1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

use std::cell::RefCell;
use std::io;
use std::sync::atomic::{AtomicUsize, Ordering};

use futures::sync::mpsc::UnboundedSender;
use futures::Future;
use tokio_current_thread::Handle;

use crate::arbiter::{Arbiter, SystemCommand};
use crate::builder::{Builder, SystemRunner};

static SYSTEM_COUNT: AtomicUsize = AtomicUsize::new(0);

/// System is a runtime manager.
#[derive(Clone, Debug)]
pub struct System {
    id: usize,
    sys: UnboundedSender<SystemCommand>,
    arbiter: Arbiter,
    stop_on_panic: bool,
}

thread_local!(
    static CURRENT: RefCell<Option<System>> = RefCell::new(None);
);

impl System {
    /// Constructs new system and sets it as current
    pub(crate) fn construct(
        sys: UnboundedSender<SystemCommand>,
        arbiter: Arbiter,
        stop_on_panic: bool,
    ) -> Self {
        let sys = System {
            sys,
            arbiter,
            stop_on_panic,
            id: SYSTEM_COUNT.fetch_add(1, Ordering::SeqCst),
        };
        System::set_current(sys.clone());
        sys
    }

    /// Build a new system with a customized tokio runtime.
    ///
    /// This allows to customize the runtime. See struct level docs on
    /// `Builder` for more information.
    pub fn builder() -> Builder {
        Builder::new()
    }

    #[allow(clippy::new_ret_no_self)]
    /// Create new system.
    ///
    /// This method panics if it can not create tokio runtime
    pub fn new<T: Into<String>>(name: T) -> SystemRunner {
        Self::builder().name(name).build()
    }

    #[allow(clippy::new_ret_no_self)]
    /// Create new system using provided CurrentThread Handle.
    ///
    /// This method panics if it can not spawn system arbiter
    pub fn run_in_executor<T: Into<String>>(
        name: T,
        executor: Handle,
    ) -> impl Future<Item = (), Error = io::Error> + Send {
        Self::builder()
            .name(name)
            .build_async(executor)
            .run_nonblocking()
    }

    /// Get current running system.
    pub fn current() -> System {
        CURRENT.with(|cell| match *cell.borrow() {
            Some(ref sys) => sys.clone(),
            None => panic!("System is not running"),
        })
    }

    /// Set current running system.
    pub(crate) fn is_set() -> bool {
        CURRENT.with(|cell| cell.borrow().is_some())
    }

    /// Set current running system.
    #[doc(hidden)]
    pub fn set_current(sys: System) {
        CURRENT.with(|s| {
            *s.borrow_mut() = Some(sys);
        })
    }

    /// Execute function with system reference.
    pub fn with_current<F, R>(f: F) -> R
    where
        F: FnOnce(&System) -> R,
    {
        CURRENT.with(|cell| match *cell.borrow() {
            Some(ref sys) => f(sys),
            None => panic!("System is not running"),
        })
    }

    /// System id
    pub fn id(&self) -> usize {
        self.id
    }

    /// Stop the system
    pub fn stop(&self) {
        self.stop_with_code(0)
    }

    /// Stop the system with a particular exit code.
    pub fn stop_with_code(&self, code: i32) {
        let _ = self.sys.unbounded_send(SystemCommand::Exit(code));
    }

    pub(crate) fn sys(&self) -> &UnboundedSender<SystemCommand> {
        &self.sys
    }

    /// Return status of 'stop_on_panic' option which controls whether the System is stopped when an
    /// uncaught panic is thrown from a worker thread.
    pub fn stop_on_panic(&self) -> bool {
        self.stop_on_panic
    }

    /// System arbiter
    pub fn arbiter(&self) -> &Arbiter {
        &self.arbiter
    }

    /// This function will start tokio runtime and will finish once the
    /// `System::stop()` message get called.
    /// Function `f` get called within tokio runtime context.
    pub fn run<F>(f: F) -> io::Result<()>
    where
        F: FnOnce() + 'static,
    {
        Self::builder().run(f)
    }
}