This change ports some changes from the main PBSS PR:
- get rid of callback function in `trie.Database.Commit` which is not required anymore
- rework the `nodeResolver` in `trie.Iterator` to make it compatible with multiple state scheme
- some other shallow changes in tests and typo-fixes
This PR introduces a node scheme abstraction. The interface is only implemented by `hashScheme` at the moment, but will be extended by `pathScheme` very soon.
Apart from that, a few changes are also included which is worth mentioning:
- port the changes in the stacktrie, tracking the path prefix of nodes during commit
- use ethdb.Database for constructing trie.Database. This is not necessary right now, but it is required for path-based used to open reverse diff freezer
With this commit, core/state's access to the underlying key/value database is
mediated through an interface. Database errors are tracked in StateDB and
returned by CommitTo or the new Error method.
Motivation for this change: We can remove the light client's duplicated copy of
core/state. The light client now supports node iteration, so tracing and storage
enumeration can work with the light client (not implemented in this commit).
Guillaume Ballet
rjl493456442
Martin Holst Swende
Péter Szilágyi
Felix Lange
Felix Lange