feat(backups): validate VHD streams (#6770)

@vates/diff/.USAGE.md

@@ -0,0 +1,32 @@
+```js
+import diff from '@vates/diff'
+
+diff('foo bar baz', 'Foo qux')
+// → [ 0, 'F', 4, 'qux', 7, '' ]
+//
+// Differences of the second string from the first one:
+// - at position 0, it contains `F`
+// - at position 4, it contains `qux`
+// - at position 7, it ends
+
+diff('Foo qux', 'foo bar baz')
+// → [ 0, 'f', 4, 'bar', 7, ' baz' ]
+//
+// Differences of the second string from the first one:
+// - at position 0, it contains f`
+// - at position 4, it contains `bar`
+// - at position 7, it contains `baz`
+
+// works with all collections that supports
+// - `.length`
+// - `collection[index]`
+// - `.slice(start, end)`
+//
+// which includes:
+// - arrays
+// - strings
+// - `Buffer`
+// - `TypedArray`
+diff([0, 1, 2], [3, 4])
+// → [ 0, [ 3, 4 ], 2, [] ]
+```

@vates/diff/.npmignore

@@ -0,0 +1 @@
+../../scripts/npmignore

@vates/diff/README.md

@@ -0,0 +1,65 @@
+<!-- DO NOT EDIT MANUALLY, THIS FILE HAS BEEN GENERATED -->
+
+# @vates/diff
+
+[![Package Version](https://badgen.net/npm/v/@vates/diff)](https://npmjs.org/package/@vates/diff) ![License](https://badgen.net/npm/license/@vates/diff) [![PackagePhobia](https://badgen.net/bundlephobia/minzip/@vates/diff)](https://bundlephobia.com/result?p=@vates/diff) [![Node compatibility](https://badgen.net/npm/node/@vates/diff)](https://npmjs.org/package/@vates/diff)
+
+> Computes differences between two arrays, buffers or strings
+
+## Install
+
+Installation of the [npm package](https://npmjs.org/package/@vates/diff):
+
+```sh
+npm install --save @vates/diff
+```
+
+## Usage
+
+```js
+import diff from '@vates/diff'
+
+diff('foo bar baz', 'Foo qux')
+// → [ 0, 'F', 4, 'qux', 7, '' ]
+//
+// Differences of the second string from the first one:
+// - at position 0, it contains `F`
+// - at position 4, it contains `qux`
+// - at position 7, it ends
+
+diff('Foo qux', 'foo bar baz')
+// → [ 0, 'f', 4, 'bar', 7, ' baz' ]
+//
+// Differences of the second string from the first one:
+// - at position 0, it contains f`
+// - at position 4, it contains `bar`
+// - at position 7, it contains `baz`
+
+// works with all collections that supports
+// - `.length`
+// - `collection[index]`
+// - `.slice(start, end)`
+//
+// which includes:
+// - arrays
+// - strings
+// - `Buffer`
+// - `TypedArray`
+diff([0, 1, 2], [3, 4])
+// → [ 0, [ 3, 4 ], 2, [] ]
+```
+
+## Contributions
+
+Contributions are _very_ welcomed, either on the documentation or on
+the code.
+
+You may:
+
+- report any [issue](https://github.com/vatesfr/xen-orchestra/issues)
+  you've encountered;
+- fork and create a pull request.
+
+## License
+
+[ISC](https://spdx.org/licenses/ISC) © [Vates SAS](https://vates.fr)

@vates/diff/index.js

@@ -0,0 +1,37 @@
+'use strict'
+
+/**
+ * Compare two data arrays, buffers or strings and invoke the provided callback function for each difference.
+ *
+ * @template {Array|Buffer|string} T
+ * @param {Array|Buffer|string} data1 - The first data array or buffer to compare.
+ * @param {T} data2 - The second data array or buffer to compare.
+ * @param {(index: number, diff: T) => void} [cb] - The callback function to invoke for each difference. If not provided, an array of differences will be returned.
+ * @returns {Array<number|T>|undefined} - An array of differences if no callback is provided, otherwise undefined.
+ */
+module.exports = function diff(data1, data2, cb) {
+  let result
+  if (cb === undefined) {
+    result = []
+    cb = result.push.bind(result)
+  }
+
+  const n1 = data1.length
+  const n2 = data2.length
+  const n = Math.min(n1, n2)
+  for (let i = 0; i < n; ++i) {
+    if (data1[i] !== data2[i]) {
+      let j = i + 1
+      while (j < n && data1[j] !== data2[j]) {
+        ++j
+      }
+      cb(i, data2.slice(i, j))
+      i = j
+    }
+  }
+  if (n1 !== n2) {
+    cb(n, n1 < n2 ? data2.slice(n) : data2.slice(0, 0))
+  }
+
+  return result
+}

