Feature #4232: [ce, ee, pr, compare] redo diffs, support side by side diffs, html diffs
[ce, ee] unify controllers that use diffs
Currently diffs are being used in these controllers:
- files controller: eg
- compare controller: eg.
- changeset controller: eg.
- pullrequest controller: eg.
These controllers use about 80% duplicate code which can be moved to a common base
Also some controller have options such as increase/decrease context which are not implemented in other controllers.