Setting a priority folder

Depending on user actions, your client application may need to interrupt a synchronization in progress and begin synchronizing a new folder. The priority folder synchronization feature helps you reduce the time required for making media content from a certain folder available for viewing or playing.

Suppose your application must display up-to-date folder information in a mediastore file browser and, during a synchronization, the user selects a different folder to view or play tracks from. In this case, you should do a priority synchronization of the newly selected folder. This action displays the folder's metadata and makes the folder's media files playable ahead of those from other folders. If you're running mm-detect, which automatically starts synchronizing newly detected mediastores by calling mm-sync, your application may have to set a new priority folder to react to a change in the user's activity shortly after they insert a mediastore.

To start a priority folder synchronization, call mm_sync_control() or run the sync_control command with the following extended option settings:

• the action key is set to "priority_folder_set"
• the folderID key is set to the folderID of the folder you want to synchronize immediately (you can look up the folderID in the folders table)

When it receives such a request, mm-sync interrupts any synchronization in progress on the same device on which the priority folder is stored and synchronizes the priority folder's contents before resuming the original synchronization.

The priority folder feature has the following behavior:

• Requests to synchronize the current folder are silently ignored.
• Priority synchronizations can't be recursive; only the priority folder (and not its subfolders) is synchronized before the original synchronization resumes.
• Priority synchronizations can be done only on a mediastore currently being synchronized, because the invocation command requires a valid operation ID.
• The synchronization passes done for the priority folder are the same as those requested in the original synchronization.
• New priority synchronization requests preempt any priority synchronization in progress, meaning the second priority folder gets synchronized, then the first folder (whose synchronization was interrupted) gets synchronized, and then the original synchronization resumes.
• Priority synchronization requests are queued, so if a second request is sent before the synchronization for the first request is started, the second priority folder gets synchronized, then the first folder, and then the original synchronization resumes.