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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
/// Tracks the life times of `LifetimeTracked` instances, providing a method
/// to validate checkpoints where no instances should exist.
///
/// - Note: `LifetimeTracker` is not designed for multithreaded use. Trying to
/// instantiate or deinitialize instances belonging to the same tracker
/// from multiple concurrent threads (or reentrantly) will lead to
/// exclusivity violations and therefore undefined behavior.
public class LifetimeTracker {
public internal(set) var instances = 0
var _nextSerialNumber = 0
public init() {}
deinit {
check()
}
public func check(file: StaticString = #file, line: UInt = #line) {
expectEqual(instances, 0,
"Potential leak of \(instances) objects",
file: file, line: line)
}
public func instance<Payload>(for payload: Payload) -> LifetimeTracked<Payload> {
LifetimeTracked(payload, for: self)
}
public func instances<S: Sequence>(for items: S) -> [LifetimeTracked<S.Element>] {
return items.map { LifetimeTracked($0, for: self) }
}
public func instances<S: Sequence, T>(
for items: S, by transform: (S.Element) -> T
) -> [LifetimeTracked<T>] {
items.map { instance(for: transform($0)) }
}
}
@inlinable
public func withLifetimeTracking<R>(
file: StaticString = #file,
line: UInt = #line,
_ body: (LifetimeTracker) throws -> R
) rethrows -> R {
let tracker = LifetimeTracker()
defer { tracker.check(file: file, line: line) }
return try body(tracker)
}
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