Add consolidated log streamer

3 files changed, 90 insertions, 2 deletions

diff --git a/ios/MullvadVPN.xcodeproj/project.pbxproj b/ios/MullvadVPN.xcodeproj/project.pbxproj
index 6ce6bcc2c7..1052ad7602 100644
--- a/ios/MullvadVPN.xcodeproj/project.pbxproj
+++ b/ios/MullvadVPN.xcodeproj/project.pbxproj
@@ -90,6 +90,7 @@
 		5857F24724C882D700CF6F47 /* SelectLocationNavigationController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5857F24624C882D700CF6F47 /* SelectLocationNavigationController.swift */; };
 		585834F824D2BC1F00A8AF56 /* Logging in Frameworks */ = {isa = PBXBuildFile; productRef = 585834F724D2BC1F00A8AF56 /* Logging */; };
 		585834FC24D2BC9500A8AF56 /* Logging in Frameworks */ = {isa = PBXBuildFile; productRef = 585834FB24D2BC9500A8AF56 /* Logging */; };
+		585FE2F124E1365400439C50 /* LogStreamer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 585FE2F024E1365400439C50 /* LogStreamer.swift */; };
 		5860F1C223A785C600CEA666 /* WireguardDevice.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5860F1C123A785C600CEA666 /* WireguardDevice.swift */; };
 		5860F1C423A8D25F00CEA666 /* WireguardConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5860F1C323A8D25F00CEA666 /* WireguardConfiguration.swift */; };
 		5862805422428EF100F5A6E1 /* TranslucentButtonBlurView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5862805322428EF100F5A6E1 /* TranslucentButtonBlurView.swift */; };
@@ -292,6 +293,7 @@
 		58561C98239A5D1500BD6B5E /* IPEndpoint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IPEndpoint.swift; sourceTree = "<group>"; };
 		5857F24224C8662600CF6F47 /* SelectLocationHeaderView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SelectLocationHeaderView.swift; sourceTree = "<group>"; };
 		5857F24624C882D700CF6F47 /* SelectLocationNavigationController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SelectLocationNavigationController.swift; sourceTree = "<group>"; };
+		585FE2F024E1365400439C50 /* LogStreamer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LogStreamer.swift; sourceTree = "<group>"; };
 		5860F1C123A785C600CEA666 /* WireguardDevice.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WireguardDevice.swift; sourceTree = "<group>"; };
 		5860F1C323A8D25F00CEA666 /* WireguardConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WireguardConfiguration.swift; sourceTree = "<group>"; };
 		5862805322428EF100F5A6E1 /* TranslucentButtonBlurView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TranslucentButtonBlurView.swift; sourceTree = "<group>"; };
@@ -468,6 +470,7 @@
 				581503A524D6F4AE00C9C50E /* Logging.swift */,
 				5815039324D6EB7200C9C50E /* LogRotation.swift */,
 				58141EC824DAC0ED0013F79C /* TextFileStream.swift */,
+				585FE2F024E1365400439C50 /* LogStreamer.swift */,
 			);
 			path = Logging;
 			sourceTree = "<group>";
@@ -995,6 +998,7 @@
 				582BB1AF229566420055B6EF /* SettingsCell.swift in Sources */,
 				5873884D239E6D7E00E96C4E /* EmbeddedViewContainerView.swift in Sources */,
 				58F3C0A4249CB069003E76BE /* HeaderBarView.swift in Sources */,
+				585FE2F124E1365400439C50 /* LogStreamer.swift in Sources */,
 				58B9EB132488ED2100095626 /* AlertPresenter.swift in Sources */,
 				587A01FC23F1F0BE00B68763 /* SimulatorTunnelProviderHost.swift in Sources */,
 				5862805422428EF100F5A6E1 /* TranslucentButtonBlurView.swift in Sources */,
diff --git a/ios/MullvadVPN/Logging/LogStreamer.swift b/ios/MullvadVPN/Logging/LogStreamer.swift
new file mode 100644