@vates/diff/index.test.js

@@ -0,0 +1,51 @@
+'use strict'
+
+const assert = require('node:assert/strict')
+const test = require('test')
+
+const diff = require('./index.js')
+
+test('data of equal length', function () {
+  const data1 = 'foo bar baz'
+  const data2 = 'baz bar foo'
+  assert.deepEqual(diff(data1, data2), [0, 'baz', 8, 'foo'])
+})
+
+test('data1 is longer', function () {
+  const data1 = 'foo bar'
+  const data2 = 'foo'
+  assert.deepEqual(diff(data1, data2), [3, ''])
+})
+
+test('data2 is longer', function () {
+  const data1 = 'foo'
+  const data2 = 'foo bar'
+  assert.deepEqual(diff(data1, data2), [3, ' bar'])
+})
+
+test('with arrays', function () {
+  const data1 = 'foo bar baz'.split('')
+  const data2 = 'baz bar foo'.split('')
+  assert.deepEqual(diff(data1, data2), [0, 'baz'.split(''), 8, 'foo'.split('')])
+})
+
+test('with buffers', function () {
+  const data1 = Buffer.from('foo bar baz')
+  const data2 = Buffer.from('baz bar foo')
+  assert.deepEqual(diff(data1, data2), [0, Buffer.from('baz'), 8, Buffer.from('foo')])
+})
+
+test('cb param', function () {
+  const data1 = 'foo bar baz'
+  const data2 = 'baz bar foo'
+
+  const calls = []
+  const cb = (...args) => calls.push(args)
+
+  diff(data1, data2, cb)
+
+  assert.deepEqual(calls, [
+    [0, 'baz'],
+    [8, 'foo'],
+  ])
+})

@vates/diff/package.json

@@ -0,0 +1,36 @@
+{
+  "private": false,
+  "name": "@vates/diff",
+  "description": "Computes differences between two arrays, buffers or strings",
+  "keywords": [
+    "array",
+    "binary",
+    "buffer",
+    "diff",
+    "differences",
+    "string"
+  ],
+  "homepage": "https://github.com/vatesfr/xen-orchestra/tree/master/@vates/diff",
+  "bugs": "https://github.com/vatesfr/xen-orchestra/issues",
+  "repository": {
+    "directory": "@vates/diff",
+    "type": "git",
+    "url": "https://github.com/vatesfr/xen-orchestra.git"
+  },
+  "author": {
+    "name": "Vates SAS",
+    "url": "https://vates.fr"
+  },
+  "license": "ISC",
+  "version": "0.0.0",
+  "engines": {
+    "node": ">=8.10"
+  },
+  "scripts": {
+    "postversion": "npm publish --access public",
+    "test": "node--test"
+  },
+  "devDependencies": {
+    "test": "^3.3.0"
+  }
+}

@vates/stream-reader/.USAGE.md

@@ -0,0 +1,42 @@
+```js
+import StreamReader from '@vates/stream-reader'
+
+const reader = new StreamReader(stream)
+```
+
+### `.read([size])`
+
+- returns the next available chunk of data
+- like `stream.read()`, a number of bytes can be specified
+- returns with less data than expected if stream has ended
+- returns `null` if the stream has ended and no data has been read
+
+```js
+const chunk = await reader.read(512)
+```
+
+### `.readStrict([size])`
+
+Similar behavior to `readChunk` but throws if the stream ended before the requested data could be read.
+
+```js
+const chunk = await reader.readStrict(512)
+```
+
+### `.skip(size)`
+
+Skips a given number of bytes from a stream.
+
+Returns the number of bytes actually skipped, which may be less than the requested size if the stream has ended.
+
+```js
+const bytesSkipped = await reader.skip(2 * 1024 * 1024 * 1024)
+```
+
+### `.skipStrict(size)`
+
+Skips a given number of bytes from a stream and throws if the stream ended before enough stream has been skipped.
+
+```js
+await reader.skipStrict(2 * 1024 * 1024 * 1024)
+```

