Make MANAGE_DOCUMENTS permission optional

for those who can not or do not want to use it

Fixes #58

README.md

@@ -26,11 +26,11 @@ It uses the same internal APIs as `adb backup` which is deprecated and thus need
 ## Permissions
 * `android.permission.BACKUP` to back up application data.
 * `android.permission.ACCESS_NETWORK_STATE` to check if there is internet access when network storage is used.
-* `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 and enable call log backup.
 * `android.permission.QUERY_ALL_PACKAGES` to get information about all installed apps for backup.
 * `android.permission.INSTALL_PACKAGES` to re-install apps when restoring from backup.
+* `android.permission.MANAGE_DOCUMENTS` to retrieve the available storage roots (optional) for better UX.
 
 ## Contributing
 Bug reports and pull requests are welcome on GitHub at https://github.com/stevesoltys/seedvault.

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageActivity.kt

@@ -1,7 +1,16 @@
 package com.stevesoltys.seedvault.ui.storage
 
+import android.Manifest.permission.MANAGE_DOCUMENTS
+import android.content.Context
+import android.content.Intent
+import android.content.Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION
+import android.content.Intent.FLAG_GRANT_READ_URI_PERMISSION
+import android.content.Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+import android.content.pm.PackageManager.PERMISSION_GRANTED
+import android.net.Uri
 import android.os.Bundle
 import android.util.Log
+import androidx.activity.result.contract.ActivityResultContracts.OpenDocumentTree
 import androidx.annotation.CallSuper
 import androidx.appcompat.app.AlertDialog
 import com.stevesoltys.seedvault.R
@@ -17,6 +26,24 @@ class StorageActivity : BackupActivity() {
 
     private lateinit var viewModel: StorageViewModel
 
+    /**
+     * The official way to get a SAF [Uri] which we only use if we don't have the
+     * [MANAGE_DOCUMENTS] permission (via [canUseStorageRootsFragment]).
+     */
+    private val openDocumentTree = registerForActivityResult(OpenPersistableDocumentTree()) { uri ->
+        if (uri != null) {
+            Log.e(TAG, "OpenDocumentTree: $uri")
+            val authority = uri.authority ?: throw AssertionError("No authority in $uri")
+            val storageRoot = StorageRootResolver.getStorageRoots(this, authority).getOrNull(0)
+            if (storageRoot == null) {
+                viewModel.onUriPermissionResultReceived(null)
+            } else {
+                viewModel.onStorageRootChosen(storageRoot)
+                viewModel.onUriPermissionResultReceived(uri)
+            }
+        }
+    }
+
     @CallSuper
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -47,7 +74,11 @@ class StorageActivity : BackupActivity() {
         })
 
         if (savedInstanceState == null) {
+            if (canUseStorageRootsFragment()) {
                 showFragment(StorageRootsFragment.newInstance(isRestore()))
+            } else {
+                openDocumentTree.launch(null)
+            }
         }
     }
 
@@ -61,13 +92,28 @@ class StorageActivity : BackupActivity() {
 
     private fun onInvalidLocation(errorMsg: String) {
         if (viewModel.isRestoreOperation) {
-            supportFragmentManager.popBackStack()
+            val dialog = AlertDialog.Builder(this)
-            AlertDialog.Builder(this)
                 .setTitle(getString(R.string.restore_invalid_location_title))
                 .setMessage(errorMsg)
                 .setPositiveButton(android.R.string.ok) { dialog, _ -> dialog.dismiss() }
-                .show()
+            if (canUseStorageRootsFragment()) {
+                // We have permission to use StorageRootsFragment,
+                // so pop the back stack to show it again
+                supportFragmentManager.popBackStack()
+                dialog.setPositiveButton(android.R.string.ok) { d, _ -> d.dismiss() }
             } else {
+                // We don't have permission to use StorageRootsFragment,
+                // so give option to choose again or cancel.
+                dialog.setPositiveButton(android.R.string.ok) { _, _ ->
+                    openDocumentTree.launch(null)
+                }
+                dialog.setNegativeButton(android.R.string.cancel) { _, _ ->
+                    finishAfterTransition()
+                }
+            }
+            dialog.show()
+        } else {
+            // just show error message, if this isn't restore
             showFragment(StorageCheckFragment.newInstance(getCheckFragmentTitle(), errorMsg))
         }
     }
@@ -80,6 +126,10 @@ class StorageActivity : BackupActivity() {
         return intent?.getBooleanExtra(INTENT_EXTRA_IS_SETUP_WIZARD, false) ?: false
     }
 
