/*

 parsers.c - efficient content parsing

 Copyright 2008 Matt Mackall <mpm@selenic.com> and others

 This software may be used and distributed according to the terms of

 the GNU General Public License, incorporated herein by reference.

*/

#include <Python.h>

#include <ctype.h>

#include <string.h>

#include "util.h"

static int hexdigit(char c)

{

	if (c >= '0' && c <= '9')

		return c - '0';

	if (c >= 'a' && c <= 'f')

		return c - 'a' + 10;

	if (c >= 'A' && c <= 'F')

		return c - 'A' + 10;

	PyErr_SetString(PyExc_ValueError, "input contains non-hex character");

	return 0;

}

/*

 * Turn a hex-encoded string into binary.

 */

static PyObject *unhexlify(const char *str, int len)

{

	PyObject *ret;

	const char *c;

	char *d;

	ret = PyBytes_FromStringAndSize(NULL, len / 2);

	if (!ret)

		return NULL;

	d = PyBytes_AsString(ret);

	for (c = str; c < str + len;) {

		int hi = hexdigit(*c++);

		int lo = hexdigit(*c++);

		*d++ = (hi << 4) | lo;

	}

	return ret;

}

/*

 * This code assumes that a manifest is stitched together with newline

 * ('\n') characters.

 */

static PyObject *parse_manifest(PyObject *self, PyObject *args)

{

	PyObject *mfdict, *fdict;

	char *str, *cur, *start, *zero;

	int len;

	if (!PyArg_ParseTuple(args, "O!O!s#:parse_manifest",

			      &PyDict_Type, &mfdict,

			      &PyDict_Type, &fdict,

			      &str, &len))

		goto quit;

	for (start = cur = str, zero = NULL; cur < str + len; cur++) {

		PyObject *file = NULL, *node = NULL;

		PyObject *flags = NULL;

		int nlen;

		if (!*cur) {

			zero = cur;

			continue;

		}

		else if (*cur != '\n')

			continue;

		if (!zero) {

			PyErr_SetString(PyExc_ValueError,

					"manifest entry has no separator");

			goto quit;

		}

		file = PyBytes_FromStringAndSize(start, zero - start);

		if (!file)

			goto bail;

		nlen = cur - zero - 1;

		node = unhexlify(zero + 1, nlen > 40 ? 40 : nlen);

		if (!node)

			goto bail;

		if (nlen > 40) {

			flags = PyBytes_FromStringAndSize(zero + 41,

							   nlen - 40);

			if (!flags)

				goto bail;

			if (PyDict_SetItem(fdict, file, flags) == -1)

				goto bail;

		}

		if (PyDict_SetItem(mfdict, file, node) == -1)

			goto bail;

		start = cur + 1;

		zero = NULL;

		Py_XDECREF(flags);

		Py_XDECREF(node);

		Py_XDECREF(file);

		continue;

	bail:

		Py_XDECREF(flags);

		Py_XDECREF(node);

		Py_XDECREF(file);

		goto quit;

	}

	if (len > 0 && *(cur - 1) != '\n') {

		PyErr_SetString(PyExc_ValueError,

				"manifest contains trailing garbage");

		goto quit;

	}

	Py_INCREF(Py_None);

	return Py_None;

quit:

	return NULL;

}

#ifdef _WIN32

#ifdef _MSC_VER

/* msvc 6.0 has problems */

#define inline __inline

typedef unsigned long uint32_t;

typedef unsigned __int64 uint64_t;

#else

#include <stdint.h>

#endif

static uint32_t ntohl(uint32_t x)

{

	return ((x & 0x000000ffUL) << 24) |

	       ((x & 0x0000ff00UL) <<  8) |

	       ((x & 0x00ff0000UL) >>  8) |

	       ((x & 0xff000000UL) >> 24);

}

#else

/* not windows */

#include <sys/types.h>

#if defined __BEOS__ && !defined __HAIKU__

#include <ByteOrder.h>

#else

#include <arpa/inet.h>

#endif

#include <inttypes.h>

#endif

static PyObject *parse_dirstate(PyObject *self, PyObject *args)

{

	PyObject *dmap, *cmap, *parents = NULL, *ret = NULL;

	PyObject *fname = NULL, *cname = NULL, *entry = NULL;

	char *str, *cur, *end, *cpos;

	int state, mode, size, mtime;

	unsigned int flen;

	int len;

	char decode[16]; /* for alignment */

	if (!PyArg_ParseTuple(args, "O!O!s#:parse_dirstate",

			      &PyDict_Type, &dmap,

			      &PyDict_Type, &cmap,

			      &str, &len))

		goto quit;

	/* read parents */

	if (len < 40)

		goto quit;

	parents = Py_BuildValue("s#s#", str, 20, str + 20, 20);

	if (!parents)

		goto quit;

	/* read filenames */

	cur = str + 40;

	end = str + len;

	while (cur < end - 17) {

		/* unpack header */

		state = *cur;

		memcpy(decode, cur + 1, 16);

		mode = ntohl(*(uint32_t *)(decode));

		size = ntohl(*(uint32_t *)(decode + 4));

		mtime = ntohl(*(uint32_t *)(decode + 8));

		flen = ntohl(*(uint32_t *)(decode + 12));

		cur += 17;

		if (cur + flen > end || cur + flen < cur) {

			PyErr_SetString(PyExc_ValueError, "overflow in dirstate");

			goto quit;

		}

		entry = Py_BuildValue("ciii", state, mode, size, mtime);

		if (!entry)

			goto quit;

