The LevelDB docs seem to indicate that an iterator will not take
snapshots (even providing instructions on how to do so yourself).
In several of the places we use them, we assume snapshots to have
been taken.
In order to make sure LevelDB doesn't change out from under us
(and to prevent the next person who reads the docs from having the
same fright I did), verify that snapshots are taken in our tests.
Use of `sprintf` is seen as a red flag as many of its uses are insecure.
OpenBSD warns about it while compiling, and some modern platforms, e.g.
[cloudlibc from cloudabi](https://github.com/NuxiNL/cloudlibc) don't
even provide it anymore.
Although our uses of these functions are secure, it can't hurt to
replace them anyway. There are only 3 occurences left, all in the
tests.
Remove the nType and nVersion as parameters to all serialization methods
and functions. There is only one place where it's read and has an impact
(in CAddress), and even there it does not impact any of the recursively
invoked serializers.
Instead, the few places that need nType or nVersion are changed to read
it directly from the stream object, through GetType() and GetVersion()
methods which are added to all stream classes.
I made a silly mistake in a database wrapper where keys
were sorted by char instead of uint8_t. As x86 char is signed
the sorting for the block index database was messed up, resulting
in a segfault due to missing records.
Add a test to catch:
- Wrong sorting
- Seeking errors
- Iteration result not complete
Pass parent wrapper directly instead of obfuscation key. This
makes it possible for other databases which re-use this code
to use other properties from the database.
Add a namespace dbwrapper_private for private functions to be used
only in dbwrapper.h/cpp and dbwrapper_tests.
