FileShuttle: allow OPEN_DOCUMENT_TREE [WIP]

implement isChildDocument() for this.

app/build.gradle

@@ -7,8 +7,8 @@ android {
         applicationId "net.typeblog.shelter"
         minSdkVersion 24
         targetSdkVersion 28
-        versionCode 7
+        versionCode 8
-        versionName "1.2"
+        versionName "1.3-alpha"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
     buildTypes {

app/src/main/aidl/net/typeblog/shelter/services/IFileShuttleService.aidl

@@ -12,4 +12,5 @@ interface IFileShuttleService {
     ParcelFileDescriptor openThumbnail(String path, in Point sizeHint);
     String createFile(String path, String mimeType, String displayName);
     String deleteFile(String path);
+    boolean isChildOf(String parentPath, String childPath);
 }

app/src/main/java/net/typeblog/shelter/services/FileShuttleService.java

@@ -12,6 +12,7 @@ import android.os.Handler;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.ParcelFileDescriptor;
+import android.os.RemoteException;
 import android.provider.DocumentsContract;
 import android.provider.MediaStore;
 import android.support.annotation.Nullable;
@@ -164,6 +165,19 @@ public class FileShuttleService extends Service {
             f.delete();
             return f.getParentFile().getAbsolutePath();
         }
+
+        @Override
+        public boolean isChildOf(String parent, String child) {
+            File parentFile = new File(resolvePath(parent));
+            File childFile = new File(resolvePath(child));
+            String parentPath = parentFile.getAbsolutePath();
+            if (parentPath.charAt(parentPath.length() - 1) != '/') {
+                parentPath += "/"; // Make sure it ends with '/'
+            }
+            return parentFile.exists() && parentFile.isDirectory()
+                    && childFile.exists()
+                    && childFile.getAbsolutePath().startsWith(parentPath);
+        }
     };
 
     @Nullable

app/src/main/java/net/typeblog/shelter/util/CrossProfileDocumentsProvider.java

@@ -127,7 +127,9 @@ public class CrossProfileDocumentsProvider extends DocumentsProvider {
                 Utility.isProfileOwner(getContext()) ?
                         getContext().getString(R.string.fragment_profile_main) :
                         getContext().getString(R.string.fragment_profile_work));
-        row.add(DocumentsContract.Root.COLUMN_FLAGS, DocumentsContract.Root.FLAG_SUPPORTS_CREATE);
+        row.add(DocumentsContract.Root.COLUMN_FLAGS,
+                DocumentsContract.Root.FLAG_SUPPORTS_CREATE | DocumentsContract.Root.FLAG_LOCAL_ONLY |
+                        DocumentsContract.Root.FLAG_SUPPORTS_IS_CHILD); // SUPPORTS_IS_CHILD is required for OPEN_DOCUMENT_TREE
         return result;
     }
 
@@ -211,6 +213,16 @@ public class CrossProfileDocumentsProvider extends DocumentsProvider {
         }
     }
 
+    @Override
+    public boolean isChildDocument(String parentDocumentId, String documentId) {
+        ensureServiceBound();
+        try {
+            return mService.isChildOf(parentDocumentId, documentId);
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
+
     private void includeFile(MatrixCursor cursor, Map<String, Object> fileInfo) {
         final MatrixCursor.RowBuilder row = cursor.newRow();
         for (String col : DEFAULT_DOCUMENT_PROJECTION) {