static struct sol_mainloop_source *
event_create_source(sd_event *event)
{
struct sol_mainloop_source *source;
struct source_ctx *ctx;
ctx = malloc(sizeof(*ctx));
SOL_NULL_CHECK(ctx, NULL);
ctx->event = sd_event_ref(event);
ctx->fd_handler = sol_fd_add(sd_event_get_fd(event),
SOL_FD_FLAGS_IN | SOL_FD_FLAGS_HUP | SOL_FD_FLAGS_ERR,
on_sd_event_fd, ctx);
SOL_NULL_CHECK_GOTO(ctx->fd_handler, error_fd);
source = sol_mainloop_add_source(&source_type, ctx);
SOL_NULL_CHECK_GOTO(source, error_source);
return source;
error_source:
sol_fd_del(ctx->fd_handler);
error_fd:
sd_event_unref(ctx->event);
free(ctx);
return NULL;
}
int
hijack_main_loop()
{
int returnValue;
uv_loop_t *uv_loop = NULL;
SOL_DBG("Entering with state %s", RESOLVE_MAINLOOP_STATE(mainloopState));
if (mainloopState == MAINLOOP_HIJACKED ||
mainloopState == MAINLOOP_HIJACKING_STARTED) {
return 0;
}
uv_loop = uv_default_loop();
// The actual hijacking starts here, inspired by node-gtk. The plan:
// 1. uv has two ways of letting us know that it needs to run its loop. One
// is that its backend timeout is >= 0, and the other is a file
// descriptor which can become readable/writable/errored. So, attach a
// source to the soletta main loop which will run the uv main loop in
// a non-blocking fashion. Also attach a file descriptor watch via which
// uv can signal that it needs to run an iteration.
// 2. Attach an idler to the uv main loop and call sol_run() from it when
// it first runs. This interrupts the uv main loop, because sol_run()
// doesn't return but, since we've already added the above sources to
// the soletta main loop in the first step, the source or the file
// descriptor watch will end up running one non-blocking iteration of
// the uv main loop which, in turn, will recursively call the idler we
// added. At that point, the idler can remove itself from the uv main
// loop. After that, only the soletta main loop runs, but it runs an
// iteration of the uv main loop in a non-blocking fashion whenever the
// uv main loop signals to the soletta main loop via the attached
// source or the attached file descriptor watch.
// 3. Attach a token handle to the uv main loop which represents all
// soletta open handles. This is necessary because the uv main loop
// would otherwise quit when it runs out of its own handles. We remove
// this token handle when we release the uv main loop so that if, at
// that point, it has no more handles, it is free to cause the node.js
// process to quit.
// We allocate the various needed structures only once. After that, we
// reuse them. We never free them, even if we release the uv main loop.
if (!uv_loop_source) {
uv_loop_source = sol_mainloop_add_source(&uv_loop_source_funcs,
uv_loop);
if (!uv_loop_source) {
return -ENOMEM;
}
}
if (!uv_loop_fd) {
uv_loop_fd = sol_fd_add(uv_backend_fd(uv_loop),
SOL_FD_FLAGS_IN | SOL_FD_FLAGS_OUT | SOL_FD_FLAGS_ERR,
uv_loop_fd_changed, uv_loop);
if (!uv_loop_fd) {
return -ENOMEM;
}
}
returnValue = uv_prepare_init(uv_loop, &uv_token_handle);
if (returnValue) {
return returnValue;
}
returnValue = uv_idle_init(uv_loop, &uv_idle);
if (returnValue) {
return returnValue;
}
SOL_DBG("Starting token handle");
returnValue = uv_prepare_start(&uv_token_handle, uv_token_callback);
if (returnValue) {
return returnValue;
}
SOL_DBG("Starting idler");
returnValue = uv_idle_start(&uv_idle, uv_idle_callback);
if (returnValue) {
return returnValue;
}
mainloopState = MAINLOOP_HIJACKING_STARTED;
return 0;
}
