avoid loading uris from content resolver on main thread

because uris might point to network locations, which triggers an exception
main thread is still blocked by loading, this is purely to get around the crash (files are small, and usually stored locally)

app/src/main/java/helium314/keyboard/latin/common/FileUtils.java

@@ -6,12 +6,18 @@
 
 package helium314.keyboard.latin.common;
 
+import android.content.Context;
+import android.net.Uri;
+
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.concurrent.CountDownLatch;
+
+import helium314.keyboard.latin.utils.ExecutorUtils;
 
 /**
  * A simple class to help with removing directories recursively.
@@ -47,7 +53,32 @@ public class FileUtils {
         return hasDeletedAllFiles;
     }
 
-    public static void copyStreamToNewFile(InputStream in, File outfile) throws IOException {
+    /**
+     *  copy data to file on different thread to avoid NetworkOnMainThreadException
+     *  still effectively blocking, as we only use small files which are mostly stored locally
+     */
+    public static void copyContentUriToNewFile(final Uri uri, final Context context, final File outfile) throws IOException {
+        final boolean[] allOk = new boolean[] { true };
+        final CountDownLatch wait = new CountDownLatch(1);
+        ExecutorUtils.getBackgroundExecutor(ExecutorUtils.KEYBOARD).execute(() -> {
+            try {
+                copyStreamToNewFile(context.getContentResolver().openInputStream(uri), outfile);
+            } catch (IOException e) {
+                allOk[0] = false;
+            } finally {
+                wait.countDown();
+            }
+        });
+        try {
+            wait.await();
+        } catch (InterruptedException e) {
+            allOk[0] = false;
+        }
+        if (!allOk[0])
+            throw new IOException("could not copy from uri");
+    }
+
+    public static void copyStreamToNewFile(final InputStream in, final File outfile) throws IOException {
         File parentFile = outfile.getParentFile();
         if (parentFile == null || (!parentFile.exists() && !parentFile.mkdirs())) {
             throw new IOException("could not create parent folder");
@@ -57,7 +88,7 @@ public class FileUtils {
         out.close();
     }
 
-    public static void copyStreamToOtherStream(InputStream in, OutputStream out) throws IOException {
+    public static void copyStreamToOtherStream(final InputStream in, final OutputStream out) throws IOException {
         byte[] buf = new byte[1024];
         int len;
         while ((len = in.read(buf)) > 0) {

app/src/main/java/helium314/keyboard/latin/settings/AboutFragment.kt

@@ -17,6 +17,7 @@ import androidx.appcompat.app.AlertDialog
 import androidx.preference.Preference
 import helium314.keyboard.latin.BuildConfig
 import helium314.keyboard.latin.R
+import helium314.keyboard.latin.utils.ExecutorUtils
 import helium314.keyboard.latin.utils.Log
 import helium314.keyboard.latin.utils.SpannableStringUtils
 
@@ -46,10 +47,12 @@ class AboutFragment : SubScreenFragment() {
     private val logFilePicker = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
         if (result.resultCode != Activity.RESULT_OK) return@registerForActivityResult
         val uri = result.data?.data ?: return@registerForActivityResult
+        ExecutorUtils.getBackgroundExecutor(ExecutorUtils.KEYBOARD).execute {
             activity?.contentResolver?.openOutputStream(uri)?.use { os ->
                 os.bufferedWriter().use { it.write(Log.getLog().joinToString("\n")) }
             }
         }
+    }
 
     private fun setupHiddenFeatures() {
         findPreference<Preference>("hidden_features")?.onPreferenceClickListener =

