jiti-meet/ios/app/broadcast-extension/SampleHandler.swift

/*
 * Copyright @ 2021-present 8x8, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import ReplayKit

private enum Constants {
    // the App Group ID value that the app and the broadcast extension targets are setup with. It differs for each app.
    static let appGroupIdentifier = "group.org.jitsi.meet.appgroup"
}

class SampleHandler: RPBroadcastSampleHandler {
    
    private var clientConnection: SocketConnection?
    private var uploader: SampleUploader?
    
    private var frameCount: Int = 0
    
    var socketFilePath: String {
      let sharedContainer = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: Constants.appGroupIdentifier)
        
        return sharedContainer?.appendingPathComponent("rtc_SSFD").path ?? ""
    }
    
    override init() {
      super.init()
        if let connection = SocketConnection(filePath: socketFilePath) {
          clientConnection = connection
          setupConnection()
          
          uploader = SampleUploader(connection: connection)
        }
    }

    override func broadcastStarted(withSetupInfo setupInfo: [String: NSObject]?) {
        // User has requested to start the broadcast. Setup info from the UI extension can be supplied but optional.
        print("broadcast started")
        
        frameCount = 0
        
        DarwinNotificationCenter.shared.postNotification(.broadcastStarted)
        openConnection()
    }
    
    override func broadcastPaused() {
        // User has requested to pause the broadcast. Samples will stop being delivered.
    }
    
    override func broadcastResumed() {
        // User has requested to resume the broadcast. Samples delivery will resume.
    }
    
    override func broadcastFinished() {
        // User has requested to finish the broadcast.
        DarwinNotificationCenter.shared.postNotification(.broadcastStopped)
        clientConnection?.close()
    }
    
    override func processSampleBuffer(_ sampleBuffer: CMSampleBuffer, with sampleBufferType: RPSampleBufferType) {
        switch sampleBufferType {
        case RPSampleBufferType.video:
            // very simple mechanism for adjusting frame rate by using every third frame
            frameCount += 1
            if frameCount % 3 == 0 {
                uploader?.send(sample: sampleBuffer)
            }
        default:
            break
        }
    }
}

private extension SampleHandler {
  
    func setupConnection() {
        clientConnection?.didClose = { [weak self] error in
            print("client connection did close \(String(describing: error))")
          
            if let error = error {
                self?.finishBroadcastWithError(error)
            } else {
                // the displayed failure message is more user friendly when using NSError instead of Error
                let JMScreenSharingStopped = 10001
                let customError = NSError(domain: RPRecordingErrorDomain, code: JMScreenSharingStopped, userInfo: [NSLocalizedDescriptionKey: "Screen sharing stopped"])
                self?.finishBroadcastWithError(customError)
            }
        }
    }
    
    func openConnection() {
        let queue = DispatchQueue(label: "broadcast.connectTimer")
        let timer = DispatchSource.makeTimerSource(queue: queue)
        timer.schedule(deadline: .now(), repeating: .milliseconds(100), leeway: .milliseconds(500))
        timer.setEventHandler { [weak self] in
            guard self?.clientConnection?.open() == true else {
                return
            }
            
            timer.cancel()
        }
        
        timer.resume()
    }
}