Mercurial > hg
view mercurial/dirs.c @ 27015:341cb90ffd18
util: disable floating point stat times (issue4836)
Alternate fix for this issue which avoids putting extra function calls
and exception handling in the fast path.
For almost all purposes, integer timestamps are preferable to
Mercurial. It stores integer timestamps in the dirstate and would thus
like to avoid doing any float/int comparisons or conversions. We will
continue to have to deal with 1-second granularity on filesystems for
quite some time, so this won't significantly hinder our capabilities.
This has some impact on our file cache validation code in that it
lowers timestamp resolution. But as we still have to deal with
low-resolution filesystems, we're not relying on this anyway.
An alternate approach is to use stat[ST_MTIME], which is guaranteed to
be an integer. But since this support isn't already in our extension,
we can't depend on it being available without adding a hard Python->C
API dependency that's painful for people like yours truly who have
bisect regularly and people without compilers.
author | Matt Mackall <mpm@selenic.com> |
---|---|
date | Thu, 19 Nov 2015 13:21:24 -0600 |
parents | fe3a72a3e7ca |
children | 63e1dca2d6a4 |
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/* dirs.c - dynamic directory diddling for dirstates Copyright 2013 Facebook 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 "util.h" /* * This is a multiset of directory names, built from the files that * appear in a dirstate or manifest. * * A few implementation notes: * * We modify Python integers for refcounting, but those integers are * never visible to Python code. * * We mutate strings in-place, but leave them immutable once they can * be seen by Python code. */ typedef struct { PyObject_HEAD PyObject *dict; } dirsObject; static inline Py_ssize_t _finddir(const char *path, Py_ssize_t pos) { while (pos != -1) { if (path[pos] == '/') break; pos -= 1; } return pos; } static int _addpath(PyObject *dirs, PyObject *path) { const char *cpath = PyString_AS_STRING(path); Py_ssize_t pos = PyString_GET_SIZE(path); PyObject *key = NULL; int ret = -1; while ((pos = _finddir(cpath, pos - 1)) != -1) { PyObject *val; /* It's likely that every prefix already has an entry in our dict. Try to avoid allocating and deallocating a string for each prefix we check. */ if (key != NULL) ((PyStringObject *)key)->ob_shash = -1; else { /* Force Python to not reuse a small shared string. */ key = PyString_FromStringAndSize(cpath, pos < 2 ? 2 : pos); if (key == NULL) goto bail; } PyString_GET_SIZE(key) = pos; PyString_AS_STRING(key)[pos] = '\0'; val = PyDict_GetItem(dirs, key); if (val != NULL) { PyInt_AS_LONG(val) += 1; break; } /* Force Python to not reuse a small shared int. */ val = PyInt_FromLong(0x1eadbeef); if (val == NULL) goto bail; PyInt_AS_LONG(val) = 1; ret = PyDict_SetItem(dirs, key, val); Py_DECREF(val); if (ret == -1) goto bail; Py_CLEAR(key); } ret = 0; bail: Py_XDECREF(key); return ret; } static int _delpath(PyObject *dirs, PyObject *path) { char *cpath = PyString_AS_STRING(path); Py_ssize_t pos = PyString_GET_SIZE(path); PyObject *key = NULL; int ret = -1; while ((pos = _finddir(cpath, pos - 1)) != -1) { PyObject *val; key = PyString_FromStringAndSize(cpath, pos); if (key == NULL) goto bail; val = PyDict_GetItem(dirs, key); if (val == NULL) { PyErr_SetString(PyExc_ValueError, "expected a value, found none"); goto bail; } if (--PyInt_AS_LONG(val) <= 