class ErgoTreeSerializer extends AnyRef
Rationale for soft-forkable ErgoTree serialization. There are 2 points:
1) we can make size bit obligatory, i.e. always save total size of script body (in this case we don't need size bit in the header). This will allow to always skip right number of bytes in case of any exception (including ValidationException) thrown during deserialization and produce UnparsedErgoTree. The decision about soft-fork can be done later. But is looks like this is not necessary if we do as described below.
2) HeaderVersionCheck: we can also strictly check during deserialization the content of the script against version number in the header. Thus if the header have vS, then script is allowed to have instructions from versions from v1 to vS. On a node vN, N > S, this should also be enforced, i.e. vN node will reject scripts as invalid if the script has vS in header and vS+1 instruction in body.
Keeping this in mind, if we have a vN node and a script with vS in its header then: During script deserialization: 1) if vN >= vS then the node knows all the instructions and should check that only instructions up to vS are used in the script. It either parses successfully or throws MalformedScriptException. If during the process some unknown instruction is encountered (i.e. ValidationException is thrown), this cannot be a soft-fork, because vN >= vS guarantees that all instructions are known, thus the script is malformed.
2) if vN < vS then the vN node is expecting unknown instructions. If the script is parsed successfully, then vN subset of the language is used and script is accepted for execution else if ValidationException is thrown then UnparsedErgoTree is created, delaying decision about soft-fork until stateful validation. if bodySize is stored then script body is skipped and whole TX deserialization continues. otherwise we cannot skip the body which leads to whole TX to be rejected (CannotSkipScriptException) else if some other exception is thrown then the whole TX is rejected due to said exception.
In the stateful context: if vN >= vS then we can execute script, but we do additional check if vS > the current version of protocol (vP) then the script is rejected as invalid because its version exceeds the current consensus version of the protocol else the script can be executed if vN < vS then if we have Right(tree) the script is executed if Left(UnparsedErgoTree()) then check soft fork and either execute or throw
Proposition: CannotSkipScriptException can only happen on < 10% of the nodes, which is safe for consensus. Proof. If follows from the fact that vN >= vS nodes will reject the script until new vP is upgraded to vS, which means the majority has upgraded to at least vS Thus, before vP is upgraded to vS, majority reject (either because they cannot parse, or because vP is not actualized) after that majority accept (however old nodes still reject but they are < 10%) End of proof.
- Alphabetic
- By Inheritance
- ErgoTreeSerializer
- AnyRef
- Any
- Hide All
- Show All
- Public
- All
Instance Constructors
- new ErgoTreeSerializer()
Value Members
-
final
def
!=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
- Definition Classes
- AnyRef → Any
-
final
def
==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
final
def
asInstanceOf[T0]: T0
- Definition Classes
- Any
-
def
clone(): AnyRef
- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( ... ) @native()
- def deserializeErgoTree(r: SigmaByteReader, maxTreeSizeBytes: Int): ErgoTree
-
def
deserializeErgoTree(bytes: Array[Byte]): ErgoTree
Default deserialization of ErgoTree (should be inverse to
serializeErgoTree
).Default deserialization of ErgoTree (should be inverse to
serializeErgoTree
). Doesn't apply any transformations to the parsed tree. -
def
deserializeHeaderWithTreeBytes(r: SigmaByteReader): (Byte, Option[Int], IndexedSeq[Constant[SType]], Array[Byte])
Deserialize header and constant sections, but output the rest of the bytes as separate array.
-
final
def
eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
-
def
equals(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
-
def
finalize(): Unit
- Attributes
- protected[java.lang]
- Definition Classes
- AnyRef
- Annotations
- @throws( classOf[java.lang.Throwable] )
-
final
def
getClass(): Class[_]
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
-
def
hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
-
final
def
isInstanceOf[T0]: Boolean
- Definition Classes
- Any
-
final
def
ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
-
final
def
notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
-
final
def
notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
-
def
serializeErgoTree(ergoTree: ErgoTree): Array[Byte]
Default serialization of ErgoTree.
Default serialization of ErgoTree. Doesn't apply any transformations and guarantee to preserve original structure after deserialization.
-
def
substituteConstants(scriptBytes: Array[Byte], positions: Array[Int], newVals: Array[Constant[SType]])(implicit vs: SigmaValidationSettings): (Array[Byte], Int)
Transforms serialized bytes of ErgoTree with segregated constants by replacing constants at given positions with new values.
Transforms serialized bytes of ErgoTree with segregated constants by replacing constants at given positions with new values. This operation allow to use serialized scripts as pre-defined templates. See sigmastate.SubstConstants for details.
- scriptBytes
serialized ErgoTree with ConstantSegregationFlag set to 1.
- positions
zero based indexes in ErgoTree.constants array which should be replaced with new values
- newVals
new values to be injected into the corresponding positions in ErgoTree.constants array
- returns
a pair (newBytes, len), where: newBytes - the original array scriptBytes such that only specified constants are replaced and all other bytes remain exactly the same len - length of the
constants
array of the given ErgoTree bytes
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
toString(): String
- Definition Classes
- AnyRef → Any
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... ) @native()