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refactoring the parsing algorithm into functions that can be reused across data types

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This commit is contained in:
Chris Stewart 2016-01-22 13:23:12 -06:00
parent d12cc97e21
commit 60bb8e0e6b
6 changed files with 183 additions and 60 deletions
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94
src/main/scala/org/scalacoin/marshallers/script/ScriptParser.scala
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@ -16,6 +16,7 @@ trait ScriptParser extends ScalacoinUtil {
/**
* Parses an asm output script of a transaction
* example: "OP_DUP OP_HASH160 e2e7c1ab3f807151e832dd1accb3d4f5d7d19b4b OP_EQUALVERIFY OP_CHECKSIG"
* example: ["0", "IF 0x50 ENDIF 1", "P2SH,STRICTENC", "0x50 is reserved (ok if not executed)"] (from script_valid.json)
* @param str
* @return
*/
@ -26,13 +27,21 @@ trait ScriptParser extends ScalacoinUtil {
def loop(operations : List[String], accum : List[ScriptToken]) : List[ScriptToken] = {
logger.debug("Attempting to parse: " + operations.headOption)
operations match {
//if we see a byte constant in the form of "0x09"
//if we see a byte constant of just 0x09
//parse the two characters as a hex op
case h :: t if (h.size == 4 && h.substring(0,2) == "0x") =>
val hexString = h.substring(2,h.size)
loop(t,ScriptOperationFactory.fromHex(hexString).get :: accum)
//if we see a byte constant in the form of "0x09adb"
case h :: t if (h.size > 1 && h.substring(0,2) == "0x") => loop(t,parseBytesFromString(h) ++ accum)
//skip the empty string
case h :: t if (h == "") => loop(t,accum)
case h :: t if (h == "0") => loop(t, OP_0 :: accum)
case h :: t if (ScriptOperationFactory.fromString(h).isDefined) =>
loop(t,ScriptOperationFactory.fromString(h).get :: accum)
val op = ScriptOperationFactory.fromString(h).get
val parsingHelper : ParsingHelper[String] = parseOperationString(op,accum,t)
loop(parsingHelper.tail,parsingHelper.accum)
case h :: t => loop(t, ScriptConstantImpl(h) :: accum)
case Nil => accum
}
@ -68,30 +77,29 @@ trait ScriptParser extends ScalacoinUtil {
logger.debug("Byte to be parsed: " + bytes.headOption)
bytes match {
case h :: t =>
logger.debug("Op for matching: " + h)
val op = ScriptOperationFactory.fromByte(h).get
logger.debug("Matched op: " + op)
op match {
case scriptNumber : ScriptNumberImpl =>
//means that we need to push x amount of bytes on to the stack
val (constant,tail) = pushConstant(scriptNumber,t)
loop(tail, constant :: accum)
case _ =>
//means that we need to push the operation onto the stack
loop(t, op :: accum)
}
val parsingHelper : ParsingHelper[Byte] = parseOperationByte(op,accum,t)
loop(parsingHelper.tail,parsingHelper.accum)
case Nil => accum
}
}
loop(bytes, List()).reverse
}
private def pushConstant(op : ScriptNumber, bytes : List[Byte]) : (ScriptConstant, List[Byte]) = {
/**
* Slices the amount of bytes specified in the op parameter and then creates a script constant
* from those bytes. Returns the script constant and the byte array without the script constant
* @param op
* @param bytes
* @return
*/
private def sliceConstant[T](op : ScriptNumber, data : List[T]) : (List[T], List[T]) = {
val finalIndex = op.opCode
val constant : ScriptConstantImpl = ScriptConstantImpl(encodeHex(bytes.slice(0,finalIndex)))
(constant, bytes.slice(finalIndex,bytes.size))
val dataConstant = data.slice(0,finalIndex)
(dataConstant,data.slice(finalIndex,data.size))
}
/**
* Parses the bytes in string format, an example input would look like this
* "0x09 0x00000000 0x00000000 0x10"
@ -106,11 +114,63 @@ trait ScriptParser extends ScalacoinUtil {
.map(g => BigInt(g.group(1), 16).toString(16))
.toList)
val paddedHexStrings = hexStrings.map(hex => if (hex.size == 1) "0"+hex else hex )
logger.debug("Padded hex strings: " + paddedHexStrings)
//logger.debug("Padded hex strings: " + paddedHexStrings)
//TODO: Figure out a better way to do this without calling .get on the result of fromByte
val constants = paddedHexStrings.map(ScriptConstantImpl(_))
constants
}
case class ParsingHelper[T](tail : List[T], accum : List[ScriptToken])
/**
* Parses an operation if the tail is a List[Byte]
* If the operation is a script number, it pushes the number of bytes onto the stack
* specified by the script number
* i.e. If the operation was ScriptNumber(5), it would slice 5 bytes off of the tail and
* places them into a ScriptConstant and add them to the accumulator.
* @param op
* @param accum
* @param tail
* @return
*/
private def parseOperationByte(op : ScriptOperation, accum : List[ScriptToken], tail : List[Byte]) : ParsingHelper[Byte] = {
op match {
case scriptNumber : ScriptNumberImpl =>
//means that we need to push x amount of bytes on to the stack
val (constant,newTail) = sliceConstant(scriptNumber,tail)
val scriptConstant = new ScriptConstantImpl(constant)
ParsingHelper(newTail,scriptConstant :: accum)
case _ =>
//means that we need to push the operation onto the stack
ParsingHelper(tail,op :: accum)
}
}
/**
* Parses an operation if the tail is a List[String]
* If the operation is a script number, it pushes the number of bytes onto the stack
* specified by the script number
* i.e. If the operation was ScriptNumber(5), it would slice 5 bytes off of the tail and
* places them into a ScriptConstant and add them to the accumulator.
* @param op
* @param accum
* @param tail
* @return
*/
private def parseOperationString(op : ScriptOperation, accum : List[ScriptToken], tail : List[String]) : ParsingHelper[String] = {
op match {
case scriptNumber : ScriptNumberImpl =>
//means that we need to push x amount of bytes on to the stack
val (constant,newTail) = sliceConstant[String](scriptNumber,tail)
val scriptConstant = ScriptConstantImpl(constant.mkString)
ParsingHelper(newTail,scriptConstant :: accum)
case _ =>
//means that we need to push the operation onto the stack
ParsingHelper(tail,op :: accum)
}
}
}
object ScriptParser extends ScriptParser

