Serial executor warnings (#94)

* wip * Fix some executor warnings * wip
pointfreeco · May 26, 2023 · de1a984 · de1a984
1 parent 25c9b67
commit de1a984
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Showing 2 changed files with 20 additions and 16 deletions.
diff --git a/Dependencies.xcworkspace/xcshareddata/swiftpm/Package.resolved b/Dependencies.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -5,8 +5,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/combine-schedulers",
       "state" : {
-        "revision" : "882ac01eb7ef9e36d4467eb4b1151e74fcef85ab",
-        "version" : "0.9.1"
+        "revision" : "0625932976b3ae23949f6b816d13bd97f3b40b7c",
+        "version" : "0.10.0"
       }
     },
     {
@@ -32,8 +32,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-clocks",
       "state" : {
-        "revision" : "20b25ca0dd88ebfb9111ec937814ddc5a8880172",
-        "version" : "0.2.0"
+        "revision" : "f9acfa1a45f4483fe0f2c434a74e6f68f865d12d",
+        "version" : "0.3.0"
       }
     },
     {

diff --git a/Sources/Dependencies/ConcurrencySupport/MainSerialExecutor.swift b/Sources/Dependencies/ConcurrencySupport/MainSerialExecutor.swift
@@ -1,23 +1,27 @@
 #if !os(WASI) && !os(Windows)
   import Foundation
 
-  @_spi(Concurrency) public func withMainSerialExecutor<T>(
-    @_implicitSelfCapture operation: () async throws -> T
+  @_spi(Concurrency)
+  @MainActor
+  public func withMainSerialExecutor<T>(
+    @_implicitSelfCapture operation: @MainActor () async throws -> T
   ) async rethrows -> T {
-    guard let pointer = swift_task_enqueueGlobal_hook else { return try await operation() }
-    let hook = pointer.pointee
-    defer { pointer.pointee = hook }
-    pointer.pointee = { job, original in
+    let hook = swift_task_enqueueGlobal_hook
+    defer { swift_task_enqueueGlobal_hook = hook }
+    swift_task_enqueueGlobal_hook = { job, original in
       MainActor.shared.enqueue(job)
     }
     return try await operation()
   }
 
-  // here be dragons
-  private typealias Orig = @convention(thin) (UnownedJob) -> Void
-  private typealias Hook = @convention(thin) (UnownedJob, Orig) -> Void
-  private var swift_task_enqueueGlobal_hook: UnsafeMutablePointer<Hook>? = {
-    dlsym(dlopen(nil, 0), "swift_task_enqueueGlobal_hook")?
-      .assumingMemoryBound(to: Hook.self)
+  typealias Original = @convention(thin) (UnownedJob) -> Void
+  typealias Hook = @convention(thin) (UnownedJob, Original) -> Void
+  private let _swift_task_enqueueGlobal_hook: UnsafeMutablePointer<Hook?> = {
+    dlsym(dlopen(nil, 0), "swift_task_enqueueGlobal_hook").assumingMemoryBound(to: Hook?.self)
   }()
+
+  var swift_task_enqueueGlobal_hook: Hook? {
+    get { _swift_task_enqueueGlobal_hook.pointee }
+    set { _swift_task_enqueueGlobal_hook.pointee = newValue }
+  }
 #endif