Mercurial > hg
view mercurial/cext/mpatch.c @ 36227:69080ee1fb0e
mpatch: allow clang-format oversight
Differential Revision: https://phab.mercurial-scm.org/D2183
author | Augie Fackler <augie@google.com> |
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date | Mon, 12 Feb 2018 10:41:00 -0500 |
parents | 3028a3215a2e |
children | a2d11d23bb25 |
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/* mpatch.c - efficient binary patching for Mercurial This implements a patch algorithm that's O(m + nlog n) where m is the size of the output and n is the number of patches. Given a list of binary patches, it unpacks each into a hunk list, then combines the hunk lists with a treewise recursion to form a single hunk list. This hunk list is then applied to the original text. The text (or binary) fragments are copied directly from their source Python objects into a preallocated output string to avoid the allocation of intermediate Python objects. Working memory is about 2x the total number of hunks. Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> This software may be used and distributed according to the terms of the GNU General Public License, incorporated herein by reference. */ #define PY_SSIZE_T_CLEAN #include <Python.h> #include <stdlib.h> #include <string.h> #include "bitmanipulation.h" #include "compat.h" #include "mpatch.h" #include "util.h" static char mpatch_doc[] = "Efficient binary patching."; static PyObject *mpatch_Error; static void setpyerr(int r) { switch (r) { case MPATCH_ERR_NO_MEM: PyErr_NoMemory(); break; case MPATCH_ERR_CANNOT_BE_DECODED: PyErr_SetString(mpatch_Error, "patch cannot be decoded"); break; case MPATCH_ERR_INVALID_PATCH: PyErr_SetString(mpatch_Error, "invalid patch"); break; } } struct mpatch_flist *cpygetitem(void *bins, ssize_t pos) { const char *buffer; struct mpatch_flist *res; ssize_t blen; int r; PyObject *tmp = PyList_GetItem((PyObject *)bins, pos); if (!tmp) return NULL; if (PyObject_AsCharBuffer(tmp, &buffer, (Py_ssize_t *)&blen)) return NULL; if ((r = mpatch_decode(buffer, blen, &res)) < 0) { if (!PyErr_Occurred()) setpyerr(r); return NULL; } return res; } static PyObject *patches(PyObject *self, PyObject *args) { PyObject *text, *bins, *result; struct mpatch_flist *patch; const char *in; int r = 0; char *out; Py_ssize_t len, outlen, inlen; if (!PyArg_ParseTuple(args, "OO:mpatch", &text, &bins)) return NULL; len = PyList_Size(bins); if (!len) { /* nothing to do */ Py_INCREF(text); return text; } if (PyObject_AsCharBuffer(text, &in, &inlen)) return NULL; patch = mpatch_fold(bins, cpygetitem, 0, len); if (!patch) { /* error already set or memory error */ if (!PyErr_Occurred()) PyErr_NoMemory(); return NULL; } outlen = mpatch_calcsize(inlen, patch); if (outlen < 0) { r = (int)outlen; result = NULL; goto cleanup; } result = PyBytes_FromStringAndSize(NULL, outlen); if (!result) { result = NULL; goto cleanup; } out = PyBytes_AsString(result); r = mpatch_apply(out, in, inlen, patch); if (r < 0) { Py_DECREF(result); result = NULL; } cleanup: mpatch_lfree(patch); if (!result && !PyErr_Occurred()) setpyerr(r); return result; } /* calculate size of a patched file directly */ static PyObject *patchedsize(PyObject *self, PyObject *args) { long orig, start, end, len, outlen = 0, last = 0, pos = 0; Py_ssize_t patchlen; char *bin; if (!PyArg_ParseTuple(args, "ls#", &orig, &bin, &patchlen)) return NULL; while (pos >= 0 && pos < patchlen) { start = getbe32(bin + pos); end = getbe32(bin + pos + 4); len = getbe32(bin + pos + 8); if (start > end) break; /* sanity check */ pos += 12 + len; outlen += start - last; last = end; outlen += len; } if (pos != patchlen) { if (!PyErr_Occurred()) PyErr_SetString(mpatch_Error, "patch cannot be decoded"); return NULL; } outlen += orig - last; return Py_BuildValue("l", outlen); } static PyMethodDef methods[] = { {"patches", patches, METH_VARARGS, "apply a series of patches\n"}, {"patchedsize", patchedsize, METH_VARARGS, "calculed patched size\n"}, {NULL, NULL}, }; static const int version = 1; #ifdef IS_PY3K static struct PyModuleDef mpatch_module = { PyModuleDef_HEAD_INIT, "mpatch", mpatch_doc, -1, methods, }; PyMODINIT_FUNC PyInit_mpatch(void) { PyObject *m; m = PyModule_Create(&mpatch_module); if (m == NULL) return NULL; mpatch_Error = PyErr_NewException("mercurial.cext.mpatch.mpatchError", NULL, NULL); Py_INCREF(mpatch_Error); PyModule_AddObject(m, "mpatchError", mpatch_Error); PyModule_AddIntConstant(m, "version", version); return m; } #else PyMODINIT_FUNC initmpatch(void) { PyObject *m; m = Py_InitModule3("mpatch", methods, mpatch_doc); mpatch_Error = PyErr_NewException("mercurial.cext.mpatch.mpatchError", NULL, NULL); PyModule_AddIntConstant(m, "version", version); } #endif