app/src/main/java/helium314/keyboard/latin/settings/AdvancedSettingsFragment.kt

@@ -43,6 +43,7 @@ import helium314.keyboard.latin.settings.SeekBarDialogPreference.ValueProxy
 import helium314.keyboard.latin.utils.AdditionalSubtypeUtils
 import helium314.keyboard.latin.utils.CUSTOM_LAYOUT_PREFIX
 import helium314.keyboard.latin.utils.DeviceProtectedUtils
+import helium314.keyboard.latin.utils.ExecutorUtils
 import helium314.keyboard.latin.utils.JniUtils
 import helium314.keyboard.latin.utils.editCustomLayout
 import helium314.keyboard.latin.utils.getStringResourceOrName
@@ -54,6 +55,7 @@ import java.io.FileInputStream
 import java.io.FileOutputStream
 import java.io.IOException
 import java.io.OutputStream
+import java.util.concurrent.CountDownLatch
 import java.util.zip.ZipEntry
 import java.util.zip.ZipInputStream
 import java.util.zip.ZipOutputStream
@@ -207,12 +209,15 @@ class AdvancedSettingsFragment : SubScreenFragment() {
     private fun copyLibrary(uri: Uri) {
         val tmpfile = File(requireContext().filesDir.absolutePath + File.separator + "tmplib")
         try {
-            val inputStream = requireContext().contentResolver.openInputStream(uri)
+            val otherTemporaryFile = File(requireContext().filesDir.absolutePath + File.separator + "tmpfile")
+            FileUtils.copyContentUriToNewFile(uri, requireContext(), otherTemporaryFile)
+            val inputStream = FileInputStream(otherTemporaryFile)
             val outputStream = FileOutputStream(tmpfile)
             outputStream.use {
                 tmpfile.setReadOnly() // as per recommendations in https://developer.android.com/about/versions/14/behavior-changes-14#safer-dynamic-code-loading
                 FileUtils.copyStreamToOtherStream(inputStream, it)
             }
+            otherTemporaryFile.delete()
 
             val checksum = ChecksumCalculator.checksum(tmpfile.inputStream()) ?: ""
             if (checksum == JniUtils.expectedDefaultChecksum()) {
@@ -269,7 +274,7 @@ class AdvancedSettingsFragment : SubScreenFragment() {
 
     private fun loadImage(uri: Uri, night: Boolean) {
         val imageFile = Settings.getCustomBackgroundFile(requireContext(), night)
-        FileUtils.copyStreamToNewFile(requireContext().contentResolver.openInputStream(uri), imageFile)
+        FileUtils.copyContentUriToNewFile(uri, requireContext(), imageFile)
         try {
             BitmapFactory.decodeFile(imageFile.absolutePath)
         } catch (_: Exception) {
@@ -334,6 +339,9 @@ class AdvancedSettingsFragment : SubScreenFragment() {
             if (backupFilePatterns.any { path.matches(it) })
                 protectedFiles.add(file)
         }
+        var error: String? = ""
+        val wait = CountDownLatch(1)
+        ExecutorUtils.getBackgroundExecutor(ExecutorUtils.KEYBOARD).execute {
             try {
                 activity?.contentResolver?.openOutputStream(uri)?.use { os ->
                     // write files to zip
@@ -361,18 +369,28 @@ class AdvancedSettingsFragment : SubScreenFragment() {
                     zipStream.close()
                 }
             } catch (t: Throwable) {
-            // inform about every error
+                error = t.message
                 Log.w(TAG, "error during backup", t)
-            infoDialog(requireContext(), requireContext().getString(R.string.backup_error, t.message))
+            } finally {
+                wait.countDown()
+            }
+        }
+        wait.await()
+        if (!error.isNullOrBlank()) {
+            // inform about every error
+            infoDialog(requireContext(), requireContext().getString(R.string.backup_error, error))
         }
     }
 
