Mercurial > hg
view mercurial/diffhelpers.c @ 31553:56acc4250900
scmutil: add a simple key-value file helper
The purpose of the added class is to serve purposes like save files of shelve
or state files of shelve, rebase and histedit. Keys of these files can be
alphanumeric and start with letters, while values must not contain newlines.
In light of Mercurial's reluctancy to use Python's json module, this tries
to provide a reasonable alternative for a non-nested named data.
Comparing to current approach of storing state in plain text files, where
semantic meaning of lines of text is only determined by their oreder,
simple key-value file allows for reordering lines and thus helps handle
optional values.
Initial use-case I see for this is obs-shelve's shelve files. Later we
can possibly migrate state files to this approach.
The test is in a new file beause I did not figure out where to put it
within existing test suite. If you give me a better idea, I will gladly
follow it.
author | Kostia Balytskyi <ikostia@fb.com> |
---|---|
date | Fri, 10 Mar 2017 14:33:42 -0800 |
parents | f1c127df7c4f |
children | 2f51f4c535d2 |
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/* * diffhelpers.c - helper routines for mpatch * * Copyright 2007 Chris Mason <chris.mason@oracle.com> * * This software may be used and distributed according to the terms * of the GNU General Public License v2, incorporated herein by reference. */ #include <Python.h> #include <stdlib.h> #include <string.h> #include "util.h" static char diffhelpers_doc[] = "Efficient diff parsing"; static PyObject *diffhelpers_Error; /* fixup the last lines of a and b when the patch has no newline at eof */ static void _fix_newline(PyObject *hunk, PyObject *a, PyObject *b) { Py_ssize_t hunksz = PyList_Size(hunk); PyObject *s = PyList_GET_ITEM(hunk, hunksz-1); char *l = PyBytes_AsString(s); Py_ssize_t alen = PyList_Size(a); Py_ssize_t blen = PyList_Size(b); char c = l[0]; PyObject *hline; Py_ssize_t sz = PyBytes_GET_SIZE(s); if (sz > 1 && l[sz-2] == '\r') /* tolerate CRLF in last line */ sz -= 1; hline = PyBytes_FromStringAndSize(l, sz-1); if (!hline) { return; } if (c == ' ' || c == '+') { PyObject *rline = PyBytes_FromStringAndSize(l + 1, sz - 2); PyList_SetItem(b, blen-1, rline); } if (c == ' ' || c == '-') { Py_INCREF(hline); PyList_SetItem(a, alen-1, hline); } PyList_SetItem(hunk, hunksz-1, hline); } /* python callable form of _fix_newline */ static PyObject * fix_newline(PyObject *self, PyObject *args) { PyObject *hunk, *a, *b; if (!PyArg_ParseTuple(args, "OOO", &hunk, &a, &b)) return NULL; _fix_newline(hunk, a, b); return Py_BuildValue("l", 0); } #if (PY_VERSION_HEX < 0x02050000) static const char *addlines_format = "OOiiOO"; #else static const char *addlines_format = "OOnnOO"; #endif /* * read lines from fp into the hunk. The hunk is parsed into two arrays * a and b. a gets the old state of the text, b gets the new state * The control char from the hunk is saved when inserting into a, but not b * (for performance while deleting files) */ static PyObject * addlines(PyObject *self, PyObject *args) { PyObject *fp, *hunk, *a, *b, *x; Py_ssize_t i; Py_ssize_t lena, lenb; Py_ssize_t num; Py_ssize_t todoa, todob; char *s, c; PyObject *l; if (!PyArg_ParseTuple(args, addlines_format, &fp, &hunk, &lena, &lenb, &a, &b)) return NULL; while (1) { todoa = lena - PyList_Size(a); todob = lenb - PyList_Size(b); num = todoa > todob ? todoa : todob; if (num == 0) break; for (i = 0; i < num; i++) { x = PyFile_GetLine(fp, 0); s = PyBytes_AsString(x); c = *s; if (strcmp(s, "\\ No newline at end of file\n") == 0) { _fix_newline(hunk, a, b); continue; } if (c == '\n') { /* Some patches may be missing the control char * on empty lines. Supply a leading space. */ Py_DECREF(x); x = PyBytes_FromString(" \n"); } PyList_Append(hunk, x); if (c == '+') { l = PyBytes_FromString(s + 1); PyList_Append(b, l); Py_DECREF(l); } else if (c == '-') { PyList_Append(a, x); } else { l = PyBytes_FromString(s + 1); PyList_Append(b, l); Py_DECREF(l); PyList_Append(a, x); } Py_DECREF(x); } } return Py_BuildValue("l", 0); } /* * compare the lines in a with the lines in b. a is assumed to have * a control char at the start of each line, this char is ignored in the * compare */ static PyObject * testhunk(PyObject *self, PyObject *args) { PyObject *a, *b; long bstart; Py_ssize_t alen, blen; Py_ssize_t i; char *sa, *sb; if (!PyArg_ParseTuple(args, "OOl", &a, &b, &bstart)) return NULL; alen = PyList_Size(a); blen = PyList_Size(b); if (alen > blen - bstart || bstart < 0) { return Py_BuildValue("l", -1); } for (i = 0; i < alen; i++) { sa = PyBytes_AsString(PyList_GET_ITEM(a, i)); sb = PyBytes_AsString(PyList_GET_ITEM(b, i + bstart)); if (strcmp(sa + 1, sb) != 0) return Py_BuildValue("l", -1); } return Py_BuildValue("l", 0); } static PyMethodDef methods[] = { {"addlines", addlines, METH_VARARGS, "add lines to a hunk\n"}, {"fix_newline", fix_newline, METH_VARARGS, "fixup newline counters\n"}, {"testhunk", testhunk, METH_VARARGS, "test lines in a hunk\n"}, {NULL, NULL} }; #ifdef IS_PY3K static struct PyModuleDef diffhelpers_module = { PyModuleDef_HEAD_INIT, "diffhelpers", diffhelpers_doc, -1, methods }; PyMODINIT_FUNC PyInit_diffhelpers(void) { PyObject *m; m = PyModule_Create(&diffhelpers_module); if (m == NULL) return NULL; diffhelpers_Error = PyErr_NewException("diffhelpers.diffhelpersError", NULL, NULL); Py_INCREF(diffhelpers_Error); PyModule_AddObject(m, "diffhelpersError", diffhelpers_Error); return m; } #else PyMODINIT_FUNC initdiffhelpers(void) { Py_InitModule3("diffhelpers", methods, diffhelpers_doc); diffhelpers_Error = PyErr_NewException("diffhelpers.diffhelpersError", NULL, NULL); } #endif