Xcode, changing applications subfolder?

Question

Hi have noticed today whilst writing a simple iPhone app that Xcode sometimes starts a new folder in applications, whilst your still working on the same app.

/Users/Fuzzygoat/Library/Application Support/iPhone Simulator/User/Applications/4E5EF4F0-F410-46A6-888C-0D23BB97D2DC

Does anyone know what causes Xcode to swap to a new app folder (i.e. the one named "4E5EF4F0-F410-46A6-888C-0D23BB97D2DC")

EDIT_001: One thing I have noticed is that I have been doing a lot of quitting an application and restarting to check a set of archive methods, and that does tend to confuse it sometimes. A couple of times it has not found saved data, I guess this is just a side effect of constantly running the simulator over and over via Xcode. Things seem to go just fine if I test on the Simulator without Xcode, for a start the folder keeps the same name.

NB: I am using NSSearchPathForDirectoriesInDomains to get the documents folder each time.

gary

Answer 1

I know it happens when you restart the simulator. At least, that is when I have definitely observed it.

The developer docs tell you that the path can change without warning and to never depend on it. This is part of the iPhone's security system which prevents malicious apps from using hardcoded paths to find and exploit system resources.

Answer 2

For security reasons, iPhone OS restricts an application (including its preferences and data) to a unique location in the file system. This restriction is part of the security feature known as the application’s “sandbox.” The sandbox is a set of fine-grained controls limiting an application’s access to files, preferences, network resources, hardware, and so on. In iPhone OS, an application and its data reside in a secure location that no other application can access. When an application is installed, the system computes a unique opaque identifier for the application. Using a root application directory and this identifier, the system constructs a path to the application’s home directory. Thus an application’s home directory could be depicted as having the following structure:

  /ApplicationRoot/ApplicationID/

During the installation process, the system creates the application’s home directory and several key subdirectories, configures the application sandbox, and copies the application bundle to the home directory. The use of a unique location for each application and its data simplifies backup-and-restore operations, application updates, and uninstallation. For more information about the application-specific directories created for each application and about application updates and backup-and-restore operations.

see The Application Sandbox