150 lines
4.0 KiB
Nim
150 lines
4.0 KiB
Nim
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# nimbus-eth1
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# Copyright (c) 2021 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed
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# except according to those terms.
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## In-memory backend for Kvt DB
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## ============================
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##
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## The iterators provided here are currently available only by direct
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## backend access
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## ::
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## import
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## kvt/kvt_init,
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## kvt/kvt_init/kvt_memory
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##
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## let rc = newKvtDbRef(BackendMemory)
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## if rc.isOk:
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## let be = rc.value.to(MemBackendRef)
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## for (n, key, vtx) in be.walkVtx:
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## ...
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##
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{.push raises: [].}
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import
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std/tables,
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chronicles,
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eth/common,
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results,
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../kvt_desc,
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../kvt_desc/desc_backend,
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./init_common
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type
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MemBackendRef* = ref object of TypedBackendRef
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## Inheriting table so access can be extended for debugging purposes
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tab: Table[Blob,Blob] ## Structural key-value table
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MemPutHdlRef = ref object of TypedPutHdlRef
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tab: Table[Blob,Blob]
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# ------------------------------------------------------------------------------
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# Private helpers
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# ------------------------------------------------------------------------------
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template logTxt(info: static[string]): static[string] =
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"MemoryDB " & info
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proc newSession(db: MemBackendRef): MemPutHdlRef =
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new result
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result.TypedPutHdlRef.beginSession db
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proc getSession(hdl: PutHdlRef; db: MemBackendRef): MemPutHdlRef =
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hdl.TypedPutHdlRef.verifySession db
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hdl.MemPutHdlRef
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proc endSession(hdl: PutHdlRef; db: MemBackendRef): MemPutHdlRef =
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hdl.TypedPutHdlRef.finishSession db
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hdl.MemPutHdlRef
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# ------------------------------------------------------------------------------
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# Private functions: interface
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# ------------------------------------------------------------------------------
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proc getKvpFn(db: MemBackendRef): GetKvpFn =
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result =
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proc(key: Blob): Result[Blob,KvtError] =
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if key.len == 0:
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return err(KeyInvalid)
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let data = db.tab.getOrVoid key
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if data.isValid:
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return ok(data)
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err(GetNotFound)
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# -------------
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proc putBegFn(db: MemBackendRef): PutBegFn =
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result =
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proc(): PutHdlRef =
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db.newSession()
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proc putKvpFn(db: MemBackendRef): PutKvpFn =
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result =
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proc(hdl: PutHdlRef; kvps: openArray[(Blob,Blob)]) =
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let hdl = hdl.getSession db
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if hdl.error == KvtError(0):
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for (k,v) in kvps:
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if k.isValid:
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hdl.tab[k] = v
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else:
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hdl.error = KeyInvalid
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proc putEndFn(db: MemBackendRef): PutEndFn =
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result =
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proc(hdl: PutHdlRef): Result[void,KvtError] =
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let hdl = hdl.endSession db
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if hdl.error != KvtError(0):
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debug logTxt "putEndFn: key/value failed", error=hdl.error
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return err(hdl.error)
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for (k,v) in hdl.tab.pairs:
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db.tab[k] = v
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ok()
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# -------------
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proc closeFn(db: MemBackendRef): CloseFn =
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result =
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proc(ignore: bool) =
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discard
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc memoryBackend*: BackendRef =
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let db = MemBackendRef(
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beKind: BackendMemory)
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db.getKvpFn = getKvpFn db
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db.putBegFn = putBegFn db
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db.putKvpFn = putKvpFn db
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db.putEndFn = putEndFn db
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db.closeFn = closeFn db
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db
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# ------------------------------------------------------------------------------
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# Public iterators (needs direct backend access)
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# ------------------------------------------------------------------------------
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iterator walk*(
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be: MemBackendRef;
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): tuple[key: Blob, data: Blob] =
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## Walk over all key-value pairs of the database.
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for (k,v) in be.tab.pairs:
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yield (k,v)
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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