From e35adee88e5e0a8096c36c04b49282f8a261e153 Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 21:31:13 +0200
Subject: [PATCH 1/9] Adding tests for AnyView initializer
---
Tests/OpenSwiftUITests/OpenSwiftUITests.swift | 30 +++++++++++++++----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/Tests/OpenSwiftUITests/OpenSwiftUITests.swift b/Tests/OpenSwiftUITests/OpenSwiftUITests.swift
index 0658af0..876b954 100644
--- a/Tests/OpenSwiftUITests/OpenSwiftUITests.swift
+++ b/Tests/OpenSwiftUITests/OpenSwiftUITests.swift
@@ -8,15 +8,35 @@ final class OpenSwiftUITests: XCTestCase {
Text("World")
}
- let body = HStack {
- if true {
- Text("Hello")
- }
- Text("World")
+ }
+
+ func testAnyViewFromValueWithInDoesNotYieldView() {
+ let anyView = AnyView(_fromValue: 42)
+ XCTAssertNil(anyView)
+ }
+
+ func testAnyViewFromValueWithTextYieldsAnyView() {
+ let expectedText = "Hello"
+ let value: Any = Text(expectedText)
+ let anyView = AnyView(_fromValue: value)
+ XCTAssertNotNil(anyView)
+
+ guard let storage = anyView?._storage as? AnyViewStorage<Text> else {
+ XCTFail("View storage is not an AnyViewStorage of Text")
+ return
+ }
+
+ switch storage._view._storage {
+ case .verbatim(let string):
+ XCTAssertEqual(string, expectedText)
+ case .anyTextStorage(let storage):
+ XCTAssertEqual(storage.storage, expectedText)
}
}
static var allTests = [
("testExample", testExample),
+ ("testAnyViewFromValueWithInDoesNotYieldView", testAnyViewFromValueWithInDoesNotYieldView),
+ ("testAnyViewFromValueWithTextYieldsAnyView", testAnyViewFromValueWithTextYieldsAnyView),
]
}
From 143be54eeafbef34b984e0dad38c5f7d9d9cc809 Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 21:31:54 +0200
Subject: [PATCH 2/9] Adding symbol lookup target in C
---
Package.swift | 5 ++++-
Sources/CSymbols/include/CSymbols.h | 7 +++++++
Sources/CSymbols/symbols.c | 13 +++++++++++++
3 files changed, 24 insertions(+), 1 deletion(-)
create mode 100644 Sources/CSymbols/include/CSymbols.h
create mode 100644 Sources/CSymbols/symbols.c
diff --git a/Package.swift b/Package.swift
index 7ec0d9c..37c77b6 100644
--- a/Package.swift
+++ b/Package.swift
@@ -24,7 +24,10 @@ let package = Package(
// Targets can depend on other targets in this package, and on products in packages which this package depends on.