105
src/main/scala/org/scalacoin/script/constant/Constants.scala
View File

@ -18,34 +18,24 @@ trait ScriptOperation extends ScriptToken {
sealed trait ScriptConstant extends ScriptToken
sealed trait ScriptBoolean extends ScriptConstant
sealed trait ScriptBoolean extends ScriptNumber
case object ScriptTrue extends ScriptBoolean {
override def hex = "1"
override def opCode = 1
}
case object ScriptFalse extends ScriptBoolean {
override def hex = "0"
override def opCode = 0
}
/**
* Represent a pubkey or hash of a pub key on our stack
* @param hex
*/
case class ScriptConstantImpl(hex : String) extends ScriptConstant
case class ScriptConstantImpl(hex : String) extends ScriptConstant {
def this(bytes : List[Byte]) = this(ScalacoinUtil.encodeHex(bytes))
}
/**
* An empty array of bytes is pushed onto the stack. (This is not a no-op: an item is added to the stack.)
*/
case object OP_0 extends ScriptOperation with ScriptNumber {
override def opCode = 0
}
/**
* An empty array of bytes is pushed onto the stack. (This is not a no-op: an item is added to the stack.)
*/
case object OP_FALSE extends ScriptOperation {
override def opCode = OP_0.opCode
}
/**
* The next byte contains the number of bytes to be pushed onto the stack.
@ -68,130 +58,177 @@ case object OP_PUSHDATA4 extends ScriptOperation {
override def opCode = 78
}
/**
* Represents a script number operation where the the number in the operation is pushed onto the stack
* i.e. OP_0 would be push 0 onto the stack, OP_1 would be push 1 onto the stack
*/
sealed trait ScriptNumberOperation extends ScriptNumber {
/**
* Represents the script number that needs to be pushed onto the stack
* if the op is interpreted
* i.e. OP_1 would be matched with the ScriptNumber(1)
* @return
*/
def scriptNumber : ScriptNumber
}
/**
* An empty array of bytes is pushed onto the stack. (This is not a no-op: an item is added to the stack.)
*/
case object OP_0 extends ScriptNumberOperation {
override def opCode = 0
override def scriptNumber = this
}
/**
* An empty array of bytes is pushed onto the stack. (This is not a no-op: an item is added to the stack.)
*/
case object OP_FALSE extends ScriptNumberOperation {
override def opCode = OP_0.opCode
override def scriptNumber = OP_0.scriptNumber
}
/**
* The number -1 is pushed onto the stack.
*/
case object OP_1NEGATE extends ScriptOperation {
case object OP_1NEGATE extends ScriptNumberOperation {
override def opCode = 79
override def scriptNumber = ScriptNumberFactory.factory(-1).get
}
/**
* The number 1 is pushed onto the stack.
*/
case object OP_TRUE extends ScriptOperation {
case object OP_TRUE extends ScriptNumberOperation {
override def opCode = 81
override def scriptNumber = ScriptNumberFactory.factory(1).get
}
/**
* The number 1 is pushed onto the stack.
*/
case object OP_1 extends ScriptOperation with ScriptNumber {
case object OP_1 extends ScriptNumberOperation {
override def opCode = OP_TRUE.opCode
override def scriptNumber = ScriptNumberFactory.factory(1).get
}
/**
* The number 2 is pushed onto the stack.
*/
case object OP_2 extends ScriptOperation with ScriptNumber {
case object OP_2 extends ScriptNumberOperation {
override def opCode = 82
override def scriptNumber = ScriptNumberFactory.factory(2).get
}
/**
* The number 3 is pushed onto the stack.
*/
case object OP_3 extends ScriptOperation with ScriptNumber {
