Add BufferReader to Transaction and fix tests

BitGo · Jan 15, 2020 · 06674b1 · 06674b1
1 parent 91e6c8a
commit 06674b1
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Showing 5 changed files with 40 additions and 113 deletions.
diff --git a/src/transaction.js b/src/transaction.js
@@ -1,6 +1,5 @@
 'use strict';
 Object.defineProperty(exports, '__esModule', { value: true });
-const bufferutils = require('./bufferutils');
 const bufferutils_1 = require('./bufferutils');
 const bcrypto = require('./crypto');
 const bscript = require('./script');
@@ -47,80 +46,48 @@ class Transaction {
     this.outs = [];
   }
   static fromBuffer(buffer, _NO_STRICT) {
-    let offset = 0;
-    function readSlice(n) {
-      offset += n;
-      return buffer.slice(offset - n, offset);
-    }
-    function readUInt32() {
-      const i = buffer.readUInt32LE(offset);
-      offset += 4;
-      return i;
-    }
-    function readInt32() {
-      const i = buffer.readInt32LE(offset);
-      offset += 4;
-      return i;
-    }
-    function readUInt64() {
-      const i = bufferutils.readUInt64LE(buffer, offset);
-      offset += 8;
-      return i;
-    }
-    function readVarInt() {
-      const vi = varuint.decode(buffer, offset);
-      offset += varuint.decode.bytes;
-      return vi;
-    }
-    function readVarSlice() {
-      return readSlice(readVarInt());
-    }
-    function readVector() {
-      const count = readVarInt();
-      const vector = [];
-      for (let i = 0; i < count; i++) vector.push(readVarSlice());
-      return vector;
-    }
+    const bufferReader = new bufferutils_1.BufferReader(buffer);
     const tx = new Transaction();
-    tx.version = readInt32();
-    const marker = buffer.readUInt8(offset);
-    const flag = buffer.readUInt8(offset + 1);
+    tx.version = bufferReader.readInt32();
+    const marker = bufferReader.readUInt8();
+    const flag = bufferReader.readUInt8();
     let hasWitnesses = false;
     if (
       marker === Transaction.ADVANCED_TRANSACTION_MARKER &&
       flag === Transaction.ADVANCED_TRANSACTION_FLAG
     ) {
-      offset += 2;
       hasWitnesses = true;
+    } else {
+      bufferReader.offset -= 2;
     }
-    const vinLen = readVarInt();
+    const vinLen = bufferReader.readVarInt();
     for (let i = 0; i < vinLen; ++i) {
       tx.ins.push({
-        hash: readSlice(32),
-        index: readUInt32(),
-        script: readVarSlice(),
-        sequence: readUInt32(),
+        hash: bufferReader.readSlice(32),
+        index: bufferReader.readUInt32(),
+        script: bufferReader.readVarSlice(),
+        sequence: bufferReader.readUInt32(),
         witness: EMPTY_WITNESS,
       });
     }
-    const voutLen = readVarInt();
+    const voutLen = bufferReader.readVarInt();
     for (let i = 0; i < voutLen; ++i) {
       tx.outs.push({
-        value: readUInt64(),
-        script: readVarSlice(),
+        value: bufferReader.readUInt64(),
+        script: bufferReader.readVarSlice(),
       });
     }
     if (hasWitnesses) {
       for (let i = 0; i < vinLen; ++i) {
-        tx.ins[i].witness = readVector();
+        tx.ins[i].witness = bufferReader.readVector();
       }
       // was this pointless?
       if (!tx.hasWitnesses())
         throw new Error('Transaction has superfluous witness data');
     }
-    tx.locktime = readUInt32();
+    tx.locktime = bufferReader.readUInt32();
     if (_NO_STRICT) return tx;
-    if (offset !== buffer.length)
+    if (bufferReader.offset !== buffer.length)
       throw new Error('Transaction has unexpected data');
     return tx;
   }

diff --git a/test/buffer_writer.spec.ts b/test/buffer_writer.spec.ts
@@ -1,6 +1,6 @@
 import * as assert from 'assert';
 import { describe, it } from 'mocha';
-import { BufferWriter } from '../src/buffer_writer';
+import { BufferWriter } from '../src/bufferutils';
 
 const varuint = require('varuint-bitcoin');
 

diff --git a/ts_src/bufferutils.ts b/ts_src/bufferutils.ts
@@ -52,7 +52,7 @@ export function reverseBuffer(buffer: Buffer): Buffer {
  * Helper class for serialization of bitcoin data types into a pre-allocated buffer.
  */
 export class BufferWriter {
-  constructor(private buffer: Buffer, public offset: number = 0) {
+  constructor(public buffer: Buffer, public offset: number = 0) {
     typeforce(types.tuple(types.Buffer, types.UInt32), [buffer, offset]);
   }
 
