gdk/
rt.rs

1// Copyright 2013-2015, The Gtk-rs Project Developers.
2// See the COPYRIGHT file at the top-level directory of this distribution.
3// Licensed under the MIT license, see the LICENSE file or <http://opensource.org/licenses/MIT>
4
5//! General — Library initialization and miscellaneous functions
6
7use gdk_sys;
8use std::cell::Cell;
9use std::ptr;
10use std::sync::atomic::{AtomicBool, Ordering, ATOMIC_BOOL_INIT};
11
12thread_local! {
13    static IS_MAIN_THREAD: Cell<bool> = Cell::new(false)
14}
15
16static INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT;
17
18/// Asserts that this is the main thread and either `gdk::init` or `gtk::init` has been called.
19macro_rules! assert_initialized_main_thread {
20    () => {
21        if !::rt::is_initialized_main_thread() {
22            if ::rt::is_initialized() {
23                panic!("GDK may only be used from the main thread.");
24            } else {
25                panic!("GDK has not been initialized. Call `gdk::init` or `gtk::init` first.");
26            }
27        }
28    };
29}
30
31/// No-op.
32macro_rules! skip_assert_initialized {
33    () => {};
34}
35
36/// Asserts that neither `gdk::init` nor `gtk::init` has been called.
37macro_rules! assert_not_initialized {
38    () => {
39        if ::rt::is_initialized() {
40            panic!("This function has to be called before `gdk::init` or `gtk::init`.");
41        }
42    };
43}
44
45/// Returns `true` if GDK has been initialized.
46#[inline]
47pub fn is_initialized() -> bool {
48    skip_assert_initialized!();
49    INITIALIZED.load(Ordering::Acquire)
50}
51
52/// Returns `true` if GDK has been initialized and this is the main thread.
53#[inline]
54pub fn is_initialized_main_thread() -> bool {
55    skip_assert_initialized!();
56    IS_MAIN_THREAD.with(|c| c.get())
57}
58
59/// Informs this crate that GDK has been initialized and the current thread is the main one.
60pub unsafe fn set_initialized() {
61    skip_assert_initialized!();
62    if is_initialized_main_thread() {
63        return;
64    } else if is_initialized() {
65        panic!("Attempted to initialize GDK from two different threads.");
66    }
67    INITIALIZED.store(true, Ordering::Release);
68    IS_MAIN_THREAD.with(|c| c.set(true));
69}
70
71pub fn init() {
72    assert_not_initialized!();
73    unsafe {
74        gdk_sys::gdk_init(ptr::null_mut(), ptr::null_mut());
75        set_initialized();
76    }
77}