index 0000000000..5c5e34ea40
--- /dev/null
+++ b/ios/MullvadVPN/Logging/LogStreamer.swift
@@ -0,0 +1,84 @@
+//
+//  LogStreamer.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 10/08/2020.
+//  Copyright © 2020 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+
+private let kLogPollIntervalSeconds = 2
+
+/// A class that consolidates multiple log streams into one
+class LogStreamer<Codec> where Codec: UnicodeCodec {
+    private let fileURLs: [URL]
+    private var remainingFileURLs: [URL]
+    private var streams = [TextFileStream<Codec>]()
+    private let queue = DispatchQueue(label: "net.mullvad.MullvadVPN.LogStreamer<\(Codec.self)>")
+    private var retry: DispatchWorkItem?
+    private var handlerBlock: ((String) -> Void)?
+
+    init(fileURLs: [URL]) {
+        self.fileURLs = fileURLs
+        self.remainingFileURLs = fileURLs
+    }
+
+    func start(handler: @escaping (String) -> Void) {
+        queue.async {
+            self.handlerBlock = handler
+            self.poll()
+        }
+    }
+
+    func stop() {
+        queue.async {
+            self.retry?.cancel()
+            self.handlerBlock = nil
+
+            self.streams.removeAll()
+            self.remainingFileURLs = self.fileURLs
+        }
+    }
+
+    private func openRemainingStreams() -> Bool {
+        var failedURLs = [URL]()
+        for fileURL in remainingFileURLs {
+            if let stream = TextFileStream<Codec>(fileURL: fileURL, separator: "\n") {
+                streams.append(stream)
+
+                didAddStream(stream)
+            } else {
+                failedURLs.append(fileURL)
+            }
+        }
+
+        remainingFileURLs = failedURLs
+
+        return failedURLs.isEmpty
+    }
+
+    private func poll() {
+        if !self.openRemainingStreams() {
+            self.scheduleRetry()
+        }
+    }
+
+    private func scheduleRetry() {
+        let workItem = DispatchWorkItem(block: { [weak self] in
+            self?.poll()
+        })
+        queue.asyncAfter(wallDeadline: .now() + .seconds(kLogPollIntervalSeconds), execute: workItem)
+        retry = workItem
+    }
+
+    private func didAddStream(_ stream: TextFileStream<Codec>) {
+        stream.read { [weak self] (s) in
+            guard let self = self else { return }
+
+            self.queue.async {
+                self.handlerBlock?(s)
+            }
+        }
+    }
+}
diff --git a/ios/MullvadVPN/Logging/TextFileStream.swift b/ios/MullvadVPN/Logging/TextFileStream.swift
index 2ae9b3e82f..f37ae0b522 100644
--- a/ios/MullvadVPN/Logging/TextFileStream.swift
+++ b/ios/MullvadVPN/Logging/TextFileStream.swift
@@ -15,7 +15,7 @@ class TextFileStream<Codec> where Codec: UnicodeCodec {
     private let queue = DispatchQueue(label: "net.mullvad.MullvadVPN.TextFileStream<\(Codec.self)>")
     private let stringStream: StringStreamIterator<Codec>
 
-    init?(fileURL: URL, separator: Character, encoding: String.Encoding = .utf8) {
+    init?(fileURL: URL, separator: Character) {
         let filePath = fileURL.path.utf8CString.map { $0 }
 
         let fileDescriptor = open(filePath, O_RDONLY)
@@ -50,7 +50,7 @@ class TextFileStream<Codec> where Codec: UnicodeCodec {
             let actual = Darwin.read(self.fileDescriptor, &buffer, estimated)
 
             if actual == -1 {
-                print("TextFileInputStream: read error: \(errno)")
+                print("TextFileStream<\(Codec.self)>: read error: \(errno)")
             }
 
             if actual > 0 {