case object OP_3 extends ScriptNumberOperation {
override def opCode = 83
override def scriptNumber = ScriptNumberFactory.factory(3).get
}
/**
* The number 4 is pushed onto the stack.
*/
case object OP_4 extends ScriptOperation with ScriptNumber {
case object OP_4 extends ScriptNumberOperation {
override def opCode = 84
override def scriptNumber = ScriptNumberFactory.factory(4).get
}
/**
* The number 5 is pushed onto the stack.
*/
case object OP_5 extends ScriptOperation with ScriptNumber {
case object OP_5 extends ScriptNumberOperation {
override def opCode = 85
override def scriptNumber = ScriptNumberFactory.factory(5).get
}
/**
* The number 6 is pushed onto the stack.
*/
case object OP_6 extends ScriptOperation with ScriptNumber {
case object OP_6 extends ScriptNumberOperation {
override def opCode = 86
override def scriptNumber = ScriptNumberFactory.factory(6).get
}
/**
* The number 7 is pushed onto the stack.
*/
case object OP_7 extends ScriptOperation with ScriptNumber {
case object OP_7 extends ScriptNumberOperation {
override def opCode = 87
override def scriptNumber = ScriptNumberFactory.factory(7).get
}
/**
* The number 8 is pushed onto the stack.
*/
case object OP_8 extends ScriptOperation with ScriptNumber {
case object OP_8 extends ScriptNumberOperation {
override def opCode = 88
override def scriptNumber = ScriptNumberFactory.factory(8).get
}
/**
* The number 9 is pushed onto the stack.
*/
case object OP_9 extends ScriptOperation with ScriptNumber {
case object OP_9 extends ScriptNumberOperation {
override def opCode = 89
override def scriptNumber = ScriptNumberFactory.factory(9).get
}
/**
* The number 10 is pushed onto the stack.
*/
case object OP_10 extends ScriptOperation with ScriptNumber {
case object OP_10 extends ScriptNumberOperation {
override def opCode = 90
override def scriptNumber = ScriptNumberFactory.factory(10).get
}
/**
* The number 11 is pushed onto the stack.
*/
case object OP_11 extends ScriptOperation with ScriptNumber {
case object OP_11 extends ScriptNumberOperation {
override def opCode = 91
override def scriptNumber = ScriptNumberFactory.factory(11).get
}
/**
* The number 12 is pushed onto the stack.
*/
case object OP_12 extends ScriptOperation with ScriptNumber {
case object OP_12 extends ScriptNumberOperation {
override def opCode = 92
override def scriptNumber = ScriptNumberFactory.factory(12).get
}
/**
* The number 13 is pushed onto the stack.
*/
case object OP_13 extends ScriptOperation with ScriptNumber {
case object OP_13 extends ScriptNumberOperation {
override def opCode = 93
override def scriptNumber = ScriptNumberFactory.factory(13).get
}
/**
* The number 14 is pushed onto the stack.
*/
case object OP_14 extends ScriptOperation with ScriptNumber {
case object OP_14 extends ScriptNumberOperation {
override def opCode = 94
override def scriptNumber = ScriptNumberFactory.factory(14).get
}
/**
* The number 15 is pushed onto the stack.
*/
case object OP_15 extends ScriptOperation with ScriptNumber {
case object OP_15 extends ScriptNumberOperation {
override def opCode = 95
override def scriptNumber = ScriptNumberFactory.factory(15).get
}
/**
* The number 16 is pushed onto the stack.
*/
case object OP_16 extends ScriptOperation with ScriptNumber {
case object OP_16 extends ScriptNumberOperation {
override def opCode = 96
override def scriptNumber = ScriptNumberFactory.factory(16).get
}