@vates/stream-reader/.npmignore

@@ -0,0 +1 @@
+../../scripts/npmignore

@vates/stream-reader/README.md

@@ -0,0 +1,75 @@
+<!-- DO NOT EDIT MANUALLY, THIS FILE HAS BEEN GENERATED -->
+
+# @vates/stream-reader
+
+[![Package Version](https://badgen.net/npm/v/@vates/stream-reader)](https://npmjs.org/package/@vates/stream-reader) ![License](https://badgen.net/npm/license/@vates/stream-reader) [![PackagePhobia](https://badgen.net/bundlephobia/minzip/@vates/stream-reader)](https://bundlephobia.com/result?p=@vates/stream-reader) [![Node compatibility](https://badgen.net/npm/node/@vates/stream-reader)](https://npmjs.org/package/@vates/stream-reader)
+
+> Efficiently reads and skips chunks of a given size in a stream
+
+## Install
+
+Installation of the [npm package](https://npmjs.org/package/@vates/stream-reader):
+
+```sh
+npm install --save @vates/stream-reader
+```
+
+## Usage
+
+```js
+import StreamReader from '@vates/stream-reader'
+
+const reader = new StreamReader(stream)
+```
+
+### `.read([size])`
+
+- returns the next available chunk of data
+- like `stream.read()`, a number of bytes can be specified
+- returns with less data than expected if stream has ended
+- returns `null` if the stream has ended and no data has been read
+
+```js
+const chunk = await reader.read(512)
+```
+
+### `.readStrict([size])`
+
+Similar behavior to `readChunk` but throws if the stream ended before the requested data could be read.
+
+```js
+const chunk = await reader.readStrict(512)
+```
+
+### `.skip(size)`
+
+Skips a given number of bytes from a stream.
+
+Returns the number of bytes actually skipped, which may be less than the requested size if the stream has ended.
+
+```js
+const bytesSkipped = await reader.skip(2 * 1024 * 1024 * 1024)
+```
+
+### `.skipStrict(size)`
+
+Skips a given number of bytes from a stream and throws if the stream ended before enough stream has been skipped.
+
+```js
+await reader.skipStrict(2 * 1024 * 1024 * 1024)
+```
+
+## Contributions
+
+Contributions are _very_ welcomed, either on the documentation or on
+the code.
+
+You may:
+
+- report any [issue](https://github.com/vatesfr/xen-orchestra/issues)
+  you've encountered;
+- fork and create a pull request.
+
+## License
+
+[ISC](https://spdx.org/licenses/ISC) © [Vates SAS](https://vates.fr)

@vates/stream-reader/index.js

@@ -0,0 +1,123 @@
+'use strict'
+
+const assert = require('node:assert')
+const { finished, Readable } = require('node:stream')
+
+const noop = Function.prototype
+
+// Inspired by https://github.com/nodejs/node/blob/85705a47958c9ae5dbaa1f57456db19bdefdc494/lib/internal/streams/readable.js#L1107
+class StreamReader {
+  #ended = false
+  #error
+  #executor = resolve => {
+    this.#resolve = resolve
+  }
+  #stream
+  #resolve = noop
+
+  constructor(stream) {
+    stream = typeof stream.pipe === 'function' ? stream : Readable.from(stream)
+
+    this.#stream = stream
+
+    stream.on('readable', () => this.#resolve())
+
+    finished(stream, { writable: false }, error => {
+      this.#error = error
+      this.#ended = true
+      this.#resolve()
+    })
+  }
+
+  async read(size) {
+    if (size !== undefined) {
+      assert(size > 0)
+    }
+
+    do {
+      if (this.#ended) {
+        if (this.#error) {
+          throw this.#error
+        }
+        return null
+      }
+
+      const value = this.#stream.read(size)
+      if (value !== null) {
+        return value
+      }
+
+      await new Promise(this.#executor)
+    } while (true)
+  }
+
+  async readStrict(size) {
+    const chunk = await this.read(size)
+    if (chunk === null) {
+      throw new Error('stream has ended without data')
+    }
+
+    if (size !== undefined && chunk.length !== size) {
+      const error = new Error(`stream has ended with not enough data (actual: ${chunk.length}, expected: ${size})`)
+      Object.defineProperties(error, {
+        chunk: {
+          value: chunk,
+        },
+      })
+      throw error
+    }
+
+    return chunk
+  }
+
+  async skip(size) {
+    if (size === 0) {
+      return size
+    }
+
+    let toSkip = size
+    do {
+      if (this.#ended) {
+        if (this.#error) {
+          throw this.#error
+        }
+        return size - toSkip
+      }
+
+      const data = this.#stream.read()
+      if (data !== null) {
+        toSkip -= data === null ? 0 : data.length
+        if (toSkip > 0) {
+          // continue to read
+        } else {
+          // if more than wanted has been read, push back the rest
+          if (toSkip < 0) {
+            this.#stream.unshift(data.slice(toSkip))
+          }
+
+          return size
+        }
+      }
+
+      await new Promise(this.#executor)
+    } while (true)
+  }
+
+  async skipStrict(size) {
+    const bytesSkipped = await this.skip(size)
+    if (bytesSkipped !== size) {
+      const error = new Error(`stream has ended with not enough data (actual: ${bytesSkipped}, expected: ${size})`)
+      error.bytesSkipped = bytesSkipped
+      throw error
+    }
+  }
+}
+
+StreamReader.prototype[Symbol.asyncIterator] = async function* asyncIterator() {
+  let chunk
+  while ((chunk = await this.read()) !== null) {
+    yield chunk
+  }
+}
+
+module.exports = StreamReader

