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 
7 use gdk_sys;
8 use std::cell::Cell;
9 use std::ptr;
10 use std::sync::atomic::{AtomicBool, Ordering, ATOMIC_BOOL_INIT};
11 
12 thread_local! {
13     static IS_MAIN_THREAD: Cell<bool> = Cell::new(false)
14 }
15 
16 static INITIALIZED: AtomicBool = ATOMIC_BOOL_INIT;
17 
18 /// Asserts that this is the main thread and either `gdk::init` or `gtk::init` has been called.
19 macro_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.
32 macro_rules! skip_assert_initialized {
33     () => {};
34 }
35 
36 /// Asserts that neither `gdk::init` nor `gtk::init` has been called.
37 macro_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]
is_initialized() -> bool47 pub 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]
is_initialized_main_thread() -> bool54 pub 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.
set_initialized()60 pub 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 
init()71 pub fn init() {
72     assert_not_initialized!();
73     unsafe {
74         gdk_sys::gdk_init(ptr::null_mut(), ptr::null_mut());
75         set_initialized();
76     }
77 }
78