refactor(wasm-utxo): extract base classes for PSBT and transaction

Introduce `PsbtBase` and `TransactionBase` to eliminate duplication
across `Psbt`/`BitGoPsbt` and `Transaction`/`ZcashTransaction`/
`DashTransaction`. Common methods (input/output counts, serialization,
KV access) are now implemented once in the base classes.

On the Rust side, add a `WasmPsbtOps` trait and macro to generate
consistent WASM bindings. Move `remove_input`/`remove_output` into
the `PsbtAccess` trait for uniformity.

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

packages/wasm-utxo/js/descriptorWallet/Psbt.ts

@@ -3,29 +3,22 @@ import {
   type WasmBIP32,
   type WasmECPair,
   type WrapDescriptor,
-  type PsbtInputData,
-  type PsbtOutputData,
   type PsbtOutputDataWithAddress,
 } from "../wasm/wasm_utxo.js";
 import type { IPsbt } from "../psbt.js";
-import type { PsbtKvKey } from "../fixedScriptWallet/BitGoKeySubtype.js";
 import type { CoinName } from "../coinName.js";
-import type { BIP32 } from "../bip32.js";
 import { Transaction } from "../transaction.js";
+import { PsbtBase } from "../psbtBase.js";
 
 export type SignPsbtResult = {
   [inputIndex: number]: [pubkey: string][];
 };
 
-export class Psbt implements IPsbt {
-  private _wasm: WasmPsbt;
-
+export class Psbt extends PsbtBase<WasmPsbt> implements IPsbt {
   constructor(versionOrWasm?: number | WasmPsbt, lockTime?: number) {
-    if (versionOrWasm instanceof WasmPsbt) {
-      this._wasm = versionOrWasm;
-    } else {
-      this._wasm = new WasmPsbt(versionOrWasm, lockTime);
-    }
+    super(
+      versionOrWasm instanceof WasmPsbt ? versionOrWasm : new WasmPsbt(versionOrWasm, lockTime),
+    );
   }
 
   /** @internal Access the underlying WASM instance */
@@ -45,48 +38,12 @@ export class Psbt implements IPsbt {
 
   // -- Serialization --
 
-  serialize(): Uint8Array {
-    return this._wasm.serialize();
-  }
-
   clone(): Psbt {
     return new Psbt(this._wasm.clone());
   }
 
   // -- IPsbt: introspection --
 
-  inputCount(): number {
-    return this._wasm.input_count();
-  }
-
-  outputCount(): number {
-    return this._wasm.output_count();
-  }
-
-  version(): number {
-    return this._wasm.version();
-  }
-
-  lockTime(): number {
-    return this._wasm.lock_time();
-  }
-
-  unsignedTxId(): string {
-    return this._wasm.unsigned_tx_id();
-  }
-
-  getInputs(): PsbtInputData[] {
-    return this._wasm.get_inputs() as PsbtInputData[];
-  }
-
-  getOutputs(): PsbtOutputData[] {
-    return this._wasm.get_outputs() as PsbtOutputData[];
-  }
-
-  getGlobalXpubs(): BIP32[] {
-    return this._wasm.get_global_xpubs() as BIP32[];
-  }
-
   getOutputsWithAddress(coin: CoinName): PsbtOutputDataWithAddress[] {
     return this._wasm.get_outputs_with_address(coin) as PsbtOutputDataWithAddress[];
   }
@@ -122,38 +79,6 @@ export class Psbt implements IPsbt {
     return this._wasm.add_output(script, value);
   }
 
-  removeInput(index: number): void {
-    this._wasm.remove_input(index);
-  }
-
-  removeOutput(index: number): void {
-    this._wasm.remove_output(index);
-  }
-
-  setKV(key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_kv(key, value);
-  }
-
-  getKV(key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_kv(key) ?? undefined;
-  }
-
-  setInputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_input_kv(index, key, value);
-  }
-
-  getInputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_input_kv(index, key) ?? undefined;
-  }
-
-  setOutputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_output_kv(index, key, value);
-  }
-
-  getOutputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_output_kv(index, key) ?? undefined;
-  }
-
   // -- Descriptor updates --
 
   updateInputWithDescriptor(inputIndex: number, descriptor: WrapDescriptor): void {

