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Further tweaks based on feedback - simplified the embedded timelock contract

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This commit is contained in:
jamescarlyle
2016-09-08 22:49:24 +01:00
parent cdb2c3efa6
commit e187c4d91d
4 changed files with 35 additions and 22 deletions
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9
core/src/main/kotlin/com/r3corda/core/contracts/Structures.kt
View File

@ -115,10 +115,11 @@ interface ContractState {
/**
* All contract states may be _encumbered_ by up to one other state.
*
* The encumbrance state, if present, forces additional controls over this state, since the encumbrance state contract
* will also be verified during the execution of the transaction. For example, a contract state could be encumbered
* with a time-lock contract state; the state is then only processable in a transaction that verifies that the time
* specified in the encumbrance time-lock has passed.
* The encumbrance state, if present, forces additional controls over the encumbered state, since the platform checks
* that the encumbrance state is present as an input in the same transaction that consumes the encumbered state, and
* the contract code and rules of the encumbrance state will also be verified during the execution of the transaction.
* For example, a cash contract state could be encumbered with a time-lock contract state; the cash state is then only
* processable in a transaction that verifies that the time specified in the encumbrance time-lock has passed.
*
* The encumbered state refers to another by index, and the referred encumbrance state
* is an output state in a particular position on the same transaction that created the encumbered state. An alternative

37
core/src/test/kotlin/com/r3corda/core/contracts/TransactionEncumbranceTests.kt
View File

@ -2,13 +2,11 @@ package com.r3corda.core.contracts
import com.r3corda.contracts.asset.Cash
import com.r3corda.core.crypto.SecureHash
import com.r3corda.core.serialization.OpaqueBytes
import com.r3corda.core.testing.*
import org.junit.Test
import java.security.PublicKey
import java.time.Instant
import java.time.temporal.ChronoUnit
import kotlin.test.assertFailsWith
val TEST_TIMELOCK_ID = TransactionEncumbranceTests.TestTimeLock()
@ -32,32 +30,30 @@ class TransactionEncumbranceTests {
class TestTimeLock : Contract {
override val legalContractReference = SecureHash.sha256("TestTimeLock")
override fun verify(tx: TransactionForContract) {
val timestamp: Timestamp? = tx.timestamp
val time = timestamp?.before ?: throw IllegalArgumentException("Transactions containing time-locks must be timestamped")
val time = tx.timestamp?.before ?: throw IllegalArgumentException("Transactions containing time-locks must be timestamped")
requireThat {
"the time specified in the time-lock has passed" by
(time >= tx.inputs.filterIsInstance<TestTimeLock.State>().single().validFrom)
}
}
data class State(
val validFrom: Instant
) : ContractState {
override val participants: List<PublicKey>
get() = throw UnsupportedOperationException()
override val participants: List<PublicKey> = emptyList()
override val contract: Contract = TEST_TIMELOCK_ID
}
}
@Test
fun trivial() {
// A transaction containing an input state that is encumbered must fail if the encumbrance is missing on the inputs.
assertFailsWith(TransactionVerificationException.TransactionMissingEncumbranceException::class) {
transaction {
input { encumberedState }
output { unencumberedState }
command(DUMMY_PUBKEY_1) { Cash.Commands.Move() }
this.verifies()
}
// A transaction containing an input state that is encumbered must fail if the encumbrance has not been presented
// on the input states.
transaction {
input { encumberedState }
output { unencumberedState }
command(DUMMY_PUBKEY_1) { Cash.Commands.Move() }
this `fails with` "Missing required encumbrance 1 in INPUT"
}
// An encumbered state must not be encumbered by itself.
transaction {
@ -70,6 +66,7 @@ class TransactionEncumbranceTests {
this `fails with` "Missing required encumbrance 1 in OUTPUT"
}
// An encumbered state must not reference an index greater than the size of the output states.
// In this test, the output encumbered state refers to an encumbrance in position 1, but there is only one output.
transaction {
input { unencumberedState }
// The encumbered state refers to an encumbrance in position 1, so there should be at least 2 outputs.
@ -82,8 +79,10 @@ class TransactionEncumbranceTests {
@Test
fun testEncumbranceEffects() {
// A transaction containing an input state that is encumbered must fail if the encumbrance is not in the correct position.
ledger {
// This test fails because the encumbered state is pointing to the ordinary cash state as the encumbrance,
// instead of the timelock by mistake, so when we try and use it the transaction fails as we didn't include the
// encumbrance cash state.
ledger {
unverifiedTransaction {
output("state encumbered by 5pm time-lock") { encumberedState }
output { unencumberedState }
@ -98,7 +97,10 @@ class TransactionEncumbranceTests {
this `fails with` "Missing required encumbrance 1 in INPUT"
}
}
// A transaction containing an input state that is encumbered must fail if the encumbrance is not in the correct transaction.
// A transaction containing an input state that is encumbered must fail if the encumbrance is not in the correct
// transaction. In this test, the intended encumbrance is presented alongside the encumbered state for consumption,
// although the encumbered state always refers to the encumbrance produced in the same transaction, and the in this case
// the encumbrance was created in a separate transaction.
ledger {
unverifiedTransaction {
output("state encumbered by 5pm time-lock") { encumberedState }
@ -133,6 +135,7 @@ class TransactionEncumbranceTests {
}
}
// A transaction with an input state that is encumbered must fail if the rules of the encumbrance are not met.
// In this test, the time-lock encumbrance is being processed in a transaction before the time allowed.
ledger {
unverifiedTransaction {
output("state encumbered by 5pm time-lock") { encumberedState }