gtk/
rt.rs

1// Take a look at the license at the top of the repository in the LICENSE file.
2
3use glib::translate::*;
4use std::cell::Cell;
5use std::sync::atomic::{AtomicBool, Ordering};
6
7#[cfg(target_os = "macos")]
8extern "C" {
9    fn pthread_main_np() -> i32;
10}
11
12thread_local! {
13    static IS_MAIN_THREAD: Cell<bool> = Cell::new(false)
14}
15
16static INITIALIZED: AtomicBool = AtomicBool::new(false);
17
18/// Asserts that this is the main thread and `gtk::init` has been called.
19macro_rules! assert_initialized_main_thread {
20    () => {
21        if !crate::rt::is_initialized_main_thread() {
22            if crate::rt::is_initialized() {
23                panic!("GTK may only be used from the main thread.");
24            } else {
25                panic!("GTK has not been initialized. Call `gtk::init` first.");
26            }
27        }
28    };
29}
30
31/// No-op.
32macro_rules! skip_assert_initialized {
33    () => {};
34}
35
36/// Asserts that `gtk::init` has not been called.
37#[allow(unused_macros)]
38macro_rules! assert_not_initialized {
39    () => {
40        if crate::rt::is_initialized() {
41            panic!("This function has to be called before `gtk::init`.");
42        }
43    };
44}
45
46/// Returns `true` if GTK has been initialized.
47#[inline]
48pub fn is_initialized() -> bool {
49    skip_assert_initialized!();
50    if cfg!(not(feature = "unsafe-assume-initialized")) {
51        INITIALIZED.load(Ordering::Acquire)
52    } else {
53        true
54    }
55}
56
57/// Returns `true` if GTK has been initialized and this is the main thread.
58#[inline]
59pub fn is_initialized_main_thread() -> bool {
60    skip_assert_initialized!();
61    if cfg!(not(feature = "unsafe-assume-initialized")) {
62        IS_MAIN_THREAD.with(|c| c.get())
63    } else {
64        true
65    }
66}
67
68/// Informs this crate that GTK has been initialized and the current thread is the main one.
69///
70/// # Panics
71///
72/// This function will panic if you attempt to initialise GTK from more than
73/// one thread.
74///
75/// # Safety
76///
77/// You must only call this if:
78///
79/// 1. You have initialised the underlying GTK library yourself.
80/// 2. You did 1 on the thread with which you are calling this function
81/// 3. You ensure that this thread is the main thread for the process.
82pub unsafe fn set_initialized() {
83    skip_assert_initialized!();
84    if is_initialized_main_thread() {
85        return;
86    } else if is_initialized() {
87        panic!("Attempted to initialize GTK from two different threads.");
88    }
89
90    //  OS X has its own notion of the main thread and init must be called on that thread.
91    #[cfg(target_os = "macos")]
92    {
93        assert_eq!(
94            pthread_main_np(),
95            1,
96            "Attempted to initialize GTK on OSX from non-main thread"
97        );
98    }
99
100    gdk::set_initialized();
101    INITIALIZED.store(true, Ordering::Release);
102    IS_MAIN_THREAD.with(|c| c.set(true));
103}
104
105/// Tries to initialize GTK+.
106///
107/// Call either this function or [`Application::new`][new] before using any
108/// other GTK+ functions.
109///
110/// [new]: struct.Application.html#method.new
111///
112/// Note that this function calls `gtk_init_check()` rather than `gtk_init()`,
113/// so will not cause the program to terminate if GTK could not be initialized.
114/// Instead, an Ok is returned if the windowing system was successfully
115/// initialized otherwise an Err is returned.
116#[doc(alias = "gtk_init")]
117pub fn init() -> Result<(), glib::BoolError> {
118    skip_assert_initialized!();
119    if is_initialized_main_thread() {
120        return Ok(());
121    } else if is_initialized() {
122        panic!("Attempted to initialize GTK from two different threads.");
123    }
124    unsafe {
125        // We just want to keep the program's name since more arguments could lead to unwanted
126        // behaviors...
127        let argv = ::std::env::args().take(1).collect::<Vec<_>>();
128
129        if from_glib(ffi::gtk_init_check(&mut 1, &mut argv.to_glib_none().0)) {
130            // See https://github.com/gtk-rs/gtk-rs-core/issues/186 for reasoning behind
131            // acquiring and leaking the main context here.
132            let result: bool = from_glib(glib::ffi::g_main_context_acquire(
133                glib::ffi::g_main_context_default(),
134            ));
135            if !result {
136                return Err(glib::bool_error!("Failed to acquire default main context"));
137            }
138            set_initialized();
139            Ok(())
140        } else {
141            Err(glib::bool_error!("Failed to initialize GTK"))
142        }
143    }
144}
145
146#[doc(alias = "gtk_main_quit")]
147pub fn main_quit() {
148    assert_initialized_main_thread!();
149    unsafe {
150        if ffi::gtk_main_level() > 0 {
151            ffi::gtk_main_quit();
152        } else if cfg!(debug_assertions) {
153            panic!("Attempted to quit a GTK main loop when none is running.");
154        }
155    }
156}
157
158#[cfg(test)]
159mod tests {
160    use crate::TEST_THREAD_WORKER;
161
162    #[test]
163    fn init_should_acquire_default_main_context() {
164        TEST_THREAD_WORKER
165            .push(move || {
166                let context = glib::MainContext::ref_thread_default();
167                assert!(context.is_owner());
168            })
169            .expect("Failed to schedule a test call");
170        while TEST_THREAD_WORKER.unprocessed() > 0 {}
171    }
172}
gtk/rt.rs

gtk/
rt.rs
