zstd.ZstdCompressionWriter",  /* tp_name */
	sizeof(ZstdCompressionWriter),  /* tp_basicsize */
	0,                              /* tp_itemsize */
	(destructor)ZstdCompressionWriter_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 */
	ZstdCompresssionWriter__doc__,  /* tp_doc */
	0,                              /* tp_traverse */
	0,                              /* tp_clear */
	0,                              /* tp_richcompare */
	0,                              /* tp_weaklistoffset */
	0,                              /* tp_iter */
	0,                              /* tp_iternext */
	ZstdCompressionWriter_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 compressionwriter_module_init(PyObject* mod) {
	Py_TYPE(&ZstdCompressionWriterType) = &PyType_Type;
	if (PyType_Ready(&ZstdCompressionWriterType) < 0) {
		return;
	}
}