Parity-ethereum: Tracking issue util refactor

[debris]

• [x] @Hawstein journaldb and rocksdb dependencies should be separated from util.
• [ ] @Hawstein all trie traits from util should be separated from util.
• [x] migrations should be a library
• [x] @debris -> replace sha3::Hashable trait and all of usages of it with a simple function called hash
• [x] @debris -> this hash function should be a standalone library importing C impl of sha3 and tiny-keccak (for updatable sha3s)
• [x] @folsen util should not reexport bigint
• [x] @Hawstein util should not reexport ansi_term
• [x] @axelchalon -> util should not reexport HeapSizeOf
• [x] @Hawstein util should not reexport ParkingLot
• [x] @debris util should not reexport vector::*
• [x] @debris triehash should be separated from util
• [x] @Hawstein semantic_version should be separated from util
• [x] @Hawstein timer::PerfTimer should be a part of ethcore
• [x] @debris error::UtilError should be replaced by error_chain
• [ ] remove public reexports of traits modules
• ~flatten util subcrates~ (controversial)

[rphmeier]

I'm not convinced about flattening util subcrates. Why not group non-blockchain-specific utilities within a single folder?

[debris]

ok, let's keep all subcrates in util directory for now. We'll discuss it again someday

[debris]

I'll take

- [ ] replace sha3::Hashable trait and all of usages of it with a simple function called `hash`
- [ ] this `hash` function should be a standalone library importing C impl of sha3 and tiny-keccak (for updatable sha3s)

[NikVolf]

Also fixed hash should be crates.io library dependant on bigint and little more

[axelchalon]

I'll take util should not reexport HeapSizeOf for now

[debris]

I will take triehash should be separated from util

[folsen]

I'll take util should not reexport bigint

[Hawstein]

I'll take util should not reexport ansi_term if you guys don't mind:)

[Hawstein]

I'll take one more: util should not reexport ParkingLot.

[debris]

@Hawstein thanks, merged!

[Hawstein]

I will take timer::PerfTimer should be a part of ethcore.

[Hawstein]

I will take semantic_version should be separated from util.

[Hawstein]

I will take

• journaldb and rocksdb dependencies should be separated from util.
• all trie traits from util should be separated from util.

[Hawstein]

@debris Should I move the journaldb, migration and trie out of util/src dir and put them in the util/ dir just like other libs. Seems that this is a reasonable way to arrange them.

[debris]

@debris Should I move the journaldb, migration and trie out of util/src dir and put them in the util/ dir just like other libs. Seems that this is a reasonable way to arrange them.

@Hawstein yes, this would be a great first step. Eventually, we would also like to decouple journaldb and rocksdb :)

[rphmeier]

@debris they are already decoupled to some degree via the KeyValueDB trait.

[debris]

I will take error::UtilError should be replaced by error_chain

[Hawstein]

@debris Hi, I am working on the all trie traits from util should be separated from util. Since it depends lots of stuffs in util/src, so I decide to move all the *.rs file in util/src out of the src dir and make it a lib. It needs to be done for other tasks too. Does it make sense for you?

[debris]

@Hawstein yes, I believe it's one of the last things needed ;)

[Hawstein]

@debris Great! Then I will take the following tasks too:

• migrations should be a library
• remove public reexports of traits modules

Since once I make those *.rs files into a lib, the above tasks are almost done.