import os, json, tables, options, chronicles, serialization, json_serialization, eth/common/eth_types_json_serialization, spec/[datatypes, digest, crypto], eth/trie/db, ssz type BeaconChainDB* = ref object ## Database storing resolved blocks and states - resolved blocks are such ## blocks that form a chain back to the tail block. backend: TrieDatabaseRef DbKeyKind = enum kHashToState kHashToBlock kHeadBlock # Pointer to the most recent block selected by the fork choice kTailBlock ##\ ## Pointer to the earliest finalized block - this is the genesis block when ## the chain starts, but might advance as the database gets pruned ## TODO: determine how aggressively the database should be pruned. For a ## healthy network sync, we probably need to store blocks at least ## past the weak subjectivity period. kBlockSlotStateRoot ## BlockSlot -> state_root mapping func subkey(kind: DbKeyKind): array[1, byte] = result[0] = byte ord(kind) func subkey[N: static int](kind: DbKeyKind, key: array[N, byte]): array[N + 1, byte] = result[0] = byte ord(kind) result[1 .. ^1] = key func subkey(kind: DbKeyKind, key: uint64): array[sizeof(key) + 1, byte] = result[0] = byte ord(kind) copyMem(addr result[1], unsafeAddr key, sizeof(key)) func subkey(kind: type BeaconState, key: Eth2Digest): auto = subkey(kHashToState, key.data) func subkey(kind: type BeaconBlock, key: Eth2Digest): auto = subkey(kHashToBlock, key.data) func subkey(root: Eth2Digest, slot: Slot): auto = # TODO: Copy the SSZ data to `ret` properly. # We don't need multiple calls to SSZ.encode # Use memoryStream(ret) and SszWriter explicitly var # takes care of endians.. rootSSZ = SSZ.encode(root) slotSSZ = SSZ.encode(slot) var ret: array[1 + 32 + 8, byte] doAssert sizeof(ret) == 1 + rootSSZ.len + slotSSZ.len, "Can't sizeof this in VM" ret[0] = byte ord(kBlockSlotStateRoot) copyMem(addr ret[1], unsafeaddr root, sizeof(root)) copyMem(addr ret[1 + sizeof(root)], unsafeaddr slot, sizeof(slot)) ret proc init*(T: type BeaconChainDB, backend: TrieDatabaseRef): BeaconChainDB = new result result.backend = backend proc putBlock*(db: BeaconChainDB, key: Eth2Digest, value: BeaconBlock) = db.backend.put(subkey(type value, key), SSZ.encode(value)) proc putHead*(db: BeaconChainDB, key: Eth2Digest) = db.backend.put(subkey(kHeadBlock), key.data) # TODO head block? proc putState*(db: BeaconChainDB, key: Eth2Digest, value: BeaconState) = # TODO prune old states - this is less easy than it seems as we never know # when or if a particular state will become finalized. db.backend.put(subkey(type value, key), SSZ.encode(value)) proc putState*(db: BeaconChainDB, value: BeaconState) = db.putState(hash_tree_root(value), value) proc putStateRoot*(db: BeaconChainDB, root: Eth2Digest, slot: Slot, value: Eth2Digest) = db.backend.put(subkey(root, slot), value.data) proc putBlock*(db: BeaconChainDB, value: BeaconBlock) = db.putBlock(signing_root(value), value) proc putHeadBlock*(db: BeaconChainDB, key: Eth2Digest) = db.backend.put(subkey(kHeadBlock), key.data) # TODO head block? proc putTailBlock*(db: BeaconChainDB, key: Eth2Digest) = db.backend.put(subkey(kTailBlock), key.data) proc get(db: BeaconChainDB, key: auto, T: typedesc): Option[T] = let res = db.backend.get(key) if res.len != 0: try: some(SSZ.decode(res, T)) except SerializationError: none(T) else: none(T) proc getBlock*(db: BeaconChainDB, key: Eth2Digest): Option[BeaconBlock] = db.get(subkey(BeaconBlock, key), BeaconBlock) proc getBlock*(db: BeaconChainDB, slot: Slot): Option[BeaconBlock] = # TODO implement this discard proc getState*(db: BeaconChainDB, key: Eth2Digest): Option[BeaconState] = db.get(subkey(BeaconState, key), BeaconState) proc getStateRoot*(db: BeaconChainDB, root: Eth2Digest, slot: Slot): Option[Eth2Digest] = db.get(subkey(root, slot), Eth2Digest) proc getHeadBlock*(db: BeaconChainDB): Option[Eth2Digest] = db.get(subkey(kHeadBlock), Eth2Digest) proc getTailBlock*(db: BeaconChainDB): Option[Eth2Digest] = db.get(subkey(kTailBlock), Eth2Digest) proc containsBlock*( db: BeaconChainDB, key: Eth2Digest): bool = db.backend.contains(subkey(BeaconBlock, key)) proc containsState*( db: BeaconChainDB, key: Eth2Digest): bool = db.backend.contains(subkey(BeaconState, key)) iterator getAncestors*(db: BeaconChainDB, root: Eth2Digest): tuple[root: Eth2Digest, blck: BeaconBlock] = ## Load a chain of ancestors for blck - returns a list of blocks with the ## oldest block last (blck will be at result[0]). ## ## The search will go on until the ancestor cannot be found. var root = root while (let blck = db.getBlock(root); blck.isSome()): yield (root, blck.get()) root = blck.get().parent_root