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Kyle-YeKyle-Ye
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Implement EnvironmentalModifier (#493)
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4 files changed

+152
-17
lines changed

4 files changed

+152
-17
lines changed

‎Sources/OpenSwiftUICore/Modifier/CustomViewModifier.swift‎

Lines changed: 3 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -161,13 +161,11 @@ extension ViewModifier {
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inputs: inout _GraphInputs,
162162
fields: DynamicPropertyCache.Fields
163163
) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
164-
let kind = Metadata(Self.self).kind
165-
switch kind {
166-
case .struct, .enum, .optional, .tuple:
167-
return ModifierBodyAccessor().makeBody(container: modifier, inputs: &inputs, fields: fields)
168-
default:
164+
guard Metadata(Self.self).isValueType else {
169165
preconditionFailure("view modifiers must be value types: \(Self.self)")
170166
}
167+
let accessor = ModifierBodyAccessor<Self>()
168+
return accessor.makeBody(container: modifier, inputs: &inputs, fields: fields)
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}
172170
}
173171

‎Sources/OpenSwiftUICore/Modifier/ViewModifier/EnvironmentalModifier.swift‎

Lines changed: 143 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,143 @@
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//
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// EnvironmentalModifier.swift
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// OpenSwiftUICore
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//
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// Audited for 6.5.4
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// Status: Complete
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// ID: A1B6966B83442495FADFE75F475ECBE2 (SwiftUICore)
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import OpenAttributeGraphShims
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// MARK: - EnvironmentalModifier
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/// A modifier that must resolve to a concrete modifier in an environment before
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/// use.
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@available(OpenSwiftUI_v1_0, *)
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public protocol EnvironmentalModifier: ViewModifier where Body == Never {
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/// The type of modifier to use after being resolved.
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associatedtype ResolvedModifier: ViewModifier
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/// Resolve to a concrete modifier in the given `environment`.
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func resolve(in environment: EnvironmentValues) -> ResolvedModifier
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@available(OpenSwiftUI_v3_0, *)
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static var _requiresMainThread: Bool { get }
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@available(OpenSwiftUI_v5_0, *)
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static var _tracksEnvironmentDependencies: Bool { get }
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}
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// MARK: - EnvironmentalModifier Default Implementations
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@available(OpenSwiftUI_v1_0, *)
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extension EnvironmentalModifier {
34+
nonisolated public static func _makeView(
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modifier: _GraphValue<Self>,
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inputs: _ViewInputs,
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body: @escaping (_Graph, _ViewInputs) -> _ViewOutputs
38+
) -> _ViewOutputs {
39+
var inputs = inputs
40+
let fields = DynamicPropertyCache.fields(of: Self.self)
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let (resolvedModifier, buffer) = makeResolvedModifier(modifier: modifier, inputs: &inputs.base, fields: fields)
42+
let outputs = ResolvedModifier.makeDebuggableView(
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modifier: resolvedModifier,
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inputs: inputs,
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body: body
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)
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if let buffer {
48+
buffer.traceMountedProperties(to: modifier, fields: fields)
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}
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return outputs
51+
}
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nonisolated public static func _makeViewList(
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modifier: _GraphValue<Self>,
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inputs: _ViewListInputs,
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body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
57+
) -> _ViewListOutputs {
58+
var inputs = inputs
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let fields = DynamicPropertyCache.fields(of: Self.self)
60+
let (resolvedModifier, buffer) = makeResolvedModifier(modifier: modifier, inputs: &inputs.base, fields: fields)
61+
let outputs = ResolvedModifier.makeDebuggableViewList(
62+
modifier: resolvedModifier,
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inputs: inputs,
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body: body
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)
66+
if let buffer {
67+
buffer.traceMountedProperties(to: modifier, fields: fields)
68+
}
69+
return outputs
70+
}
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72+
nonisolated private static func makeResolvedModifier(
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modifier: _GraphValue<Self>,
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inputs: inout _GraphInputs,
75+
fields: DynamicPropertyCache.Fields
76+
) -> (_GraphValue<ResolvedModifier>, _DynamicPropertyBuffer?) {
77+
guard Metadata(Self.self).isValueType else {
78+
preconditionFailure("Environmental modifiers must be value types: \(Self.self)")
79+
}
80+
var fields = fields
81+
if !fields.behaviors.contains(.requiresMainThread), !_requiresMainThread {
82+
fields.behaviors.formUnion(
83+
!fields.behaviors.contains(.allowsAsync) && isLinkedOnOrAfter(.v4) ? .allowsAsync : []
84+
)
85+
}
86+
let accessor = EnvironmentalBodyAccessor<Self>(
87+
environment: inputs.environment,
88+
tracksDependencies: _tracksEnvironmentDependencies
89+
)
90+
return accessor.makeBody(container: modifier, inputs: &inputs, fields: fields)
91+
}
92+
93+
@available(OpenSwiftUI_v3_0, *)
94+
public static var _requiresMainThread: Bool {
95+
true
96+
}
97+
98+
@available(OpenSwiftUI_v5_0, *)
99+
public static var _tracksEnvironmentDependencies: Bool {
100+
true
101+
}
102+
}
103+
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// MARK: - EnvironmentalBodyAccessor
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106+
private struct EnvironmentalBodyAccessor<V>: BodyAccessor where V: EnvironmentalModifier {
107+
typealias Container = V
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109+
typealias Body = V.ResolvedModifier
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@Attribute
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var environment: EnvironmentValues
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let tracker: PropertyList.Tracker
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let tracksDependencies: Bool
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init(
117+
environment: Attribute<EnvironmentValues>,
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tracksDependencies: Bool
119+
) {
120+
self._environment = environment
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self.tracker = .init()
122+
self.tracksDependencies = tracksDependencies
123+
}
124+
125+
func updateBody(of container: V, changed: Bool) {
126+
let (environment, environmentChanged) = $environment.changedValue()
127+
guard changed ||
128+
(
129+
environmentChanged && (
130+
!tracksDependencies ||
131+
tracker.hasDifferentUsedValues(environment.plist)
132+
)
133+
)
134+
else {
135+
return
136+
}
137+
tracker.reset()
138+
let newEnvironment = EnvironmentValues(environment.plist, tracker: tracker)
139+
setBody {
140+
container.resolve(in: newEnvironment)
141+
}
142+
}
143+
}

