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#include "io_lock.h"
#include <assert.h>
#include <ccan/io/io_plan.h>
struct io_lock {
bool locked;
};
/* Struct to hold information while we wait for the lock to be freed */
struct io_lock_waiter {
struct io_plan *(*next)(struct io_conn *conn, void *next_arg);
void *arg;
struct io_lock *lock;
enum io_direction dir;
};
struct io_lock *io_lock_new(const tal_t *ctx)
{
struct io_lock *lock = tal(ctx, struct io_lock);
lock->locked = false;
return lock;
}
static struct io_plan *io_lock_try_acquire(struct io_conn *conn,
struct io_lock_waiter *waiter)
{
/* Destructure waiter, since we might be freeing it below */
struct io_plan *(*next)(struct io_conn *, void *) = waiter->next;
void *next_arg = waiter->arg;
if (!waiter->lock->locked) {
waiter->lock->locked = true;
tal_free(waiter);
return next(conn, next_arg);
} else {
switch (waiter->dir) {
case IO_IN:
return io_wait(conn, waiter->lock, io_lock_try_acquire,
waiter);
case IO_OUT:
return io_out_wait(conn, waiter->lock,
io_lock_try_acquire, waiter);
}
/* Should not happen if waiter->dir is a valid enum
* value */
abort();
}
}
static struct io_plan *io_lock_acquire_dir(
struct io_conn *conn, struct io_lock *lock, enum io_direction dir,
struct io_plan *(*next)(struct io_conn *, void *), void *arg)
{
/* FIXME: We can avoid one allocation if we lock and call next here directly */
struct io_lock_waiter *waiter = tal(lock, struct io_lock_waiter);
waiter->next = next;
waiter->arg = arg;
waiter->lock = lock;
waiter->dir = dir;
return io_lock_try_acquire(conn, waiter);
}
struct io_plan *
io_lock_acquire_out_(struct io_conn *conn, struct io_lock *lock,
struct io_plan *(*next)(struct io_conn *, void *), void *arg)
{
return io_lock_acquire_dir(conn, lock, IO_OUT, next, arg);
}
struct io_plan *
io_lock_acquire_in_(struct io_conn *conn, struct io_lock *lock,
struct io_plan *(*next)(struct io_conn *, void *), void *arg)
{
return io_lock_acquire_dir(conn, lock, IO_IN, next, arg);
}
void io_lock_release(struct io_lock *lock)
{
assert(lock->locked);
lock->locked = false;
io_wake(lock);
}
bool io_lock_taken(const struct io_lock *lock)
{
return lock->locked;
}