State handles

Abstract

State handles mark application data states within a sequence of operations for preservation. Applications can maintain non-linear sets of operations that include multiple sequences of operations between state handles. Applications can determine a sequence of operations between any two state handles, allowing applications to change from the data state associated with one state handle to the data state associated with another state handle. The sequence of operations between any two state handles may include executing operations and/or reversing operations. An application automatically adds new branches in the set of operations to preserve the sequences of operations necessary to reconstruct data states of previously set handles and removes branches that are not needed. Applications may use state handles to implement non-linear undo and redo functions, to validate journal entries, to combine incremental operations into a cumulative operation, and to speculatively execute operations for error detection, user guidance, or performance optimization.