.target(
name: "OpenSwiftUI",
- dependencies: ["CoreGraphicsShim"]),
+ dependencies: ["CoreGraphicsShim", "CSymbols"]),
+
+ .target(name: "CSymbols"),
+
.testTarget(
name: "OpenSwiftUITests",
dependencies: ["OpenSwiftUI"]),
diff --git a/Sources/CSymbols/include/CSymbols.h b/Sources/CSymbols/include/CSymbols.h
new file mode 100644
index 0000000..f14df88
--- /dev/null
+++ b/Sources/CSymbols/include/CSymbols.h
@@ -0,0 +1,7 @@
+
+#ifndef csymbols_h
+#define csymbols_h
+
+void *loadAddressForSymbol(const char *symbolName);
+
+#endif
diff --git a/Sources/CSymbols/symbols.c b/Sources/CSymbols/symbols.c
new file mode 100644
index 0000000..7050b32
--- /dev/null
+++ b/Sources/CSymbols/symbols.c
@@ -0,0 +1,13 @@
+
+#ifdef __linux__
+#define _GNU_SOURCE
+#endif
+
+#include <CSymbols.h>
+#include <stddef.h>
+#include <dlfcn.h>
+
+void *loadAddressForSymbol(const char *symbolName) {
+ void *handle = dlopen(NULL, RTLD_GLOBAL);
+ return dlsym(handle, symbolName);
+}
From 56e477a32db2cf3517e7b12f857ee979c6ae0c0b Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 21:45:58 +0200
Subject: [PATCH 3/9] Implementing AnyView.init(_fromValue:)
---
.../Views/AnyView+initFromValue.swift | 88 +++++++++++++++++++
Sources/OpenSwiftUI/Views/AnyView.swift | 4 -
2 files changed, 88 insertions(+), 4 deletions(-)
create mode 100644 Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
new file mode 100644
index 0000000..86690ea
--- /dev/null
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -0,0 +1,88 @@
+import CSymbols
+
+// MARK: AnyView init(_ fromValue: Any) implementation
+
+extension AnyView {
+
+ public init?(_fromValue value: Any) {
+ // Synthesize a fake protocol conformance record to AnyViewConvertible
+ let conformance = ProtocolConformanceRecord(type: type(of: value), witnessTable: 0)
+ let type = unsafeBitCast(conformance, to: AnyViewConvertible.Type.self)
+
+ // Call static function on that type, pretending it conforms to AnyViewConvertible
+ guard let view = type.anyView(from: value) else { return nil }
+ self = view
+ }
+
+}
+
+// MARK: - AnyViewConvertible
+
+// Extract metadata for the `View` Protocol via the mangled name.
+//
+// It needs to be done this way because the associated type
+// prevents us from using `View.Type`.
+private let viewMetadata: ProtocolMetadata = {
+ let module = "OpenSwiftUI"
+ let name = "View"
+ let postfix = "_p"
+ let mangled = "\(module.count)\(module)\(name.count)\(name)\(postfix)"
+ return ProtocolMetadata(type: _typeByName(mangled)!)
+}()
+
+private protocol AnyViewConvertible { }
+extension AnyViewConvertible {
+ static func anyView(from view: Any) -> AnyView? {
+ // Find witness table to View.
+ // This should be equivalent to saying `view as? View`, if it was allowed.
+ guard let witnessTable = _conformsToProtocol(Self.self, viewMetadata.protocolDescriptorVector) else { return nil }
+
+ let pointer = UnsafeMutablePointer<Self>.allocate(capacity: 1)
+ pointer.initialize(to: view as! Self)
+ return anyViewFactory(pointer, Self.self, witnessTable)
+ }
+}
+
+// MARK: - Protocol Runtime Information
+
+private struct ProtocolConformanceRecord {
+ let type: Any.Type
+ let witnessTable: Int
+}
+
+private struct ProtocolDescriptor { }
+
+private struct ProtocolMetadata {
+ let kind: Int
+ let layoutFlags: UInt32
+ let numberOfProtocols: UInt32
+ let protocolDescriptorVector: UnsafeMutablePointer<ProtocolDescriptor>
+
+ init(type: Any.Type) {
+ self = unsafeBitCast(type, to: UnsafeMutablePointer<Self>.self).pointee
+ }
+}
+
+@_silgen_name("swift_conformsToProtocol")
+private func _conformsToProtocol(
+ _ type: Any.Type,
+ _ protocolDescriptor: UnsafeMutablePointer<ProtocolDescriptor>
+) -> UnsafeRawPointer?
+
+// MARK: - Factory method for AnyView
+
+// This has to be public in order to be exported.
+@_silgen_name("_open_swift_ui_anyViewFactory")
+public func _anyViewFactory<C : View>(from view: C) -> AnyView {
+ return AnyView(view)
+}
+
+private typealias AnyViewFactory = @convention(thin) (UnsafeRawPointer, Any.Type, UnsafeRawPointer) ->(AnyView)
+
+// In order to call `_anyViewFactory` without knowing the Type at compile time
+// We can find the address of the function and call it ourselves
+private let anyViewFactory: AnyViewFactory = {
+ let symbolName = "_open_swift_ui_anyViewFactory".cString(using: .utf8)!
