Provide callback instead of doing UI tasks of calling app #49

lib/src/main/java/at/bitfire/cert4android/CustomCertManager.kt

@@ -6,7 +6,7 @@ package at.bitfire.cert4android
 
 import android.annotation.SuppressLint
 import android.content.Context
-import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.CoroutineScope
 import java.security.cert.CertificateException
 import java.security.cert.X509Certificate
 import javax.net.ssl.SSLSession
@@ -18,18 +18,18 @@ import javax.net.ssl.X509TrustManager
  * Initializes Conscrypt when it is first loaded.
  *
  * @param trustSystemCerts whether system certificates will be trusted
- * @param appInForeground  - `true`: if needed, directly launches [TrustCertificateActivity] and shows notification (if possible)
- *                         - `false`: if needed, shows notification (if possible)
- *                         - `null`: non-interactive mode: does not show notification or launch activity
+ * @param getUserDecision  anonymous function to retrieve user decision on whether to trust a
+ *                         certificate; should return *true* if the user trusts the certificate
  */
 @SuppressLint("CustomX509TrustManager")
 class CustomCertManager @JvmOverloads constructor(
     context: Context,
+    scope: CoroutineScope,
     val trustSystemCerts: Boolean = true,
-    var appInForeground: StateFlow<Boolean>?
+    private val getUserDecision: suspend (X509Certificate) -> Boolean
 ): X509TrustManager {
 
-    val certStore = CustomCertStore.getInstance(context)
+    val certStore = CustomCertStore.getInstance(context, scope)
 
 
     @Throws(CertificateException::class)
@@ -47,7 +47,7 @@ class CustomCertManager @JvmOverloads constructor(
      */
     @Throws(CertificateException::class)
     override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {
-        if (!certStore.isTrusted(chain, authType, trustSystemCerts, appInForeground))
+        if (!certStore.isTrusted(chain, authType, trustSystemCerts, getUserDecision))
             throw CertificateException("Certificate chain not trusted")
     }
 
@@ -71,7 +71,7 @@ class CustomCertManager @JvmOverloads constructor(
             // Allow users to explicitly accept certificates that have a bad hostname here
             (session.peerCertificates.firstOrNull() as? X509Certificate)?.let { cert ->
                 // Check without trusting system certificates so that the user will be asked even for system-trusted certificates
-                if (certStore.isTrusted(arrayOf(cert), "RSA", false, appInForeground))
+                if (certStore.isTrusted(arrayOf(cert), "RSA", false, getUserDecision))
                     return true
             }
 

lib/src/main/java/at/bitfire/cert4android/CustomCertStore.kt

@@ -7,8 +7,8 @@ package at.bitfire.cert4android
 import android.annotation.SuppressLint
 import android.content.Context
 import androidx.annotation.VisibleForTesting
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.TimeoutCancellationException
-import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
 import org.conscrypt.Conscrypt
@@ -22,6 +22,7 @@ import java.util.logging.Level
 
 class CustomCertStore internal constructor(
     private val context: Context,
+    private val scope: CoroutineScope,
     private val userTimeout: Long = 60000L
 ) {
 
@@ -34,12 +35,12 @@ class CustomCertStore internal constructor(
         private var instance: CustomCertStore? = null
 
         @Synchronized
-        fun getInstance(context: Context): CustomCertStore {
+        fun getInstance(context: Context, scope: CoroutineScope): CustomCertStore {
             instance?.let {
                 return it
             }
 
-            val newInstance = CustomCertStore(context.applicationContext)
+            val newInstance = CustomCertStore(context.applicationContext, scope)
             instance = newInstance
             return newInstance
         }
@@ -77,7 +78,12 @@ class CustomCertStore internal constructor(
     /**
      * Determines whether a certificate chain is trusted.
      */
-    fun isTrusted(chain: Array<X509Certificate>, authType: String, trustSystemCerts: Boolean, appInForeground: StateFlow<Boolean>?): Boolean {
+    fun isTrusted(
+        chain: Array<X509Certificate>,
+        authType: String,
+        trustSystemCerts: Boolean,
+        getUserDecision: suspend (X509Certificate) -> Boolean
+    ): Boolean {
         if (chain.isEmpty())
             throw IllegalArgumentException("Certificate chain must not be empty")
         val cert = chain[0]
@@ -103,17 +109,12 @@ class CustomCertStore internal constructor(
                 }
         }
 
-        if (appInForeground == null) {
-            Cert4Android.log.log(Level.INFO, "Certificate not known and running in non-interactive mode, rejecting")
-            return false
-        }
-
         return runBlocking {
-            val ui = UserDecisionRegistry.getInstance(context)
+            val ui = UserDecisionRegistry.getInstance(context, scope)
 
             try {
                 withTimeout(userTimeout) {
-                    ui.check(cert, appInForeground.value)
+                    ui.check(cert, getUserDecision)
                 }
             } catch (_: TimeoutCancellationException) {
                 Cert4Android.log.log(Level.WARNING, "User timeout while waiting for certificate decision, rejecting")