cartel_sqlite/engine/conn/
mod.rs

1use crate::{api, catalogs};
2use api::{exec, tx};
3use dope_fiber::abi;
4use dope_runtime::client;
5use phase::{Borrow, Live, Phase};
6use std::{marker, mem, ptr};
7
8mod phase;
9pub(crate) mod raw;
10
11/// An exclusive database capability bound to its installed application scope.
12///
13#[repr(transparent)]
14pub struct Connection<'app, 'local: 'app, 'd: 'local, I: catalogs::Catalog = catalogs::Empty> {
15    app: client::Bound<'app, 'd, Installed<'local, 'd, I>, ptr::NonNull<Live<'local, 'd, I>>>,
16}
17
18impl<'app, 'local: 'app, 'd: 'local, I: catalogs::Catalog> Connection<'app, 'local, 'd, I> {
19    const LAYOUT: () = {
20        let word = mem::size_of::<usize>();
21        assert!(mem::size_of::<Self>() == word);
22        assert!(mem::align_of::<Self>() == mem::align_of::<usize>());
23        assert!(mem::size_of::<Option<Self>>() == word);
24    };
25
26    fn try_new(
27        context: client::Context<'_, 'app, 'd, Installed<'local, 'd, I>>,
28    ) -> Result<Self, crate::Error> {
29        let (app, bound) = context.into_parts();
30        // SAFETY: the provider context retains this exact pinned application.
31        let phase = unsafe { &*app.get_ref().phase.as_ptr() };
32        let live = match phase {
33            Phase::Live(live) => live,
34            Phase::Closing(_) | Phase::Retiring(_) | Phase::Empty => {
35                return Err(crate::Error::LocalConnectionClosed);
36            }
37        };
38        match live.borrow.get() {
39            Borrow::Vacant => {}
40            Borrow::Borrowed => return Err(crate::Error::LocalConnectionBorrowed),
41            Borrow::Closed | Borrow::Closing => return Err(crate::Error::LocalConnectionClosed),
42        }
43        live.borrow.set(Borrow::Borrowed);
44        Ok(Self {
45            app: bound.bind(ptr::NonNull::from(live)),
46        })
47    }
48
49    fn state(&mut self) -> &mut api::State<'local, 'd, I> {
50        // SAFETY: this guard exclusively owns the borrowed phase until drop.
51        unsafe { &mut *self.app.as_ref().state.get() }
52    }
53
54    pub fn query(&mut self) -> exec::Query<'_, 'local, 'd, I> {
55        self.state().query()
56    }
57
58    pub fn transaction(
59        &mut self,
60    ) -> impl abi::Fiber<'d, Output = Result<tx::Transaction<'_, 'local, 'd, I>, crate::Error>>
61    + use<'_, 'app, 'local, 'd, I> {
62        self.state().transaction()
63    }
64}
65
66impl<I: catalogs::Catalog> Drop for Connection<'_, '_, '_, I> {
67    fn drop(&mut self) {
68        // SAFETY: Installed stays pinned for the application lease.
69        let live = unsafe { self.app.as_ref() };
70        live.borrow.set(live.borrow.get().returned());
71    }
72}
73
74impl<'query, 'app: 'query, 'local: 'app, 'd: 'local, I: catalogs::Catalog>
75    api::IntoQuery<'query, 'local, 'd, I> for &'query mut Connection<'app, 'local, 'd, I>
76{
77    fn into_query(self) -> exec::Query<'query, 'local, 'd, I> {
78        self.query()
79    }
80}
81
82/// Installed database application owned by one executor generation.
83pub struct Installed<'local, 'd: 'local, I: catalogs::Catalog> {
84    phase: ptr::NonNull<Phase<'local, 'd, I>>,
85    ownership: marker::PhantomData<(Phase<'local, 'd, I>, marker::PhantomPinned)>,
86}
87
88impl<'local, 'd: 'local, I: catalogs::Catalog> client::Provider<'d> for Installed<'local, 'd, I> {
89    type Client<'app>
90        = Result<Connection<'app, 'local, 'd, I>, crate::Error>
91    where
92        Self: 'app,
93        'd: 'app;
94
95    fn provide<'app>(context: client::Context<'_, 'app, 'd, Self>) -> Self::Client<'app>
96    where
97        Self: 'app,
98        'd: 'app,
99    {
100        Connection::try_new(context)
101    }
102}
103
104const _: () = Connection::<catalogs::Empty>::LAYOUT;
105
106const _: () = {
107    assert!(mem::size_of::<Installed<'_, '_, catalogs::Empty>>() == mem::size_of::<usize>());
108    assert!(mem::align_of::<Installed<'_, '_, catalogs::Empty>>() == mem::align_of::<usize>());
109};
cartel_sqlite/engine/conn/mod.rs

cartel_sqlite/engine/conn/
mod.rs
