From 72871d3d663d2cfbb1a0e8f0defcebd4b971b1ba Mon Sep 17 00:00:00 2001
From: Torsten Grote <t@grobox.de>
Date: Wed, 2 Sep 2020 14:37:02 -0300
Subject: [PATCH] Enable backup of call logs

It turned out that call log backup is already in AOSP, but it is
disabled by an undocumented flag. This commit sets this flag (for new
and existing installs) to enable call log backup.
---
 README.md                                       |  2 +-
 .../seedvault/settings/SettingsFragment.kt      |  3 +++
 .../seedvault/settings/SettingsViewModel.kt     | 17 +++++++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 5561ed48..872a8001 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ It uses the same internal APIs as `adb backup` which is deprecated and thus need
 * `android.permission.BACKUP` to back up application data.
 * `android.permission.MANAGE_DOCUMENTS` to retrieve the available storage roots. 
 * `android.permission.MANAGE_USB` to access the serial number of USB mass storage devices.
-* `android.permission.WRITE_SECURE_SETTINGS` to change system backup settings.
+* `android.permission.WRITE_SECURE_SETTINGS` to change system backup settings and enable call log backup.
 * `android.permission.INSTALL_PACKAGES` to re-install apps when restoring from backup.
 
 ## Contributing
diff --git a/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt b/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt
index 954cb9d0..5c0ad928 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt
@@ -70,6 +70,7 @@ class SettingsFragment : PreferenceFragmentCompat() {
             val enabled = newValue as Boolean
             try {
                 backupManager.isBackupEnabled = enabled
+                if (enabled) viewModel.enableCallLogBackup()
                 return@OnPreferenceChangeListener true
             } catch (e: RemoteException) {
                 e.printStackTrace()
@@ -171,6 +172,8 @@ class SettingsFragment : PreferenceFragmentCompat() {
         try {
             backup.isChecked = backupManager.isBackupEnabled
             backup.isEnabled = true
+            // enable call log backups for existing installs (added end of 2020)
+            if (backup.isChecked) viewModel.enableCallLogBackup()
         } catch (e: RemoteException) {
             Log.e(TAG, "Error communicating with BackupManager", e)
             backup.isEnabled = false
diff --git a/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt b/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt
index 02c30622..3b11506f 100644
--- a/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt
+++ b/app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt
@@ -2,6 +2,7 @@ package com.stevesoltys.seedvault.settings
 
 import android.app.Application
 import android.content.pm.PackageManager.NameNotFoundException
+import android.provider.Settings
 import android.util.Log
 import androidx.annotation.UiThread
 import androidx.core.content.ContextCompat.getDrawable
@@ -34,6 +35,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import java.util.Locale
 
+private const val USER_FULL_DATA_BACKUP_AWARE = "user_full_data_backup_aware"
+
 private val TAG = SettingsViewModel::class.java.simpleName
 
 internal class SettingsViewModel(
@@ -121,4 +124,18 @@ internal class SettingsViewModel(
         settingsManager.onAppBackupStatusChanged(status)
     }
 
+    /**
+     * Ensures that the call log will be included in backups.
+     *
+     * An AOSP code search found that call log backups get disabled if [USER_FULL_DATA_BACKUP_AWARE]
+     * is not set. This method sets this flag, if it is not already set.
+     * No other apps were found to check for this, so this should affect only call log.
+     */
+    fun enableCallLogBackup() {
+        // first check if the flag is already set
+        if (Settings.Secure.getInt(app.contentResolver, USER_FULL_DATA_BACKUP_AWARE, 0) == 0) {
+            Settings.Secure.putInt(app.contentResolver, USER_FULL_DATA_BACKUP_AWARE, 1)
+        }
+    }
+
 }