‎Sources/OpenSwiftUICore/View/CustomView.swift‎

Lines changed: 3 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -51,14 +51,11 @@ extension View {
5151
inputs: inout _GraphInputs,
5252
fields: DynamicPropertyCache.Fields
5353
) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
54-
let kind = Metadata(Self.self).kind
55-
switch kind {
56-
case .struct, .enum, .optional, .tuple:
57-
let accessor = ViewBodyAccessor<Self>()
58-
return accessor.makeBody(container: view, inputs: &inputs, fields: fields)
59-
default:
54+
guard Metadata(Self.self).isValueType else {
6055
preconditionFailure("views must be value types (either a struct or an enum); \(Self.self) is a class.")
6156
}
57+
let accessor = ViewBodyAccessor<Self>()
58+
return accessor.makeBody(container: view, inputs: &inputs, fields: fields)
6259
}
6360
}
6461

‎Sources/OpenSwiftUICore/View/VariadicView.swift‎

Lines changed: 3 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -348,14 +348,11 @@ extension _VariadicView.ViewRoot {
348348
inputs: inout _GraphInputs,
349349
fields: DynamicPropertyCache.Fields
350350
) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
351-
let kind = Metadata(Self.self).kind
352-
switch kind {
353-
case .struct, .enum, .optional, .tuple:
354-
let accessor = ViewRootBodyAccessor<Self>(list: list, contentSubgraph: .current!)
355-
return accessor.makeBody(container: root, inputs: &inputs, fields: fields)
356-
default:
351+
guard Metadata(Self.self).isValueType else {
357352
preconditionFailure("views root must be value types (either a struct or an enum); \(Self.self) is a class.")
358353
}
354+
let accessor = ViewRootBodyAccessor<Self>(list: list, contentSubgraph: .current!)
355+
return accessor.makeBody(container: root, inputs: &inputs, fields: fields)
359356
}
360357
}
361358

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