keymap: More robust state machine

[elogind.git] / extras / keymap / keymap.c

diff --git a/extras/keymap/keymap.c b/extras/keymap/keymap.c
index 2d68e7f0c2eadeb30b96d3d035559d5948a72c85..ed6b69d5f141d4b59c9bae21d473b1feb3864fca 100644 (file)
--- a/extras/keymap/keymap.c
+++ b/extras/keymap/keymap.c
@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdint.h>
 #include <ctype.h>
 #include <unistd.h>
 #include <errno.h>
@@ -274,41 +275,87 @@ static int read_event(int fd, struct input_event* ev)
        return 1;
 }
 
-static void print_key(struct input_event *event)
+static void print_key(uint32_t scancode, uint16_t keycode, int has_scan, int has_key)
 {
-       static int cur_scancode = 0;
        const char *keyname;
 
-       /* save scan code for next EV_KEY event */
-       if (event->type == EV_MSC && event->code == MSC_SCAN)
-           cur_scancode = event->value;
+       /* ignore key release events */
+       if (has_key == 1)
+               return;
 
-       /* key press */
-       if (event->type == EV_KEY && event->value) {
-               keyname = key_names[event->code];
-               if (keyname != NULL)
-                       printf("scan code: 0x%02X   key code: %s\n", cur_scancode,
-                           format_keyname(key_names[event->code]));
-               else
-                       printf("scan code: 0x%02X   key code: %03X\n", cur_scancode,
-                           event->code);
+       if (has_key == 0 && has_scan != 0) {
+               fprintf(stderr, "got scan code event 0x%02X without a key code event\n",
+                       scancode);
+               return;
        }
+
+       if (has_scan != 0)
+               printf("scan code: 0x%02X   ", scancode);
+       else
+               printf("(no scan code received)  ");
+
+       keyname = key_names[keycode];
+       if (keyname != NULL)
+               printf("key code: %s\n", format_keyname(keyname));
+       else
+               printf("key code: %03X\n", keycode);
 }
 
 static void interactive(int fd)
 {
        struct input_event ev;
+       uint32_t last_scan = 0;
+       uint16_t last_key = 0;
+       int has_scan; /* boolean */
+       int has_key; /* 0: none, 1: release, 2: press */
 
        /* grab input device */
        ioctl(fd, EVIOCGRAB, 1);
-
        puts("Press ESC to finish");
+
+       has_scan = has_key = 0;
        while (read_event(fd, &ev)) {
-               print_key(&ev);
+               /* Drivers usually send the scan code first, then the key code,
+                * then a SYN. Some drivers (like thinkpad_acpi) send the key
+                * code first, and some drivers might not send SYN events, so
+                * keep a robust state machine which can deal with any of those
+                */
+
+               if (ev.type == EV_MSC && ev.code == MSC_SCAN) {
+                       if (has_scan) {
+                               fputs("driver did not send SYN event in between key events; previous event:\n",
+                                     stderr);
+                               print_key(last_scan, last_key, has_scan, has_key);
+                               has_key = 0;
+                       }
+
+                       last_scan = ev.value;
+                       has_scan = 1;
+                       /*printf("--- got scan %u; has scan %i key %i\n", last_scan, has_scan, has_key); */
+               }
+               else if (ev.type == EV_KEY) {
+                       if (has_key) {
+                               fputs("driver did not send SYN event in between key events; previous event:\n",
+                                     stderr);
+                               print_key(last_scan, last_key, has_scan, has_key);
+                               has_scan = 0;
+                       }
+
+                       last_key = ev.code;
+                       has_key = 1 + ev.value;
+                       /*printf("--- got key %hu; has scan %i key %i\n", last_key, has_scan, has_key);*/
+
+                       /* Stop on ESC */
+                       if (ev.code == KEY_ESC && ev.value == 0)
+                               break;
+               }
+               else if (ev.type == EV_SYN) {
+                       /*printf("--- got SYN; has scan %i key %i\n", has_scan, has_key);*/
+                       print_key(last_scan, last_key, has_scan, has_key);
+
+                       has_scan = has_key = 0;
+               }
 
-               /* stop on Escape key release */
-               if (ev.type == EV_KEY && ev.code == KEY_ESC && ev.value == 0)
-                       break;
        }
 
        /* release input device */