+ let pointer = loadAddressForSymbol(symbolName)
+ return unsafeBitCast(pointer, to: AnyViewFactory.self)
+}()
diff --git a/Sources/OpenSwiftUI/Views/AnyView.swift b/Sources/OpenSwiftUI/Views/AnyView.swift
index f6e60ee..7421646 100644
--- a/Sources/OpenSwiftUI/Views/AnyView.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView.swift
@@ -17,10 +17,6 @@ public struct AnyView: View {
_storage = AnyViewStorage<V>(view)
}
- public init?(_fromValue value: Any) {
- fatalError()
- }
-
public typealias Body = Never
public var body: Never {
fatalError()
From d998d4e5c96df72630f77e94f21129418a819a76 Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 21:46:42 +0200
Subject: [PATCH 4/9] Marking any view as done
---
README.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/README.md b/README.md
index f3fb993..a2c9faa 100644
--- a/README.md
+++ b/README.md
@@ -159,7 +159,7 @@ Xcode 11.2 or higher is required.
| Status | Name | Notes |
| --- | --- | --- |
-| ⚠️ | `struct AnyView` | `init?(_fromValue value: Any)` missing. |
+| ✅ | `struct AnyView` | |
| ✅ | `struct TupleView` | |
### Drawing and Animation
From c76b69e1f31f2c921afd65cb72197393f7198ace Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 23:04:56 +0200
Subject: [PATCH 5/9] Deallocate pointer when returning anyView
---
Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift | 1 +
1 file changed, 1 insertion(+)
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
index 86690ea..2c76c2b 100644
--- a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -39,6 +39,7 @@ extension AnyViewConvertible {
let pointer = UnsafeMutablePointer<Self>.allocate(capacity: 1)
pointer.initialize(to: view as! Self)
+ defer { pointer.deallocate() }
return anyViewFactory(pointer, Self.self, witnessTable)
}
}
From 4c96b8d5f31f2cc147e89a5bbc5f091d11db0e1c Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 21 May 2020 23:15:35 +0200
Subject: [PATCH 6/9] Using conformance record for clarity
---
Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
index 2c76c2b..7316dbe 100644
--- a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -36,11 +36,13 @@ extension AnyViewConvertible {
// Find witness table to View.
// This should be equivalent to saying `view as? View`, if it was allowed.
guard let witnessTable = _conformsToProtocol(Self.self, viewMetadata.protocolDescriptorVector) else { return nil }
+ let conformanceRecord = ProtocolConformanceRecord(type: Self.self,
+ witnessTable: Int(bitPattern: witnessTable))
let pointer = UnsafeMutablePointer<Self>.allocate(capacity: 1)
pointer.initialize(to: view as! Self)
defer { pointer.deallocate() }
- return anyViewFactory(pointer, Self.self, witnessTable)
+ return anyViewFactory(pointer, conformanceRecord)
}
}
@@ -78,7 +80,7 @@ public func _anyViewFactory<C : View>(from view: C) -> AnyView {
return AnyView(view)
}
-private typealias AnyViewFactory = @convention(thin) (UnsafeRawPointer, Any.Type, UnsafeRawPointer) ->(AnyView)
+private typealias AnyViewFactory = @convention(thin) (UnsafeRawPointer, ProtocolConformanceRecord) ->(AnyView)
// In order to call `_anyViewFactory` without knowing the Type at compile time
// We can find the address of the function and call it ourselves
From a5fea6b8687ff1b2fd7f011c01cc29144725f6de Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Sat, 23 May 2020 16:43:53 +0200
