Mercurial > hg
view mercurial/cext/mpatch.c @ 34124:b90e5b2a9c82
merge: flush any deferred writes before, and after, running any workers
Since we fork to create workers, any changes they queue up will be lost after
the worker terminates, so the easiest solution is to have each worker flush
the writes they accumulate--we are close to the end of the merge in any case.
To prevent duplicated writes, we also have the master processs flush before
forking.
In an in-memory merge (M2), we'll instead disable the use of workers.
Differential Revision: https://phab.mercurial-scm.org/D628
author | Phil Cohen <phillco@fb.com> |
---|---|
date | Mon, 11 Sep 2017 13:03:27 -0700 |
parents | 151cc3b3d799 |
children | b90e8da190da |
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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 "util.h" #include "bitmanipulation.h" #include "compat.h" #include "mpatch.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); if ((r = mpatch_apply(out, in, inlen, patch)) < 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