mirror of https://github.com/status-im/nim-eth.git
314 lines
10 KiB
Nim
314 lines
10 KiB
Nim
# eth
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# Copyright (c) 2019-2024 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import
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std/options,
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pkg/results,
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stew/[arraybuf, assign2, bitops2, shims/macros],
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./priv/defs
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export arraybuf
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type
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RlpWriter* = object
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pendingLists: seq[tuple[remainingItems, startPos: int]]
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output: seq[byte]
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RlpIntBuf* = ArrayBuf[9, byte]
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## Small buffer for holding a single RLP-encoded integer
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const
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wrapObjsInList* = true
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func bytesNeeded(num: SomeUnsignedInt): int =
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# Number of non-zero bytes in the big endian encoding
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sizeof(num) - (num.leadingZeros() shr 3)
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func writeBigEndian(outStream: var auto, number: SomeUnsignedInt,
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lastByteIdx: int, numberOfBytes: int) =
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var n = number
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for i in countdown(lastByteIdx, lastByteIdx - numberOfBytes + 1):
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outStream[i] = byte(n and 0xff)
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n = n shr 8
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func writeBigEndian(outStream: var auto, number: SomeUnsignedInt,
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numberOfBytes: int) {.inline.} =
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outStream.setLen(outStream.len + numberOfBytes)
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outStream.writeBigEndian(number, outStream.len - 1, numberOfBytes)
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func writeCount(bytes: var auto, count: int, baseMarker: byte) =
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if count < THRESHOLD_LIST_LEN:
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bytes.add(baseMarker + byte(count))
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else:
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let
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origLen = bytes.len
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lenPrefixBytes = uint64(count).bytesNeeded
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bytes.setLen(origLen + lenPrefixBytes + 1)
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bytes[origLen] = baseMarker + (THRESHOLD_LIST_LEN - 1) + byte(lenPrefixBytes)
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bytes.writeBigEndian(uint64(count), bytes.len - 1, lenPrefixBytes)
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func writeInt(outStream: var auto, i: SomeUnsignedInt) =
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if i == typeof(i)(0):
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outStream.add BLOB_START_MARKER
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elif i < typeof(i)(BLOB_START_MARKER):
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outStream.add byte(i)
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else:
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let bytesNeeded = i.bytesNeeded
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outStream.writeCount(bytesNeeded, BLOB_START_MARKER)
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outStream.writeBigEndian(i, bytesNeeded)
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proc initRlpWriter*: RlpWriter =
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# Avoid allocations during initial write of small items - since the writer is
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# expected to be short-lived, it doesn't hurt to allocate this buffer
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result.output = newSeqOfCap[byte](2000)
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proc maybeClosePendingLists(self: var RlpWriter) =
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while self.pendingLists.len > 0:
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let lastListIdx = self.pendingLists.len - 1
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doAssert self.pendingLists[lastListIdx].remainingItems > 0
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self.pendingLists[lastListIdx].remainingItems -= 1
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# if one last item is remaining in the list
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if self.pendingLists[lastListIdx].remainingItems == 0:
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# A list have been just finished. It was started in `startList`.
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let listStartPos = self.pendingLists[lastListIdx].startPos
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self.pendingLists.setLen lastListIdx
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# How many bytes were written since the start?
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let listLen = self.output.len - listStartPos
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# Compute the number of bytes required to write down the list length
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let totalPrefixBytes = if listLen < int(THRESHOLD_LIST_LEN): 1
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else: int(uint64(listLen).bytesNeeded) + 1
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# Shift the written data to make room for the prefix length
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self.output.setLen(self.output.len + totalPrefixBytes)
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moveMem(addr self.output[listStartPos + totalPrefixBytes],
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unsafeAddr self.output[listStartPos],
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listLen)
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# Write out the prefix length
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if listLen < THRESHOLD_LIST_LEN:
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self.output[listStartPos] = LIST_START_MARKER + byte(listLen)
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else:
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let listLenBytes = totalPrefixBytes - 1
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self.output[listStartPos] = LEN_PREFIXED_LIST_MARKER + byte(listLenBytes)
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self.output.writeBigEndian(uint64(listLen), listStartPos + listLenBytes, listLenBytes)
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else:
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# The currently open list is not finished yet. Nothing to do.
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return
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proc appendRawBytes*(self: var RlpWriter, bytes: openArray[byte]) =
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self.output.setLen(self.output.len + bytes.len)
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assign(self.output.toOpenArray(
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self.output.len - bytes.len, self.output.len - 1), bytes)
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self.maybeClosePendingLists()
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proc startList*(self: var RlpWriter, listSize: int) =
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if listSize == 0:
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self.output.writeCount(0, LIST_START_MARKER)
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self.appendRawBytes([])
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else:
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self.pendingLists.add((listSize, self.output.len))
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proc appendBlob(self: var RlpWriter, data: openArray[byte]) =
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if data.len == 1 and byte(data[0]) < BLOB_START_MARKER:
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self.output.add byte(data[0])
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self.maybeClosePendingLists()
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else:
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self.output.writeCount(data.len, BLOB_START_MARKER)
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self.appendRawBytes(data)
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proc appendInt(self: var RlpWriter, i: SomeUnsignedInt) =
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# this is created as a separate proc as an extra precaution against
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# any overloading resolution problems when matching the IntLike concept.