Subject: [PATCH 7/9] Using withUnsafePointer(to:) instead of allocating the
pointer ourselves
---
Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
index 7316dbe..b4f7707 100644
--- a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -39,10 +39,9 @@ extension AnyViewConvertible {
let conformanceRecord = ProtocolConformanceRecord(type: Self.self,
witnessTable: Int(bitPattern: witnessTable))
- let pointer = UnsafeMutablePointer<Self>.allocate(capacity: 1)
- pointer.initialize(to: view as! Self)
- defer { pointer.deallocate() }
- return anyViewFactory(pointer, conformanceRecord)
+ return withUnsafePointer(to: view as! Self) { pointer in
+ return anyViewFactory(pointer, conformanceRecord)
+ }
}
}
From e3750c59798b868d2a8cc17e5e45030ce35733c4 Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Thu, 2 Jul 2020 00:29:54 +0200
Subject: [PATCH 8/9] =?UTF-8?q?No=20longer=20using=20dlfcn.h=20to=20load?=
=?UTF-8?q?=20the=20symbol=20of=20the=20factory=20method=20but=20using=20C?=
=?UTF-8?q?=E2=80=99s=20extern=20function?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
Sources/CSymbols/include/CSymbols.h | 2 +-
Sources/CSymbols/symbols.c | 13 ++++---------
.../OpenSwiftUI/Views/AnyView+initFromValue.swift | 4 +---
3 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/Sources/CSymbols/include/CSymbols.h b/Sources/CSymbols/include/CSymbols.h
index f14df88..5888c76 100644
--- a/Sources/CSymbols/include/CSymbols.h
+++ b/Sources/CSymbols/include/CSymbols.h
@@ -2,6 +2,6 @@
#ifndef csymbols_h
#define csymbols_h
-void *loadAddressForSymbol(const char *symbolName);
+void *anyViewFactorySymbol();
#endif
diff --git a/Sources/CSymbols/symbols.c b/Sources/CSymbols/symbols.c
index 7050b32..2574d47 100644
--- a/Sources/CSymbols/symbols.c
+++ b/Sources/CSymbols/symbols.c
@@ -1,13 +1,8 @@
-#ifdef __linux__
-#define _GNU_SOURCE
-#endif
-
#include <CSymbols.h>
-#include <stddef.h>
-#include <dlfcn.h>
-void *loadAddressForSymbol(const char *symbolName) {
- void *handle = dlopen(NULL, RTLD_GLOBAL);
- return dlsym(handle, symbolName);
+extern void _open_swift_ui_anyViewFactory(void);
+
+void *anyViewFactorySymbol() {
+ return &_open_swift_ui_anyViewFactory;
}
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
index b4f7707..a519469 100644
--- a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -84,7 +84,5 @@ private typealias AnyViewFactory = @convention(thin) (UnsafeRawPointer, Protocol
// In order to call `_anyViewFactory` without knowing the Type at compile time
// We can find the address of the function and call it ourselves
private let anyViewFactory: AnyViewFactory = {
- let symbolName = "_open_swift_ui_anyViewFactory".cString(using: .utf8)!
- let pointer = loadAddressForSymbol(symbolName)
- return unsafeBitCast(pointer, to: AnyViewFactory.self)
+ return unsafeBitCast(anyViewFactorySymbol(), to: AnyViewFactory.self)
}()
From 7fe7eeed5296e7fb0f740b9fa7c8bf34ea31922d Mon Sep 17 00:00:00 2001
From: Mathias Quintero <me@quintero.io>
Date: Tue, 20 Oct 2020 00:08:50 +0200
Subject: [PATCH 9/9] Moving to using associated type requirements kit
---
Package.resolved | 25 ++++++
Package.swift | 5 +-
Sources/CSymbols/include/CSymbols.h | 7 --
Sources/CSymbols/symbols.c | 8 --
...iewAssociatedTypeRequirementsVisitor.swift | 20 +++++