+    private fun canUseStorageRootsFragment(): Boolean {
+        return checkSelfPermission(MANAGE_DOCUMENTS) == PERMISSION_GRANTED
+    }
+
     private fun getCheckFragmentTitle() = if (viewModel.isRestoreOperation) {
         getString(R.string.storage_check_fragment_restore_title)
     } else {
@@ -87,3 +137,13 @@ class StorageActivity : BackupActivity() {
     }
 
 }
+
+private class OpenPersistableDocumentTree : OpenDocumentTree() {
+    override fun createIntent(context: Context, input: Uri?): Intent {
+        return super.createIntent(context, input).apply {
+            val flags = FLAG_GRANT_PERSISTABLE_URI_PERMISSION or
+                FLAG_GRANT_READ_URI_PERMISSION or FLAG_GRANT_WRITE_URI_PERMISSION
+            addFlags(flags)
+        }
+    }
+}

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageRootFetcher.kt

@@ -8,27 +8,15 @@ import android.content.Intent.FLAG_ACTIVITY_NEW_TASK
 import android.content.pm.PackageManager.GET_META_DATA
 import android.content.pm.ProviderInfo
 import android.database.ContentObserver
-import android.database.Cursor
 import android.graphics.drawable.Drawable
 import android.net.Uri
 import android.os.Handler
 import android.os.Looper
 import android.provider.DocumentsContract
 import android.provider.DocumentsContract.PROVIDER_INTERFACE
-import android.provider.DocumentsContract.Root.COLUMN_AVAILABLE_BYTES
-import android.provider.DocumentsContract.Root.COLUMN_DOCUMENT_ID
-import android.provider.DocumentsContract.Root.COLUMN_FLAGS
-import android.provider.DocumentsContract.Root.COLUMN_ICON
-import android.provider.DocumentsContract.Root.COLUMN_ROOT_ID
-import android.provider.DocumentsContract.Root.COLUMN_SUMMARY
-import android.provider.DocumentsContract.Root.COLUMN_TITLE
-import android.provider.DocumentsContract.Root.FLAG_LOCAL_ONLY
-import android.provider.DocumentsContract.Root.FLAG_REMOVABLE_USB
-import android.provider.DocumentsContract.Root.FLAG_SUPPORTS_CREATE
-import android.provider.DocumentsContract.Root.FLAG_SUPPORTS_IS_CHILD
 import android.util.Log
 import com.stevesoltys.seedvault.R
-import java.lang.Long.parseLong
+import com.stevesoltys.seedvault.ui.storage.StorageRootResolver.getIcon
 
 private val TAG = StorageRootFetcher::class.java.simpleName
 
@@ -116,51 +104,12 @@ internal class StorageRootFetcher(private val context: Context, private val isRe
     private fun getRoots(providerInfo: ProviderInfo): List<StorageRoot> {
         val authority = providerInfo.authority
         val provider = packageManager.resolveContentProvider(authority, GET_META_DATA)
-        if (provider == null || !provider.isSupported()) {
+        return if (provider == null || !provider.isSupported()) {
             Log.w(TAG, "Failed to get provider info for $authority")
-            return emptyList()
+            emptyList()
+        } else {
+            StorageRootResolver.getStorageRoots(context, authority)
         }
-
-        val roots = ArrayList<StorageRoot>()
-        val rootsUri = DocumentsContract.buildRootsUri(authority)
-
-        var cursor: Cursor? = null
-        try {
-            cursor = contentResolver.query(rootsUri, null, null, null, null)
-            while (cursor!!.moveToNext()) {
-                val root = getStorageRoot(authority, cursor)
-                if (root != null) roots.add(root)
-            }
-        } catch (e: Exception) {
-            Log.w(TAG, "Failed to load some roots from $authority", e)
-        } finally {
-            cursor?.close()
-        }
-        return roots
-    }
-
-    private fun getStorageRoot(authority: String, cursor: Cursor): StorageRoot? {
-        val flags = cursor.getInt(COLUMN_FLAGS)
-        val supportsCreate = flags and FLAG_SUPPORTS_CREATE != 0
-        val supportsIsChild = flags and FLAG_SUPPORTS_IS_CHILD != 0
-        if (!supportsCreate || !supportsIsChild) return null
-        val rootId = cursor.getString(COLUMN_ROOT_ID)!!
-        if (authority == AUTHORITY_STORAGE && rootId == ROOT_ID_HOME) return null
-        val documentId = cursor.getString(COLUMN_DOCUMENT_ID) ?: return null
-        return StorageRoot(
-            authority = authority,
-            rootId = rootId,
-            documentId = documentId,
-            icon = getIcon(context, authority, rootId, cursor.getInt(COLUMN_ICON)),
-            title = cursor.getString(COLUMN_TITLE)!!,
-            summary = cursor.getString(COLUMN_SUMMARY),
-            availableBytes = cursor.getLong(COLUMN_AVAILABLE_BYTES).let { bytes ->
-                // AOSP 11 reports -1 instead of null
-                if (bytes == -1L) null else bytes
-            },
-            isUsb = flags and FLAG_REMOVABLE_USB != 0,
-            requiresNetwork = flags and FLAG_LOCAL_ONLY == 0 // not local only == requires network
-        )
     }
 
