minui/events.c

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/poll.h>

#include <linux/input.h>

#include "minui.h"

#define MAX_DEVICES 16
#define MAX_MISC_FDS 16

#define test_bit(bit, array)   ((array)[(bit)/8] & (1<<((bit)%8)))

struct fd_info {
    ev_callback cb;
    void *data;
};

static struct pollfd ev_fds[MAX_DEVICES + MAX_MISC_FDS];
static struct fd_info ev_fdinfo[MAX_DEVICES + MAX_MISC_FDS];

static unsigned ev_count = 0;
static unsigned ev_dev_count = 0;
static unsigned ev_misc_count = 0;

int ev_init(ev_callback input_cb, void *data)
{
    DIR *dir;
    struct dirent *de;
    int fd;

    dir = opendir("/dev/input");
    if(dir != 0) {
        while((de = readdir(dir))) {
            uint8_t ev_bits[(EV_MAX + 1) / 8];

//            fprintf(stderr,"/dev/input/%s\n", de->d_name);
            if(strncmp(de->d_name,"event",5)) continue;
            fd = openat(dirfd(dir), de->d_name, O_RDONLY);
            if(fd < 0) continue;

            /* read the evbits of the input device */
            if (ioctl(fd, EVIOCGBIT(0, sizeof(ev_bits)), ev_bits) < 0) {
                close(fd);
                continue;
            }

            /* TODO: add ability to specify event masks. For now, just assume
             * that only EV_KEY and EV_REL event types are ever needed. */
            if (!test_bit(EV_KEY, ev_bits) && !test_bit(EV_REL, ev_bits)) {
                close(fd);
                continue;
            }

            ev_fds[ev_count].fd = fd;
            ev_fds[ev_count].events = POLLIN;
            ev_fdinfo[ev_count].cb = input_cb;
            ev_fdinfo[ev_count].data = data;
            ev_count++;
            ev_dev_count++;
            if(ev_dev_count == MAX_DEVICES) break;
        }
    }

    return 0;
}

int ev_add_fd(int fd, ev_callback cb, void *data)
{
    if (ev_misc_count == MAX_MISC_FDS || cb == NULL)
        return -1;

    ev_fds[ev_count].fd = fd;
    ev_fds[ev_count].events = POLLIN;
    ev_fdinfo[ev_count].cb = cb;
    ev_fdinfo[ev_count].data = data;
    ev_count++;
    ev_misc_count++;
    return 0;
}

void ev_exit(void)
{
    while (ev_count > 0) {
        close(ev_fds[--ev_count].fd);
    }
    ev_misc_count = 0;
    ev_dev_count = 0;
}

int ev_wait(int timeout)
{
    int r;

    r = poll(ev_fds, ev_count, timeout);
    if (r <= 0)
        return -1;
    return 0;
}

void ev_dispatch(void)
{
    unsigned n;
    int ret;

    for (n = 0; n < ev_count; n++) {
        ev_callback cb = ev_fdinfo[n].cb;
        if (cb && (ev_fds[n].revents & ev_fds[n].events))
            cb(ev_fds[n].fd, ev_fds[n].revents, ev_fdinfo[n].data);
    }
}

int ev_get_input(int fd, short revents, struct input_event *ev)
{
    int r;

    if (revents & POLLIN) {
        r = read(fd, ev, sizeof(*ev));
        if (r == sizeof(*ev))
            return 0;
    }
    return -1;
}