@vates/stream-reader/index.test.js

@@ -0,0 +1,141 @@
+'use strict'
+
+const { describe, it } = require('test')
+const assert = require('node:assert').strict
+
+const { Readable } = require('stream')
+
+const StreamReader = require('./index.js')
+
+const makeStream = it => Readable.from(it, { objectMode: false })
+makeStream.obj = Readable.from
+
+const rejectionOf = promise =>
+  promise.then(
+    value => {
+      throw value
+    },
+    error => error
+  )
+
+const makeErrorTests = method => {
+  it('rejects if the stream errors', async () => {
+    const error = new Error()
+    const stream = makeStream([])
+
+    const pError = rejectionOf(new StreamReader(stream)[method](10))
+    stream.destroy(error)
+
+    assert.strict(await pError, error)
+  })
+
+  it('rejects if the stream has already errored', async () => {
+    const error = new Error()
+    const stream = makeStream([])
+
+    await new Promise(resolve => {
+      stream.once('error', resolve).destroy(error)
+    })
+
+    assert.strict(await rejectionOf(new StreamReader(stream)[method](10)), error)
+  })
+}
+
+describe('read()', () => {
+  it('rejects if size is less than or equal to 0', async () => {
+    const error = await rejectionOf(new StreamReader(makeStream([])).read(0))
+    assert.strictEqual(error.code, 'ERR_ASSERTION')
+  })
+
+  it('returns null if stream is empty', async () => {
+    assert.strictEqual(await new StreamReader(makeStream([])).read(), null)
+  })
+
+  makeErrorTests('read')
+
+  it('returns null if the stream is already ended', async () => {
+    const reader = new StreamReader(makeStream([]))
+
+    await reader.read()
+
+    assert.strictEqual(await reader.read(), null)
+  })
+
+  describe('with binary stream', () => {
+    it('returns the first chunk of data', async () => {
+      assert.deepEqual(await new StreamReader(makeStream(['foo', 'bar'])).read(), Buffer.from('foo'))
+    })
+
+    it('returns a chunk of the specified size (smaller than first)', async () => {
+      assert.deepEqual(await new StreamReader(makeStream(['foo', 'bar'])).read(2), Buffer.from('fo'))
+    })
+
+    it('returns a chunk of the specified size (larger than first)', async () => {
+      assert.deepEqual(await new StreamReader(makeStream(['foo', 'bar'])).read(4), Buffer.from('foob'))
+    })
+
+    it('returns less data if stream ends', async () => {
+      assert.deepEqual(await new StreamReader(makeStream(['foo', 'bar'])).read(10), Buffer.from('foobar'))
+    })
+  })
+
+  describe('with object stream', () => {
+    it('returns the first chunk of data verbatim', async () => {
+      const chunks = [{}, {}]
+      assert.strictEqual(await new StreamReader(makeStream.obj(chunks)).read(), chunks[0])
+    })
+  })
+})
+
+describe('readStrict()', function () {
+  it('throws if stream is empty', async () => {
+    const error = await rejectionOf(new StreamReader(makeStream([])).readStrict())
+    assert(error instanceof Error)
+    assert.strictEqual(error.message, 'stream has ended without data')
+    assert.strictEqual(error.chunk, undefined)
+  })
+
+  it('throws if stream ends with not enough data', async () => {
+    const error = await rejectionOf(new StreamReader(makeStream(['foo', 'bar'])).readStrict(10))
+    assert(error instanceof Error)
+    assert.strictEqual(error.message, 'stream has ended with not enough data (actual: 6, expected: 10)')
+    assert.deepEqual(error.chunk, Buffer.from('foobar'))
+  })
+})
+
+describe('skip()', function () {
+  makeErrorTests('skip')
+
+  it('returns 0 if size is 0', async () => {
+    assert.strictEqual(await new StreamReader(makeStream(['foo'])).skip(0), 0)
+  })
+
+  it('returns 0 if the stream is already ended', async () => {
+    const reader = new StreamReader(makeStream([]))
+
+    await reader.read()
+
+    assert.strictEqual(await reader.skip(10), 0)
+  })
+
+  it('skips a number of bytes', async () => {
+    const reader = new StreamReader(makeStream('foo bar'))
+
+    assert.strictEqual(await reader.skip(4), 4)
+    assert.deepEqual(await reader.read(4), Buffer.from('bar'))
+  })
+
+  it('returns less size if stream ends', async () => {
+    assert.deepEqual(await new StreamReader(makeStream('foo bar')).skip(10), 7)
+  })
+})
+
+describe('skipStrict()', function () {
+  it('throws if stream ends with not enough data', async () => {
+    const error = await rejectionOf(new StreamReader(makeStream('foo bar')).skipStrict(10))
+
+    assert(error instanceof Error)
+    assert.strictEqual(error.message, 'stream has ended with not enough data (actual: 7, expected: 10)')
+    assert.deepEqual(error.bytesSkipped, 7)
+  })
+})

