glib-compat.h

/*
 * GLIB Compatibility Functions
 *
 * Copyright IBM, Corp. 2013
 *
 * Authors:
 *  Anthony Liguori   <aliguori@us.ibm.com>
 *  Michael Tokarev   <mjt@tls.msk.ru>
 *  Paolo Bonzini     <pbonzini@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#ifndef QEMU_GLIB_COMPAT_H
#define QEMU_GLIB_COMPAT_H

/* Ask for warnings for anything that was marked deprecated in
 * the defined version, or before. It is a candidate for rewrite.
 */
#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_40

/* Ask for warnings if code tries to use function that did not
 * exist in the defined version. These risk breaking builds
 */
#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_40

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"

#include <glib.h>

/*
 * Note that because of the GLIB_VERSION_MAX_ALLOWED constant above, allowing
 * use of functions from newer GLib via this compat header needs a little
 * trickery to prevent warnings being emitted.
 *
 * Consider a function from newer glib-X.Y that we want to use
 *
 *    int g_foo(const char *wibble)
 *
 * We must define a static inline function with the same signature that does
 * what we need, but with a "_qemu" suffix e.g.
 *
 * static inline void g_foo_qemu(const char *wibble)
 * {
 *     #if GLIB_CHECK_VERSION(X, Y, 0)
 *        g_foo(wibble)
 *     #else
 *        g_something_equivalent_in_older_glib(wibble);
 *     #endif
 * }
 *
 * The #pragma at the top of this file turns off -Wdeprecated-declarations,
 * ensuring this wrapper function impl doesn't trigger the compiler warning
 * about using too new glib APIs. Finally we can do
 *
 *   #define g_foo(a) g_foo_qemu(a)
 *
 * So now the code elsewhere in QEMU, which *does* have the
 * -Wdeprecated-declarations warning active, can call g_foo(...) as normal,
 * without generating warnings.
 */

static inline gboolean g_strv_contains_qemu(const gchar *const *strv,
                                            const gchar *str)
{
#if GLIB_CHECK_VERSION(2, 44, 0)
    return g_strv_contains(strv, str);
#else
    g_return_val_if_fail(strv != NULL, FALSE);
    g_return_val_if_fail(str != NULL, FALSE);

    for (; *strv != NULL; strv++) {
        if (g_str_equal(str, *strv)) {
            return TRUE;
        }
    }

    return FALSE;
#endif
}
#define g_strv_contains(a, b) g_strv_contains_qemu(a, b)

#if !GLIB_CHECK_VERSION(2, 58, 0)
typedef struct QemuGSpawnFds {
    GSpawnChildSetupFunc child_setup;
    gpointer user_data;
    gint stdin_fd;
    gint stdout_fd;
    gint stderr_fd;
} QemuGSpawnFds;

static inline void
qemu_gspawn_fds_setup(gpointer user_data)
{
    QemuGSpawnFds *q = (QemuGSpawnFds *)user_data;

    dup2(q->stdin_fd, 0);
    dup2(q->stdout_fd, 1);
    dup2(q->stderr_fd, 2);
    q->child_setup(q->user_data);
}
#endif

static inline gboolean
g_spawn_async_with_fds_qemu(const gchar *working_directory,
                            gchar **argv,
                            gchar **envp,
                            GSpawnFlags flags,
                            GSpawnChildSetupFunc child_setup,
                            gpointer user_data,
                            GPid *child_pid,
                            gint stdin_fd,
                            gint stdout_fd,
                            gint stderr_fd,
                            GError **error)
{
#if GLIB_CHECK_VERSION(2, 58, 0)
    return g_spawn_async_with_fds(working_directory, argv, envp, flags,
                                  child_setup, user_data,
                                  child_pid, stdin_fd, stdout_fd, stderr_fd,
                                  error);
#else
    QemuGSpawnFds setup = {
        .child_setup = child_setup,
        .user_data = user_data,
        .stdin_fd = stdin_fd,
        .stdout_fd = stdout_fd,
        .stderr_fd = stderr_fd,
    };

    return g_spawn_async(working_directory, argv, envp, flags,
                         qemu_gspawn_fds_setup, &setup,
                         child_pid, error);
#endif
}

#define g_spawn_async_with_fds(wd, argv, env, f, c, d, p, ifd, ofd, efd, err) \
    g_spawn_async_with_fds_qemu(wd, argv, env, f, c, d, p, ifd, ofd, efd, err)

#if defined(_WIN32) && !GLIB_CHECK_VERSION(2, 50, 0)
/*
 * g_poll has a problem on Windows when using
 * timeouts < 10ms, so use wrapper.
 */
#define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout)
gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout);
#endif


#ifndef g_assert_cmpmem
#define g_assert_cmpmem(m1, l1, m2, l2)                                        \
    do {                                                                       \
        gconstpointer __m1 = m1, __m2 = m2;                                    \
        int __l1 = l1, __l2 = l2;                                              \
        if (__l1 != __l2) {                                                    \
            g_assertion_message_cmpnum(                                        \
                G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC,                   \
                #l1 " (len(" #m1 ")) == " #l2 " (len(" #m2 "))", __l1, "==",   \
                __l2, 'i');                                                    \
        } else if (memcmp(__m1, __m2, __l1) != 0) {                            \
            g_assertion_message(G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC,   \
                                "assertion failed (" #m1 " == " #m2 ")");      \
        }                                                                      \
    } while (0)
#endif

#pragma GCC diagnostic pop

#endif