Files
taskwarrior-2.x/lib/src/taskmut.rs
2022-01-29 03:08:45 +00:00

68 lines
2.2 KiB
Rust

use crate::{status::TCStatus, string::TCString, uuid::TCUuid};
use taskchampion::{TaskMut, Replica};
use std::cell::RefMut;
/// A mutable task.
///
/// A mutable task carries an exclusive reference to the replica,
/// meaning that no other replica operations can be carried out while
/// the mutable task still exists.
pub struct TCTaskMut {
inner: TaskMut<'static>,
replica: RefMut<Replica>,
}
impl TCTaskMut {
/// Borrow a TCTaskMut from C as an argument.
///
/// # Safety
///
/// The pointer must not be NULL. It is the caller's responsibility to ensure that the
/// lifetime assigned to the reference and the lifetime of the TCTaskMut itself do not outlive
/// the lifetime promised by C.
pub(crate) unsafe fn from_arg_ref<'a>(tctask: *mut TCTaskMut) -> &'a mut Self {
debug_assert!(!tctask.is_null());
&mut *tctask
}
/// Convert this to a return value for handing off to C.
pub(crate) fn return_val(self) -> *mut TCTaskMut {
Box::into_raw(Box::new(self))
}
/// Create a new TCTaskMut, given a RefMut to the replica.
pub(crate) fn from_immut(task: Task, rep: RefMut<Replica>) -> Self {
// SAFETY:
// This ref will be embedded in the TaskMut, and we will hang onto
// the RefMut for that duration, guaranteeing no other mutable borrows.
let rep_ref: &'static mut = unsafe { rep.deref_mut() }
let task_mut = task.into_mut(rep_ref);
TCTaskMut {
inner: task_mut,
replica: rep,
}
}
}
impl From<TaskMut> for TCTaskMut {
fn from(rep: Replica) -> TCReplica {
TCReplica {
inner: RefCell::new(rep),
error: None,
}
}
}
/// Free a task. The given task must not be NULL. The task must not be used after this function
/// returns, and must not be freed more than once.
#[no_mangle]
pub extern "C" fn tc_task_mut_free(task: *mut TCTaskMut) {
debug_assert!(!task.is_null());
// SAFETY:
// - task is not NULL (promised by caller)
// - task's lifetime exceeds the drop (promised by caller)
// - task does not outlive this function (promised by caller)
drop(unsafe { Box::from_raw(task) });
}