@vates/stream-reader/package.json

@@ -0,0 +1,39 @@
+{
+  "private": false,
+  "name": "@vates/stream-reader",
+  "description": "Efficiently reads and skips chunks of a given size in a stream",
+  "keywords": [
+    "async",
+    "chunk",
+    "data",
+    "node",
+    "promise",
+    "read",
+    "reader",
+    "skip",
+    "stream"
+  ],
+  "homepage": "https://github.com/vatesfr/xen-orchestra/tree/master/@vates/stream-reader",
+  "bugs": "https://github.com/vatesfr/xen-orchestra/issues",
+  "repository": {
+    "directory": "@vates/stream-reader",
+    "type": "git",
+    "url": "https://github.com/vatesfr/xen-orchestra.git"
+  },
+  "author": {
+    "name": "Vates SAS",
+    "url": "https://vates.fr"
+  },
+  "license": "ISC",
+  "version": "0.0.0",
+  "engines": {
+    "node": ">=10"
+  },
+  "scripts": {
+    "postversion": "npm publish --access public",
+    "test": "node--test"
+  },
+  "devDependencies": {
+    "test": "^3.3.0"
+  }
+}

@xen-orchestra/backups/Backup.js

@@ -49,6 +49,7 @@ const DEFAULT_VM_SETTINGS = {
   timeout: 0,
   useNbd: false,
   unconditionalSnapshot: false,
+  validateVhdStreams: true,
   vmTimeout: 0,
 }
 

@xen-orchestra/backups/_VmBackup.js

@@ -6,11 +6,13 @@ const groupBy = require('lodash/groupBy.js')
 const ignoreErrors = require('promise-toolbox/ignoreErrors')
 const keyBy = require('lodash/keyBy.js')
 const mapValues = require('lodash/mapValues.js')
+const vhdStreamValidator = require('vhd-lib/vhdStreamValidator.js')
 const { asyncMap } = require('@xen-orchestra/async-map')
 const { createLogger } = require('@xen-orchestra/log')
 const { decorateMethodsWith } = require('@vates/decorate-with')
 const { defer } = require('golike-defer')
 const { formatDateTime } = require('@xen-orchestra/xapi')
+const { pipeline } = require('node:stream')
 
 const { DeltaBackupWriter } = require('./writers/DeltaBackupWriter.js')
 const { DeltaReplicationWriter } = require('./writers/DeltaReplicationWriter.js')
@@ -44,6 +46,8 @@ const forkDeltaExport = deltaExport =>
     },
   })
 
