From a349c9e1285c769ebd69da8e669834a89c78f370 Mon Sep 17 00:00:00 2001
From: David Dias <daviddias.p@gmail.com>
Date: Tue, 31 Jan 2017 09:36:14 +0000
Subject: [PATCH] feat: CBOR TAG

---
 package.json |  6 +++-
 src/util.js  | 96 +++++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 85 insertions(+), 17 deletions(-)

diff --git a/package.json b/package.json
index d319c41..ba17000 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,10 @@
     "borc": "^2.0.2",
     "bs58": "^4.0.0",
     "cids": "^0.4.0",
+    "is-circular": "^1.0.1",
+    "lodash.clonedeep": "^4.5.0",
+    "lodash.defaults": "^4.2.0",
+    "lodash.includes": "^4.3.0",
     "multihashes": "^0.3.2",
     "multihashing-async": "^0.4.0",
     "traverse": "^0.6.6"
@@ -59,4 +63,4 @@
     "npmcdn-to-unpkg-bot <npmcdn-to-unpkg-bot@users.noreply.github.com>",
     "wanderer <mjbecze@gmail.com>"
   ]
-}
\ No newline at end of file
+}
diff --git a/src/util.js b/src/util.js
index c49bae8..9cd21c7 100644
--- a/src/util.js
+++ b/src/util.js
@@ -5,39 +5,103 @@ const multihashing = require('multihashing-async')
 const CID = require('cids')
 const waterfall = require('async/waterfall')
 const setImmediate = require('async/setImmediate')
+const cloneDeep = require('lodash.cloneDeep')
+const includes = require('lodash.includes')
+const defaults = require('lodash.defaults')
+const isCircular = require('is-circular')
 
 const resolver = require('./resolver')
 
+function tagCID (cid) {
+  // https://github.com/ipfs/go-ipfs/issues/3570#issuecomment-273931692
+  const CID_CBOR_TAG = 42
+
+  return new cbor.Tagged(CID_CBOR_TAG, cid)
+}
+
+function replaceCIDbyTAG (dagNode) {
+  if (isCircular(dagNode)) {
+    throw new Error('The object passes has circular references')
+  }
+
+  const copy = cloneDeep(dagNode)
+
+  function transform (obj) {
+    const keys = Object.keys(obj)
+
+    // Recursive transform
+    keys.forEach((key) => {
+      if (typeof obj[key] === 'object') {
+        obj[key] = transform(obj[key])
+      }
+    })
+
+    if (includes(keys, '/')) {
+      let cid = obj['/']
+
+      // Multiaddr encoding
+      // if (typeof link === 'string' && isMultiaddr(link)) {
+      //  link = new Multiaddr(link).buffer
+      // }
+
+      delete obj['/'] // Remove the /
+      return tagCID(cid)
+    }
+
+    return obj
+  }
+
+  return transform(copy)
+}
+
+function replaceTAGbyCID (dagNode) {
+  function transform (obj) {
+    Object.keys(obj).forEach((key) => {
+      const val = obj[key]
+
+      if (val instanceof cbor.Tagged) {
+        if (typeof val.value === 'string') {
+          obj[key] = { '/': val.value }
+        } else {
+          obj[key] = defaults({ '/': val.value[0] }, transform(val.value[1]))
+        }
+      } else if (typeof val === 'object') {
+        obj[key] = transform(val)
+      }
+    })
+
+    return obj
+  }
+
+  return transform(dagNode)
+}
+
 exports = module.exports
 
 exports.serialize = (dagNode, callback) => {
   let serialized
+
   try {
-    serialized = cbor.encode(dagNode)
+    const dagNodeTagged = replaceCIDbyTAG(dagNode)
+    serialized = cbor.encode(dagNodeTagged)
   } catch (err) {
-    // return is important, otherwise in case of error the execution would continue
-    return setImmediate(() => {
-      callback(err)
-    })
+    return setImmediate(() => callback(err))
   }
-  setImmediate(() => {
-    callback(null, serialized)
-  })
+  setImmediate(() => callback(null, serialized))
 }
 
 exports.deserialize = (data, callback) => {
-  let res
+  let deserialized
+
   try {
-    res = cbor.decodeFirst(data)
+    deserialized = cbor.decodeFirst(data)
   } catch (err) {
-    return setImmediate(() => {
-      callback(err)
-    })
+    return setImmediate(() => callback(err))
   }
 
-  setImmediate(() => {
-    callback(null, res)
-  })
+  const dagNode = replaceTAGbyCID(deserialized)
+
+  setImmediate(() => callback(null, dagNode))
 }
 
 exports.cid = (dagNode, callback) => {