Update ViewGraph implementation (#58)

* Update GraphHost preference

* Update EmptyView

* Add LayoutDirection implementation

* Add SafeAreaInsets API

* Add RootGeometry

* Update ViewGraph instantiateOutputs

* Fix Linux build issue

.swiftformat

@@ -0,0 +1,86 @@
+--acronyms ID,URL,UUID
+--allman false
+--anonymousforeach convert
+--assetliterals visual-width
+--asynccapturing 
+--beforemarks 
+--binarygrouping 4,8
+--categorymark "MARK: %c"
+--classthreshold 0
+--closingparen balanced
+--closurevoid remove
+--commas always
+--conflictmarkers reject
+--decimalgrouping 3,6
+--elseposition same-line
+--emptybraces no-space
+--enumnamespaces always
+--enumthreshold 0
+--exponentcase lowercase
+--exponentgrouping disabled
+--extensionacl on-declarations
+--extensionlength 0
+--extensionmark "MARK: - %t + %c"
+--fractiongrouping disabled
+--fragment false
+--funcattributes preserve
+--generictypes 
+--groupedextension "MARK: %c"
+--guardelse auto
+--header ignore
+--hexgrouping 4,8
+--hexliteralcase uppercase
+--ifdef no-indent
+--importgrouping alpha
+--indent 4
+--indentcase false
+--indentstrings false
+--lifecycle 
+--lineaftermarks true
+--linebreaks lf
+--markcategories true
+--markextensions always
+--marktypes always
+--maxwidth none
+--modifierorder 
+--nevertrailing 
+--nospaceoperators 
+--nowrapoperators 
+--octalgrouping 4,8
+--onelineforeach ignore
+--operatorfunc spaced
+--organizetypes actor,class,enum,struct
+--patternlet hoist
+--ranges spaced
+--redundanttype inferred
+--self remove
+--selfrequired 
+--semicolons inline
+--shortoptionals always
+--smarttabs enabled
+--someany false
+--stripunusedargs always
+--structthreshold 0
+--swiftversion 5.10
+--tabwidth unspecified
+--throwcapturing 
+--trailingclosures 
+--trimwhitespace nonblank-lines
+--typeattributes preserve
+--typeblanklines remove
+--typemark "MARK: - %t"
+--varattributes preserve
+--voidtype void
+--wraparguments preserve
+--wrapcollections preserve
+--wrapconditions preserve
+--wrapeffects preserve
+--wrapenumcases always
+--wrapparameters default
+--wrapreturntype preserve
+--wrapternary default
+--wraptypealiases preserve
+--xcodeindentation disabled
+--yodaswap always
+--disable blankLineAfterImports,wrapMultilineStatementBraces
+--enable acronyms,blankLinesBetweenImports

Sources/OpenSwiftUI/Core/Data/VersionSeed.swift

@@ -47,6 +47,16 @@ struct VersionSeed: CustomStringConvertible {
         newValue.merge(seed)
         return newValue
     }
+
+    @inline(__always)
+    static func == (lhs: VersionSeed, rhs: VersionSeed) -> Bool {
+        lhs.value == rhs.value
+    }
+
+    @inline(__always)
+    static func != (lhs: VersionSeed, rhs: VersionSeed) -> Bool {
+        lhs.value != rhs.value
+    }
 }
 
 private func merge32(_ a: UInt32, _ b: UInt32) -> UInt32 {

Sources/OpenSwiftUI/Core/Graph/GraphHost.swift

@@ -17,7 +17,7 @@ class GraphHost {
 
     private(set) var data: Data
     private(set) var isInstantiated = false
-    private(set) var hostPreferenceValues: OptionalAttribute<PreferenceList>
+   /* private(set)*/ var hostPreferenceValues: OptionalAttribute<PreferenceList>
     private(set) var lastHostPreferencesSeed: VersionSeed = .invalid
     private var pendingTransactions: [AsyncTransaction] = []
     /*private(set)*/ var inTransaction = false
@@ -147,16 +147,33 @@ class GraphHost {
     }
 
