1 files changed, 42 insertions, 0 deletions
diff --git a/Sources/SleepInhibition.swift b/Sources/SleepInhibition.swift
new file mode 100644
index 0000000..0d9a05e
--- /dev/null
+++ b/Sources/SleepInhibition.swift
@@ -0,0 +1,42 @@
+#if canImport(IOKit.pwr_mgt)
+import IOKit.pwr_mgt
+
+func withSleepInhibited(operation: () async throws -> Void) async throws {
+  let assertionID = try {
+    var assertionID = IOPMAssertionID(0)
+    let ioReturn = IOPMAssertionCreateWithDescription(
+      kIOPMAssertionTypePreventUserIdleSystemSleep as CFString,
+      "caffeinate-downloads" as CFString,
+      "There are files being downloaded" as CFString,
+      nil, nil, 0, nil,
+      &assertionID
+    )
+    guard ioReturn == kIOReturnSuccess else {
+      throw SleepInhibitionError("failed to inhibit sleep", ioReturn)
+    }
+    return assertionID
+  }()
+
+  do {
+    try await operation()
+  } catch is CancellationError {
+  }
+
+  let ioReturn = IOPMAssertionRelease(assertionID)
+  guard ioReturn == kIOReturnSuccess else {
+    throw SleepInhibitionError("failed to allow sleep", ioReturn)
+  }
+}
+
+struct SleepInhibitionError: CustomStringConvertible, Error {
+    let description: String
+
+    init(_ description: String, _ code: IOReturn) {
+        if let code = mach_error_string(code) {
+            self.description = "\(description): \(String(cString: code))"
+        } else {
+            self.description = "\(description): \(code)"
+        }
+    }
+}
+#endif