darcs-2.14.1: a distributed, interactive, smart revision control system

Darcs.Util.Tree.Plain

Contents

Description

The plain format implementation resides in this module. The plain format does not use any hashing and basically just wraps a normal filesystem tree in the hashed-storage API.

NB. The read function on Blobs coming from a plain tree is susceptible to file content changes. Since we use mmap in read, this will break referential transparency and produce unexpected results. Please always make sure that all parallel access to the underlying filesystem tree never mutates files. Unlink + recreate is fine though (in other words, the writePlainTree implemented in this module is safe in this respect).

Synopsis

# Obtaining Trees.

Please note that Trees obtained this way will contain Stub items. These need to be executed (they are IO actions) in order to be accessed. Use expand to do this. However, many operations are perfectly fine to be used on a stubbed Tree (and it is often more efficient to do everything that can be done before expanding a Tree).

# Writing trees.

Write out full tree to a plain directory structure. If you instead want to make incremental updates, refer to Darcs.Util.Tree.Monad.