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Implement find-or-create for createMap / createCounter
TODO check code and tests TODO expose semantics so that we don't have to fish it out (minor)
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‎Sources/AblyLiveObjects/Internal/ObjectsPool.swift‎

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Original file line numberDiff line numberDiff line change
@@ -306,6 +306,97 @@ internal struct ObjectsPool {
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logger.log("applySyncObjectsPool completed. Pool now contains \(entries.count) objects", level: .debug)
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}
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/// Gets or creates a counter object in the pool, implementing the "find or create zero-value" behavior of RTO12h1.
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///
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/// - Parameters:
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/// - creationOperation: The ObjectCreationOperation containing the object ID and operation to merge
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/// - logger: The logger to use for any created LiveObject
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/// - userCallbackQueue: The callback queue to use for any created LiveObject
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/// - clock: The clock to use for any created LiveObject
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/// - Returns: The existing or newly created counter object
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internal mutating func getOrCreateCounter(
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creationOperation: ObjectCreationHelpers.ObjectCreationOperation,
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logger: AblyPlugin.Logger,
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userCallbackQueue: DispatchQueue,
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clock: SimpleClock,
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) -> InternalDefaultLiveCounter {
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// RTO12h1: While waiting for the publish operation to complete, the client library may have already received the echoed ObjectMessage operation
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// RTO12h2: If an object with the ObjectMessage.operation.objectId exists in the internal ObjectsPool, return it
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if let existingEntry = entries[creationOperation.objectID] {
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switch existingEntry {
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case let .counter(counter):
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return counter
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case .map:
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// TODO: Add the ability to statically reason about the type of pool entries in https://github.com/ably/ably-cocoa-liveobjects-plugin/issues/36
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preconditionFailure("Expected counter object with ID \(creationOperation.objectID) but found map object")
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}
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}
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// RTO12h3: Otherwise, if the object does not exist in the internal ObjectsPool:
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// RTO12h3a: Create a zero-value LiveCounter, set its objectId to ObjectMessage.operation.objectId, and merge the initial value
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let counter = InternalDefaultLiveCounter.createZeroValued(
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objectID: creationOperation.objectID,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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// Merge the initial value from the creation operation
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_ = counter.mergeInitialValue(from: creationOperation.operation)
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// RTO12h3b: Add the created LiveCounter instance to the internal ObjectsPool
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entries[creationOperation.objectID] = .counter(counter)
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// RTO12h3c: Return the created LiveCounter instance
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return counter
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}
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/// Gets or creates a map object in the pool, implementing the "find or create zero-value" behavior of RTO11h1.
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///
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/// - Parameters:
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/// - creationOperation: The ObjectCreationOperation containing the object ID and operation to merge
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/// - logger: The logger to use for any created LiveObject
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/// - userCallbackQueue: The callback queue to use for any created LiveObject
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/// - clock: The clock to use for any created LiveObject
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/// - Returns: The existing or newly created map object
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internal mutating func getOrCreateMap(
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creationOperation: ObjectCreationHelpers.ObjectCreationOperation,
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logger: AblyPlugin.Logger,
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userCallbackQueue: DispatchQueue,
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clock: SimpleClock,
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) -> InternalDefaultLiveMap {
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// RTO11h1: While waiting for the publish operation to complete, the client library may have already received the echoed ObjectMessage operation
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// RTO11h2: If an object with the ObjectMessage.operation.objectId exists in the internal ObjectsPool, return it
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if let existingEntry = entries[creationOperation.objectID] {
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switch existingEntry {
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case let .map(map):
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return map
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case .counter:
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// TODO: Add the ability to statically reason about the type of pool entries in https://github.com/ably/ably-cocoa-liveobjects-plugin/issues/36
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preconditionFailure("Expected map object with ID \(creationOperation.objectID) but found counter object")
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}
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}
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// RTO11h3: Otherwise, if the object does not exist in the internal ObjectsPool:
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// RTO11h3a: Create a zero-value LiveMap, set its objectId to ObjectMessage.operation.objectId, set its semantics to ObjectMessage.operation.map.semantics, and merge the initial value
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let map = InternalDefaultLiveMap.createZeroValued(
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objectID: creationOperation.objectID,
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semantics: creationOperation.operation.map?.semantics,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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// Merge the initial value from the creation operation
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_ = map.mergeInitialValue(from: creationOperation.operation, objectsPool: &self)
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// RTO11h3b: Add the created LiveMap instance to the internal ObjectsPool
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entries[creationOperation.objectID] = .map(map)
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// RTO11h3c: Return the created LiveMap instance
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return map
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}
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/// Removes all entries except the root, and clears the root's data. This is to be used when an `ATTACHED` ProtocolMessage indicates that the only object in a channel is an empty root map, per RTO4b.
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internal mutating func reset() {
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let root = root

