Add Synchronizer side of PCZT logic

sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt

@@ -51,6 +51,7 @@ import cash.z.ecc.android.sdk.model.FastestServersResult
 import cash.z.ecc.android.sdk.model.FetchFiatCurrencyResult
 import cash.z.ecc.android.sdk.model.FirstClassByteArray
 import cash.z.ecc.android.sdk.model.ObserveFiatCurrencyResult
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.PercentDecimal
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionOutput
@@ -93,6 +94,7 @@ import kotlinx.coroutines.flow.channelFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
@@ -857,6 +859,22 @@ class SdkSynchronizer private constructor(
             }
     }
 
+    override suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ) = txManager.createPcztFromProposal(accountUuid, proposal)
+
+    override suspend fun addProofsToPczt(pczt: Pczt) = txManager.addProofsToPczt(pczt)
+
+    override suspend fun createTransactionFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt
+    ): Flow<TransactionSubmitResult> {
+        // Internally, this logic submits and checks the newly stored and encoded transaction
+        return flowOf(txManager.extractAndStoreTxFromPczt(pcztWithProofs, pcztWithSignatures))
+            .map { transaction -> txManager.submit(transaction) }
+    }
+
     override suspend fun refreshUtxos(
         account: Account,
         since: BlockHeight

sdk-lib/src/main/java/cash/z/ecc/android/sdk/Synchronizer.kt

@@ -6,6 +6,7 @@ import cash.z.ecc.android.sdk.WalletInitMode.NewWallet
 import cash.z.ecc.android.sdk.WalletInitMode.RestoreWallet
 import cash.z.ecc.android.sdk.block.processor.CompactBlockProcessor
 import cash.z.ecc.android.sdk.exception.InitializeException
+import cash.z.ecc.android.sdk.exception.PcztException
 import cash.z.ecc.android.sdk.ext.ZcashSdk
 import cash.z.ecc.android.sdk.internal.FastestServerFetcher
 import cash.z.ecc.android.sdk.internal.Files
@@ -22,6 +23,7 @@ import cash.z.ecc.android.sdk.model.AccountUuid
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.FastestServersResult
 import cash.z.ecc.android.sdk.model.ObserveFiatCurrencyResult
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.PercentDecimal
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionOutput
@@ -301,6 +303,54 @@ interface Synchronizer {
         usk: UnifiedSpendingKey
     ): Flow<TransactionSubmitResult>
 
+    /**
+     * Creates a partially-created (unsigned without proofs) transaction from the given proposal.
+     *
+     * Do not call this multiple times in parallel, or you will generate PCZT instances that, if
+     * finalized, would double-spend the same notes.
+     *
+     * @param accountUuid The account for which the proposal was created.
+     * @param proposal The proposal for which to create the transaction.
+     *
+     * @return The partially created transaction in [Pczt] format.
+     *
+     * @throws PcztException.CreatePcztFromProposalException as a common indicator of the operation failure
+     */
+    @Throws(PcztException.CreatePcztFromProposalException::class)
+    suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ): Pczt
+
+    /**
+     * Adds proofs to the given PCZT.
+     *
+     * @param pczt The partially created transaction in its serialized format.
+     *
+     * @return The updated PCZT in its serialized format.
+     *
+     * @throws PcztException.AddProofsToPcztException as a common indicator of the operation failure
+     */
+    @Throws(PcztException.AddProofsToPcztException::class)
+    suspend fun addProofsToPczt(pczt: Pczt): Pczt
+
+    /**
+     * Takes a PCZT that has been separately proven and signed, finalizes it, and stores
+     * it in the wallet. Internally, this logic also submits and checks the newly stored and encoded transaction.
+     *
+     * @param pcztWithProofs
+     * @param pcztWithSignatures
+     *
+     * @return The submission result of the completed transaction.
+     *
+     * @throws PcztException.ExtractAndStoreTxFromPcztException as a common indicator of the operation failure
+     */
+    @Throws(PcztException.ExtractAndStoreTxFromPcztException::class)
+    suspend fun createTransactionFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt,
+    ): Flow<TransactionSubmitResult>
+
     // TODO [#1534]: Add RustLayerException.ValidateAddressException
     // TODO [#1534]: https://github.com/Electric-Coin-Company/zcash-android-wallet-sdk/issues/1534
 

sdk-lib/src/main/java/cash/z/ecc/android/sdk/exception/Exceptions.kt

@@ -327,6 +327,38 @@ sealed class LightWalletException(message: String, cause: Throwable? = null) : S
     )
 }
 
