Additions to enable CLI support

Examples/apps/SegmentUIKitExample/SegmentUIKitExample/AppDelegate.swift

@@ -28,6 +28,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
         Analytics.support.track(name: "test event")
 
+        Analytics.main.screen(title: "home screen shown", category: nil, properties: nil)
 
         return true
     }

Examples/other_plugins/CellularCarrier.swift

@@ -59,7 +59,7 @@ class CellularCarrier: Plugin {
     func execute<T: RawEvent>(event: T?) -> T? {
         guard var workingEvent = event else { return event }
 
-        if let isCellular: Bool = workingEvent.context?[keyPath: "network"],
+        if let isCellular: Bool = workingEvent.context?[keyPath: "network.cellular"],
             isCellular,
            let carriers = self.carriers
         {

Sources/Segment/Analytics.swift

@@ -157,3 +157,43 @@ extension Analytics {
     }
 
 }
+
+extension Analytics {
+    /// Determine if there are any events that have yet to be sent to Segment
+    public var hasUnsentEvents: Bool {
+        if let segmentDest = self.find(pluginType: SegmentDestination.self) {
+            if segmentDest.pendingUploads > 0 {
+                return true
+            }
+            if segmentDest.eventCount > 0 {
+                return true
+            }
+        }
+
+        if let files = storage.read(Storage.Constants.events) {
+            if files.count > 0 {
+                return true
+            }
+        }
+
+        return false
+    }
+
+    /// Provides a list of finished, but unsent events.
+    public var pendingUploads: [URL]? {
+        return storage.read(Storage.Constants.events)
+    }
+
+    /// Wait until the Analytics object has completed startup.
+    /// This method is primarily useful for command line utilities where
+    /// it's desirable to wait until the system is up and running
+    /// before executing commands.  GUI apps could potentially use this via
+    /// a background thread if needed.
+    public func waitUntilStarted() {
+        if let startupQueue = find(pluginType: StartupQueue.self) {
+            while startupQueue.running != true {
+                RunLoop.main.run(until: Date.distantPast)
+            }
+        }
+    }
+}

Sources/Segment/Plugins/SegmentDestination.swift

@@ -47,7 +47,7 @@ public class SegmentDestination: DestinationPlugin {
     private var apiKey: String? = nil
     private var apiHost: String? = nil
 
-    @Atomic private var eventCount: Int = 0
+    @Atomic internal var eventCount: Int = 0
     internal var flushTimer: QueueTimer? = nil
 
     internal func initialSetup() {
@@ -99,7 +99,6 @@ public class SegmentDestination: DestinationPlugin {
         storage.write(.events, value: event)
         eventCount += 1
         if eventCount >= analytics.configuration.values.flushAt {
-            eventCount = 0
             flush()
         }
     }
@@ -112,6 +111,7 @@ public class SegmentDestination: DestinationPlugin {
         // Read events from file system
         guard let data = storage.read(Storage.Constants.events) else { return }
 
+        eventCount = 0
         cleanupUploads()
 
         analytics.log(message: "Uploads in-progress: \(pendingUploads)")
@@ -124,6 +124,7 @@ public class SegmentDestination: DestinationPlugin {
                     switch result {
                         case .success(_):
                             storage.remove(file: url)
+                            self.cleanupUploads()
                         default:
                             analytics.logFlush()
                     }

Sources/Segment/Plugins/StartupQueue.swift

@@ -8,14 +8,14 @@
 import Foundation
 import Sovran
 
-internal class StartupQueue: Plugin, Subscriber {
+public class StartupQueue: Plugin, Subscriber {
     static let maxSize = 1000
 
-    @Atomic var running: Bool = false
+    @Atomic public var running: Bool = false
 
-    let type: PluginType = .before
+    public let type: PluginType = .before
 
-    var analytics: Analytics? = nil {
+    public var analytics: Analytics? = nil {
         didSet {
             analytics?.store.subscribe(self, handler: runningUpdate)
         }
@@ -26,7 +26,7 @@ internal class StartupQueue: Plugin, Subscriber {
 
     required init() { }
 
-    func execute<T: RawEvent>(event: T?) -> T? {
+    public func execute<T: RawEvent>(event: T?) -> T? {
         if running == false, let e = event  {
             // timeline hasn't started, so queue it up.
             syncQueue.sync {

Sources/Segment/Utilities/JSON.swift

@@ -397,7 +397,7 @@ extension JSON {
                             do {
                                 result = try JSONDecoder().decode(T.self, from: jsonData)
                             } catch {
-                                Analytics.segmentLog(message: "Unable to decode object to a Codable: \(error)", kind: .error)
+                                Analytics.segmentLog(message: "Unable to decode object (\(keyPath)) to a Codable: \(error)", kind: .error)
                             }
                         }
                         if result == nil {

Sources/Segment/Utilities/Storage.swift

@@ -285,6 +285,10 @@ extension Storage {
     }
 
     private func finish(file: URL) {
+        if self.fileHandle == nil {
+            self.fileHandle = try? FileHandle(forWritingTo: file)
+        }
+
         guard let fileHandle = self.fileHandle else {
             // we haven't actually started a file yet and being told to flush
             // so ignore it and get out.