nih/test_divert.h

/* libnih
 *
 * Copyright © 2009 Scott James Remnant <scott@netsplit.com>.
 * Copyright © 2009 Canonical Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef NIH_TEST_DIVERT_H
#define NIH_TEST_DIVERT_H

#ifndef NIH_IN_TEST_H
# error "This header may only be included by <nih/test.h>"
#endif /* NIH_IN_TEST_H */

#include <stdio.h>
#include <assert.h>
#include <unistd.h>

/**
 * TEST_DIVERT_STDOUT_FD:
 * @_fd: fd to send standard output to.
 *
 * This macro diverts standard output to a different file descriptor
 * for the duration of a block of code that should follow it.
 **/
#define TEST_DIVERT_STDOUT_FD(_fd) \
	for (int _test_stdout = 0, _test_oldstdout = dup (STDOUT_FILENO); \
	     _test_stdout < 3; _test_stdout++) \
		if (_test_stdout < 1) { \
			fflush (stdout); \
			assert (dup2 ((_fd), STDOUT_FILENO) >= 0); \
		} else if (_test_stdout > 1) { \
			fflush (stdout); \
			assert (dup2 (_test_oldstdout, STDOUT_FILENO) >= 0); \
			close (_test_oldstdout); \
		} else

/**
 * TEST_DIVERT_STDOUT:
 * @_file: FILE to send standard output to.
 *
 * This macro diverts standard output to a different file for the duration
 * of a block of code that should follow it.
 */
#define TEST_DIVERT_STDOUT(_file) \
	TEST_DIVERT_STDOUT_FD (fileno (_file))

/**
 * TEST_DIVERT_STDERR_FD:
 * @_fd: fd to send standard error to.
 *
 * This macro diverts standard error to a different file descriptor for the
 * duration of a block of code that should follow it.
 */
#define TEST_DIVERT_STDERR_FD(_fd) \
	for (int _test_stderr = 0, _test_oldstderr = dup (STDERR_FILENO); \
	     _test_stderr < 3; _test_stderr++) \
		if (_test_stderr < 1) { \
			fflush (stderr); \
			assert (dup2 ((_fd), STDERR_FILENO) >= 0); \
		} else if (_test_stderr > 1) { \
			fflush (stderr); \
			assert (dup2 (_test_oldstderr, STDERR_FILENO) >= 0); \
			close (_test_oldstderr); \
		} else

/**
 * TEST_DIVERT_STDERR:
 * @_file: FILE to send standard error to.
 *
 * This macro diverts standard error to a different file for the duration
 * of a block of code that should follow it.
 */
#define TEST_DIVERT_STDERR(_file) \
	TEST_DIVERT_STDERR_FD (fileno (_file))

#endif /* NIH_TEST_DIVERT_H */