Allow to dynamically load and unload Modules

.github/workflows/build-and-test.yml

@@ -85,3 +85,5 @@ jobs:
     uses: StanfordSpezi/.github/.github/workflows/create-and-upload-coverage-report.yml@v2
     with:
       coveragereports: Spezi-Package-iOS.xcresult Spezi-Package-watchOS.xcresult Spezi-Package-visionOS.xcresult Spezi-Package-tvOS.xcresult Spezi-Package-macOS.xcresult TestApp-iOS.xcresult TestApp-visionOS.xcresult
+    secrets:
+      token: ${{ secrets.CODECOV_TOKEN }}

Sources/Spezi/Capabilities/ApplicationPropertyWrapper.swift

@@ -44,6 +44,11 @@ extension _ApplicationPropertyWrapper: SpeziPropertyWrapper {
             self.shadowCopy = spezi[keyPath: keyPath]
         }
     }
+
+    func clear() {
+        spezi = nil
+        shadowCopy = nil
+    }
 }
 
 

Sources/Spezi/Capabilities/Communication/CollectPropertyWrapper.swift

@@ -38,6 +38,17 @@ public class _CollectPropertyWrapper<Value> {
 }
 
 
+extension _CollectPropertyWrapper: StorageValueCollector {
+    public func retrieve<Repository: SharedRepository<SpeziAnchor>>(from repository: Repository) {
+        injectedValues = repository[CollectedModuleValues<Value>.self]?.map { $0.value } ?? []
+    }
+
+    func clear() {
+        injectedValues = nil
+    }
+}
+
+
 extension Module {
     /// The `@Collect` property wrapper can be used to retrieve data communicated by other `Module`s.
     ///
@@ -63,10 +74,3 @@ extension Module {
     /// ```
     public typealias Collect = _CollectPropertyWrapper
 }
-
-
-extension _CollectPropertyWrapper: StorageValueCollector {
-    public func retrieve<Repository: SharedRepository<SpeziAnchor>>(from repository: Repository) {
-        injectedValues = repository[CollectedModuleValue<Value>.self] ?? []
-    }
-}

Sources/Spezi/Capabilities/Communication/CollectedModuleValues.swift

@@ -0,0 +1,79 @@
+//
+// This source file is part of the Stanford Spezi open-source project
+//
+// SPDX-FileCopyrightText: 2023 Stanford University and the project authors (see CONTRIBUTORS.md)
+//
+// SPDX-License-Identifier: MIT
+//
+
+import SpeziFoundation
+
+protocol AnyCollectModuleValue {
+    associatedtype Value
+
+    var moduleReference: ModuleReference { get }
+}
+
+protocol AnyCollectModuleValues {
+    associatedtype Value
+
+    var values: [any AnyCollectModuleValue] { get }
+
+    mutating func removeValues(from module: any Module) -> Bool
+
+    func store(into storage: inout SpeziStorage)
+}
+
+
+struct CollectModuleValue<Value>: AnyCollectModuleValue {
+    let value: Value
+    let moduleReference: ModuleReference
+
+    init(_ value: Value) {
+        self.value = value
+
+        guard let module = Spezi.moduleInitContext else {
+            preconditionFailure("Tried to initialize CollectModuleValue with unknown module init context.")
+        }
+        self.moduleReference = ModuleReference(module)
+    }
+}
+
+/// Provides the ``KnowledgeSource`` for any value we store in the ``SpeziStorage`` that is
+/// provided or request from am ``Module``.
+///
+/// For more information, look at the ``Module/Provide`` or ``Module/Collect`` property wrappers.
+struct CollectedModuleValues<ModuleValue>: DefaultProvidingKnowledgeSource {
+    typealias Anchor = SpeziAnchor
+
+    typealias Value = [CollectModuleValue<ModuleValue>]
+
+
+    static var defaultValue: Value {
+        []
+    }
+}
+
+
+extension Array: AnyCollectModuleValues where Element: AnyCollectModuleValue {
+    typealias Value = Element.Value
+
+    var values: [any AnyCollectModuleValue] {
+        self
+    }
+
+    mutating func removeValues(from module: any Module) -> Bool {
+        let previousCount = count
+        removeAll { entry in
+            entry.moduleReference == ModuleReference(module)
+        }
+        return previousCount != count
+    }
+
+    func store(into storage: inout SpeziStorage) {
+        guard let values = self as? [CollectModuleValue<Value>] else {
+            preconditionFailure("Unexpected array type: \(type(of: self))")
+        }
+        storage[CollectedModuleValues<Value>.self] = values
+    }
+}

