fix(iOS): KV, Context fixes (#83)

.changeset/late-peas-scream.md

@@ -0,0 +1,8 @@
+---
+"@capacitor/background-runner": minor
+"ios-engine": minor
+---
+
+(iOS) KV: calling `get` on an non-existent key returns null instead of empty object
+(iOS) Fixed an issue within Runner that could potentially cause EXC_BAD_ACCESS crashes
+

apps/example-app/ios/App/Podfile.lock

@@ -49,4 +49,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 023978344a0d202e5020371cd007ff62c16044ac
 
-COCOAPODS: 1.13.0
+COCOAPODS: 1.15.2

packages/capacitor-plugin/ios/Plugin/BackgroundRunner.swift

@@ -5,8 +5,8 @@ import JavaScriptCore
 
 public class BackgroundRunner {
     public static let shared = BackgroundRunner()
-
-    private var config: RunnerConfig?
+    public var config: RunnerConfig?
+
     private var runner = Runner()
 
     public init() {
@@ -17,93 +17,51 @@ public class BackgroundRunner {
             print("could not initialize BackgroundRunner: \(error)")
         }
     }
-
-    public func registerBackgroundTask() {
+    
+    public func scheduleBackgroundTasks() throws {
         guard let config = config else {
-            print("no runner to register")
-            return
+            throw BackgroundRunnerPluginError.noRunnerConfig
         }
-
-        if config.event == nil {
-            print("cannot register background task without a event to call")
-            return
-        }
-
-        BGTaskScheduler.shared.register(forTaskWithIdentifier: config.label, using: nil) { task in
-            do {
-                task.expirationHandler = {
-                    print("task timed out")
-                }
-
-                guard let event = config.event else {
-                    throw BackgroundRunnerPluginError.invalidRunnerConfig(reason: "runner event is missing or invalid")
-                }
-
-                _ = try BackgroundRunner.shared.execute(config: config, event: event)
-
-                task.setTaskCompleted(success: true)
-            } catch {
-                print("background task error: \(error)")
-                task.setTaskCompleted(success: false)
-            }
-        }
-    }
-
-    public func scheduleBackgroundTasks() {
-        guard let config = config else {
+
+        if !config.autoSchedule {
             return
         }
 
         guard let interval = config.interval else {
-            print("cannot register background task without a configured interval")
-            return
+            throw BackgroundRunnerPluginError.invalidRunnerConfig(reason: "cannot register background task without a configured interval")
         }
 
         let request = BGAppRefreshTaskRequest(identifier: config.label)
         request.earliestBeginDate = Date(timeIntervalSinceNow: Double(interval) * 60)
 
-        do {
-            print("Scheduling \(config.label)")
+        print("Scheduling \(config.label)")
 
-            try BGTaskScheduler.shared.submit(request)
-        } catch {
-            print("Could not schedule app refresh: \(error)")
-        }
-    }
-
-    public func getConfig() -> RunnerConfig? {
-        return config
+        try BGTaskScheduler.shared.submit(request)
     }
 
-    public func dispatchEvent(event: String, inputArgs: [String: Any]?, callbackId: String? = nil) throws {
-        if let config = config {
-            let waitGroup = DispatchGroup()
-            waitGroup.enter()
-
-            var err: Error?
+    public func registerBackgroundTask() throws {
+        guard let config = config else {
+            throw BackgroundRunnerPluginError.noRunnerConfig
+        }
 
-            // swiftlint:disable:next unowned_variable_capture
-            DispatchQueue.global(qos: .userInitiated).async { [unowned self] in
-                do {
-                    _ = try self.execute(config: config, event: event, inputArgs: inputArgs, callbackId: callbackId)
-                } catch {
-                    err = error
-                    print("[\(config.label)]: \(error)")
+        BGTaskScheduler.shared.register(forTaskWithIdentifier: config.label, using: nil) { task in
+            do {
+                task.expirationHandler = {
+                    print("task timed out")
                 }
 
