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Sources/Internals.Mutext.swift

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+//
+//  Internals.Mutex.swift
+//  CoreStore
+//
+//  Copyright © 2026 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+import Synchronization
+import os
+
+
+// MARK: - Internals
+
+extension Internals {
+    
+    // MARK: - Mutex
+    
+    internal struct Mutex<Value: ~Copyable>: ~Copyable, @unchecked Sendable {
+        
+        // MARK: Internal
+        
+        init(_ initialValue: consuming sending Value) {
+            
+            self.storage = .init(initialValue)
+        }
+        
+        borrowing func withLock<Result, E>(
+            _ body: (inout sending Value) throws(E) -> sending Result
+        ) throws(E) -> sending Result
+        where E: Error, Result: ~Copyable {
+            
+            let storage = self.storage
+            storage.lock()
+            defer {
+                
+                storage.unlock()
+            }
+            return try body(&storage.value)
+        }
+        
+        borrowing func withLockUnchecked<Result, E>(
+            _ body: (inout sending Value) throws(E) -> Result
+        ) throws(E) -> sending Result
+        where E: Error {
+            
+            let storage = self.storage
+            storage.lock()
+            defer {
+                
+                storage.unlock()
+            }
+            return try body(&storage.value)
+        }
+        
+        
+        // MARK: Private
+        
+        private let storage: Storage
+        
+        
+        // MARK: - Storage
+        
+        fileprivate final class Storage {
+            
+            // MARK: FilePrivate
+            
+            var value: Value
+            
+            init(_ initialValue: consuming sending Value) {
+                
+                self.unfairLock = .allocate(capacity: 1)
+                self.unfairLock.initialize(to: os_unfair_lock())
+                self.value = initialValue
+            }
+            
+            deinit {
+                
+                self.unfairLock.deinitialize(count: 1)
+                self.unfairLock.deallocate()
+            }
+            
+            func lock() {
+                os_unfair_lock_lock(self.unfairLock)
+            }
+
+            func unlock() {
+                os_unfair_lock_unlock(self.unfairLock)
+            }
+            
+            
+            // MARK: Private
+            
+            private let unfairLock: os_unfair_lock_t
+        }
+    }
+}