Sources/Spezi/Capabilities/Communication/ProvidePropertyWrapper.swift

@@ -116,27 +116,38 @@ extension _ProvidePropertyWrapper: StorageValueProvider {
         } else if let wrapperWithArray = self as? CollectionBasedProvideProperty {
             wrapperWithArray.collectArrayElements(into: &repository)
         } else {
-            // concatenation is handled by the `CollectedModuleValue/reduce` implementation.
-            repository[CollectedModuleValue<Value>.self] = [storedValue]
+            repository.appendValues([CollectModuleValue(storedValue)])
         }
 
         collected = true
     }
+
+    func clear() {
+        collected = false
+    }
 }
 
 
 extension _ProvidePropertyWrapper: CollectionBasedProvideProperty where Value: AnyArray {
     func collectArrayElements<Repository: SharedRepository<SpeziAnchor>>(into repository: inout Repository) {
-        // concatenation is handled by the `CollectedModuleValue/reduce` implementation.
-        repository[CollectedModuleValue<Value.Element>.self] = storedValue.unwrappedArray
+        repository.appendValues(storedValue.unwrappedArray.map { CollectModuleValue($0) })
     }
 }
 
 
 extension _ProvidePropertyWrapper: OptionalBasedProvideProperty where Value: AnyOptional {
     func collectOptional<Repository: SharedRepository<SpeziAnchor>>(into repository: inout Repository) {
         if let storedValue = storedValue.unwrappedOptional {
-            repository[CollectedModuleValue<Value.Wrapped>.self] = [storedValue]
+            repository.appendValues([CollectModuleValue(storedValue)])
         }
     }
 }
+
+
+extension SharedRepository where Anchor == SpeziAnchor {
+    fileprivate mutating func appendValues<Value>(_ values: [CollectModuleValue<Value>]) {
+        var current = self[CollectedModuleValues<Value>.self]
+        current.append(contentsOf: values)
+        self[CollectedModuleValues<Value>.self] = current
+    }
+}

Sources/Spezi/Capabilities/Communication/StorageValueCollector.swift

@@ -13,7 +13,7 @@ import SpeziFoundation
 /// data provided by other ``Module``s.
 ///
 /// Data requested through a Storage Value Collector might be provided through a ``_StorageValueProvider``.
-protocol StorageValueCollector {
+protocol StorageValueCollector: SpeziPropertyWrapper {
     /// This method is called to retrieve all the requested values from the given ``SpeziStorage`` repository.
     /// - Parameter repository: Provides access to the ``SpeziStorage`` repository for read access.
     func retrieve<Repository: SharedRepository<SpeziAnchor>>(from repository: Repository)

Sources/Spezi/Capabilities/Communication/StorageValueProvider.swift

@@ -13,7 +13,7 @@ import SpeziFoundation
 /// data with other ``Module``s.
 ///
 /// Data provided through a Storage Value Provider can be retrieved through a ``_StorageValueCollector``.
-protocol StorageValueProvider {
+protocol StorageValueProvider: SpeziPropertyWrapper {
     /// This method is called to collect all provided values into the given ``SpeziStorage`` repository.
     /// - Parameter repository: Provides access to the ``SpeziStorage`` repository.
     func collect<Repository: SharedRepository<SpeziAnchor>>(into repository: inout Repository)

Sources/Spezi/Capabilities/Observable/ModelPropertyWrapper.swift

@@ -47,6 +47,13 @@ public class _ModelPropertyWrapper<Model: Observable & AnyObject> {
 }
 
 
+extension _ModelPropertyWrapper: SpeziPropertyWrapper {
+    func clear() {
+        collected = false
+    }
+}
+
+
 extension Module {
     /// Places an observable object in the global view environment.
     ///

Sources/Spezi/Capabilities/ViewModifier/ModifierPropertyWrapper.swift

@@ -46,6 +46,13 @@ public class _ModifierPropertyWrapper<Modifier: ViewModifier> {
 }
 
 
+extension _ModifierPropertyWrapper: SpeziPropertyWrapper {
+    func clear() {
+        collected = false
+    }
+}
+
+
 extension Module {
     /// Provide a SwiftUI `ViewModifier` to modify the global view hierarchy.
     ///

Sources/Spezi/Capabilities/ViewModifier/ViewModifierProvider.swift

@@ -28,7 +28,7 @@ protocol ViewModifierProvider {
 
     /// Defines the placement order of this view modifier.
     ///
-    /// `ViewModifier`s retrieved from a ``Module` might modify the view hierarchy in a different order than they
+    /// `ViewModifier`s retrieved from a ``Module`` might modify the view hierarchy in a different order than they
     /// are supplied. This is important to, e.g., ensure that modifiers injecting model types are placed at the outermost
     /// level to ensure other view modifiers supplied by the module can access those model types.
     var placement: ModifierPlacement { get }