NSSavePanel和Sandbox

Question

我對理解新的Lion's Sandbox有些問題。

我知道Lion包含一個名爲Powerbox的可信守護進程，其工作是代表沙盒應用程序呈現和控制打開/保存對話框。

像Code Signing And Application Sandboxing Guide說：

Any time an application running inside a sandbox invokes an NSOpenPanel or NSSavePanel dialog, rather than showing the panels directly, AppKit automatically asks the Powerbox to present the dialog. From a developer perspective, there are no code changes required in terms of how these panels are used; this process is fully transparent.

After the user selects a set of files or directories, the Powerbox uses new functionality in the sandbox kernel module to expand the invoking application's sandbox to allow access to the selected files. By the time the application code queries the panel for the returned URLs or filenames, it already has permission to access those files, and can continue to use the files through almost any API it already uses.

確定。我沒有使用此代碼一些實際測試：

NSSavePanel *savePanel = [NSSavePanel savePanel]; 
savePanel.delegate = self; 

savePanel.directoryURL = ...; 
savePanel.nameFieldStringValue = ...; 

[savePanel beginSheetModalForWindow:self.window 
        completionHandler:^(NSInteger returnCode) { 
/* the completion handler */ 
}]; 

奇怪的是，NSOpenSavePanelDelegate方法的，是被稱爲前完成處理，沒有對文件系統訪問文件。

這是正確的嗎？

但如果是這樣，代表的方法如panel:validateURL:error:變得沒用！

你能幫我解釋一下應用程序和Powerbox之間的關係嗎？

Answer 1

聯繫Apple後，我可以確認Rob Keniger寫了什麼：NSOpenSavePanelDelegate方法無法訪問沙盒應用程序中的文件系統。