Add built-in broadcast receiver to open files

app/src/main/AndroidManifest.xml

@@ -90,6 +90,14 @@
             android:name="com.termux.app.TermuxService"
             android:exported="false" />
 
+        <receiver android:name=".app.TermuxOpenReceiver" />
+
+        <provider android:authorities="com.termux.files"
+                  android:readPermission="android.permission.permRead"
+                  android:exported="true"
+                  android:grantUriPermissions="true"
+                  android:name="com.termux.app.TermuxOpenReceiver$ContentProvider" />
+
     </application>
 
 </manifest>

app/src/main/java/com/termux/app/TermuxOpenReceiver.java

@@ -0,0 +1,179 @@
+package com.termux.app;
+
+import android.content.ActivityNotFoundException;
+import android.content.BroadcastReceiver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.Intent;
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.net.Uri;
+import android.os.ParcelFileDescriptor;
+import android.provider.MediaStore;
+import android.util.Log;
+import android.webkit.MimeTypeMap;
+
+import com.termux.terminal.EmulatorDebug;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+public class TermuxOpenReceiver extends BroadcastReceiver {
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        final Uri data = intent.getData();
+        if (data == null) {
+            Log.e(EmulatorDebug.LOG_TAG, "termux-open: Called without intent data");
+            return;
+        }
+
+        final boolean isExternalUrl = data.getScheme() != null && !data.getScheme().equals("file");
+        if (isExternalUrl) {
+            Intent viewIntent = new Intent(Intent.ACTION_VIEW, data);
+            try {
+                context.startActivity(viewIntent);
+            } catch (ActivityNotFoundException e) {
+                Log.e(EmulatorDebug.LOG_TAG, "termux-open: No app handles the url " + data);
+            }
+            return;
+        }
+
+        final String filePath = data.getPath();
+        final String contentTypeExtra = intent.getStringExtra("content-type");
+        final boolean useChooser = intent.getBooleanExtra("chooser", false);
+        final String actionExtra = intent.getAction();
+
+        String intentAction = null;
+        if (actionExtra == null) {
+            intentAction = Intent.ACTION_VIEW;
+        } else {
+            switch (actionExtra) {
+                case "edit":
+                    intentAction = Intent.ACTION_EDIT;
+                    break;
+                case "send":
+                    intentAction = Intent.ACTION_SEND;
+                    break;
+                case "view":
+                    intentAction = Intent.ACTION_VIEW;
+                    break;
+                default:
+                    Log.e(EmulatorDebug.LOG_TAG, "Invalid action '" + actionExtra + "', using 'view'");
+                    break;
+            }
+        }
+
+        final File fileToShare = new File(filePath);
+        if (!(fileToShare.isFile() && fileToShare.canRead())) {
+            Log.e(EmulatorDebug.LOG_TAG, "termux-open: Not a readable file: '" + fileToShare.getAbsolutePath() + "'");
+            return;
+        }
+
+        Intent sendIntent = new Intent();
+        sendIntent.setAction(intentAction);
+        Uri uriToShare = Uri.withAppendedPath(Uri.parse("content://com.termux.files/"), filePath);
+        sendIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_GRANT_READ_URI_PERMISSION);
+
+        String contentTypeToUse;
+        if (contentTypeExtra == null) {
+            String fileName = fileToShare.getName();
+            int lastDotIndex = fileName.lastIndexOf('.');
+            String fileExtension = fileName.substring(lastDotIndex + 1, fileName.length());
+            MimeTypeMap mimeTypes = MimeTypeMap.getSingleton();
+            // Lower casing makes it work with e.g. "JPG":
+            contentTypeToUse = mimeTypes.getMimeTypeFromExtension(fileExtension.toLowerCase());
+            if (contentTypeToUse == null) contentTypeToUse = "application/octet-stream";
+        } else {
+            contentTypeToUse = contentTypeExtra;
+        }
+
+        sendIntent.putExtra(Intent.EXTRA_SUBJECT, fileToShare.getName());
+
+        if (Intent.ACTION_SEND.equals(intentAction)) {
+            sendIntent.putExtra(Intent.EXTRA_STREAM, uriToShare);
+            sendIntent.setType(contentTypeToUse);
+        } else {
+            sendIntent.setDataAndType(uriToShare, contentTypeToUse);
+        }
+
+        if (useChooser) {
+            sendIntent = Intent.createChooser(sendIntent, null).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        }
+
+        context.startActivity(sendIntent);
+    }
+
+    public static class ContentProvider extends android.content.ContentProvider {
+
+        @Override
+        public boolean onCreate() {
+            return true;
+        }
+
+        @Override
+        public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+            File file = new File(uri.getPath());
+            String fileName = file.getName();
+
+            if (projection == null) {
+                projection = new String[]{
+                    MediaStore.MediaColumns.DISPLAY_NAME,
+                    MediaStore.MediaColumns.SIZE,
+                    MediaStore.MediaColumns._ID
+                };
+            }
+
+            Object[] row = new Object[projection.length];
+            for (int i = 0; i < projection.length; i++) {
+                String column = projection[i];
+                Object value;
+                switch (column) {
+                    case MediaStore.MediaColumns.DISPLAY_NAME:
+                        value = file.getName();
+                        break;
+                    case MediaStore.MediaColumns.SIZE:
+                        value = (int) file.length();
+                        break;
+                    case MediaStore.MediaColumns._ID:
+                        value = 1;
+                        break;
+                    default:
+                        value = null;
+                }
+                row[i] = value;
+            }
+
+            MatrixCursor cursor = new MatrixCursor(projection);
+            cursor.addRow(row);
+            return cursor;
+        }
+
+        @Override
+        public String getType(Uri uri) {
+            return null;
+        }
+
+        @Override
+        public Uri insert(Uri uri, ContentValues values) {
+            return null;
+        }
+
+        @Override
+        public int delete(Uri uri, String selection, String[] selectionArgs) {
+            return 0;
+        }
+
+        @Override
+        public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
+            return 0;
+        }
+
+        @Override
+        public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+            File file = new File(uri.getPath());
+            return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
+        }
+    }
+
+}