Pippin
====

Pippin is a database inspired by distributed version control systems (notably
git). Unlike git it is designed to store thousands to millions (or more) small
objects in only a few dozen files. Unlike regular databases, it is designed
with distributed synchronisation in mind and convenient access to objects of a
single user-defined type. Pippin does not (currently) have a true index for
searching its database, but does have partitioning to reduce searches to a
smaller subset.

For more, see the documentation in [src/lib.rs](src/lib.rs) or take a look at the [examples](examples/).


Change-log
----------

### Pippin 0.1.0

Pippin is 'alpha' status.

Partition-oriented usage (i.e. a single 'partition') should have all the basic
features there and is ready for testing, but the API may change. Perhaps the
biggest caveat is that every commit is written to a new file due to not yet
working out how to safely extend files.

Repository-oriented usage is still far from ready.

What should work:

*   persistance of data within a single 'partition' via snapshots
*   storing changes via commit logs
*   reconstruction of state from snapshot + logs
*   auto-detecting latest state(s)
*   merging of multiple latest states (may require user-interaction)
*   checksumming & detecting corrupt stuff
*   recovery of some data when files are missing (though this needs more work)
*   file formats are mosly final except that headers will get extra data and object diffs

What is planned:

*   tracking mutliple partitions in a distributed manner via file headers
*   user-specified classifiers
*   (possibly) indexes of some kind
*   reclassification of objects as necessary
*   partially-automated division of "large" partitions via classifiers
*   object diffs (current commits include a full copy of all changed entries)
*   log file extension (currently a new file is used per commit to avoid data loss)


Doc
----

The [doc](doc/) directory contains some file-format documentation and various notes
planning Pippin's development.

Tickets were originally stored in files. Several "tags" are still in use; where
applicable these are mentioned in tickets and can be used to find relevant bits
of code. All of these can be found with grep:

    egrep -IR "#00[0-9]{2}" doc/ src/


Building, running, testing
-------------------------

Pippin uses [Cargo](http://crates.io/). A few example commands:

    cargo test
    cargo build --release
    cargo run --example pippincmd -- -h
    cargo help run
    cargo doc && open target/doc/pippin/index.html

Generated binaries can be found in the `target` directory.


## Licence

Pippin is licenced under the Mozilla Public License, version 2.0.
A copy of this licence can be found in the LICENSE-MPL2.txt file
or obtained at http://mozilla.org/MPL/2.0/ .

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the MPL-2.0 license, shall be
licensed as above, without any additional terms or conditions.