     final func preferenceValue<Key: HostPreferenceKey>(_ key: Key.Type) -> Key.Value {
-        fatalError("TODO")
+        if data.hostPreferenceKeys.contains(key) {
+            return preferenceValues()[key].value
+        } else {
+            defer { removePreference(key) }
+            addPreference(key)
+            return preferenceValues()[key].value
+        }
     }
-    
+
     final func addPreference<Key: HostPreferenceKey>(_ key: Key.Type) {
-        fatalError("TODO")
+        OGGraph.withoutUpdate {
+            data.hostPreferenceKeys.add(key)
+        }
     }
-
+
+    final func removePreference<Key: HostPreferenceKey>(_ key: Key.Type) {
+        OGGraph.withoutUpdate {
+            data.hostPreferenceKeys.remove(key)
+        }
+    }
+
     final func updatePreferences() -> Bool {
-        // fatalError("TODO")
-        return false
+        let seed = hostPreferenceValues.value?.mergedSeed ?? .empty
+        let lastSeed = lastHostPreferencesSeed
+        let didUpdate = seed.isInvalid || lastSeed.isInvalid || (seed != lastSeed)
+        lastHostPreferencesSeed = seed
+        return didUpdate
     }
 
     final func updateRemovedState() {
@@ -203,11 +220,11 @@ class GraphHost {
         }
     }
 
-    final func uninstantiate(immediately: Bool) {
+    final func uninstantiate(immediately _: Bool) {
         guard isInstantiated else {
             return
         }
-        // TODO
+        // TODO:
     }
 
     final func graphInvalidation(from attribute: OGAttribute?) {
@@ -224,7 +241,7 @@ class GraphHost {
         } else {
             asyncTransaction(
                 transaction,
-                mutation: EmptyGraphMutation(), 
+                mutation: EmptyGraphMutation(),
                 style: ._1,
                 mayDeferUpdate: true
             )
@@ -264,7 +281,7 @@ class GraphHost {
 
     final func continueTransaction(_ body: @escaping () -> Void) {
         var host = self
-        while(!host.inTransaction) {
+        while !host.inTransaction {
             guard let parent = host.parentHost else {
                 asyncTransaction(
                     Transaction(),
@@ -349,7 +366,7 @@ private final class AsyncTransaction {
     func append<Mutation: GraphMutation>(_ mutation: Mutation) {
         // ``GraphMutation/combine`` is mutating function
         // So we use ``Array.subscript/_modify`` instead of ``Array.last/getter`` to mutate inline
-        if !mutations.isEmpty, mutations[mutations.count-1].combine(with: mutation) {
+        if !mutations.isEmpty, mutations[mutations.count - 1].combine(with: mutation) {
             return
         }
         mutations.append(mutation)

Sources/OpenSwiftUI/Core/Modifier/ViewModifier/SafeAreaInsetsModifier.swift

@@ -0,0 +1,13 @@
+//
+//  ViewBuilder.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2023
+//  Status: WIP
+
+struct _SafeAreaInsetsModifier: PrimitiveViewModifier/*, MultiViewModifier*/ {
+    var elements: [SafeAreaInsets.Element]
+    var nextInsets: SafeAreaInsets.OptionalValue?
+
+    var insets: EdgeInsets = .init() // FIXME
+}

Sources/OpenSwiftUI/Core/View/TODO/_ViewInputs.swift

@@ -7,5 +7,5 @@ public struct _ViewInputs {
     var position: Attribute<ViewOrigin>
     var containerPosition: Attribute<ViewOrigin>
     var size: Attribute<ViewSize>
-    // var safeAreaInsets: OptionalAttribute<SafeAreaInsets>
+    var safeAreaInsets: OptionalAttribute<SafeAreaInsets>
 }