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self.output.writeInt(i)
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self.maybeClosePendingLists()
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template appendImpl(self: var RlpWriter, data: openArray[byte]) =
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self.appendBlob(data)
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template appendImpl(self: var RlpWriter, data: openArray[char]) =
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self.appendBlob(data.toOpenArrayByte(0, data.high))
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template appendImpl(self: var RlpWriter, data: string) =
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self.appendBlob(data.toOpenArrayByte(0, data.high))
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template appendImpl(self: var RlpWriter, i: SomeUnsignedInt) =
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self.appendInt(i)
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template appendImpl(self: var RlpWriter, e: enum) =
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# TODO: check for negative enums
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self.appendInt(uint64(e))
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template appendImpl(self: var RlpWriter, b: bool) =
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self.appendInt(uint64(b))
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proc appendImpl[T](self: var RlpWriter, list: openArray[T]) =
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mixin append
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self.startList list.len
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for i in 0 ..< list.len:
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self.append list[i]
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proc countOptionalFields(T: type): int {.compileTime.} =
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mixin enumerateRlpFields
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var dummy: T
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# closure signature matches the one in object_serialization.nim
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template op(RT, fN, f) =
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when f is Option or f is Opt:
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inc result
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else: # this will count only optional fields at the end
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result = 0
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enumerateRlpFields(dummy, op)
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proc genPrevFields(obj: NimNode, fd: openArray[FieldDescription], hi, lo: int): NimNode =
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result = newStmtList()
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for i in countdown(hi, lo):
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let fieldName = fd[i].name
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let msg = fieldName.strVal & " expected"
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result.add quote do:
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doAssert(`obj`.`fieldName`.isSome, `msg`)
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macro genOptionalFieldsValidation(obj: untyped, T: type, num: static[int]): untyped =
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let
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Tresolved = getType(T)[1]
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fd = recordFields(Tresolved.getImpl)
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loidx = fd.len-num
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result = newStmtList()
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for i in countdown(fd.high, loidx):
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let fieldName = fd[i].name
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let prevFields = genPrevFields(obj, fd, i-1, loidx-1)
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result.add quote do:
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if `obj`.`fieldName`.isSome:
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`prevFields`
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# generate something like
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when false:
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if obj.fee.isNone:
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doAssert(obj.withdrawalsRoot.isNone, "withdrawalsRoot needs fee")
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doAssert(obj.blobGasUsed.isNone, "blobGasUsed needs fee")
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doAssert(obj.excessBlobGas.isNone, "excessBlobGas needs fee")
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if obj.withdrawalsRoot.isNone:
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doAssert(obj.blobGasUsed.isNone, "blobGasUsed needs withdrawalsRoot")
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doAssert(obj.excessBlobGas.isNone, "excessBlobGas needs withdrawalsRoot")
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doAssert obj.blobGasUsed.isSome == obj.excessBlobGas.isSome,
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"blobGasUsed and excessBlobGas must both be present or absent"
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proc countFieldsRuntime(obj: object|tuple): int =
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mixin enumerateRlpFields
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var numOptionals: int = 0
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template op(RT, fN, f) {.used.} =
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when f is Option or f is Opt:
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if f.isSome: # if optional and non empty
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inc numOptionals
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else: # if mandatory field
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inc result
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numOptionals = 0 # count only optionals at the end (after mandatory)
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enumerateRlpFields(obj, op)
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result += numOptionals
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proc appendRecordType*(self: var RlpWriter, obj: object|tuple, wrapInList = wrapObjsInList) =
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mixin enumerateRlpFields, append
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type ObjType = type obj
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const
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cof = countOptionalFields(ObjType)
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when cof > 0:
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# ignoring first optional fields
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genOptionalFieldsValidation(obj, ObjType, cof - 1)
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if wrapInList:
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when cof > 0:
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self.startList(obj.countFieldsRuntime)
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else:
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self.startList(ObjType.rlpFieldsCount)
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template op(RecordType, fieldName, field) {.used.} =
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when hasCustomPragmaFixed(RecordType, fieldName, rlpCustomSerialization):
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append(self, obj, field)
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elif (field is Option or field is Opt) and cof > 0:
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# this works for optional fields at the end of an object/tuple
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# if the optional field is followed by a mandatory field,
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# custom serialization for a field or for the parent object
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# will be better
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if field.isSome:
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append(self, field.unsafeGet)
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else:
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append(self, field)
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enumerateRlpFields(obj, op)
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template appendImpl(self: var RlpWriter, data: object) =
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self.appendRecordType(data)
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template appendImpl(self: var RlpWriter, data: tuple) =
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self.appendRecordType(data)
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# We define a single `append` template with a pretty low specificity
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# score in order to facilitate easier overloading with user types:
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template append*[T](w: var RlpWriter; data: T) =
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appendImpl(w, data)
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template append*(w: var RlpWriter; data: SomeSignedInt) =
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{.error: "Signed integer encoding is not defined for rlp".}
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proc initRlpList*(listSize: int): RlpWriter =
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result = initRlpWriter()
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startList(result, listSize)
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# TODO: This should return a lent value
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template finish*(self: RlpWriter): seq[byte] =
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doAssert self.pendingLists.len == 0, "Insufficient number of elements written to a started list"
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self.output
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func clear*(w: var RlpWriter) =
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# Prepare writer for reuse
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w.pendingLists.setLen(0)
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w.output.setLen(0)
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proc encode*[T](v: T): seq[byte] =
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mixin append
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var writer = initRlpWriter()
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writer.append(v)
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move(writer.finish)
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func encodeInt*(i: SomeUnsignedInt): RlpIntBuf =
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var buf: RlpIntBuf
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buf.writeInt(i)
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buf
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macro encodeList*(args: varargs[untyped]): seq[byte] =
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var
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listLen = args.len
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writer = genSym(nskVar, "rlpWriter")
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body = newStmtList()
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append = bindSym("append", brForceOpen)
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for arg in args:
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body.add quote do:
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`append`(`writer`, `arg`)
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result = quote do:
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var `writer` = initRlpList(`listLen`)
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`body`
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move(finish(`writer`))
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