     private fun restore(uri: Uri) {
+        var error: String? = ""
+        val wait = CountDownLatch(1)
+        ExecutorUtils.getBackgroundExecutor(ExecutorUtils.KEYBOARD).execute {
             try {
                 activity?.contentResolver?.openInputStream(uri)?.use { inputStream ->
                     ZipInputStream(inputStream).use { zip ->
                         var entry: ZipEntry? = zip.nextEntry
-                    val filesDir = requireContext().filesDir?.path ?: return
+                        val filesDir = requireContext().filesDir?.path ?: return@execute
                         val deviceProtectedFilesDir = DeviceProtectedUtils.getFilesDir(requireContext()).path
                         Settings.getInstance().stopListener()
                         while (entry != null) {
@@ -403,10 +421,17 @@ class AdvancedSettingsFragment : SubScreenFragment() {
                     }
                 }
             } catch (t: Throwable) {
-            // inform about every error
+                error = t.message
                 Log.w(TAG, "error during restore", t)
-            infoDialog(requireContext(), requireContext().getString(R.string.restore_error, t.message))
             } finally {
+                wait.countDown()
+            }
+        }
+        wait.await()
+        if (!error.isNullOrBlank()) {
+            // inform about every error
+            infoDialog(requireContext(), requireContext().getString(R.string.restore_error, error))
+        }
         checkVersionUpgrade(requireContext())
         Settings.getInstance().startListener()
         val additionalSubtypes = Settings.readPrefAdditionalSubtypes(sharedPreferences, resources);
@@ -419,7 +444,6 @@ class AdvancedSettingsFragment : SubScreenFragment() {
         setupPreferences()
         KeyboardSwitcher.getInstance().forceUpdateKeyboardTheme(requireContext())
     }
-    }
 
     // todo (later): remove this when new package name has been in use for long enough, this is only for migrating from old openboard name
     private fun upgradeFileNames(originalName: String): String {

app/src/main/java/helium314/keyboard/latin/settings/SettingsFragment.java

@@ -128,7 +128,7 @@ public final class SettingsFragment extends PreferenceFragmentCompat {
         if (intent.getResultCode() != Activity.RESULT_OK || intent.getData() == null) return;
         final Uri uri = intent.getData().getData();
         if (uri != null)
-            saveCrashReport(uri);
+            ExecutorUtils.getBackgroundExecutor(ExecutorUtils.KEYBOARD).execute(() -> saveCrashReport(uri));
     });
 
     private void saveCrashReport(final Uri uri) {

app/src/main/java/helium314/keyboard/latin/utils/CustomLayoutUtils.kt

@@ -18,6 +18,7 @@ import helium314.keyboard.keyboard.internal.keyboard_parser.POPUP_KEYS_NORMAL
 import helium314.keyboard.keyboard.internal.keyboard_parser.SimpleKeyboardParser
 import helium314.keyboard.keyboard.internal.keyboard_parser.addLocaleKeyTextsToParams
 import helium314.keyboard.latin.R
+import helium314.keyboard.latin.common.FileUtils
 import helium314.keyboard.latin.settings.Settings
 import java.io.File
 import java.io.IOException
@@ -28,8 +29,10 @@ fun loadCustomLayout(uri: Uri?, languageTag: String, context: Context, onAdded:
         return infoDialog(context, context.getString(R.string.layout_error, "layout file not found"))
     val layoutContent: String
     try {
-        val i = context.contentResolver.openInputStream(uri)
-        layoutContent = i?.use { it.reader().readText() } ?: throw IOException()
+        val tmpFile = File(context.filesDir.absolutePath + File.separator + "tmpfile")
+        FileUtils.copyContentUriToNewFile(uri, context, tmpFile)
+        layoutContent = tmpFile.readText()
+        tmpFile.delete()
     } catch (e: IOException) {
         return infoDialog(context, context.getString(R.string.layout_error, "cannot read layout file"))
     }

app/src/main/java/helium314/keyboard/latin/utils/NewDictionaryAdder.kt

@@ -30,8 +30,7 @@ class NewDictionaryAdder(private val context: Context, private val onAdded: ((Bo
 
         cachedDictionaryFile.delete()
         try {
-            val i = context.contentResolver.openInputStream(uri)
-            FileUtils.copyStreamToNewFile(i, cachedDictionaryFile)
+            FileUtils.copyContentUriToNewFile(uri, context, cachedDictionaryFile)
         } catch (e: IOException) {
             return onDictionaryLoadingError(R.string.dictionary_load_error)
         }