util: add helper APIs for dealing with inotify in portable manner

[mirror_qemu.git] / util / qemu-progress.c

/*
 * QEMU progress printing utility functions
 *
 * Copyright (C) 2011 Jes Sorensen <Jes.Sorensen@redhat.com>
 *
 * 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.
 */

#include "qemu/osdep.h"
#include "qemu-common.h"

struct progress_state {
    float current;
    float last_print;
    float min_skip;
    void (*print)(void);
    void (*end)(void);
};

static struct progress_state state;
static volatile sig_atomic_t print_pending;

/*
 * Simple progress print function.
 * @percent relative percent of current operation
 * @max percent of total operation
 */
static void progress_simple_print(void)
{
    printf("    (%3.2f/100%%)\r", state.current);
    fflush(stdout);
}

static void progress_simple_end(void)
{
    printf("\n");
}

static void progress_simple_init(void)
{
    state.print = progress_simple_print;
    state.end = progress_simple_end;
}

#ifdef CONFIG_POSIX
static void sigusr_print(int signal)
{
    print_pending = 1;
}
#endif

static void progress_dummy_print(void)
{
    if (print_pending) {
        fprintf(stderr, "    (%3.2f/100%%)\n", state.current);
        print_pending = 0;
    }
}

static void progress_dummy_end(void)
{
}

static void progress_dummy_init(void)
{
#ifdef CONFIG_POSIX
    struct sigaction action;
    sigset_t set;

    memset(&action, 0, sizeof(action));
    sigfillset(&action.sa_mask);
    action.sa_handler = sigusr_print;
    action.sa_flags = 0;
    sigaction(SIGUSR1, &action, NULL);
#ifdef SIGINFO
    sigaction(SIGINFO, &action, NULL);
#endif

    /*
     * SIGUSR1 is SIG_IPI and gets blocked in qemu_init_main_loop(). In the
     * tools that use the progress report SIGUSR1 isn't used in this meaning
     * and instead should print the progress, so reenable it.
     */
    sigemptyset(&set);
    sigaddset(&set, SIGUSR1);
    pthread_sigmask(SIG_UNBLOCK, &set, NULL);
#endif

    state.print = progress_dummy_print;
    state.end = progress_dummy_end;
}

/*
 * Initialize progress reporting.
 * If @enabled is false, actual reporting is suppressed.  The user can
 * still trigger a report by sending a SIGUSR1.
 * Reports are also suppressed unless we've had at least @min_skip
 * percent progress since the last report.
 */
void qemu_progress_init(int enabled, float min_skip)
{
    state.min_skip = min_skip;
    if (enabled) {
        progress_simple_init();
    } else {
        progress_dummy_init();
    }
}

void qemu_progress_end(void)
{
    state.end();
}

/*
 * Report progress.
 * @delta is how much progress we made.
 * If @max is zero, @delta is an absolut value of the total job done.
 * Else, @delta is a progress delta since the last call, as a fraction
 * of @max.  I.e. the delta is @delta * @max / 100. This allows
 * relative accounting of functions which may be a different fraction of
 * the full job, depending on the context they are called in. I.e.
 * a function might be considered 40% of the full job if used from
 * bdrv_img_create() but only 20% if called from img_convert().
 */
void qemu_progress_print(float delta, int max)
{
    float current;

    if (max == 0) {
        current = delta;
    } else {
        current = state.current + delta / 100 * max;
    }
    if (current > 100) {
        current = 100;
    }
    state.current = current;

    if (current > (state.last_print + state.min_skip) ||
        current < (state.last_print - state.min_skip) ||
        current == 100 || current == 0) {
        state.last_print = state.current;
        state.print();
    }
}