view mercurial/bdiff.h @ 35460:8652ab4046e4

osutil: add a function to unblock signals

Signals could be blocked by something like:

  #include <unistd.h>
  #include <signal.h>
  int main(int argc, char * const argv[]) {
    sigset_t set;
    sigfillset(&set);
    sigprocmask(SIG_BLOCK, &set, NULL);
    execv("/bin/hg", argv);
    return 0;
  }

One of the problems is if SIGCHLD is blocked, chgserver would not reap
zombie workers since it depends on SIGCHLD handler entirely.

While it's the parent process to blame but it seems a good idea to just
unblock the signal from hg. FWIW git does that for SIGPIPE already [1].

Unfortunately Python 2 does not reset or provide APIs to change signal
masks. Therefore let's add one in osutil. Note: Python 3.3 introduced
`signal.pthread_sigmask` which solves the problem.

`sigprocmask` is part of POSIX [2] so there is no feature testing in
`setup.py`.

[1]: https://github.com/git/git/commit/7559a1be8a0afb10df41d25e4cf4c5285a5faef1
[2]: http://pubs.opengroup.org/onlinepubs/7908799/xsh/sigprocmask.html

Differential Revision: https://phab.mercurial-scm.org/D1736

#ifndef _HG_BDIFF_H_
#define _HG_BDIFF_H_

#include "compat.h"

struct bdiff_line {
	int hash, n, e;
	ssize_t len;
	const char *l;
};

struct bdiff_hunk;
struct bdiff_hunk {
	int a1, a2, b1, b2;
	struct bdiff_hunk *next;
};

int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
               struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);

#endif