packages/wasm-utxo/js/fixedScriptWallet/BitGoPsbt.ts

@@ -1,20 +1,17 @@
 import {
   BitGoPsbt as WasmBitGoPsbt,
   FixedScriptWalletNamespace,
-  WasmBIP32,
-  type PsbtInputData,
-  type PsbtOutputData,
   type PsbtOutputDataWithAddress,
 } from "../wasm/wasm_utxo.js";
 import type { IPsbtWithAddress } from "../psbt.js";
+import { PsbtBase } from "../psbtBase.js";
 import { type WalletKeysArg, RootWalletKeys } from "./RootWalletKeys.js";
 import { type ReplayProtectionArg, ReplayProtection } from "./ReplayProtection.js";
 import { type BIP32Arg, BIP32, isBIP32Arg } from "../bip32.js";
 import { type ECPairArg, ECPair } from "../ecpair.js";
 import type { UtxolibName } from "../utxolibCompat.js";
 import type { CoinName } from "../coinName.js";
 import type { InputScriptType } from "./scriptType.js";
-import type { PsbtKvKey } from "./BitGoKeySubtype.js";
 import {
   Transaction,
   DashTransaction,
@@ -133,8 +130,10 @@ export type HydrationUnspent = {
   value: bigint;
 };
 
-export class BitGoPsbt implements IPsbtWithAddress {
-  protected constructor(protected _wasm: WasmBitGoPsbt) {}
+export class BitGoPsbt extends PsbtBase<WasmBitGoPsbt> implements IPsbtWithAddress {
+  protected constructor(wasm: WasmBitGoPsbt) {
+    super(wasm);
+  }
 
   /**
    * Get the underlying WASM instance
@@ -532,64 +531,6 @@ export class BitGoPsbt implements IPsbtWithAddress {
     );
   }
 
-  removeInput(index: number): void {
-    this._wasm.remove_input(index);
-  }
-
-  removeOutput(index: number): void {
-    this._wasm.remove_output(index);
-  }
-
-  /**
-   * Get the unsigned transaction ID
-   * @returns The unsigned transaction ID
-   */
-  unsignedTxId(): string {
-    return this._wasm.unsigned_txid();
-  }
-
-  /**
-   * Get the transaction version
-   * @returns The transaction version number
-   */
-  version(): number {
-    return this._wasm.version();
-  }
-
-  lockTime(): number {
-    return this._wasm.lock_time();
-  }
-
-  /** Set an arbitrary KV pair on the PSBT global map. */
-  setKV(key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_kv(key, value);
-  }
-
-  /** Get a KV value from the PSBT global map. Returns `undefined` if not present. */
-  getKV(key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_kv(key) ?? undefined;
-  }
-
-  /** Set an arbitrary KV pair on a specific PSBT input. */
-  setInputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_input_kv(index, key, value);
-  }
-
-  /** Get a KV value from a specific PSBT input. Returns `undefined` if not present. */
-  getInputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_input_kv(index, key) ?? undefined;
-  }
-
-  /** Set an arbitrary KV pair on a specific PSBT output. */
-  setOutputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
-    this._wasm.set_output_kv(index, key, value);
-  }
-
-  /** Get a KV value from a specific PSBT output. Returns `undefined` if not present. */
-  getOutputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
-    return this._wasm.get_output_kv(index, key) ?? undefined;
-  }
-
   /**
    * Parse transaction with wallet keys to identify wallet inputs/outputs
    * @param walletKeys - The wallet keys to use for identification
@@ -850,15 +791,6 @@ export class BitGoPsbt implements IPsbtWithAddress {
     return this._wasm.verify_replay_protection_signature(inputIndex, rp.wasm);
   }
 
-  /**
-   * Serialize the PSBT to bytes
-   *
-   * @returns The serialized PSBT as a byte array
-   */
-  serialize(): Uint8Array {
-    return this._wasm.serialize();
-  }
-
   /**
    * Generate and store MuSig2 nonces for all MuSig2 inputs
    *
@@ -983,43 +915,6 @@ export class BitGoPsbt implements IPsbtWithAddress {
     return this._wasm.extract_half_signed_legacy_tx();
   }
 