-                waitGroup.leave()
-            }
+                _ = try BackgroundRunner.shared.execute(config: config)
 
-            waitGroup.wait()
-
-            if let err = err {
-                throw err
+                task.setTaskCompleted(success: true)
+            } catch {
+                print("background task error: \(error)")
+                task.setTaskCompleted(success: false)
             }
         }
     }
-
+    
     // swiftlint:disable:next cyclomatic_complexity function_body_length
-    public func execute(config: RunnerConfig, event: String, inputArgs: [String: Any]? = nil, callbackId: String? = nil) throws -> [String: Any]? {
+    public func execute(config: RunnerConfig, inputArgs: [String: Any]? = nil, callbackId: String? = nil) throws -> [String: Any]? {
         do {
             let context = try initContext(config: config, callbackId: callbackId)
 
@@ -170,9 +128,10 @@ public class BackgroundRunner {
 
             waitGroup.enter()
 
-            try context.dispatchEvent(event: event, details: args)
+            try context.dispatchEvent(event: config.event, details: args)
 
             waitGroup.wait()
+
 
             if let rejection = rejectionErr {
                 throw EngineError.jsException(details: rejection.message)
@@ -185,6 +144,33 @@ public class BackgroundRunner {
         }
     }
 
+    public func dispatchEvent(event: String, inputArgs: [String: Any]?, callbackId: String? = nil) throws {
+        if let config = config {
+            let waitGroup = DispatchGroup()
+            waitGroup.enter()
+
+            var err: Error?
+
+            // swiftlint:disable:next unowned_variable_capture
+            DispatchQueue.global(qos: .userInitiated).async { [unowned self] in
+                do {
+                    _ = try self.execute(config: config, inputArgs: inputArgs, callbackId: callbackId)
+                } catch {
+                    err = error
+                    print("[\(config.label)]: \(error)")
+                }
+
+                waitGroup.leave()
+            }
+
+            waitGroup.wait()
+
+            if let err = err {
+                throw err
+            }
+        }
+    }
+
     private func loadRunnerConfig() throws -> RunnerConfig? {
         guard let capacitorConfigFileURL = Bundle.main.url(forResource: "capacitor.config.json", withExtension: nil) else {
             throw BackgroundRunnerPluginError.runnerError(reason: "capacitor.config.json file not found")

packages/capacitor-plugin/ios/Plugin/BackgroundRunnerErrors.swift

@@ -1,6 +1,7 @@
 import Foundation
 
 public enum BackgroundRunnerPluginError: Error, Equatable {
+    case noRunnerConfig
     case invalidRunnerConfig(reason: String)
     case invalidArgument(reason: String)
     case runnerError(reason: String)

packages/capacitor-plugin/ios/Plugin/BackgroundRunnerPlugin.swift

@@ -13,6 +13,7 @@ public class BackgroundRunnerPlugin: CAPPlugin {
             name: UIApplication.didEnterBackgroundNotification,
             object: nil
         )
+
         initWatchConnectivity()
     }
 
@@ -54,22 +55,23 @@ public class BackgroundRunnerPlugin: CAPPlugin {
 
     @objc func dispatchEvent(_ call: CAPPluginCall) {
         do {
-            guard let runnerEvent = call.getString("event") else {
+            guard let runnerEvent = call.getString("event"), !runnerEvent.isEmpty else {
                 throw BackgroundRunnerPluginError.invalidArgument(reason: "event is missing or invalid")
             }
 
             let details = call.getObject("details", JSObject())
 
-            guard let config = impl.getConfig() else {
-                throw BackgroundRunnerPluginError.runnerError(reason: "no runner config loaded")
+            guard var config = impl.config else {
+                throw BackgroundRunnerPluginError.noRunnerConfig
             }
+
+            config.event = runnerEvent
 
