worker: make waitforworkers reentrant
We are going to use it in the SIGCHLD handler. The handler will be executed
in the main thread with the non-blocking version of waitpid, while the
waitforworkers thread runs the blocking version. It's possible that one of
them collects a worker and makes the other error out (no child to wait).
This patch handles these errors: ECHILD is ignored. EINTR needs a retry.
The "pids" set is designed to be only modifiable by "waitforworkers". And we
only remove items after a successful waitpid. Since a child process can only
be "waitpid"-ed once. It's guaranteed that "pids.remove(p)" won't be called
with duplicated "p"s. And once a "p" is removed from "pids", that "p" does
not need to be killed or waited any more.
/*
* 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