Modify code for download folder selection to work with sandboxing

NSOpenSavePanelDelegate methods do not work with sandboxing. The URLs returned by the delegate callbacks are inaccessible until NSOpenPanel calls the completion handler. A workaround is to validate the URL after it was selected. When the URL is inaccessible (i.e. not writable) then an error is shown and the open panel reopens, giving the user the opportunity to choose a different directory or cancel.
ViennaRSS · Jul 9, 2023 · c7f5ff6 · c7f5ff6
1 parent 929b494
commit c7f5ff6
Show file tree

Hide file tree

Showing 2 changed files with 40 additions and 31 deletions.
diff --git a/Vienna/Sources/Preferences window/GeneralPreferencesViewController.h b/Vienna/Sources/Preferences window/GeneralPreferencesViewController.h
@@ -20,7 +20,7 @@
 
 @import Cocoa;
 
-@interface GeneralPreferencesViewController : NSViewController <NSOpenSavePanelDelegate>
+@interface GeneralPreferencesViewController : NSViewController
 
 // Action functions
 -(IBAction)changeCheckFrequency:(id)sender;

diff --git a/Vienna/Sources/Preferences window/GeneralPreferencesViewController.m b/Vienna/Sources/Preferences window/GeneralPreferencesViewController.m
@@ -278,20 +278,43 @@ -(IBAction)changeOpenLinksInExternalBrowser:(id)sender
  * Bring up the folder browser to pick a new download folder.
  */
 -(IBAction)changeDownloadFolder:(id)sender
+{
+    NSFileManager *fileManager = NSFileManager.defaultManager;
+    [self chooseDirectoryWithRootDirectory:fileManager.vna_downloadsDirectory];
+}
+
+- (void)chooseDirectoryWithRootDirectory:(NSURL *)rootDirectoryURL
 {
     NSOpenPanel *openPanel = [NSOpenPanel openPanel];
-    openPanel.delegate = self;
     openPanel.canChooseFiles = NO;
     openPanel.canChooseDirectories = YES;
     openPanel.canCreateDirectories = YES;
     openPanel.allowsMultipleSelection = NO;
     openPanel.prompt = NSLocalizedString(@"Select",
                                          @"Label of a button on an open panel");
-
-    openPanel.directoryURL = NSFileManager.defaultManager.vna_downloadsDirectory;
+    openPanel.directoryURL = rootDirectoryURL;
     [openPanel beginSheetModalForWindow:self.view.window
-                      completionHandler:^(NSInteger returnCode) {
-        if (returnCode == NSModalResponseOK) {
+                      completionHandler:^(NSModalResponse result) {
+        if (result == NSModalResponseOK && openPanel.URL) {
+            NSFileManager *fileManager = NSFileManager.defaultManager;
+            if (![fileManager isWritableFileAtPath:openPanel.URL.path]) {
+                NSString *str =
+                    NSLocalizedString(@"This folder cannot be chosen because "
+                                       "you don’t have permission.",
+                                      @"Message text of a modal alert");
+                NSDictionary *userInfoDict = @{NSLocalizedDescriptionKey: str};
+                NSError *error =
+                    [NSError errorWithDomain:NSCocoaErrorDomain
+                                        code:NSFileWriteNoPermissionError
+                                    userInfo:userInfoDict];
+                [self presentError:error
+                    modalForWindow:self.view.window
+                          delegate:self
+                didPresentSelector:@selector(didPresentErrorWithRecovery:contextInfo:)
+                       contextInfo:(__bridge_retained void *)openPanel.URL];
+                return;
+            }
+
             NSError *error = nil;
             NSData *data = [VNASecurityScopedBookmark bookmarkDataFromFileURL:openPanel.URL
                                                                         error:&error];
@@ -300,12 +323,22 @@ -(IBAction)changeDownloadFolder:(id)sender
                 [userDefaults setObject:data forKey:MAPref_DownloadsFolderBookmark];
                 [self updateDownloadsPopUp:openPanel.URL.path];
             }
-        } else if (returnCode == NSModalResponseCancel) {
+        } else if (result == NSModalResponseCancel) {
             [self->downloadFolder selectItemAtIndex:0];
         }
     }];
 }
 
+// Do not change this method signature without consulting the documentation of
+// `-presentError:modalForWindow:delegate:didPresentSelector:contextInfo:`. If
+// the signature does not match, the contextInfo parameter might not work.
+- (void)didPresentErrorWithRecovery:(BOOL)didRecover
+                        contextInfo:(nullable void *)contextInfo
+{
+    NSURL *previousDirectoryURL = (__bridge_transfer NSURL *)contextInfo;
+    [self chooseDirectoryWithRootDirectory:previousDirectoryURL];
+}
+
 /* updateDownloadsPopUp
  * Update the Downloads folder popup with the specified download folder path and image.
  */
@@ -445,28 +478,4 @@ -(void)dealloc
     [[NSNotificationCenter defaultCenter] removeObserver:self];
 }
 
-// MARK: - NSOpenSavePanelDelegate
-
-- (BOOL)panel:(id)sender shouldEnableURL:(NSURL *)url {
-    NSFileManager *fileManager = NSFileManager.defaultManager;
-    return [fileManager isWritableFileAtPath:url.path];
-}
-
-- (BOOL)panel:(id)sender validateURL:(NSURL *)url error:(NSError **)outError {
-    NSFileManager *fileManager = NSFileManager.defaultManager;
-    BOOL isWritable = [fileManager isWritableFileAtPath:url.path];
-    if (!isWritable) {
-        NSString *str = NSLocalizedString(@"This folder cannot be chosen "
-                                          "because you don’t have permission.",
-                                          @"Message text of a modal alert");
-        NSDictionary *userInfoDict = @{NSLocalizedDescriptionKey: str};
-        if (outError) {
-            *outError = [NSError errorWithDomain:NSCocoaErrorDomain
-                                            code:NSFileWriteNoPermissionError
-                                        userInfo:userInfoDict];
-        }
-    }
-    return isWritable;
-}
-
 @end