Add SettingsProvider interface for settings

- Modify `CustomCertManager` to use `SettingsProvider` for settings
- Remove `Flow` for setting that can change

Author: rfc2822

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

@@ -10,7 +10,6 @@
 
 package at.bitfire.cert4android
 
-import kotlinx.coroutines.flow.StateFlow
 import java.security.cert.X509Certificate
 
 interface CertStore {
@@ -23,7 +22,7 @@ interface CertStore {
     /**
      * 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, appInForeground: Boolean?): Boolean
 
     /**
      * Determines whether a certificate has been explicitly accepted by the user. In this case,

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

@@ -11,7 +11,6 @@
 package at.bitfire.cert4android
 
 import android.annotation.SuppressLint
-import kotlinx.coroutines.flow.StateFlow
 import java.security.cert.CertificateException
 import java.security.cert.X509Certificate
 import java.util.logging.Logger
@@ -21,16 +20,13 @@ import javax.net.ssl.X509TrustManager
 /**
  * TrustManager to handle custom certificates.
  *
- * @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 certStore certificate store with (un)trusted certificates
+ * @param settings  settings provider to get settings from
  */
 @SuppressLint("CustomX509TrustManager")
 class CustomCertManager @JvmOverloads constructor(
     private val certStore: CertStore,
-    val trustSystemCerts: Boolean = true,
-    var appInForeground: StateFlow<Boolean>?
+    private val settings: SettingsProvider
 ): X509TrustManager {
 
     private val logger
@@ -51,7 +47,13 @@ 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 = settings.trustSystemCerts(),
+                appInForeground = settings.appInForeground()
+            )
+        )
             throw CertificateException("Certificate chain not trusted")
     }
 
@@ -75,7 +77,13 @@ 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",
+                        trustSystemCerts = false,
+                        appInForeground = settings.appInForeground()
+                    )
+                )
                     return true
             }
 

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

@@ -14,7 +14,6 @@ import android.annotation.SuppressLint
 import android.content.Context
 import androidx.annotation.VisibleForTesting
 import kotlinx.coroutines.TimeoutCancellationException
-import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
 import java.io.File
@@ -75,7 +74,7 @@ class CustomCertStore internal constructor(
     /**
      * Determines whether a certificate chain is trusted.
      */
-    override fun isTrusted(chain: Array<X509Certificate>, authType: String, trustSystemCerts: Boolean, appInForeground: StateFlow<Boolean>?): Boolean {
+    override fun isTrusted(chain: Array<X509Certificate>, authType: String, trustSystemCerts: Boolean, appInForeground: Boolean?): Boolean {
         if (chain.isEmpty())
             throw IllegalArgumentException("Certificate chain must not be empty")
         val cert = chain[0]
@@ -111,7 +110,7 @@ class CustomCertStore internal constructor(
 
             try {
                 withTimeout(userTimeout) {
-                    ui.check(cert, appInForeground.value)
+                    ui.check(cert, appInForeground)
                 }
             } catch (_: TimeoutCancellationException) {
                 logger.log(Level.WARNING, "User timeout while waiting for certificate decision, rejecting")

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

@@ -0,0 +1,37 @@
+/*
+ * Copyright © All Contributors. See LICENSE and AUTHORS in the root directory for details.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
+package at.bitfire.cert4android
+
+interface SettingsProvider {
+
+    /*
+     * @param trustSystemCerts
+ * @param appInForeground
+
+     */
+
+    /**
+     * Returns the app foreground status:
+     *
+     * - `true`: foreground – directly launch UI ([TrustCertificateActivity]) and show notification (if possible)
+     * - `false`: background – only show notification (if possible)
+     * - `null`: non-interactive mode – don't show notification or launch activity
+     */
+    fun appInForeground(): Boolean?
+
+    /**
+     * Returns whether system certificates shall be trusted.
+     *
+     * @return `true` if system certificates are considered trustworthy, `false` otherwise
+     */
+    fun trustSystemCerts(): Boolean
+
+}