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Abstract the event queue away

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Provide a couple of handler functions to avoid erroneous queue updates. This
will make it easier if we need to swap queue implementation later.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Peter Hutterer 2013-05-30 11:05:24 +10:00
parent f3d94ecfd7
commit 549f0f0bcd
2 changed files with 117 additions and 28 deletions
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99
libevdev/libevdev-int.h
View file

@ -61,5 +61,104 @@ struct libevdev {
size_t queue_nsync; /**< number of sync events */
};
/**
* @return a pointer to the next element in the queue, or NULL if the queue
* is full.
*/
static inline struct input_event*
queue_push(struct libevdev *dev)
{
if (dev->queue_next >= dev->queue_size)
return NULL;
return &dev->queue[dev->queue_next++];
}
/**
* Set ev to the last element in the queue, removing it from the queue.
*
* @return 0 on success, 1 if the queue is empty.
*/
static inline int
queue_pop(struct libevdev *dev, struct input_event *ev)
{
if (dev->queue_next == 0)
return 1;
*ev = dev->queue[--dev->queue_next];
return 0;
}
/**
* Set ev to the first element in the queue, shifting everything else
* forward by one.
*
* @return 0 on success, 1 if the queue is empty.
*/
static inline int
queue_shift(struct libevdev *dev, struct input_event *ev)
{
int i;
if (dev->queue_next == 0)
return 1;
*ev = dev->queue[0];
for (i = 0; i < dev->queue_next - 1; i++)
dev->queue[i] = dev->queue[i + 1];
dev->queue_next--;
return 0;
}
static inline int
queue_alloc(struct libevdev *dev, int size)
{
dev->queue = calloc(size, sizeof(struct input_event));
if (!dev->queue)
return -ENOSPC;
dev->queue_size = size;
dev->queue_next = 0;
return 0;
}
static inline int
queue_num_elements(struct libevdev *dev)
{
return dev->queue_next;
}
static inline int
queue_size(struct libevdev *dev)
{
return dev->queue_size;
}
static inline int
queue_num_free_elements(struct libevdev *dev)
{
return dev->queue_size - dev->queue_next - 1;
}
static inline struct input_event *
queue_next_element(struct libevdev *dev)
{
return &dev->queue[dev->queue_next];
}
static inline int
queue_set_num_elements(struct libevdev *dev, int nelem)
{
if (nelem > dev->queue_size)
return 1;
dev->queue_next = nelem;
return 0;
}
#endif

46
libevdev/libevdev.c
View file

@ -125,14 +125,7 @@ init_event_queue(struct libevdev *dev)
const int QUEUE_SIZE = 256;
dev->queue = calloc(QUEUE_SIZE, sizeof(struct input_event));
if (!dev->queue)
return -ENOSPC;
dev->queue_size = QUEUE_SIZE;
dev->queue_next = 0;
return 0;
return queue_alloc(dev, QUEUE_SIZE);
}
static void
@ -293,12 +286,13 @@ sync_key_state(struct libevdev *dev)
goto out;
for (i = 0; i < KEY_MAX; i++) {
struct input_event *ev = &dev->queue[dev->queue_next++];
int old, new;
old = bit_is_set(dev->key_values, i);
new = bit_is_set(keystate, i);
if (old ^ new)
if (old ^ new) {
struct input_event *ev = queue_push(dev);
init_event(ev, EV_KEY, i, new ? 1 : 0);
}
set_bit_state(dev->key_values, i, new);
}
@ -327,7 +321,7 @@ sync_abs_state(struct libevdev *dev)
goto out;
if (dev->abs_info[i].value != abs_info.value) {
struct input_event *ev = &dev->queue[dev->queue_next++];
struct input_event *ev = queue_push(dev);
init_event(ev, EV_ABS, i, abs_info.value);
dev->abs_info[i].value = abs_info.value;
@ -365,7 +359,7 @@ sync_mt_state(struct libevdev *dev)
int j;
struct input_event *ev;
ev = &dev->queue[dev->queue_next++];
ev = queue_push(dev);
init_event(ev, EV_ABS, ABS_MT_SLOT, i);
for (j = ABS_MT_MIN; j < ABS_MT_MAX; j++) {
int jdx = j - ABS_MT_MIN;
@ -373,7 +367,7 @@ sync_mt_state(struct libevdev *dev)
if (dev->mt_slot_vals[i][jdx] == mt_state[jdx].val[i])
continue;
ev = &dev->queue[dev->queue_next++];
ev = queue_push(dev);
init_event(ev, EV_ABS, j, mt_state[jdx].val[i]);
dev->mt_slot_vals[i][jdx] = mt_state[jdx].val[i];
}
@ -401,10 +395,10 @@ sync_state(struct libevdev *dev)
if (rc == 0 && libevdev_has_event_code(dev, EV_ABS, ABS_MT_SLOT))
rc = sync_mt_state(dev);
ev = &dev->queue[dev->queue_next++];
ev = queue_push(dev);
init_event(ev, EV_SYN, SYN_REPORT, 0);
dev->queue_nsync = dev->queue_next;
dev->queue_nsync = queue_num_elements(dev);
dev->need_sync = 0;
return rc;
@ -466,18 +460,22 @@ read_more_events(struct libevdev *dev)
{
int free_elem;
int len;
struct input_event *next;
free_elem = dev->queue_size - dev->queue_next - 1;
free_elem = queue_num_free_elements(dev);
if (free_elem <= 0)
return 0;
len = read(dev->fd, &dev->queue[dev->queue_next], free_elem * sizeof(struct input_event));
next = queue_next_element(dev);
len = read(dev->fd, next, free_elem * sizeof(struct input_event));
if (len < 0) {
return -errno;
} else if (len > 0 && len % sizeof(struct input_event) != 0)
return -EINVAL;
else if (len > 0)
dev->queue_next += len/sizeof(struct input_event);
else if (len > 0) {
int nev = len/sizeof(struct input_event);
queue_set_num_elements(dev, queue_num_elements(dev) + nev);
}
return 0;
}
@ -485,7 +483,6 @@ read_more_events(struct libevdev *dev)
int libevdev_next_event(struct libevdev *dev, unsigned int flags, struct input_event *ev)
{
int rc = 0;
int i;
if (dev->fd < 0)
return -ENODEV;
@ -509,11 +506,9 @@ int libevdev_next_event(struct libevdev *dev, unsigned int flags, struct input_e
if (rc < 0 && rc != -EAGAIN)
goto out;
if (dev->queue_next == 0)
if (queue_shift(dev, ev) != 0)
return -EAGAIN;
*ev = dev->queue[0];
update_state(dev, ev);
rc = 0;
@ -522,11 +517,6 @@ int libevdev_next_event(struct libevdev *dev, unsigned int flags, struct input_e
rc = 1;
}
for (i = 0; dev->queue_next > 1 && i < dev->queue_next - 1; i++)
dev->queue[i] = dev->queue[i + 1];
dev->queue_next--;
if (flags & ER_SYNC && dev->queue_nsync > 0) {
dev->queue_nsync--;
rc = 1;