Write errors are often delayed and reported only by the close.
The extra close in defer on success is harmless, (*os.File).Close
protects itself against multiple closes, and this way it's immediately
obvious there is no code path that would leak open files.
Transaction created from Do() and With() are now considered "managed".
Managed transactions cannot be manually committed or rolled back since
the Do() and With() functions provide that functionally automatically.
Previously, a Tx could be manually committed and then any changes after
that would be lost.
Changes munmap to return an error and the DB now implements io.Closer.
I also removed all the OS and Syscall mocking because it's causing issues.
Corrupt file tests need to be recreated but directly using the file system
instead.
Functions such as DB.Put(), DB.Get(), and DB.Delete() were originally
added to be easy to use, however, after implementing Bolt in multiple
projects I have found these ease-of-use functions useless. Nearly
every use case requires multiple calls in a single transaction.
Using the DB ease of use functions turned out to be an antipattern.
I changed the Transaction/RWTransaction types to Tx/RWTx, respectively. This makes the naming
more consistent with other packages such as database/sql. The txnid is changed to txid as well.
Fixes#54. Previously the DB was calculating a minimum mmap size but
using the wrong variable after it calculated the size. This commit
changes the DB to use the correct variable.
