Pin code storage : add way to store the pin

features/pin/impl/src/main/kotlin/io/element/android/features/pin/impl/storage/EncryptedPinCodeStorage.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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.
+ */
+
+package io.element.android.features.pin.impl.storage
+
+/**
+ * Should be implemented by any class that provides access to the encrypted PIN code.
+ * All methods are suspending in case there are async IO operations involved.
+ */
+interface EncryptedPinCodeStorage {
+    /**
+     * Returns the encrypted PIN code.
+     */
+    suspend fun getPinCode(): String?
+
+    /**
+     * Saves the encrypted PIN code to some persistable storage.
+     */
+    suspend fun savePinCode(pinCode: String)
+
+    /**
+     * Deletes the PIN code from some persistable storage.
+     */
+    suspend fun deletePinCode()
+
+    /**
+     * Returns whether the PIN code is stored or not.
+     */
+    suspend fun hasPinCode(): Boolean
+}

features/pin/impl/src/main/kotlin/io/element/android/features/pin/impl/storage/PinCodeStore.kt

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+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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.
+ */
+
+package io.element.android.features.pin.impl.storage
+
+interface PinCodeStore : EncryptedPinCodeStorage {
+
+    interface Listener {
+        fun onPinSetUpChange(isConfigured: Boolean)
+    }
+
+    /**
+     * Returns the remaining PIN code attempts. When this reaches 0 the PIN code access won't be available for some time.
+     */
+    suspend fun getRemainingPinCodeAttemptsNumber(): Int
+
+    /**
+     * Should decrement the number of remaining PIN code attempts.
+     * @return The remaining attempts.
+     */
+    suspend fun onWrongPin(): Int
+
+    /**
+     * Resets the counter of attempts for PIN code and biometric access.
+     */
+    suspend fun resetCounter()
+
+    /**
+     * Adds a listener to be notified when the PIN code us created or removed.
+     */
+    fun addListener(listener: Listener)
+
+    /**
+     * Removes a listener to be notified when the PIN code us created or removed.
+     */
+    fun removeListener(listener: Listener)
+}
+
+

features/pin/impl/src/main/kotlin/io/element/android/features/pin/impl/storage/SharedPreferencesPinCodeStore.kt

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+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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.
+ */
+
+package io.element.android.features.pin.impl.storage
+
+import android.content.SharedPreferences
+import androidx.core.content.edit
+import com.squareup.anvil.annotations.ContributesBinding
+import io.element.android.libraries.core.coroutine.CoroutineDispatchers
+import io.element.android.libraries.di.AppScope
+import io.element.android.libraries.di.SingleIn
+import kotlinx.coroutines.withContext
+import java.util.concurrent.CopyOnWriteArrayList
+import javax.inject.Inject
+
+@SingleIn(AppScope::class)
+@ContributesBinding(AppScope::class)
+class SharedPreferencesPinCodeStore @Inject constructor(
+    private val dispatchers: CoroutineDispatchers,
+    private val sharedPreferences: SharedPreferences,
+) : PinCodeStore {
+
+    private val listeners = CopyOnWriteArrayList<PinCodeStore.Listener>()
+
+    override suspend fun getPinCode(): String? = withContext(dispatchers.io) {
+        sharedPreferences.getString(ENCODED_PIN_CODE_KEY, null)
+    }
+
+    override suspend fun savePinCode(pinCode: String) = withContext(dispatchers.io) {
+        sharedPreferences.edit {
+            putString(ENCODED_PIN_CODE_KEY, pinCode)
+        }
+        withContext(dispatchers.main) {
+            listeners.forEach { it.onPinSetUpChange(isConfigured = true) }
+        }
+    }
+
+    override suspend fun deletePinCode() = withContext(dispatchers.io) {
+        // Also reset the counters
+        resetCounter()
+        sharedPreferences.edit {
+            remove(ENCODED_PIN_CODE_KEY)
+        }
+        withContext(dispatchers.main) {
+            listeners.forEach { it.onPinSetUpChange(isConfigured = false) }
+        }
+    }
+
+    override suspend fun hasPinCode(): Boolean = withContext(dispatchers.io) {
+        sharedPreferences.contains(ENCODED_PIN_CODE_KEY)
+    }
+
+    override suspend fun getRemainingPinCodeAttemptsNumber(): Int = withContext(dispatchers.io) {
+        sharedPreferences.getInt(REMAINING_PIN_CODE_ATTEMPTS_KEY, MAX_PIN_CODE_ATTEMPTS_NUMBER_BEFORE_LOGOUT)
+    }
+
+    override suspend fun onWrongPin(): Int = withContext(dispatchers.io) {
+        val remaining = getRemainingPinCodeAttemptsNumber() - 1
+        sharedPreferences.edit {
+            putInt(REMAINING_PIN_CODE_ATTEMPTS_KEY, remaining)
+        }
+        remaining
+    }
+
+    override suspend fun resetCounter() = withContext(dispatchers.io) {
+        sharedPreferences.edit {
+            remove(REMAINING_PIN_CODE_ATTEMPTS_KEY)
+            remove(REMAINING_BIOMETRICS_ATTEMPTS_KEY)
+        }
+    }
+
+    override fun addListener(listener: PinCodeStore.Listener) {
+        listeners.add(listener)
+    }
+
+    override fun removeListener(listener: PinCodeStore.Listener) {
+        listeners.remove(listener)
+    }
+
+    companion object {
+        private const val ENCODED_PIN_CODE_KEY = "ENCODED_PIN_CODE_KEY"
+        private const val REMAINING_PIN_CODE_ATTEMPTS_KEY = "REMAINING_PIN_CODE_ATTEMPTS_KEY"
+        private const val REMAINING_BIOMETRICS_ATTEMPTS_KEY = "REMAINING_BIOMETRICS_ATTEMPTS_KEY"
+
+        private const val MAX_PIN_CODE_ATTEMPTS_NUMBER_BEFORE_LOGOUT = 3
+    }
+}