+/**
+ * Potentially user-facing exceptions thrown while creating transactions
+ */
+sealed class PcztException(
+    message: String,
+    cause: Throwable? = null
+) : SdkException(message, cause) {
+    class CreatePcztFromProposalException internal constructor(
+        description: String?,
+        cause: Throwable?
+    ) : PcztException(
+            "Failed to create PCZT from proposal with message: ${description ?: "-"}",
+            cause
+        )
+
+    class AddProofsToPcztException internal constructor(
+        description: String?,
+        cause: Throwable?
+    ) : PcztException(
+            "Failed to add proofs to PCZT with message: ${description ?: "-"}",
+            cause
+        )
+
+    class ExtractAndStoreTxFromPcztException internal constructor(
+        description: String?,
+        cause: Throwable?
+    ) : PcztException(
+            "Failed to extract and store transaction from PCZT with message: ${description ?: "-"}",
+            cause
+        )
+}
+
 /**
  * Potentially user-facing exceptions thrown while encoding transactions.
  */

sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/TypesafeBackendImpl.kt

@@ -155,7 +155,11 @@ internal class TypesafeBackendImpl(private val backend: Backend) : TypesafeBacke
         pcztWithProofs: Pczt,
         pcztWithSignatures: Pczt
     ): FirstClassByteArray =
-        FirstClassByteArray(backend.extractAndStoreTxFromPczt(pcztWithProofs.toByteArray(), pcztWithSignatures.toByteArray()))
+        FirstClassByteArray(
+            backend.extractAndStoreTxFromPczt(
+                pcztWithProofs.toByteArray(), pcztWithSignatures.toByteArray()
+            )
+        )
 
     override suspend fun getCurrentAddress(account: Account): String {
         return runCatching {

sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/OutboundTransactionManager.kt

@@ -2,6 +2,8 @@ package cash.z.ecc.android.sdk.internal.transaction
 
 import cash.z.ecc.android.sdk.internal.model.EncodedTransaction
 import cash.z.ecc.android.sdk.model.Account
+import cash.z.ecc.android.sdk.model.AccountUuid
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionRecipient
 import cash.z.ecc.android.sdk.model.TransactionSubmitResult
@@ -114,6 +116,18 @@ internal interface OutboundTransactionManager {
      */
     suspend fun submit(encodedTransaction: EncodedTransaction): TransactionSubmitResult
 
+    suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ): Pczt
+
+    suspend fun addProofsToPczt(pczt: Pczt): Pczt
+
+    suspend fun extractAndStoreTxFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt
+    ): EncodedTransaction
+
     /**
      * Return true when the given address is a valid t-addr.
      *

sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/OutboundTransactionManagerImpl.kt

@@ -4,6 +4,8 @@ import cash.z.ecc.android.sdk.internal.Twig
 import cash.z.ecc.android.sdk.internal.ext.toHexReversed
 import cash.z.ecc.android.sdk.internal.model.EncodedTransaction
 import cash.z.ecc.android.sdk.model.Account
+import cash.z.ecc.android.sdk.model.AccountUuid
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionRecipient
 import cash.z.ecc.android.sdk.model.TransactionSubmitResult
@@ -138,6 +140,18 @@ internal class OutboundTransactionManagerImpl(
         }
     }
 
+    override suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ) = encoder.createPcztFromProposal(accountUuid, proposal)
+
+    override suspend fun addProofsToPczt(pczt: Pczt) = encoder.addProofsToPczt(pczt)
+
+    override suspend fun extractAndStoreTxFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt
+    ) = encoder.extractAndStoreTxFromPczt(pcztWithProofs, pcztWithSignatures)
+
     override suspend fun isValidShieldedAddress(address: String) = encoder.isValidShieldedAddress(address)
 
     override suspend fun isValidTransparentAddress(address: String) = encoder.isValidTransparentAddress(address)

sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoder.kt

@@ -3,7 +3,9 @@ package cash.z.ecc.android.sdk.internal.transaction
 import cash.z.ecc.android.sdk.exception.TransactionEncoderException
 import cash.z.ecc.android.sdk.internal.model.EncodedTransaction
 import cash.z.ecc.android.sdk.model.Account
+import cash.z.ecc.android.sdk.model.AccountUuid
 import cash.z.ecc.android.sdk.model.BlockHeight
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionRecipient
 import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
@@ -126,6 +128,18 @@ internal interface TransactionEncoder {
         usk: UnifiedSpendingKey
     ): List<EncodedTransaction>
 
