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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use ffi_support::implement_into_ffi_by_pointer;
use interrupt_support::Interruptee;
use rusqlite::InterruptHandle;
use std::sync::{
atomic::{AtomicUsize, Ordering},
Arc,
};
// SeqCst is overkill for much of this, but whatever.
/// A Sync+Send type which can be used allow someone to interrupt an
/// operation, even if it happens while rust code (and not SQL) is
/// executing.
pub struct SqlInterruptHandle {
db_handle: InterruptHandle,
interrupt_counter: Arc<AtomicUsize>,
}
impl SqlInterruptHandle {
pub fn new(
db_handle: InterruptHandle,
interrupt_counter: Arc<AtomicUsize>,
) -> SqlInterruptHandle {
SqlInterruptHandle {
db_handle,
interrupt_counter,
}
}
pub fn interrupt(&self) {
self.interrupt_counter.fetch_add(1, Ordering::SeqCst);
self.db_handle.interrupt();
}
}
implement_into_ffi_by_pointer!(SqlInterruptHandle);
/// A helper that can be used to determine if an interrupt request has come in while
/// the object lives. This is used to avoid a case where we aren't running any
/// queries when the request to stop comes in, but we're still not done (for example,
/// maybe we've run some of the autocomplete matchers, and are about to start
/// running the others. If we rely solely on sqlite3_interrupt(), we'd miss
/// the message that we should stop).
#[derive(Debug)]
pub struct SqlInterruptScope {
// The value of the interrupt counter when the scope began
start_value: usize,
// This could be &'conn AtomicUsize, but it would prevent the connection
// from being mutably borrowed for no real reason...
ptr: Arc<AtomicUsize>,
}
impl SqlInterruptScope {
#[inline]
pub fn new(ptr: Arc<AtomicUsize>) -> Self {
let start_value = ptr.load(Ordering::SeqCst);
Self { start_value, ptr }
}
/// Add this as an inherent method to reduce the amount of things users have to bring in.
#[inline]
pub fn err_if_interrupted(&self) -> Result<(), interrupt_support::Interrupted> {
<Self as Interruptee>::err_if_interrupted(self)
}
}
impl Interruptee for SqlInterruptScope {
#[inline]
fn was_interrupted(&self) -> bool {
self.ptr.load(Ordering::SeqCst) != self.start_value
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_sync_send() {
fn is_sync<T: Sync>() {}
fn is_send<T: Send>() {}
// Make sure this compiles
is_sync::<SqlInterruptHandle>();
is_send::<SqlInterruptHandle>();
}
}
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