Transactional Blocks

[benbjohnson]

Overview

This pull request includes support for Transactional Blocks. This allows users to execute a transaction within a function without having to worry about deferring the commit/rollback. Any error returned from the function or that returns from the transaction's Commit() is returned from the block.

The transactional block is executed using the following method:

func (db *DB) Do(fn func(*RWTransaction) error) error

A read-only transactional block may be added in the future. Not sure what to call it yet.

Example

func myFunc() error {
    ...

    // Execute several commands within a write transaction.
    err := db.Do(func(t *RWTransaction) error {
        if err := t.CreateBucket("widgets"); err != nil {
            return err
        }
        if err := t.Put("widgets", []byte("foo"), []byte("bar")); err != nil {
            return err
        }
        return nil
    })

    if err != nil {
        return err
    }

    ...
}

/cc @snormore