0) { if (PyDict_DelItem(dirs, key) == -1) goto bail; } else break; Py_CLEAR(key); } ret = 0; bail: Py_XDECREF(key); return ret; } static int dirs_fromdict(PyObject *dirs, PyObject *source, char skipchar) { PyObject *key, *value; Py_ssize_t pos = 0; while (PyDict_Next(source, &pos, &key, &value)) { if (!PyString_Check(key)) { PyErr_SetString(PyExc_TypeError, "expected string key"); return -1; } if (skipchar) { if (!dirstate_tuple_check(value)) { PyErr_SetString(PyExc_TypeError, "expected a dirstate tuple"); return -1; } if (((dirstateTupleObject *)value)->state == skipchar) continue; } if (_addpath(dirs, key) == -1) return -1; } return 0; } static int dirs_fromiter(PyObject *dirs, PyObject *source) { PyObject *iter, *item = NULL; int ret; iter = PyObject_GetIter(source); if (iter == NULL) return -1; while ((item = PyIter_Next(iter)) != NULL) { if (!PyString_Check(item)) { PyErr_SetString(PyExc_TypeError, "expected string"); break; } if (_addpath(dirs, item) == -1) break; Py_CLEAR(item); } ret = PyErr_Occurred() ? -1 : 0; Py_DECREF(iter); Py_XDECREF(item); return ret; } /* * Calculate a refcounted set of directory names for the files in a * dirstate. */ static int dirs_init(dirsObject *self, PyObject *args) { PyObject *dirs = NULL, *source = NULL; char skipchar = 0; int ret = -1; self->dict = NULL; if (!PyArg_ParseTuple(args, "|Oc:__init__", &source, &skipchar)) return -1; dirs = PyDict_New(); if (dirs == NULL) return -1; if (source == NULL) ret = 0; else if (PyDict_Check(source)) ret = dirs_fromdict(dirs, source, skipchar); else if (skipchar) PyErr_SetString(PyExc_ValueError, "skip character is only supported " "with a dict source"); else ret = dirs_fromiter(dirs, source); if (ret == -1) Py_XDECREF(dirs); else self->dict = dirs; return ret; } PyObject *dirs_addpath(dirsObject *self, PyObject *args) { PyObject *path; if (!PyArg_ParseTuple(args, "O!:addpath", &PyString_Type, &path)) return NULL; if (_addpath(self->dict, path) == -1) return NULL; Py_RETURN_NONE; } static PyObject *dirs_delpath(dirsObject *self, PyObject *args) { PyObject *path; if (!PyArg_ParseTuple(args, "O!:delpath", &PyString_Type, &path)) return NULL; if (_delpath(self->dict, path) == -1) return NULL; Py_RETURN_NONE; } static int dirs_contains(dirsObject *self, PyObject *value) { return PyString_Check(value) ? PyDict_Contains(self->dict, value) : 0; } static void dirs_dealloc(dirsObject *self) { Py_XDECREF(self->dict); PyObject_Del(self); } static PyObject *dirs_iter(dirsObject *self) { return PyObject_GetIter(self->dict); } static PySequenceMethods dirs_sequence_methods; static PyMethodDef dirs_methods[] = { {"addpath", (PyCFunction)dirs_addpath, METH_VARARGS, "add a path"}, {"delpath", (PyCFunction)dirs_delpath, METH_VARARGS, "remove a path"}, {NULL} /* Sentinel */ }; static PyTypeObject dirsType = { PyObject_HEAD_INIT(NULL) }; void dirs_module_init(PyObject *mod) { dirs_sequence_methods.sq_contains = (objobjproc)dirs_contains; dirsType.tp_name = "parsers.dirs"; dirsType.tp_new = PyType_GenericNew; dirsType.tp_basicsize = sizeof(dirsObject); dirsType.tp_dealloc = (destructor)dirs_dealloc; dirsType.tp_as_sequence = &dirs_sequence_methods; dirsType.tp_flags = Py_TPFLAGS_DEFAULT; dirsType.tp_doc = "dirs"; dirsType.tp_iter = (getiterfunc)dirs_iter; dirsType.tp_methods = dirs_methods; dirsType.tp_init = (initproc)dirs_init; if (PyType_Ready(&dirsType) < 0) return; Py_INCREF(&dirsType); PyModule_AddObject(mod, "dirs", (PyObject *)&dirsType); }