     private fun checkOrAddUsbRoot(roots: ArrayList<StorageRoot>) {
@@ -256,55 +205,9 @@ internal class StorageRootFetcher(private val context: Context, private val isRe
     }
 
     private fun isAuthoritySupported(authority: String): Boolean {
-        // just restrict where to store backups, restoring can be more free for forward compatibility
+        // just restrict where to store backups,
+        // restoring can be more free for forward compatibility
         return isRestore || whitelistedAuthorities.contains(authority)
     }
 
-    private fun Cursor.getString(columnName: String): String? {
-        val index = getColumnIndex(columnName)
-        return if (index != -1) getString(index) else null
-    }
-
-    private fun Cursor.getInt(columnName: String): Int {
-        val index = getColumnIndex(columnName)
-        return if (index != -1) getInt(index) else 0
-    }
-
-    private fun Cursor.getLong(columnName: String): Long? {
-        val index = getColumnIndex(columnName)
-        if (index == -1) return null
-        val value = getString(index) ?: return null
-        return try {
-            parseLong(value)
-        } catch (e: NumberFormatException) {
-            null
-        }
-    }
-
-    private fun getIcon(context: Context, authority: String, rootId: String, icon: Int): Drawable? {
-        return getPackageIcon(context, authority, icon) ?: when {
-            authority == AUTHORITY_STORAGE && rootId == ROOT_ID_DEVICE -> {
-                context.getDrawable(R.drawable.ic_phone_android)
-            }
-            authority == AUTHORITY_STORAGE && rootId != ROOT_ID_HOME -> {
-                context.getDrawable(R.drawable.ic_usb)
-            }
-            authority == AUTHORITY_NEXTCLOUD -> {
-                context.getDrawable(R.drawable.nextcloud)
-            }
-            else -> null
-        }
-    }
-
-    private fun getPackageIcon(context: Context, authority: String, icon: Int): Drawable? {
-        if (icon != 0) {
-            val pm = context.packageManager
-            val info = pm.resolveContentProvider(authority, 0)
-            if (info != null) {
-                return pm.getDrawable(info.packageName, icon, info.applicationInfo)
-            }
-        }
-        return null
-    }
-
 }

