Fix free storage space check for all APIs

See https://stackoverflow.com/q/31171838
See https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstatvfs.html

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -859,21 +859,20 @@ public class DownloadDialog extends DialogFragment
             return;
         }
 
-        // Check for free memory space (for api 24 and up)
+        // Check for free storage space
-        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
+        final long freeSpace = mainStorage.getFreeStorageSpace();
-            final long freeSpace = mainStorage.getFreeMemory();
         if (freeSpace <= size) {
             Toast.makeText(context, getString(R.
                     string.error_insufficient_storage), Toast.LENGTH_LONG).show();
             // move the user to storage setting tab
             final Intent storageSettingsIntent = new Intent(Settings.
                     ACTION_INTERNAL_STORAGE_SETTINGS);
-                if (storageSettingsIntent.resolveActivity(context.getPackageManager()) != null) {
+            if (storageSettingsIntent.resolveActivity(context.getPackageManager())
+                    != null) {
                 startActivity(storageSettingsIntent);
             }
             return;
         }
-        }
 
         // check for existing file with the same name
         checkSelectedDownload(mainStorage, mainStorage.findFile(filenameTmp), filenameTmp,

app/src/main/java/org/schabi/newpipe/streams/io/StoredDirectoryHelper.java

@@ -1,24 +1,29 @@
 package org.schabi.newpipe.streams.io;
 
+import static android.provider.DocumentsContract.Document.COLUMN_DISPLAY_NAME;
+import static android.provider.DocumentsContract.Root.COLUMN_DOCUMENT_ID;
+import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
+
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.database.Cursor;
 import android.net.Uri;
-import android.os.Build;
+import android.os.ParcelFileDescriptor;
-import android.os.storage.StorageManager;
-import android.os.storage.StorageVolume;
 import android.provider.DocumentsContract;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.StructStatVfs;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
 import androidx.documentfile.provider.DocumentFile;
 
 import org.schabi.newpipe.settings.NewPipeSettings;
 import org.schabi.newpipe.util.FilePickerActivityHelper;
 
+import java.io.FileDescriptor;
 import java.io.IOException;
 import java.net.URI;
 import java.nio.file.Files;
@@ -27,16 +32,9 @@ import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.UUID;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static android.provider.DocumentsContract.Document.COLUMN_DISPLAY_NAME;
-import static android.provider.DocumentsContract.Root.COLUMN_DOCUMENT_ID;
-import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
-
-import us.shandian.giga.util.Utility;
-
 public class StoredDirectoryHelper {
     private static final String TAG = StoredDirectoryHelper.class.getSimpleName();
     public static final int PERMISSION_FLAGS = Intent.FLAG_GRANT_READ_URI_PERMISSION
@@ -45,6 +43,7 @@ public class StoredDirectoryHelper {
     private Path ioTree;
     private DocumentFile docTree;
 
+    // will be `null` for non-SAF files, i.e. files that use `ioTree`
     private Context context;
 
     private final String tag;
@@ -176,42 +175,42 @@ public class StoredDirectoryHelper {
     }
 
     /**
-     * Get free memory of the storage partition (root of the directory).
+     * Get free memory of the storage partition this file belongs to (root of the directory).
-     * @return amount of free memory in the volume of current directory (bytes)
+     * See <a href="https://stackoverflow.com/q/31171838">StackOverflow</a> and
+     * <a href="https://pubs.opengroup.org/onlinepubs/9699919799/functions/fstatvfs.html">
+     *     {@code statvfs()} and {@code fstatvfs()} docs</a>
+     *
+     * @return amount of free memory in the volume of current directory (bytes), or {@link
+     * Long#MAX_VALUE} if an error occurred
      */
-    @RequiresApi(api = Build.VERSION_CODES.N)  // Necessary for `getStorageVolume()`
+    public long getFreeStorageSpace() {
-    public long getFreeMemory() {
-        final Uri uri = getUri();
-        final StorageManager storageManager = (StorageManager) context.
-                getSystemService(Context.STORAGE_SERVICE);
-        final List<StorageVolume> volumes = storageManager.getStorageVolumes();
-
-        final String docId = DocumentsContract.getDocumentId(uri);
-        final String[] split = docId.split(":");
-        if (split.length > 0) {
-            final String volumeId = split[0];
-
-            for (final StorageVolume volume : volumes) {
-                // if the volume is an internal system volume
-                if (volume.isPrimary() && volumeId.equalsIgnoreCase("primary")) {
-                    return Utility.getSystemFreeMemory();
-                }
-
-                // if the volume is a removable volume (normally an SD card)
-                if (volume.isRemovable() && !volume.isPrimary()) {
-                    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
         try {
-                            final String sdCardUUID = volume.getUuid();
+            final StructStatVfs stat;
-                            return storageManager.getAllocatableBytes(UUID.fromString(sdCardUUID));
+
-                        } catch (final Exception e) {
+            if (ioTree != null) {
-                            // do nothing
+                // non-SAF file, use statvfs with the path directly (also, `context` would be null
-                        }
+                // for non-SAF files, so we wouldn't be able to call `getContentResolver` anyway)
-                    }
+                stat = Os.statvfs(ioTree.toString());
-                }
+
-            }
+            } else {
-        }
+                // SAF file, we can't get a path directly, so obtain a file descriptor first
+                // and then use fstatvfs with the file descriptor
+                try (ParcelFileDescriptor parcelFileDescriptor =
+                             context.getContentResolver().openFileDescriptor(getUri(), "r")) {
+                    if (parcelFileDescriptor == null) {
                         return Long.MAX_VALUE;
                     }
+                    final FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
+                    stat = Os.fstatvfs(fileDescriptor);
+                }
+            }
+
+            // this is the same formula used inside the FsStat class
+            return stat.f_bavail * stat.f_frsize;
+        } catch (final IOException | ErrnoException e) {
+            return Long.MAX_VALUE;
+        }
+    }
 
     /**
      * Only using Java I/O. Creates the directory named by this abstract pathname, including any

app/src/main/java/us/shandian/giga/util/Utility.java

@@ -40,20 +40,6 @@ public class Utility {
         UNKNOWN
     }
 
-    /**
-     * Get amount of free system's memory.
-     * @return free memory (bytes)
-     */
-    public static long getSystemFreeMemory() {
-        try {
-            final StatFs statFs = new StatFs(Environment.getExternalStorageDirectory().getPath());
-            return statFs.getAvailableBlocksLong() * statFs.getBlockSizeLong();
-        } catch (final Exception e) {
-            // do nothing
-        }
-        return -1;
-    }
-
     public static String formatBytes(long bytes) {
         Locale locale = Locale.getDefault();
         if (bytes < 1024) {