+const noop = Function.prototype
+
 class VmBackup {
   constructor({
     config,
@@ -251,6 +255,11 @@ class VmBackup {
       Task.info('Transfer data using NBD')
     }
     const sizeContainers = mapValues(deltaExport.streams, stream => watchStreamSize(stream))
+
+    if (this._settings.validateVhdStreams) {
+      deltaExport.streams = mapValues(deltaExport.streams, stream => pipeline(stream, vhdStreamValidator, noop))
+    }
+
     deltaExport.streams = mapValues(deltaExport.streams, this._throttleStream)
 
     const timestamp = Date.now()

CHANGELOG.unreleased.md

@@ -34,7 +34,11 @@
 
 <!--packages-start-->
 
+- @vates/diff minor
 - @vates/read-chunk patch
+- @vates/stream-reader minor
+- @xen-orchestra/backups minor
+- vhd-lib minor
 - xo-web patch
 - xo-server minor
 - xo-server-usage-report patch

packages/vhd-lib/package.json

@@ -12,11 +12,13 @@
     "url": "https://github.com/vatesfr/xen-orchestra.git"
   },
   "engines": {
-    "node": ">=14"
+    "node": ">=16"
   },
   "dependencies": {
     "@vates/async-each": "^1.0.0",
+    "@vates/diff": "^0.0.0",
     "@vates/read-chunk": "^1.1.0",
+    "@vates/stream-reader": "^0.0.0",
     "@xen-orchestra/async-map": "^0.1.2",
     "@xen-orchestra/fs": "^3.3.4",
     "@xen-orchestra/log": "^0.6.0",

packages/vhd-lib/vhdStreamValidator.js

@@ -0,0 +1,79 @@
+'use strict'
+
+const diff = require('@vates/diff')
+const StreamReader = require('@vates/stream-reader')
+
+const { FOOTER_SIZE, HEADER_SIZE } = require('./_constants.js')
+const { unpackFooter, unpackHeader } = require('./Vhd/_utils.js')
+
+// Async generator that can be in a pipeline to check the header and footers of a VHD stream.
+//
+// ```js
+// await pipeline(createVhdStream(), vhdStreamValidator, createOutputStream())
+// ```
+module.exports = async function* vhdStreamValidator(source) {
+  let offset = 0
+  try {
+    const reader = new StreamReader(source)
+
+    const footer1 = await reader.readStrict(FOOTER_SIZE)
+    yield footer1
+
+    // unpack and validate footer
+    unpackFooter(footer1)
+
+    offset += footer1.length
+
+    const header = await reader.readStrict(HEADER_SIZE)
+    yield header
+
+    // unpack and validate header
+    unpackHeader(header)
+
+    offset += header.length
+
+    let last
+    while (true) {
+      const chunk = await reader.read(FOOTER_SIZE)
+
+      if (chunk === null) {
+        // the end has been reached, `last` contains the footer
+        break
+      }
+
+      yield chunk
+
+      offset += chunk.length
+
+      if (chunk.length < FOOTER_SIZE) {
+        // the end has been reached, the footer is part in `last` and part in `chunk`
+        last = Buffer.concat([last.slice(-(FOOTER_SIZE - chunk.length)), chunk])
+        break
+      }
+
+      last = chunk
+    }
+
+    // offset is the position at which the footer was read, not the position after
+    offset -= last.length
+
+    // do not use `assert.strictDeepEqual` as it does not provide a compact (for buffers) or complete (for strings) result
+    //
+    //  - save only expected data and diff
+    // - save expected buffer as hex string for compacity and readability
+    // - save diff as an array of differences represented as hex strings
+    if (!last.equals(footer1)) {
+      const error = new Error('footer1 !== footer2')
+      error.diff = []
+      diff(footer1, last, (i, buf) => {
+        error.diff.push(i, buf.toString('hex'))
+      })
+      error.expected = footer1.toString('hex')
+
+      throw error
+    }
+  } catch (error) {
+    error.offset = offset
+    throw error
+  }
+}