orcchg

suspend fun <T> synchronized(block: suspend () -> T): T {
      val thisJobId = id.getAndIncrement()
      while (isInsideCriticalSection) {
          suspendCoroutine { cont -> // <-- suspending call
              suspendedJobs[thisJobId] = cont
          }
          suspendedJobs.remove(thisJobId)
      }
      ...
}

orcchg

fun obtainAccessToken(): String {
    val kCriticalSection = DI.get<KCriticalSection>(qualifier = "shared")
    val singleThread = DI.get<CoroutineDispatcher>(qualifier = "shared")

    return runBlocking(singleThread) {
        kCriticalSection.synchronized {
            val accessToken = readAccessTokenFromStorageOrMemory() // might be a suspending call

            if (accessToken != null && System.currentTimeMillis() < accessToken.createdAt + accessToken.expiresIn) {
                return@synchronized accessToken.toString() // access token is valid

orcchg

if (accessToken != null && System.currentTimeMillis() < accessToken.createdAt + accessToken.expiresIn) {
    return@synchronized accessToken.toString() // access token is valid
}

orcchg

suspend fun obtainAccessToken(): String {
    val kCriticalSection = DI.get<KCriticalSection>(qualifier = "shared")
    
    return kCriticalSection.synchronized {
        val accessToken = readAccessTokenFromStorageOrMemory() // might be a suspending call

        if (accessToken != null && System.currentTimeMillis() < accessToken.createdAt + accessToken.expiresIn) {
            return@synchronized accessToken.toString() // access token is valid
        }

orcchg

import java.util.concurrent.ConcurrentHashMap
import kotlin.coroutines.Continuation
import kotlin.coroutines.resume
import kotlin.coroutines.suspendCoroutine

class KCriticalSection {
    private val suspendedJobs = ConcurrentHashMap<Int, Continuation<Boolean>>()
    private var id = AtomicInteger(1000)
    @Volatile private var isInsideCriticalSection = false

orcchg

suspend fun obtainAccessToken(): String =
    KCriticalSection().synchronized {
        val accessToken = readAccessTokenFromStorageOrMemory() // might be a suspending call

        if (accessToken != null && System.currentTimeMillis() < accessToken.createdAt + accessToken.expiresIn) {
            return@synchronized accessToken.toString() // access token is valid
        }

        val refreshToken = readRefreshTokenFromSecureStorage() // normally a suspending call

orcchg

suspend fun obtainAccessToken(): String {
    val accessToken = readAccessTokenFromStorageOrMemory() // might be a suspending call
    
    if (accessToken != null && System.currentTimeMillis() < accessToken.createdAt + accessToken.expiresIn) {
        return accessToken.toString() // access token is valid
    }
    
    val refreshToken = readRefreshTokenFromSecureStorage() // normally a suspending call

    // normally suspending as it makes another API call

orcchg

suspend fun obtainAccessToken(): String {
    // do the real job to obtain access token
    return "access token"
}

orcchg

import kotlinx.coroutines.runBlocking
import okhttp3.Interceptor
import okhttp3.Response
class AuthInterceptor : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val accessToken = runBlocking { obtainAccessToken() }

        val request = chain.request()
        val newRequest = request.newBuilder()
            .addHeader("Authorization", accessToken)

orcchg

import okhttp3.Interceptor
import okhttp3.Response

class AuthInterceptor : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val accessToken = obtainAccessToken() // <-- how to get token? This might be a suspending call
        
        val request = chain.request()
        val newRequest = request.newBuilder()
            .addHeader("Authorization", accessToken)