fix: return cids from builder

Enforces CID Version 1 for non-sha2-256 hash algorithms and returns
the buffer that makes up the CID instead of the buffer that makes
up the multihash.

Returning the multihash for v0 CIDs is fine because the codec and
version are implicity but if we want to be able to load DAGNodes
stored with a v1 CID, we need to return the CID buffer instead.

src/builder/builder.js

@@ -26,7 +26,12 @@ const defaultOptions = {
 
 module.exports = function builder (createChunker, ipld, createReducer, _options) {
   const options = extend({}, defaultOptions, _options)
-  options.cidVersion = options.cidVersion || 0
+  options.cidVersion = options.cidVersion || options.cidVersion
+  options.hashAlg = options.hashAlg || defaultOptions.hashAlg
+
+  if (options.hashAlg !== 'sha2-256') {
+    options.cidVersion = 1
+  }
 
   return function (source) {
     return function (items, cb) {
@@ -71,8 +76,10 @@ module.exports = function builder (createChunker, ipld, createReducer, _options)
           return cb(null, node)
         }
 
+        node.cid = new CID(options.cidVersion, 'dag-pb', node.multihash)
+
         ipld.put(node, {
-          cid: new CID(options.cidVersion, 'dag-pb', node.multihash)
+          cid: node.cid
         }, (err) => cb(err, node))
       }
     ], (err, node) => {
@@ -81,7 +88,7 @@ module.exports = function builder (createChunker, ipld, createReducer, _options)
       }
       callback(null, {
         path: item.path,
-        multihash: node.multihash,
+        multihash: node.cid.buffer,
         size: node.size
       })
     })
@@ -155,7 +162,7 @@ module.exports = function builder (createChunker, ipld, createReducer, _options)
       pull.map((leaf) => {
         return {
           path: file.path,
-          multihash: leaf.multihash,
+          multihash: leaf.cid.buffer,
           size: leaf.size,
           leafSize: leaf.leafSize,
           name: '',

test/builder.js

@@ -40,11 +40,13 @@ module.exports = (repo) => {
           const node = nodes[0]
           expect(node).to.exist()
 
+          const cid = new CID(node.multihash)
+
           // Verify multihash has been encoded using hashAlg
-          expect(mh.decode(node.multihash).name).to.equal(hashAlg)
+          expect(mh.decode(cid.multihash).name).to.equal(hashAlg)
 
           // Fetch using hashAlg encoded multihash
-          ipld.get(new CID(node.multihash), (err, res) => {
+          ipld.get(cid, (err, res) => {
             if (err) return cb(err)
             const content = UnixFS.unmarshal(res.value.data).data
             expect(content.equals(inputFile.content)).to.be.true()
@@ -77,7 +79,8 @@ module.exports = (repo) => {
 
           try {
             expect(node).to.exist()
-            expect(mh.decode(node.multihash).name).to.equal(hashAlg)
+            const cid = new CID(node.multihash)
+            expect(mh.decode(cid.multihash).name).to.equal(hashAlg)
           } catch (err) {
             return cb(err)
           }
@@ -92,5 +95,41 @@ module.exports = (repo) => {
         )
       }, done)
     })
+
+    it('allows multihash hash algorithm to be specified for a directory', (done) => {
+      eachSeries(testMultihashes, (hashAlg, cb) => {
+        const options = { hashAlg, strategy: 'flat' }
+        const inputFile = {
+          path: `${String(Math.random() + Date.now())}-dir`,
+          content: null
+        }
+
+        const onCollected = (err, nodes) => {
+          if (err) return cb(err)
+
+          const node = nodes[0]
+
+          expect(node).to.exist()
+
+          const cid = new CID(node.multihash)
+
+          expect(mh.decode(cid.multihash).name).to.equal(hashAlg)
+
+          // Fetch using hashAlg encoded multihash
+          ipld.get(cid, (err, res) => {
+            if (err) return cb(err)
+            const meta = UnixFS.unmarshal(res.value.data)
+            expect(meta.type).to.equal('directory')
+            cb()
+          })
+        }
+
+        pull(
+          pull.values([Object.assign({}, inputFile)]),
+          createBuilder(FixedSizeChunker, ipld, options),
+          pull.collect(onCollected)
+        )
+      }, done)
+    })
   })
 }