9
src/main/scala/org/scalacoin/script/interpreter/ScriptInterpreter.scala
View File

@ -32,6 +32,8 @@ trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with Con
@tailrec
def loop(scripts : (List[ScriptToken], List[ScriptToken])) : Boolean = {
val (stack,script) = (scripts._1, scripts._2)
logger.debug("Stack: " +stack)
logger.debug("Script: " + script)
script match {
//stack operations
case OP_DUP :: t => loop(opDup(stack,script))
@ -40,8 +42,6 @@ trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with Con
//bitwise operations
case OP_EQUAL :: t => {
val (newStack,newScript) = equal(stack, script)
logger.debug("New stack: " + newStack)
logger.debug("New script: " + newScript)
if (newStack.head == ScriptTrue && newScript.size == 0) true
else if (newStack.head == ScriptFalse && newScript.size == 0) false
else loop(newStack,newScript)
@ -52,6 +52,7 @@ trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with Con
//TODO: Implement these
case ScriptConstantImpl(x) :: t if x == "1" => throw new RuntimeException("Not implemented yet")
case ScriptConstantImpl(x) :: t if x == "0" => throw new RuntimeException("Not implemented yet")
case (scriptNumberOp : ScriptNumberOperation) :: t => loop(scriptNumberOp.scriptNumber :: stack, t)
case (scriptNumber : ScriptNumber) :: t => loop(scriptNumber :: stack, t)
//TODO: is this right? I need to just push a constant on the input stack???
@ -60,8 +61,8 @@ trait ScriptInterpreter extends CryptoInterpreter with StackInterpreter with Con
//crypto operations
case OP_HASH160 :: t => loop(hash160(stack,script))
case OP_CHECKSIG :: t => checkSig(stack,script,fullScript)
//no more script operations to run, if stack top is true or '1' then it is a valid script
case Nil => stack.head == OP_1 || stack.head == ScriptTrue
//no more script operations to run, True is represented by any representation of non-zero
case Nil => stack.head != ScriptFalse
case h :: t => throw new RuntimeException(h + " was unmatched")
}
}

20
src/main/scala/org/scalacoin/script/constant/ConstantsTest.scala → src/test/scala/org/scalacoin/script/constant/ConstantsTest.scala
View File

