feat(nbd-client): implement a Disk adapter based on NBD connection

@vates/nbd-client/NbdDisk.mjs

@@ -0,0 +1,122 @@
+import { RandomAccessDisk } from '@xen-orchestra/disk-transform'
+import NbdClient from '@vates/nbd-client'
+
+/**
+ * @typedef {{ offset: number, length: number }} DataRange
+ */
+
+/**
+ * @extends {RandomAccessDisk}
+ */
+export class NbdDisk extends RandomAccessDisk {
+  #nbdInfos
+  /** @type {NbdClient|undefined} */
+  #nbdClient
+
+  /** @type {Array<DataRange> | undefined} */
+  #dataMap
+
+  /** @type {number} */
+  #blockSize
+
+  constructor(nbdInfos, blockSize, { dataMap } = {}) {
+    super()
+    this.#blockSize = blockSize
+    this.#nbdInfos = nbdInfos
+    this.#dataMap = dataMap && this.#processDatamap(dataMap)
+  }
+
+  #processDatamap(rawDataMap) {
+    return rawDataMap
+      .filter(({ type }) => type === 0)
+      .map(({ offset, length }) => ({ offset, length }))
+      .sort(({ offset: offset1 }, { offset: offset2 }) => offset1 - offset2)
+  }
+  /**
+   * @param {number} index
+   * @returns {Promise<DiskBlock>}
+   */
+  async readBlock(index) {
+    if (!this.#nbdClient) {
+      throw new Error("can't readBlock before init")
+    }
+    const data = await this.#nbdClient.readBlock(index, this.getBlockSize())
+    return {
+      index,
+      data,
+    }
+  }
+
+  /**
+   * @returns {number}
+   */
+  getVirtualSize() {
+    if (!this.#nbdClient) {
+      throw new Error("can't get size before init")
+    }
+    return Number(this.#nbdClient.exportSize)
+  }
+
+  /**
+   * @returns {number}
+   */
+  getBlockSize() {
+    return this.#blockSize
+  }
+
+  /**
+   * @returns {Promise<void>}
+   */
+  async init() {
+    this.#nbdClient = new NbdClient(this.#nbdInfos)
+    await this.#nbdClient.connect()
+    if (this.#dataMap === undefined) {
+      this.#dataMap = this.#processDatamap(await this.#nbdClient.getMap())
+    }
+  }
+
+  /**
+   * @returns {Promise<void>}
+   */
+  async close() {
+    await this.#nbdClient?.disconnect()
+  }
+
+  /**
+   * @returns {boolean}
+   */
+  isDifferencing() {
+    return false
+  }
+
+  /**
+   * @returns {Array<number>}
+   */
+  getBlockIndexes() {
+    const indexes = new Set()
+    this.#dataMap?.forEach(({ offset, length }) => {
+      if (length === 0) return
+
+      const firstBlockIndex = Math.floor(offset / this.getBlockSize())
+      const lastBlockIndex = Math.floor((offset + length - 1) / this.getBlockSize())
+
+      for (let blockIndex = firstBlockIndex; blockIndex <= lastBlockIndex; blockIndex++) {
+        indexes.add(blockIndex)
+      }
+    })
+    return [...indexes].sort((a, b) => a - b)
+  }
+
+  /**
+   * @param {number} index
+   * @returns {boolean}
+   */
+  hasBlock(index) {
+    if (!this.#dataMap) {
+      throw new Error("can't hasBlock before init")
+    }
+    const blockStart = index * this.getBlockSize()
+    const blockEnd = (index + 1) * this.getBlockSize()
+    return this.#dataMap.some(({ offset, length }) => offset + length > blockStart && blockEnd >= offset)
+  }
+}

@vates/nbd-client/package.json

@@ -22,6 +22,7 @@
     "@vates/async-each": "^1.0.0",
     "@vates/read-chunk": "^1.2.0",
     "@xen-orchestra/async-map": "^0.1.2",
+    "@xen-orchestra/disk-transform": "^1.0.1",
     "@xen-orchestra/log": "^0.7.1",
     "promise-toolbox": "^0.21.0",
     "xen-api": "^4.7.3"