-  /**
-   * Get the number of inputs in the PSBT
-   * @returns The number of inputs
-   */
-  inputCount(): number {
-    return this._wasm.input_count();
-  }
-
-  outputCount(): number {
-    return this._wasm.output_count();
-  }
-
-  /**
-   * Get all PSBT inputs as an array
-   *
-   * Returns raw PSBT input data including witness_utxo and derivation info.
-   * For parsed transaction data with address identification, use
-   * parseTransactionWithWalletKeys() instead.
-   *
-   * @returns Array of PsbtInputData objects
-   */
-  getInputs(): PsbtInputData[] {
-    return this._wasm.get_inputs() as PsbtInputData[];
-  }
-
-  /**
-   * Get all PSBT outputs as an array
-   *
-   * Returns raw PSBT output data without address resolution.
-   * For output data with addresses, use getOutputsWithAddress().
-   *
-   * @returns Array of PsbtOutputData objects
-   */
-  getOutputs(): PsbtOutputData[] {
-    return this._wasm.get_outputs() as PsbtOutputData[];
-  }
-
   /**
    * Get all PSBT outputs with resolved address strings
    *
@@ -1039,14 +934,6 @@ export class BitGoPsbt implements IPsbtWithAddress {
   getOutputsWithAddress(): PsbtOutputDataWithAddress[] {
     return this._wasm.get_outputs_with_address() as PsbtOutputDataWithAddress[];
   }
-
-  /**
-   * Returns the unordered global xpubs from this PSBT as BIP32 instances.
-   */
-  getGlobalXpubs(): BIP32[] {
-    const result = this._wasm.get_global_xpubs() as WasmBIP32[];
-    return result.map((w) => BIP32.fromWasm(w));
-  }
 }
 
 /**

packages/wasm-utxo/js/psbtBase.ts

@@ -0,0 +1,83 @@
+import type { PsbtInputData, PsbtOutputData, WasmBIP32 } from "./wasm/wasm_utxo.js";
+import { BIP32 } from "./bip32.js";
+import type { PsbtKvKey } from "./fixedScriptWallet/BitGoKeySubtype.js";
+
+interface WasmPsbtBase {
+  input_count(): number;
+  output_count(): number;
+  version(): number;
+  lock_time(): number;
+  unsigned_tx_id(): string;
+  serialize(): Uint8Array;
+  get_inputs(): unknown;
+  get_outputs(): unknown;
+  get_global_xpubs(): unknown;
+  remove_input(index: number): void;
+  remove_output(index: number): void;
+  set_kv(key: unknown, value: Uint8Array): void;
+  get_kv(key: unknown): Uint8Array | null | undefined;
+  set_input_kv(index: number, key: unknown, value: Uint8Array): void;
+  get_input_kv(index: number, key: unknown): Uint8Array | null | undefined;
+  set_output_kv(index: number, key: unknown, value: Uint8Array): void;
+  get_output_kv(index: number, key: unknown): Uint8Array | null | undefined;
+}
+
+export abstract class PsbtBase<W extends WasmPsbtBase> {
+  protected _wasm: W;
+
+  constructor(wasm: W) {
+    this._wasm = wasm;
+  }
+
+  inputCount(): number {
+    return this._wasm.input_count();
+  }
+  outputCount(): number {
+    return this._wasm.output_count();
+  }
+  version(): number {
+    return this._wasm.version();
+  }
+  lockTime(): number {
+    return this._wasm.lock_time();
+  }
+  unsignedTxId(): string {
+    return this._wasm.unsigned_tx_id();
+  }
+  serialize(): Uint8Array {
+    return this._wasm.serialize();
+  }
+  getInputs(): PsbtInputData[] {
+    return this._wasm.get_inputs() as PsbtInputData[];
+  }
+  getOutputs(): PsbtOutputData[] {
+    return this._wasm.get_outputs() as PsbtOutputData[];
+  }
+  getGlobalXpubs(): BIP32[] {
+    return (this._wasm.get_global_xpubs() as WasmBIP32[]).map((w) => BIP32.fromWasm(w));
+  }
+  removeInput(index: number): void {
+    this._wasm.remove_input(index);
+  }
+  removeOutput(index: number): void {
+    this._wasm.remove_output(index);
+  }
+  setKV(key: PsbtKvKey, value: Uint8Array): void {
+    this._wasm.set_kv(key, value);
+  }
+  getKV(key: PsbtKvKey): Uint8Array | undefined {
+    return this._wasm.get_kv(key) ?? undefined;
+  }
+  setInputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
+    this._wasm.set_input_kv(index, key, value);
+  }
+  getInputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
+    return this._wasm.get_input_kv(index, key) ?? undefined;
+  }
+  setOutputKV(index: number, key: PsbtKvKey, value: Uint8Array): void {
+    this._wasm.set_output_kv(index, key, value);
+  }
+  getOutputKV(index: number, key: PsbtKvKey): Uint8Array | undefined {
+    return this._wasm.get_output_kv(index, key) ?? undefined;
+  }
+}