fix/cid prefix (#16)

* fix: protocol block prefix

* build: v0.5.1

Author: Simone Sanfratello

package.json

@@ -1,6 +1,6 @@
 {
   "name": "e-ipfs-core-lib",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "E-IPFS core library",
   "license": "(Apache-2.0 AND MIT)",
   "homepage": "https://github.com/elastic-ipfs/core-lib",
@@ -26,6 +26,7 @@
     "protobufjs": "^7.1.2",
     "sodium-native": "^3.4.1",
     "undici": "^5.13.0",
+    "varint": "^6.0.0",
     "xml-js": "^1.6.11"
   },
   "devDependencies": {

src/protocol.js

@@ -3,7 +3,7 @@
 import { default as protobuf } from 'protobufjs'
 import path from 'path'
 
-import { dirname } from '../src/util.js'
+import { dirname, varintEncoder } from '../src/util.js'
 import { CID } from 'multiformats/cid'
 
 const definitions = protobuf.loadSync(path.join(dirname(import.meta.url), './bitswap.proto'))
@@ -144,15 +144,17 @@ class WantList {
 class Block {
   constructor (prefixOrCid, data) {
     if (prefixOrCid instanceof CID) {
-      prefixOrCid = Buffer.from([
-        prefixOrCid.version,
-        prefixOrCid.code,
-        prefixOrCid.multihash.bytes[0],
-        prefixOrCid.multihash.bytes[1]
+      const version = prefixOrCid.version
+      const codec = prefixOrCid.code
+      const multihash = prefixOrCid.multihash.code
+      const digestLength = prefixOrCid.multihash.digest.length
+      this.prefix = varintEncoder([
+        version, codec, multihash, digestLength
       ])
+    } else {
+      this.prefix = prefixOrCid
     }
 
-    this.prefix = prefixOrCid
     this.data = data
   }
 

src/util.js

@@ -2,6 +2,7 @@
 import fs from 'fs'
 import path from 'path'
 import url from 'url'
+import * as varint from 'varint'
 import { base58btc as base58 } from 'multiformats/bases/base58'
 
 function dirname (importMetaUrl) {
@@ -21,4 +22,26 @@ function cidToKey (cid) {
   }
 }
 
-export { dirname, version, cidToKey }
+/**
+ * from https://github.com/ipfs/js-ipfs-bitswap
+ * @param {Array<number>} buf
+ * @returns {Uint8Array}
+ */
+function varintEncoder (buf) {
+  let out = new Uint8Array(buf.reduce((acc, curr) => {
+    return acc + varint.default.encodingLength(curr)
+  }, 0))
+
+  let offset = 0
+
+  for (const num of buf) {
+    out = varint.encode(num, out, offset)
+
+    // @ts-expect-error types are wrong
+    offset += varint.default.encodingLength(num)
+  }
+
+  return out
+}
+
+export { dirname, version, cidToKey, varintEncoder }