+    suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ): Pczt
+
+    suspend fun addProofsToPczt(pczt: Pczt): Pczt
+
+    suspend fun extractAndStoreTxFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt
+    ): EncodedTransaction
+
     /**
      * Utility function to help with validation. This is not called during [createTransaction]
      * because this class asserts that all validation is done externally by the UI, for now.

sdk-lib/src/main/java/cash/z/ecc/android/sdk/internal/transaction/TransactionEncoderImpl.kt

@@ -1,5 +1,6 @@
 package cash.z.ecc.android.sdk.internal.transaction
 
+import cash.z.ecc.android.sdk.exception.PcztException
 import cash.z.ecc.android.sdk.exception.SdkException
 import cash.z.ecc.android.sdk.exception.TransactionEncoderException
 import cash.z.ecc.android.sdk.ext.masked
@@ -9,8 +10,10 @@ import cash.z.ecc.android.sdk.internal.TypesafeBackend
 import cash.z.ecc.android.sdk.internal.model.EncodedTransaction
 import cash.z.ecc.android.sdk.internal.repository.DerivedDataRepository
 import cash.z.ecc.android.sdk.model.Account
+import cash.z.ecc.android.sdk.model.AccountUuid
 import cash.z.ecc.android.sdk.model.BlockHeight
 import cash.z.ecc.android.sdk.model.FirstClassByteArray
+import cash.z.ecc.android.sdk.model.Pczt
 import cash.z.ecc.android.sdk.model.Proposal
 import cash.z.ecc.android.sdk.model.TransactionRecipient
 import cash.z.ecc.android.sdk.model.UnifiedSpendingKey
@@ -200,6 +203,60 @@ internal class TransactionEncoderImpl(
         return txs
     }
 
+    override suspend fun createPcztFromProposal(
+        accountUuid: AccountUuid,
+        proposal: Proposal
+    ): Pczt {
+        return runCatching {
+            backend.createPcztFromProposal(
+                account = Account.new(accountUuid),
+                proposal = proposal
+            )
+        }.onSuccess {
+            Twig.debug { "Result of createPcztFromProposal: $it" }
+        }.onFailure {
+            Twig.error(it) { "Caught exception while creating PCZT." }
+        }.getOrElse {
+            throw PcztException.CreatePcztFromProposalException(it.message, it.cause)
+        }
+    }
+
+    override suspend fun addProofsToPczt(pczt: Pczt): Pczt {
+        return runCatching {
+            backend.addProofsToPczt(
+                pczt = pczt
+            )
+        }.onSuccess {
+            Twig.debug { "Result of addProofsToPczt: $it" }
+        }.onFailure {
+            Twig.error(it) { "Caught exception while adding proofs to PCZT." }
+        }.getOrElse {
+            throw PcztException.AddProofsToPcztException(it.message, it.cause)
+        }
+    }
+
+    override suspend fun extractAndStoreTxFromPczt(
+        pcztWithProofs: Pczt,
+        pcztWithSignatures: Pczt
+    ): EncodedTransaction {
+        val txId =
+            runCatching {
+                backend.extractAndStoreTxFromPczt(
+                    pcztWithProofs = pcztWithProofs,
+                    pcztWithSignatures = pcztWithSignatures
+                )
+            }.onSuccess {
+                Twig.debug { "Result of extractAndStoreTxFromPczt: $it" }
+            }.onFailure {
+                Twig.error(it) { "Caught exception while extracting and storing transaction from PCZT." }
+            }.getOrElse {
+                throw PcztException.ExtractAndStoreTxFromPcztException(it.message, it.cause)
+            }
+
+        return repository.findEncodedTransactionByTxId(txId)
+            ?: throw TransactionEncoderException.TransactionNotFoundException(txId)
+    }
+
     /**
      * Utility function to help with validation. This is not called during [createTransaction]
      * because this class asserts that all validation is done externally by the UI, for now.

sdk-lib/src/main/java/cash/z/ecc/android/sdk/model/Pczt.kt

@@ -9,4 +9,7 @@ class Pczt(
     fun toByteArray(): ByteArray {
         return inner
     }
+
+    // Override to prevent leaking data in logs
+    override fun toString() = "Pczt(size=${inner.size})"
 }