47 lines
1.1 KiB
Nim
47 lines
1.1 KiB
Nim
import
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ranges, tables, sets,
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eth_trie/db,
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../storage_types
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type
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CachingDB* = ref object of RootObj
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backing: TrieDatabaseRef
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changed: Table[seq[byte], seq[byte]]
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deleted: HashSet[seq[byte]]
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proc newCachingDB*(backing: TrieDatabaseRef): CachingDB =
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result.new()
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result.backing = backing
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result.changed = initTable[seq[byte], seq[byte]]()
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result.deleted = initSet[seq[byte]]()
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proc get*(db: CachingDB, key: openarray[byte]): seq[byte] =
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let key = @key
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result = db.changed.getOrDefault(key)
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if result.len == 0 and key notin db.deleted:
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result = db.backing.get(key)
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proc put*(db: CachingDB, key, value: openarray[byte]) =
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let key = @key
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db.deleted.excl(key)
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db.changed[key] = @value
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proc contains*(db: CachingDB, key: openarray[byte]): bool =
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let key = @key
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result = key in db.changed
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if not result and key notin db.deleted:
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result = db.backing.contains(key)
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proc del*(db: CachingDB, key: openarray[byte]) =
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let key = @key
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db.changed.del(key)
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db.deleted.incl(key)
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proc commit*(db: CachingDB) =
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for k in db.deleted:
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db.backing.del(k)
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for k, v in db.changed:
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db.backing.put(k, v)
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