Mercurial > hg
view mercurial/cext/mpatch.c @ 47072:4c041c71ec01
revlog: introduce an explicit tracking of what the revlog is about
Since the dawn of time, people have been forced to rely to lossy introspection
of the index filename to determine what the purpose and role of the revlog they
encounter is. This is hacky, error prone, inflexible, abstraction-leaky,
<insert-your-own-complaints-here>.
In f63299ee7e4d Raphaël introduced a new attribute to track this information:
`revlog_kind`. However it is initialized in an odd place and various instances
end up not having it set. In addition is only tracking some of the information
we end up having to introspect in various pieces of code.
So we add a new attribute that holds more data and is more strictly enforced.
This work is done in collaboration with Raphaël.
The `revlog_kind` one will be removed/adapted in the next changeset. We expect
to be able to clean up various existing piece of code and to simplify coming
work around the newer revlog format.
Differential Revision: https://phab.mercurial-scm.org/D10352
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Tue, 06 Apr 2021 05:20:24 +0200 |
parents | d4ba4d51f85f |
children | ed03fffaac30 |
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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 Olivia Mackall <olivia@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) { Py_buffer buffer; struct mpatch_flist *res = NULL; int r; PyObject *tmp = PyList_GetItem((PyObject *)bins, pos); if (!tmp) { return NULL; } if (PyObject_GetBuffer(tmp, &buffer, PyBUF_CONTIG_RO)) { return NULL; } if ((r = mpatch_decode(buffer.buf, buffer.len, &res)) < 0) { if (!PyErr_Occurred()) { setpyerr(r); } res = NULL; } PyBuffer_Release(&buffer); return res; } static PyObject *patches(PyObject *self, PyObject *args) { PyObject *text, *bins, *result; struct mpatch_flist *patch; Py_buffer buffer; int r = 0; char *out; Py_ssize_t len, outlen; 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_GetBuffer(text, &buffer, PyBUF_CONTIG_RO)) { return NULL; } patch = mpatch_fold(bins, cpygetitem, 0, len); if (!patch) { /* error already set or memory error */ if (!PyErr_Occurred()) { PyErr_NoMemory(); } result = NULL; goto cleanup; } outlen = mpatch_calcsize(buffer.len, 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); /* clang-format off */ { Py_BEGIN_ALLOW_THREADS r = mpatch_apply(out, buffer.buf, buffer.len, patch); Py_END_ALLOW_THREADS } /* clang-format on */ if (r < 0) { Py_DECREF(result); result = NULL; } cleanup: mpatch_lfree(patch); PyBuffer_Release(&buffer); 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, PY23("ls#", "ly#"), &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