@ -9,7 +9,8 @@ class ConstantsTest extends FlatSpec with MustMatchers {
"Constants" must "define an OP_FALSE" in {
OP_FALSE.opCode must be (0)
OP_FALSE.hex must be ("0")
OP_FALSE.hex must be ("00")
OP_FALSE.scriptNumber must be (OP_0)
}
it must "define an OP_PUSHDATA1" in {
@ -30,6 +31,7 @@ class ConstantsTest extends FlatSpec with MustMatchers {
it must "define an OP_1NEGATE" in {
OP_1NEGATE.opCode must be (79)
OP_1NEGATE.hex must be ("4f")
OP_1NEGATE.scriptNumber must be (ScriptNumberImpl(-1))
}
it must "define an OP_TRUE" in {
@ -40,62 +42,78 @@ class ConstantsTest extends FlatSpec with MustMatchers {
it must "define an OP_2" in {
OP_2.opCode must be (82)
OP_2.hex must be ("52")
OP_2.scriptNumber must be (ScriptNumberImpl(2))
}
it must "define an OP_3" in {
OP_3.opCode must be (83)
OP_3.hex must be ("53")
OP_3.scriptNumber must be (ScriptNumberImpl(3))
}
it must "define an OP_4" in {
OP_4.opCode must be (84)
OP_4.hex must be ("54")
OP_4.scriptNumber must be (ScriptNumberImpl(4))
}
it must "define an OP_5" in {
OP_5.opCode must be (85)
OP_5.hex must be ("55")
OP_5.scriptNumber must be (ScriptNumberImpl(5))
}
it must "define an OP_6" in {
OP_6.opCode must be (86)
OP_6.hex must be ("56")
OP_6.scriptNumber must be (ScriptNumberImpl(6))
}
it must "define an OP_7" in {
OP_7.opCode must be (87)
OP_7.hex must be ("57")
OP_7.scriptNumber must be (ScriptNumberImpl(7))
}
it must "define an OP_8" in {
OP_8.opCode must be (88)
OP_8.hex must be ("58")
OP_8.scriptNumber must be (ScriptNumberImpl(8))
}
it must "define an OP_9" in {
OP_9.opCode must be (89)
OP_9.hex must be ("59")
OP_9.scriptNumber must be (ScriptNumberImpl(9))
}
it must "define an OP_10" in {
OP_10.opCode must be (90)
OP_10.hex must be ("5a")
OP_10.scriptNumber must be (ScriptNumberImpl(10))
}
it must "define an OP_11" in {
OP_11.opCode must be (91)
OP_11.hex must be ("5b")
OP_11.scriptNumber must be (ScriptNumberImpl(11))
}
it must "define an OP_12" in {
OP_12.opCode must be (92)
OP_12.hex must be ("5c")
OP_12.scriptNumber must be (ScriptNumberImpl(12))
}
it must "define an OP_13" in {
OP_13.opCode must be (93)
OP_13.hex must be ("5d")
OP_13.scriptNumber must be (ScriptNumberImpl(13))
}
it must "define an OP_14" in {
OP_14.opCode must be (94)
OP_14.hex must be ("5e")
OP_14.scriptNumber must be (ScriptNumberImpl(14))
}
it must "define an OP_15" in {
OP_15.opCode must be (95)
OP_15.hex must be ("5f")
OP_15.scriptNumber must be (ScriptNumberImpl(15))
}
it must "define an OP_16" in {
OP_16.opCode must be (96)
OP_16.hex must be ("60")
OP_16.scriptNumber must be (ScriptNumberImpl(16))
}

4
src/test/scala/org/scalacoin/script/constant/ScriptNumberFactoryTest.scala
View File

@ -27,9 +27,9 @@ class ScriptNumberFactoryTest extends FlatSpec with MustMatchers with ScriptNumb
result.get must be (ScriptNumberImpl(2))
}
it must "not allow creation of the script number -1" in {
it must "not allow creation of the script number -2" in {
intercept[IllegalArgumentException] {
operations.exists(_ == ScriptNumberImpl(-1)) must be (false)
operations.exists(_ == ScriptNumberImpl(-2)) must be (false)
}
}

11
src/test/scala/org/scalacoin/script/interpreter/ScriptInterpreterTest.scala
View File

@ -34,6 +34,14 @@ class ScriptInterpreterTest extends FlatSpec with MustMatchers with ScriptInterp
import CoreTestCaseProtocol._
val source = scala.io.Source.fromFile("src/test/scala/org/scalacoin/script/interpreter/script_valid.json")
//use this to represent a single test case from script_valid.json
val lines =
"""
|
|[["0", "IF 0x50 ENDIF 1", "P2SH,STRICTENC", "0x50 is reserved (ok if not executed)"]]
""".stripMargin
val lines = try source.getLines.filterNot(_.isEmpty).map(_.trim) mkString "\n" finally source.close()
val json = lines.parseJson
val testCasesOpt : Seq[Option[CoreTestCase]] = json.convertTo[Seq[Option[CoreTestCase]]]
@ -43,13 +51,12 @@ class ScriptInterpreterTest extends FlatSpec with MustMatchers with ScriptInterp
for {
testCase <- testCases
} yield {
logger.info("Running test case: ")
logger.info("Raw test case: " + testCase.raw)
logger.info("Parsed ScriptSig: " + testCase.scriptSig)
logger.info("Parsed ScriptPubKey: " + testCase.scriptPubKey)
logger.info("Flags: " + testCase.flags)
logger.info("Comments: " + testCase.comments)
withClue(testCase.comments) {
withClue(testCase.raw) {
ScriptInterpreter.run(testCase.scriptSig, testCase.scriptPubKey) must equal (true)
}
}