1 files changed, 48 insertions, 0 deletions
diff --git a/Sources/SleepInhibitor.swift b/Sources/SleepInhibitor.swift
new file mode 100644
index 0000000..0cfe895
--- /dev/null
+++ b/Sources/SleepInhibitor.swift
@@ -0,0 +1,48 @@
+import IOKit.pwr_mgt
+
+actor SleepInhibitor {
+  var assertionID = IOPMAssertionID?.none
+  var isInhibitingSleep: Bool { self.assertionID != nil }
+
+  func create(name: String, details: String) throws {
+    guard self.assertionID == nil else {
+      return
+    }
+
+    var assertionID = IOPMAssertionID(0)
+    let ioReturn = IOPMAssertionCreateWithDescription(
+      kIOPMAssertionTypePreventUserIdleSystemSleep as CFString,
+      name as CFString,
+      details as CFString,
+      nil, nil, 0, nil,
+      &assertionID
+    )
+    guard ioReturn == kIOReturnSuccess else {
+      throw SleepInhibitorError(ioReturn: ioReturn)
+    }
+    self.assertionID = assertionID
+  }
+
+  func release() throws {
+    guard let assertionID = self.assertionID else {
+      return
+    }
+
+    let ioReturn = IOPMAssertionRelease(assertionID)
+    guard ioReturn == kIOReturnSuccess else {
+      throw SleepInhibitorError(ioReturn: ioReturn)
+    }
+    self.assertionID = nil
+  }
+}
+
+struct SleepInhibitorError: CustomStringConvertible, Error {
+  let ioReturn: IOReturn
+
+  var description: String {
+    guard let cString = mach_error_string(self.ioReturn) else {
+      return self.ioReturn.description
+    }
+    return String(cString: cString)
+  }
+}