gdk/
rt.rs

1// Take a look at the license at the top of the repository in the LICENSE file.
2
3//! General — Library initialization and miscellaneous functions
4
5use std::cell::Cell;
6use std::ptr;
7use std::sync::atomic::{AtomicBool, Ordering};
8
9thread_local! {
10    static IS_MAIN_THREAD: Cell<bool> = Cell::new(false)
11}
12
13static INITIALIZED: AtomicBool = AtomicBool::new(false);
14
15/// Asserts that this is the main thread and either `gdk::init` or `gtk::init` has been called.
16macro_rules! assert_initialized_main_thread {
17    () => {
18        if !crate::rt::is_initialized_main_thread() {
19            if crate::rt::is_initialized() {
20                panic!("GDK may only be used from the main thread.");
21            } else {
22                panic!("GDK has not been initialized. Call `gdk::init` or `gtk::init` first.");
23            }
24        }
25    };
26}
27
28/// No-op.
29macro_rules! skip_assert_initialized {
30    () => {};
31}
32
33/// Asserts that neither `gdk::init` nor `gtk::init` has been called.
34macro_rules! assert_not_initialized {
35    () => {
36        if crate::rt::is_initialized() {
37            panic!("This function has to be called before `gdk::init` or `gtk::init`.");
38        }
39    };
40}
41
42/// Returns `true` if GDK has been initialized.
43#[inline]
44pub fn is_initialized() -> bool {
45    skip_assert_initialized!();
46    if cfg!(not(feature = "unsafe-assume-initialized")) {
47        INITIALIZED.load(Ordering::Acquire)
48    } else {
49        true
50    }
51}
52
53/// Returns `true` if GDK has been initialized and this is the main thread.
54#[inline]
55pub fn is_initialized_main_thread() -> bool {
56    skip_assert_initialized!();
57    if cfg!(not(feature = "unsafe-assume-initialized")) {
58        IS_MAIN_THREAD.with(|c| c.get())
59    } else {
60        true
61    }
62}
63
64/// Informs this crate that GDK has been initialized and the current thread is the main one.
65pub unsafe fn set_initialized() {
66    skip_assert_initialized!();
67    if is_initialized_main_thread() {
68        return;
69    } else if is_initialized() {
70        panic!("Attempted to initialize GDK from two different threads.");
71    }
72    INITIALIZED.store(true, Ordering::Release);
73    IS_MAIN_THREAD.with(|c| c.set(true));
74}
75
76#[doc(alias = "gdk_init")]
77pub fn init() {
78    assert_not_initialized!();
79    unsafe {
80        ffi::gdk_init(ptr::null_mut(), ptr::null_mut());
81        set_initialized();
82    }
83}
gdk/rt.rs

gdk/
rt.rs