		PyObject_GC_UnTrack(entry); /* don't waste time with this */

		cpos = memchr(cur, 0, flen);

		if (cpos) {

			fname = PyBytes_FromStringAndSize(cur, cpos - cur);

			cname = PyBytes_FromStringAndSize(cpos + 1,

							   flen - (cpos - cur) - 1);

			if (!fname || !cname ||

			    PyDict_SetItem(cmap, fname, cname) == -1 ||

			    PyDict_SetItem(dmap, fname, entry) == -1)

				goto quit;

			Py_DECREF(cname);

		} else {

			fname = PyBytes_FromStringAndSize(cur, flen);

			if (!fname ||

			    PyDict_SetItem(dmap, fname, entry) == -1)

				goto quit;

		}

		cur += flen;

		Py_DECREF(fname);

		Py_DECREF(entry);

		fname = cname = entry = NULL;

	}

	ret = parents;

	Py_INCREF(ret);

quit:

	Py_XDECREF(fname);

	Py_XDECREF(cname);

	Py_XDECREF(entry);

	Py_XDECREF(parents);

	return ret;

}

const char nullid[20];

const int nullrev = -1;

/* RevlogNG format (all in big endian, data may be inlined):

 *    6 bytes: offset

 *    2 bytes: flags

 *    4 bytes: compressed length

 *    4 bytes: uncompressed length

 *    4 bytes: base revision

 *    4 bytes: link revision

 *    4 bytes: parent 1 revision

 *    4 bytes: parent 2 revision

 *   32 bytes: nodeid (only 20 bytes used)

 */

static int _parse_index_ng(const char *data, int size, int inlined,

			   PyObject *index)

{

	PyObject *entry;

	int n = 0, err;

	uint64_t offset_flags;

	int comp_len, uncomp_len, base_rev, link_rev, parent_1, parent_2;

	const char *c_node_id;

	const char *end = data + size;

	char decode[64]; /* to enforce alignment with inline data */

	while (data < end) {

		unsigned int step;

		memcpy(decode, data, 64);

		offset_flags = ntohl(*((uint32_t *) (decode + 4)));

		if (n == 0) /* mask out version number for the first entry */

			offset_flags &= 0xFFFF;

		else {

			uint32_t offset_high =  ntohl(*((uint32_t *)decode));

			offset_flags |= ((uint64_t)offset_high) << 32;

		}

		comp_len = ntohl(*((uint32_t *)(decode + 8)));

		uncomp_len = ntohl(*((uint32_t *)(decode + 12)));

		base_rev = ntohl(*((uint32_t *)(decode + 16)));

		link_rev = ntohl(*((uint32_t *)(decode + 20)));

		parent_1 = ntohl(*((uint32_t *)(decode + 24)));

		parent_2 = ntohl(*((uint32_t *)(decode + 28)));

		c_node_id = decode + 32;

		entry = Py_BuildValue("Liiiiiis#", offset_flags, comp_len,

			      uncomp_len, base_rev, link_rev,

			      parent_1, parent_2, c_node_id, 20);

		if (!entry)

			return 0;

		PyObject_GC_UnTrack(entry); /* don't waste time with this */

		if (inlined) {

			err = PyList_Append(index, entry);

			Py_DECREF(entry);

			if (err)

				return 0;

		} else

			PyList_SET_ITEM(index, n, entry); /* steals reference */

		n++;

		step = 64 + (inlined ? comp_len : 0);

		if (data + step > end || data + step < data)

			break;

		data += step;

	}

	if (data != end) {

		if (!PyErr_Occurred())

			PyErr_SetString(PyExc_ValueError, "corrupt index file");

		return 0;

	}

	/* create the magic nullid entry in the index at [-1] */

	entry = Py_BuildValue("Liiiiiis#", (uint64_t)0, 0, 0, -1, -1, -1, -1, nullid, 20);

	if (!entry)

		return 0;

	PyObject_GC_UnTrack(entry); /* don't waste time with this */

	if (inlined) {

		err = PyList_Append(index, entry);

		Py_DECREF(entry);

		if (err)

			return 0;

	} else

		PyList_SET_ITEM(index, n, entry); /* steals reference */

	return 1;

}

/* This function parses a index file and returns a Python tuple of the

 * following format: (index, cache)

 *

 * index: a list of tuples containing the RevlogNG records

 * cache: if data is inlined, a tuple (index_file_content, 0) else None

 */

static PyObject *parse_index2(PyObject *self, PyObject *args)

{

	const char *data;

	int size, inlined;

	PyObject *rval = NULL, *index = NULL, *cache = NULL;

	PyObject *data_obj = NULL, *inlined_obj;

	if (!PyArg_ParseTuple(args, "s#O", &data, &size, &inlined_obj))

		return NULL;

	inlined = inlined_obj && PyObject_IsTrue(inlined_obj);

	/* If no data is inlined, we know the size of the index list in

	 * advance: size divided by the size of one revlog record (64 bytes)

	 * plus one for nullid */

	index = inlined ? PyList_New(0) : PyList_New(size / 64 + 1);

	if (!index)

		goto quit;

	/* set up the cache return value */

	if (inlined) {

		/* Note that the reference to data_obj is only borrowed */

		data_obj = PyTuple_GET_ITEM(args, 0);

		cache = Py_BuildValue("iO", 0, data_obj);

		if (!cache)

			goto quit;

	} else {

		cache = Py_None;

		Py_INCREF(Py_None);

	}

	/* actually populate the index with data */

	if (!_parse_index_ng(data, size, inlined, index))

		goto quit;

	rval = Py_BuildValue("NN", index, cache);

	if (!rval)

		goto quit;

	return rval;

quit:

	Py_XDECREF(index);

	Py_XDECREF(cache);

	Py_XDECREF(rval);

	return NULL;

}