             // swiftlint:disable:next unowned_variable_capture
             DispatchQueue.global(qos: .userInitiated).async { [unowned self] in
                 do {
                     let result = try self.impl.execute(
                         config: config,
-                        event: runnerEvent,
                         inputArgs: details as [String: Any],
                         callbackId: call.callbackId
                     )
@@ -94,14 +96,27 @@ public class BackgroundRunnerPlugin: CAPPlugin {
     }
 
     @objc private func didEnterBackground() {
-        impl.scheduleBackgroundTasks()
+        do {
+            try impl.scheduleBackgroundTasks()
+        } catch {
+            print("could not schedule background task: \(error)")
+        }
     }
 
     public static func registerBackgroundTask() {
-        BackgroundRunner.shared.registerBackgroundTask()
+        do {
+            try BackgroundRunner.shared.registerBackgroundTask()
+        } catch {
+            print("could not register background task: \(error)")
+        }
     }
 
     public static func dispatchEvent(event: String, eventArgs: [AnyHashable: Any], completionHandler: ((Result<Bool, Error>) -> Void)) {
+        if event.isEmpty {
+            completionHandler(.failure(BackgroundRunnerPluginError.invalidArgument(reason: "event is missing or invalid")))
+            return
+        }
+
         var args: [String: Any] = [:]
 
         eventArgs.forEach { (key: AnyHashable, value: Any) in
@@ -147,7 +162,7 @@ public class BackgroundRunnerPlugin: CAPPlugin {
             return
         }
 
-        guard let config = impl.getConfig() else {
+        guard let config = impl.config else {
             return
         }
 

packages/capacitor-plugin/ios/Plugin/CapacitorAPI/KV.swift

@@ -13,9 +13,11 @@ class CapacitorKVStore: NSObject, CapacitorKVStoreExports {
     }
 
     static func get(_ key: String) -> JSValue {
+        guard let value = UserDefaults.standard.string(forKey: key) else {
+            return JSValue(nullIn: JSContext.current())
+        }
+
         var valueWrapper: [String: String] = [:]
-
-        let value = UserDefaults.standard.string(forKey: key)
         valueWrapper["value"] = value
 
         return JSValue(object: valueWrapper, in: JSContext.current())

packages/capacitor-plugin/ios/Plugin/RunnerConfig.swift

@@ -5,7 +5,7 @@ public struct RunnerConfig {
     let label: String
     let src: String
     var autoSchedule: Bool
-    let event: String?
+    var event: String
     let repeats: Bool?
     let enableWatchConnectivity: Bool
 
@@ -20,7 +20,7 @@ public struct RunnerConfig {
             throw BackgroundRunnerPluginError.invalidRunnerConfig(reason: "runner source file path is missing or invalid")
         }
 
-        let event = jsObject["event"] as? String
+        let event = jsObject["event"] as? String ?? ""
         let repeats = jsObject["repeat"] as? Bool
         let interval = jsObject["interval"] as? Int
         let autoStart = jsObject["autoStart"] as? Bool

packages/ios-engine/Sources/RunnerEngine/Runner.swift

@@ -3,31 +3,17 @@ import JavaScriptCore
 
 public class Runner {
     var machine: JSVirtualMachine
-    var contexts: [String: Context]
 
     private let runLoop: RunLoop
     private var thread: Thread?
 
     public init() {
         machine = JSVirtualMachine()
-        contexts = [:]
         runLoop = RunLoop.current
     }
 
     func createContext(name: String) throws -> Context {
-        let context = try Context(vm: machine, contextName: name, runLoop: runLoop)
-
-        if contexts.keys.contains(name) {
-            throw EngineError.runnerError(details: "context with name \(name) already exists")
-        }
-
-        contexts[name] = context
-
-        return context
-    }
-
-    func destroyContext(name: String) {
-        contexts.removeValue(forKey: name)
+        return try Context(vm: machine, contextName: name, runLoop: runLoop)
     }
 
     func start() {
@@ -54,6 +40,7 @@ public class Runner {
         }
 
         thread.cancel()
+
         while !thread.isFinished {
             Thread.sleep(forTimeInterval: 0.05)
         }