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageRootResolver.kt

@@ -0,0 +1,113 @@
+package com.stevesoltys.seedvault.ui.storage
+
+import android.content.Context
+import android.database.Cursor
+import android.graphics.drawable.Drawable
+import android.provider.DocumentsContract
+import android.provider.DocumentsContract.Root.COLUMN_AVAILABLE_BYTES
+import android.provider.DocumentsContract.Root.COLUMN_DOCUMENT_ID
+import android.provider.DocumentsContract.Root.COLUMN_FLAGS
+import android.provider.DocumentsContract.Root.COLUMN_ICON
+import android.provider.DocumentsContract.Root.COLUMN_ROOT_ID
+import android.provider.DocumentsContract.Root.COLUMN_SUMMARY
+import android.provider.DocumentsContract.Root.COLUMN_TITLE
+import android.provider.DocumentsContract.Root.FLAG_LOCAL_ONLY
+import android.provider.DocumentsContract.Root.FLAG_REMOVABLE_USB
+import android.provider.DocumentsContract.Root.FLAG_SUPPORTS_CREATE
+import android.provider.DocumentsContract.Root.FLAG_SUPPORTS_IS_CHILD
+import android.util.Log
+import com.stevesoltys.seedvault.R
+
+object StorageRootResolver {
+
+    private val TAG = StorageRootResolver::class.java.simpleName
+
+    fun getStorageRoots(context: Context, authority: String): List<StorageRoot> {
+        val roots = ArrayList<StorageRoot>()
+        val rootsUri = DocumentsContract.buildRootsUri(authority)
+
+        try {
+            context.contentResolver.query(rootsUri, null, null, null, null)?.use { cursor ->
+                while (cursor.moveToNext()) {
+                    val root = getStorageRoot(context, authority, cursor)
+                    if (root != null) roots.add(root)
+                }
+            }
+        } catch (e: Exception) {
+            Log.w(TAG, "Failed to load some roots from $authority", e)
+        }
+        return roots
+    }
+
+    private fun getStorageRoot(context: Context, authority: String, cursor: Cursor): StorageRoot? {
+        val flags = cursor.getInt(COLUMN_FLAGS)
+        val supportsCreate = flags and FLAG_SUPPORTS_CREATE != 0
+        val supportsIsChild = flags and FLAG_SUPPORTS_IS_CHILD != 0
+        if (!supportsCreate || !supportsIsChild) return null
+        val rootId = cursor.getString(COLUMN_ROOT_ID)!!
+        if (authority == AUTHORITY_STORAGE && rootId == ROOT_ID_HOME) return null
+        val documentId = cursor.getString(COLUMN_DOCUMENT_ID) ?: return null
+        return StorageRoot(
+            authority = authority,
+            rootId = rootId,
+            documentId = documentId,
+            icon = getIcon(context, authority, rootId, cursor.getInt(COLUMN_ICON)),
+            title = cursor.getString(COLUMN_TITLE)!!,
+            summary = cursor.getString(COLUMN_SUMMARY),
+            availableBytes = cursor.getLong(COLUMN_AVAILABLE_BYTES).let { bytes ->
+                // AOSP 11 reports -1 instead of null
+                if (bytes == -1L) null else bytes
+            },
+            isUsb = flags and FLAG_REMOVABLE_USB != 0,
+            requiresNetwork = flags and FLAG_LOCAL_ONLY == 0 // not local only == requires network
+        )
+    }
+
+    private fun Cursor.getString(columnName: String): String? {
+        val index = getColumnIndex(columnName)
+        return if (index != -1) getString(index) else null
+    }
+
+    private fun Cursor.getInt(columnName: String): Int {
+        val index = getColumnIndex(columnName)
+        return if (index != -1) getInt(index) else 0
+    }
+
+    private fun Cursor.getLong(columnName: String): Long? {
+        val index = getColumnIndex(columnName)
+        if (index == -1) return null
+        val value = getString(index) ?: return null
+        return try {
+            java.lang.Long.parseLong(value)
+        } catch (e: NumberFormatException) {
+            null
+        }
+    }
+
+    fun getIcon(context: Context, authority: String, rootId: String, icon: Int): Drawable? {
+        return getPackageIcon(context, authority, icon) ?: when {
+            authority == AUTHORITY_STORAGE && rootId == ROOT_ID_DEVICE -> {
+                context.getDrawable(R.drawable.ic_phone_android)
+            }
+            authority == AUTHORITY_STORAGE && rootId != ROOT_ID_HOME -> {
+                context.getDrawable(R.drawable.ic_usb)
+            }
+            authority == AUTHORITY_NEXTCLOUD -> {
+                context.getDrawable(R.drawable.nextcloud)
+            }
+            else -> null
+        }
+    }
+
+    private fun getPackageIcon(context: Context, authority: String, icon: Int): Drawable? {
+        if (icon != 0) {
+            val pm = context.packageManager
+            val info = pm.resolveContentProvider(authority, 0)
+            if (info != null) {
+                return pm.getDrawable(info.packageName, icon, info.applicationInfo)
+            }
+        }
+        return null
+    }
+
+}

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageRootsFragment.kt

@@ -1,5 +1,6 @@
 package com.stevesoltys.seedvault.ui.storage
 
+import android.Manifest.permission.MANAGE_DOCUMENTS
 import android.annotation.SuppressLint
 import android.content.Context
 import android.content.Intent
@@ -17,6 +18,7 @@ import android.widget.ImageView
 import android.widget.ProgressBar
 import android.widget.TextView
 import androidx.activity.result.contract.ActivityResultContracts.OpenDocumentTree
+import androidx.annotation.RequiresPermission
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
 import androidx.recyclerview.widget.RecyclerView
@@ -27,6 +29,7 @@ import org.koin.androidx.viewmodel.ext.android.getSharedViewModel
 internal class StorageRootsFragment : Fragment(), StorageRootClickedListener {
 
     companion object {
+        @RequiresPermission(MANAGE_DOCUMENTS)
         fun newInstance(isRestore: Boolean): StorageRootsFragment {
             val f = StorageRootsFragment()
             f.arguments = Bundle().apply {

whitelist_com.stevesoltys.seedvault.xml

@@ -2,4 +2,5 @@
 <config>
     <backup-transport-whitelisted-service
         service="com.stevesoltys.seedvault/.transport.ConfigurableBackupTransportService" />
+    <hidden-api-whitelisted-app package="com.stevesoltys.seedvault" />
 </config>