@@ -96,7 +96,7 @@ export class BufferWriter {
  * Helper class for serialization of bitcoin data types into a pre-allocated buffer.
  */
 export class BufferReader {
-  constructor(private buffer: Buffer, public offset: number = 0) {
+  constructor(public buffer: Buffer, public offset: number = 0) {
     typeforce(types.tuple(types.Buffer, types.UInt32), [buffer, offset]);
   }
 

diff --git a/ts_src/transaction.ts b/ts_src/transaction.ts
@@ -1,5 +1,4 @@
-import * as bufferutils from './bufferutils';
-import { BufferWriter, reverseBuffer } from './bufferutils';
+import { BufferReader, BufferWriter, reverseBuffer } from './bufferutils';
 import * as bcrypto from './crypto';
 import * as bscript from './script';
 import { OPS as opcodes } from './script';
@@ -68,96 +67,57 @@ export class Transaction {
   static readonly ADVANCED_TRANSACTION_FLAG = 0x01;
 
   static fromBuffer(buffer: Buffer, _NO_STRICT?: boolean): Transaction {
-    let offset: number = 0;
-
-    function readSlice(n: number): Buffer {
-      offset += n;
-      return buffer.slice(offset - n, offset);
-    }
-
-    function readUInt32(): number {
-      const i = buffer.readUInt32LE(offset);
-      offset += 4;
-      return i;
-    }
-
-    function readInt32(): number {
-      const i = buffer.readInt32LE(offset);
-      offset += 4;
-      return i;
-    }
-
-    function readUInt64(): number {
-      const i = bufferutils.readUInt64LE(buffer, offset);
-      offset += 8;
-      return i;
-    }
-
-    function readVarInt(): number {
-      const vi = varuint.decode(buffer, offset);
-      offset += varuint.decode.bytes;
-      return vi;
-    }
-
-    function readVarSlice(): Buffer {
-      return readSlice(readVarInt());
-    }
-
-    function readVector(): Buffer[] {
-      const count = readVarInt();
-      const vector: Buffer[] = [];
-      for (let i = 0; i < count; i++) vector.push(readVarSlice());
-      return vector;
-    }
+    const bufferReader = new BufferReader(buffer);
 
     const tx = new Transaction();
-    tx.version = readInt32();
+    tx.version = bufferReader.readInt32();
 
-    const marker = buffer.readUInt8(offset);
-    const flag = buffer.readUInt8(offset + 1);
+    const marker = bufferReader.readUInt8();
+    const flag = bufferReader.readUInt8();
 
     let hasWitnesses = false;
     if (
       marker === Transaction.ADVANCED_TRANSACTION_MARKER &&
       flag === Transaction.ADVANCED_TRANSACTION_FLAG
     ) {
-      offset += 2;
       hasWitnesses = true;
+    } else {
+      bufferReader.offset -= 2;
     }
 
-    const vinLen = readVarInt();
+    const vinLen = bufferReader.readVarInt();
     for (let i = 0; i < vinLen; ++i) {
       tx.ins.push({
-        hash: readSlice(32),
-        index: readUInt32(),
-        script: readVarSlice(),
-        sequence: readUInt32(),
+        hash: bufferReader.readSlice(32),
+        index: bufferReader.readUInt32(),
+        script: bufferReader.readVarSlice(),
+        sequence: bufferReader.readUInt32(),
         witness: EMPTY_WITNESS,
       });
     }
 
-    const voutLen = readVarInt();
+    const voutLen = bufferReader.readVarInt();
     for (let i = 0; i < voutLen; ++i) {
       tx.outs.push({
-        value: readUInt64(),
-        script: readVarSlice(),
+        value: bufferReader.readUInt64(),
+        script: bufferReader.readVarSlice(),
       });
     }
 
     if (hasWitnesses) {
       for (let i = 0; i < vinLen; ++i) {
-        tx.ins[i].witness = readVector();
+        tx.ins[i].witness = bufferReader.readVector();
       }
 
       // was this pointless?
       if (!tx.hasWitnesses())
         throw new Error('Transaction has superfluous witness data');
     }
 
-    tx.locktime = readUInt32();
+    tx.locktime = bufferReader.readUInt32();
 
     if (_NO_STRICT) return tx;
-    if (offset !== buffer.length)
+    if (bufferReader.offset !== buffer.length)
       throw new Error('Transaction has unexpected data');
 
     return tx;

diff --git a/types/bufferutils.d.ts b/types/bufferutils.d.ts
@@ -5,7 +5,7 @@ export declare function reverseBuffer(buffer: Buffer): Buffer;
  * Helper class for serialization of bitcoin data types into a pre-allocated buffer.
  */
 export declare class BufferWriter {
-    private buffer;
+    buffer: Buffer;
     offset: number;
     constructor(buffer: Buffer, offset?: number);
     writeUInt8(i: number): void;
@@ -21,7 +21,7 @@ export declare class BufferWriter {
  * Helper class for serialization of bitcoin data types into a pre-allocated buffer.
  */
 export declare class BufferReader {
-    private buffer;
+    buffer: Buffer;
     offset: number;
     constructor(buffer: Buffer, offset?: number);
     readUInt8(): number;