‎Tests/AblyLiveObjectsTests/ObjectsPoolTests.swift‎

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Original file line numberDiff line numberDiff line change
@@ -367,4 +367,167 @@ struct ObjectsPoolTests {
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#expect(pool.entries["map:toremove@1"] == nil)
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}
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}
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/// Tests for the `getOrCreateCounter` and `getOrCreateMap` methods
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struct GetOrCreateTests {
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@Test
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func getOrCreateCounter_returnsExistingCounter() {
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let logger = TestLogger()
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let userCallbackQueue = DispatchQueue.main
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let clock = MockSimpleClock()
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// Create a counter in the pool first
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let existingCounter = InternalDefaultLiveCounter.createZeroValued(
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objectID: "counter:test@123",
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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var pool = ObjectsPool(
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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testsOnly_otherEntries: ["counter:test@123": .counter(existingCounter)],
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)
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// Create a creation operation with the same object ID as the existing counter
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let creationOperation = ObjectCreationHelpers.ObjectCreationOperation(
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objectID: "counter:test@123",
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operation: ObjectOperation(
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action: .known(.counterCreate),
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objectId: "counter:test@123",
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counter: WireObjectsCounter(count: NSNumber(value: 42.0)),
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nonce: "testnonce",
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initialValue: "{\"action\":3,\"counter\":{\"count\":42}}",
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),
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objectMessage: OutboundObjectMessage(
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operation: ObjectOperation(
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action: .known(.counterCreate),
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objectId: "counter:test@123",
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counter: WireObjectsCounter(count: NSNumber(value: 42.0)),
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nonce: "testnonce",
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initialValue: "{\"action\":3,\"counter\":{\"count\":42}}",
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),
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),
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)
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// Should return the existing counter
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let result = pool.getOrCreateCounter(
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creationOperation: creationOperation,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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#expect(result === existingCounter)
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}
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@Test
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func getOrCreateCounter_createsNewCounterWhenNotExists() {
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let logger = TestLogger()
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let userCallbackQueue = DispatchQueue.main
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let clock = MockSimpleClock()
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var pool = ObjectsPool(logger: logger, userCallbackQueue: userCallbackQueue, clock: clock)
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// Create a creation operation
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let creationOperation = ObjectCreationHelpers.creationOperationForLiveCounter(
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count: 42.0,
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timestamp: Date(),
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)
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// Should create a new counter
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let result = pool.getOrCreateCounter(
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creationOperation: creationOperation,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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#expect(result.objectID == creationOperation.objectID)
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#expect(pool.entries[creationOperation.objectID]?.counterValue === result)
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}
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@Test
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func getOrCreateMap_returnsExistingMap() {
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let logger = TestLogger()
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let userCallbackQueue = DispatchQueue.main
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let clock = MockSimpleClock()
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// Create a map in the pool first
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let existingMap = InternalDefaultLiveMap.createZeroValued(
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objectID: "map:test@123",
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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var pool = ObjectsPool(
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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testsOnly_otherEntries: ["map:test@123": .map(existingMap)],
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)
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// Create a creation operation with the same object ID as the existing map
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let creationOperation = ObjectCreationHelpers.ObjectCreationOperation(
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objectID: "map:test@123",
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operation: ObjectOperation(
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action: .known(.mapCreate),
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objectId: "map:test@123",
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map: ObjectsMap(
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semantics: .known(.lww),
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entries: [:],
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),
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nonce: "testnonce",
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initialValue: "{\"action\":0,\"map\":{\"semantics\":0,\"entries\":{}}}",
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),
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objectMessage: OutboundObjectMessage(
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operation: ObjectOperation(
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action: .known(.mapCreate),
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objectId: "map:test@123",
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map: ObjectsMap(
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semantics: .known(.lww),
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entries: [:],
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),
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nonce: "testnonce",
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initialValue: "{\"action\":0,\"map\":{\"semantics\":0,\"entries\":{}}}",
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),
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),
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)
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// Should return the existing map
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let result = pool.getOrCreateMap(
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creationOperation: creationOperation,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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#expect(result === existingMap)
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}
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@Test
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func getOrCreateMap_createsNewMapWhenNotExists() {
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let logger = TestLogger()
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let userCallbackQueue = DispatchQueue.main
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let clock = MockSimpleClock()
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var pool = ObjectsPool(logger: logger, userCallbackQueue: userCallbackQueue, clock: clock)
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// Create a creation operation
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let creationOperation = ObjectCreationHelpers.creationOperationForLiveMap(
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entries: [:],
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timestamp: Date(),
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)
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// Should create a new map
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let result = pool.getOrCreateMap(
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creationOperation: creationOperation,
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logger: logger,
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userCallbackQueue: userCallbackQueue,
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clock: clock,
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)
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#expect(result.objectID == creationOperation.objectID)
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#expect(pool.entries[creationOperation.objectID]?.mapValue === result)
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}
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}
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}

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