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
146
147
148
149
150
151
|
use std::os::raw::c_int;
use crate::error::{Error, Result};
use crate::ffi;
use crate::types::LuaRef;
use crate::util::{
assert_stack, check_stack, error_traceback, pop_error, protect_lua_closure, StackGuard,
};
use crate::value::{FromLuaMulti, MultiValue, ToLuaMulti};
/// Status of a Lua thread (or coroutine).
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub enum ThreadStatus {
/// The thread was just created, or is suspended because it has called `coroutine.yield`.
///
/// If a thread is in this state, it can be resumed by calling [`Thread::resume`].
///
/// [`Thread::resume`]: struct.Thread.html#method.resume
Resumable,
/// Either the thread has finished executing, or the thread is currently running.
Unresumable,
/// The thread has raised a Lua error during execution.
Error,
}
/// Handle to an internal Lua thread (or coroutine).
#[derive(Clone, Debug)]
pub struct Thread<'lua>(pub(crate) LuaRef<'lua>);
impl<'lua> Thread<'lua> {
/// Resumes execution of this thread.
///
/// Equivalent to `coroutine.resume`.
///
/// Passes `args` as arguments to the thread. If the coroutine has called `coroutine.yield`, it
/// will return these arguments. Otherwise, the coroutine wasn't yet started, so the arguments
/// are passed to its main function.
///
/// If the thread is no longer in `Active` state (meaning it has finished execution or
/// encountered an error), this will return `Err(CoroutineInactive)`, otherwise will return `Ok`
/// as follows:
///
/// If the thread calls `coroutine.yield`, returns the values passed to `yield`. If the thread
/// `return`s values from its main function, returns those.
///
/// # Examples
///
/// ```
/// # use mlua::{Error, Lua, Result, Thread};
/// # fn main() -> Result<()> {
/// # let lua = Lua::new();
/// let thread: Thread = lua.load(r#"
/// coroutine.create(function(arg)
/// assert(arg == 42)
/// local yieldarg = coroutine.yield(123)
/// assert(yieldarg == 43)
/// return 987
/// end)
/// "#).eval()?;
///
/// assert_eq!(thread.resume::<_, u32>(42)?, 123);
/// assert_eq!(thread.resume::<_, u32>(43)?, 987);
///
/// // The coroutine has now returned, so `resume` will fail
/// match thread.resume::<_, u32>(()) {
/// Err(Error::CoroutineInactive) => {},
/// unexpected => panic!("unexpected result {:?}", unexpected),
/// }
/// # Ok(())
/// # }
/// ```
pub fn resume<A, R>(&self, args: A) -> Result<R>
where
A: ToLuaMulti<'lua>,
R: FromLuaMulti<'lua>,
{
let lua = self.0.lua;
let args = args.to_lua_multi(lua)?;
let results = unsafe {
let _sg = StackGuard::new(lua.state);
assert_stack(lua.state, 3);
lua.push_ref(&self.0);
let thread_state = ffi::lua_tothread(lua.state, -1);
let status = ffi::lua_status(thread_state);
if status != ffi::LUA_YIELD && ffi::lua_gettop(thread_state) == 0 {
return Err(Error::CoroutineInactive);
}
ffi::lua_pop(lua.state, 1);
let nargs = args.len() as c_int;
check_stack(lua.state, nargs)?;
check_stack(thread_state, nargs + 1)?;
for arg in args {
lua.push_value(arg)?;
}
ffi::lua_xmove(lua.state, thread_state, nargs);
let ret = ffi::lua_resume(thread_state, lua.state, nargs);
if ret != ffi::LUA_OK && ret != ffi::LUA_YIELD {
protect_lua_closure(lua.state, 0, 0, |_| {
error_traceback(thread_state);
0
})?;
return Err(pop_error(thread_state, ret));
}
let nresults = ffi::lua_gettop(thread_state);
let mut results = MultiValue::new();
ffi::lua_xmove(thread_state, lua.state, nresults);
assert_stack(lua.state, 2);
for _ in 0..nresults {
results.push_front(lua.pop_value());
}
results
};
R::from_lua_multi(results, lua)
}
/// Gets the status of the thread.
pub fn status(&self) -> ThreadStatus {
let lua = self.0.lua;
unsafe {
let _sg = StackGuard::new(lua.state);
assert_stack(lua.state, 1);
lua.push_ref(&self.0);
let thread_state = ffi::lua_tothread(lua.state, -1);
ffi::lua_pop(lua.state, 1);
let status = ffi::lua_status(thread_state);
if status != ffi::LUA_OK && status != ffi::LUA_YIELD {
ThreadStatus::Error
} else if status == ffi::LUA_YIELD || ffi::lua_gettop(thread_state) > 0 {
ThreadStatus::Resumable
} else {
ThreadStatus::Unresumable
}
}
}
}
impl<'lua> PartialEq for Thread<'lua> {
fn eq(&self, other: &Self) -> bool {
self.0 == other.0
}
}
|