.../Views/AnyView+initFromValue.swift | 84 ++-----------------
6 files changed, 54 insertions(+), 95 deletions(-)
create mode 100644 Package.resolved
delete mode 100644 Sources/CSymbols/include/CSymbols.h
delete mode 100644 Sources/CSymbols/symbols.c
create mode 100644 Sources/OpenSwiftUI/Associated Types/ViewAssociatedTypeRequirementsVisitor.swift
diff --git a/Package.resolved b/Package.resolved
new file mode 100644
index 0000000..7de78ae
--- /dev/null
+++ b/Package.resolved
@@ -0,0 +1,25 @@
+{
+ "object": {
+ "pins": [
+ {
+ "package": "AssociatedTypeRequirementsKit",
+ "repositoryURL": "https://github.com/nerdsupremacist/AssociatedTypeRequirementsKit.git",
+ "state": {
+ "branch": null,
+ "revision": "5c0b95758d2d65fdb98977ee1af5648d9d192a32",
+ "version": "0.2.0"
+ }
+ },
+ {
+ "package": "CoreGraphicsShim",
+ "repositoryURL": "https://github.com/Cosmo/CoreGraphicsShim.git",
+ "state": {
+ "branch": "master",
+ "revision": "d2aec4b41d4f92371198b9a382f35749254f0a80",
+ "version": null
+ }
+ }
+ ]
+ },
+ "version": 1
+}
diff --git a/Package.swift b/Package.swift
index 37c77b6..9285b17 100644
--- a/Package.swift
+++ b/Package.swift
@@ -18,15 +18,14 @@ let package = Package(
// Dependencies declare other packages that this package depends on.
// .package(url: /* package url */, from: "1.0.0"),
.package(url: "https://github.com/Cosmo/CoreGraphicsShim.git", .branch("master")),
+ .package(url: "https://github.com/nerdsupremacist/AssociatedTypeRequirementsKit.git", from: "0.2.0"),
],
targets: [
// Targets are the basic building blocks of a package. A target can define a module or a test suite.
// Targets can depend on other targets in this package, and on products in packages which this package depends on.
.target(
name: "OpenSwiftUI",
- dependencies: ["CoreGraphicsShim", "CSymbols"]),
-
- .target(name: "CSymbols"),
+ dependencies: ["CoreGraphicsShim", "AssociatedTypeRequirementsKit"]),
.testTarget(
name: "OpenSwiftUITests",
diff --git a/Sources/CSymbols/include/CSymbols.h b/Sources/CSymbols/include/CSymbols.h
deleted file mode 100644
index 5888c76..0000000
--- a/Sources/CSymbols/include/CSymbols.h
+++ /dev/null
@@ -1,7 +0,0 @@
-
-#ifndef csymbols_h
-#define csymbols_h
-
-void *anyViewFactorySymbol();
-
-#endif
diff --git a/Sources/CSymbols/symbols.c b/Sources/CSymbols/symbols.c
deleted file mode 100644
index 2574d47..0000000
--- a/Sources/CSymbols/symbols.c
+++ /dev/null
@@ -1,8 +0,0 @@
-
-#include <CSymbols.h>
-
-extern void _open_swift_ui_anyViewFactory(void);
-
-void *anyViewFactorySymbol() {
- return &_open_swift_ui_anyViewFactory;
-}
diff --git a/Sources/OpenSwiftUI/Associated Types/ViewAssociatedTypeRequirementsVisitor.swift b/Sources/OpenSwiftUI/Associated Types/ViewAssociatedTypeRequirementsVisitor.swift
new file mode 100644
index 0000000..c27cc71
--- /dev/null
+++ b/Sources/OpenSwiftUI/Associated Types/ViewAssociatedTypeRequirementsVisitor.swift
@@ -0,0 +1,20 @@
+import AssociatedTypeRequirementsVisitor
+
+/**
+ **For internal use only.** Use to be able to call a function on a view where you don't know the concrete type at Compile Time.
+ Implement `callAsFunction` and a version that can take `Any` will be included as an extension.
+
+ Useful for occassions where your intuition is to cast `Any` to `View`, but Swift will stop you due to the associated type requirement.
