Update Ghostgram features

Swiftgram/SGDeviceToken/BUILD

@@ -0,0 +1,18 @@
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library")
+
+swift_library(
+    name = "SGDeviceToken",
+    module_name = "SGDeviceToken",
+    srcs = glob([
+        "Sources/**/*.swift",
+    ]),
+    copts = [
+        "-warnings-as-errors",
+    ],
+    deps = [
+        "//submodules/SSignalKit/SwiftSignalKit:SwiftSignalKit",
+    ],
+    visibility = [
+        "//visibility:public",
+    ],
+)

Swiftgram/SGDeviceToken/Sources/File.swift

@@ -0,0 +1,31 @@
+import SwiftSignalKit
+import DeviceCheck
+
+public enum SGDeviceTokenError {
+    case unsupportedDevice
+    case generic(String)
+}
+
+public func getDeviceToken() -> Signal<String, SGDeviceTokenError> {
+    return Signal { subscriber in
+        let currentDevice = DCDevice.current
+        if currentDevice.isSupported {
+            currentDevice.generateToken { (data, error) in
+                guard error == nil else {
+                    subscriber.putError(.generic(error!.localizedDescription))
+                    return
+                }
+                if let tokenData = data {
+                    subscriber.putNext(tokenData.base64EncodedString())
+                    subscriber.putCompletion()
+                } else {
+                    subscriber.putError(.generic("Empty Token"))
+                }
+            }
+        } else {
+            subscriber.putError(.unsupportedDevice)
+        }
+        return ActionDisposable {
+        }
+    }
+}