annotate contrib/chg/util.h @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

/*
 * Utility functions
 *
 * Copyright (c) 2011 Yuya Nishihara <[e-mail]>
 *
 * This software may be used and distributed according to the terms of the
 * GNU General Public License version 2 or any later version.
 */

#ifndef UTIL_H_
#define UTIL_H_

#ifdef __GNUC__
#define PRINTF_FORMAT_ __attribute__((format(printf, 1, 2)))
#define UNUSED_ __attribute__((unused))
#else
#define PRINTF_FORMAT_
#define UNUSED_
#endif

void abortmsg(const char *fmt, ...) PRINTF_FORMAT_;
void abortmsgerrno(const char *fmt, ...) PRINTF_FORMAT_;

void enablecolor(void);
void enabledebugmsg(void);
void debugmsg(const char *fmt, ...) PRINTF_FORMAT_;

void fchdirx(int dirfd);
void fsetcloexec(int fd);
void *mallocx(size_t size);
void *reallocx(void *ptr, size_t size);

int runshellcmd(const char *cmd, const char *envp[], const char *cwd);

#endif /* UTIL_H_ */