Calendar Talk:Feature Implementations:Calendar Cache

mvl's scratchpad:

offline (so not caching!)

Have one remote file. Have one local mirror of that file. Store all changes in the local mirror and in a changelist file. When online, sync.

syncing means: Download remote file. Play changelist on it. For every change, make sure the remote item is the item the change was applied to. When done, upload file, replace local mirror with new file, remove changelist. If the old item in the changelist doesn't match the item on the remote file, there was a conflict. This needs to be handled in a nice way. (Ask the user?)

changelist:

• item-id
• old item (or null, for addition)
• new item (or null, for deletion)

If an item was changed twice, only one item is needed. The new change item overwrites the old.

Assumes there is a file to be downloaded. Providers need a flag indicating they can do this. If there is no real file (like wcap, caldav), they could download into a storage calendar. It should still work when only part of the remote calendar is downloaded, because the local file is not used for anything execpt showing items when offline.