Implement FirestoreErrorCode

Sources/FirebaseFirestore/DocumentReference+Swift.swift

@@ -68,7 +68,7 @@ extension DocumentReference {
       self, { snapshot, errorCode, errorMessage, pvListener in
         let callback = Unmanaged<AnyObject>.fromOpaque(pvListener!).takeUnretainedValue() as! ListenerCallback
 
-        let error = NSError.firestore(errorCode, errorMessage: errorMessage)
+        let error = FirestoreErrorCode(errorCode, errorMessage: errorMessage)
         // We only return a snapshot if the error code isn't 0 (aka the 'ok' error code)
         let returned = error == nil ? snapshot?.pointee : nil
 

Sources/FirebaseFirestore/FirestoreErrorCode.swift

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+public struct FirestoreErrorCode: Error {
+  public typealias Code = firebase.firestore.Error
+
+  public let code: Code
+  public let localizedDescription: String
+
+  public init(_ error: firebase.firestore.Error, errorMessage: String?) {
+    code = error
+    localizedDescription = errorMessage ?? "\(code.rawValue)"
+  }
+
+  public init?(_ error: firebase.firestore.Error?, errorMessage: UnsafePointer<CChar>? = nil) {
+    guard let actualError = error, actualError.rawValue != 0 else { return nil }
+    var errorMessageString: String?
+    if let errorMessage {
+      errorMessageString = .init(cString: errorMessage)
+    }
+    self.init(actualError, errorMessage: errorMessageString)
+  }
+}
+
+extension FirestoreErrorCode: Equatable {}
+
+// Unfortunately `Error` is not defined as a `enum class` so we need to add
+// these wrappers.
+extension FirestoreErrorCode.Code {
+  public static var ok: Self { firebase.firestore.kErrorOk }
+  public static var none: Self { firebase.firestore.kErrorNone }
+  public static var cancelled: Self { firebase.firestore.kErrorCancelled }
+  public static var unknown: Self { firebase.firestore.kErrorUnknown }
+  public static var invalidArgument: Self { firebase.firestore.kErrorInvalidArgument }
+  public static var deadlineExceeded: Self { firebase.firestore.kErrorDeadlineExceeded }
+  public static var notFound: Self { firebase.firestore.kErrorNotFound }
+  public static var alreadyExists: Self { firebase.firestore.kErrorAlreadyExists }
+  public static var permissionDenied: Self { firebase.firestore.kErrorPermissionDenied }
+  public static var resourceExhausted: Self { firebase.firestore.kErrorResourceExhausted }
+  public static var failedPrecondition: Self { firebase.firestore.kErrorFailedPrecondition }
+  public static var aborted: Self { firebase.firestore.kErrorAborted }
+  public static var outOfRange: Self { firebase.firestore.kErrorOutOfRange }
+  public static var unimplemented: Self { firebase.firestore.kErrorUnimplemented }
+  public static var `internal`: Self { firebase.firestore.kErrorInternal }
+  public static var unavailable: Self { firebase.firestore.kErrorUnavailable }
+  public static var dataLoss: Self { firebase.firestore.kErrorDataLoss }
+  public static var unauthenticated: Self { firebase.firestore.kErrorUnauthenticated }
+}

Sources/FirebaseFirestore/Query+Swift.swift

@@ -64,7 +64,7 @@ extension QueryProtocol {
       _asQuery, { snapshot, errorCode, errorMessage, pvListener in
         let callback = Unmanaged<AnyObject>.fromOpaque(pvListener!).takeUnretainedValue() as! ListenerCallback
 
-        let error = NSError.firestore(errorCode, errorMessage: errorMessage)
+        let error = FirestoreErrorCode(errorCode, errorMessage: errorMessage)
         // We only return a snapshot if the error code isn't 0 (aka the 'ok' error code)
         let returned = error == nil ? snapshot?.pointee : nil
 

Sources/FirebaseFirestore/Transaction+Swift.swift

@@ -45,7 +45,7 @@ extension Transaction {
     let snapshot = Get(document, &error, &errorMessage)
 
     if error != firebase.firestore.kErrorNone {
-      throw NSError.firestore(error, errorMessage: String(errorMessage))
+      throw FirestoreErrorCode(error, errorMessage: String(errorMessage))
     }
 
     return snapshot