+
+ ```swift
+ guard let view = view as? View else { return }
+ // Do something
+ ```
+ */
+protocol ViewAssociatedTypeRequirementsVisitor: AssociatedTypeRequirementsVisitor {
+ associatedtype Visitor = ViewAssociatedTypeRequirementsVisitor
+ associatedtype Input = View
+ associatedtype Output
+
+ func callAsFunction<T : View>(_ value: T) -> Output
+}
diff --git a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
index a519469..a3de9cf 100644
--- a/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
+++ b/Sources/OpenSwiftUI/Views/AnyView+initFromValue.swift
@@ -1,88 +1,18 @@
-import CSymbols
-
-// MARK: AnyView init(_ fromValue: Any) implementation
+import Foundation
extension AnyView {
-
public init?(_fromValue value: Any) {
- // Synthesize a fake protocol conformance record to AnyViewConvertible
- let conformance = ProtocolConformanceRecord(type: type(of: value), witnessTable: 0)
- let type = unsafeBitCast(conformance, to: AnyViewConvertible.Type.self)
-
- // Call static function on that type, pretending it conforms to AnyViewConvertible
- guard let view = type.anyView(from: value) else { return nil }
+ guard let view = ViewTypeEraser.shared(value) else { return nil }
self = view
}
-
}
-// MARK: - AnyViewConvertible
-
-// Extract metadata for the `View` Protocol via the mangled name.
-//
-// It needs to be done this way because the associated type
-// prevents us from using `View.Type`.
-private let viewMetadata: ProtocolMetadata = {
- let module = "OpenSwiftUI"
- let name = "View"
- let postfix = "_p"
- let mangled = "\(module.count)\(module)\(name.count)\(name)\(postfix)"
- return ProtocolMetadata(type: _typeByName(mangled)!)
-}()
-
-private protocol AnyViewConvertible { }
-extension AnyViewConvertible {
- static func anyView(from view: Any) -> AnyView? {
- // Find witness table to View.
- // This should be equivalent to saying `view as? View`, if it was allowed.
- guard let witnessTable = _conformsToProtocol(Self.self, viewMetadata.protocolDescriptorVector) else { return nil }
- let conformanceRecord = ProtocolConformanceRecord(type: Self.self,
- witnessTable: Int(bitPattern: witnessTable))
-
- return withUnsafePointer(to: view as! Self) { pointer in
- return anyViewFactory(pointer, conformanceRecord)
- }
+private struct ViewTypeEraser: ViewAssociatedTypeRequirementsVisitor {
+ func callAsFunction<T: View>(_ value: T) -> AnyView {
+ return AnyView(value)
}
}
-// MARK: - Protocol Runtime Information
-
-private struct ProtocolConformanceRecord {
- let type: Any.Type
- let witnessTable: Int
+extension ViewTypeEraser {
+ static let shared = ViewTypeEraser()
}
-
-private struct ProtocolDescriptor { }
-
-private struct ProtocolMetadata {
- let kind: Int
- let layoutFlags: UInt32
- let numberOfProtocols: UInt32
- let protocolDescriptorVector: UnsafeMutablePointer<ProtocolDescriptor>
-
- init(type: Any.Type) {
- self = unsafeBitCast(type, to: UnsafeMutablePointer<Self>.self).pointee
- }
-}
-
-@_silgen_name("swift_conformsToProtocol")
-private func _conformsToProtocol(
- _ type: Any.Type,
- _ protocolDescriptor: UnsafeMutablePointer<ProtocolDescriptor>
-) -> UnsafeRawPointer?
-
-// MARK: - Factory method for AnyView
-
-// This has to be public in order to be exported.
-@_silgen_name("_open_swift_ui_anyViewFactory")
-public func _anyViewFactory<C : View>(from view: C) -> AnyView {
- return AnyView(view)
-}
-
-private typealias AnyViewFactory = @convention(thin) (UnsafeRawPointer, ProtocolConformanceRecord) ->(AnyView)
-
-// In order to call `_anyViewFactory` without knowing the Type at compile time
-// We can find the address of the function and call it ourselves
-private let anyViewFactory: AnyViewFactory = {
- return unsafeBitCast(anyViewFactorySymbol(), to: AnyViewFactory.self)
-}()