From 0818945459f8ac6564cac2c18296e470bbca074f Mon Sep 17 00:00:00 2001
From: David Dias <daviddias.p@gmail.com>
Date: Sun, 16 Oct 2016 08:11:29 +0100
Subject: [PATCH] feat: main resolver (understands dag-pb)

---
 package.json             |  1 +
 src/index.js             | 44 ++++++++++++++++++++++++--
 test/test-ipld-dag-pb.js | 68 ++++++++++++++++++++++++++++++++++++----
 3 files changed, 105 insertions(+), 8 deletions(-)

diff --git a/package.json b/package.json
index f81f1c7..f93f759 100644
--- a/package.json
+++ b/package.json
@@ -48,6 +48,7 @@
     "rimraf": "^2.5.4"
   },
   "dependencies": {
+    "async": "^2.1.1",
     "babel-runtime": "^6.11.6",
     "interface-pull-blob-store": "^0.5.0",
     "ipfs-block": "^0.3.0",
diff --git a/src/index.js b/src/index.js
index f5ce8f2..e0897f5 100644
--- a/src/index.js
+++ b/src/index.js
@@ -4,6 +4,8 @@ const Block = require('ipfs-block')
 const pull = require('pull-stream')
 const traverse = require('pull-traverse')
 const utils = require('./utils')
+const CID = require('cids')
+const until = require('async/until')
 const IPFSRepo = require('ipfs-repo')
 const MemoryStore = require('../node_modules/interface-pull-blob-store/lib/reference.js')
 const BlockService = require('ipfs-block-service')
@@ -38,8 +40,46 @@ class IPLDResolver {
     }
   }
 
-  resolve (cid, path) {
-    // TODO
+  resolve (cid, path, callback) {
+    if (path === '/') {
+      return this.get(cid, callback)
+    }
+
+    let value
+
+    until(
+      () => {
+        if (!path || path === '' || path === '/') {
+          return true
+        } else {
+          // continue traversing
+          if (value) {
+            cid = new CID(value['/'])
+          }
+          return false
+        }
+      },
+      (cb) => {
+        // get block
+        // use local resolver
+        // update path value
+        this.bs.get(cid, (err, block) => {
+          if (err) {
+            return cb(err)
+          }
+          const result = this.resolvers[cid.codec].resolver.resolve(block, path)
+          value = result.value
+          path = result.remainderPath
+          cb()
+        })
+      },
+      (err, results) => {
+        if (err) {
+          return callback(err)
+        }
+        return callback(null, value)
+      }
+    )
   }
 
   // Node operations (get and retrieve nodes, not values)
diff --git a/test/test-ipld-dag-pb.js b/test/test-ipld-dag-pb.js
index 9f267ec..8bb6dff 100644
--- a/test/test-ipld-dag-pb.js
+++ b/test/test-ipld-dag-pb.js
@@ -10,10 +10,10 @@ const pull = require('pull-stream')
 const IPLDResolver = require('../src')
 
 module.exports = (repo) => {
-  const bs = new BlockService(repo)
-  const resolver = new IPLDResolver(bs)
-
   describe('IPLD Resolver with dag-pb (MerkleDAG Protobuf)', () => {
+    const bs = new BlockService(repo)
+    const resolver = new IPLDResolver(bs)
+
     let node1
     let node2
     let node3
@@ -126,8 +126,64 @@ module.exports = (repo) => {
   })
 
   describe('IPLD Path Resolver', () => {
-    it.skip('resolves path of a non nested value', () => {})
-    it.skip('resolves path of a level 1 nested value', () => {})
-    it.skip('resolves path of a level 2 nested value', () => {})
+    let resolver
+
+    let node1
+    let node2
+    let node3
+
+    before((done) => {
+      resolver = new IPLDResolver()
+
+      node1 = new dagPB.DAGNode(new Buffer('I am 1'))
+      node2 = new dagPB.DAGNode(new Buffer('I am 2'))
+      node3 = new dagPB.DAGNode(new Buffer('I am 3'))
+
+      node2.addNodeLink('1', node1)
+
+      node3.addNodeLink('1', node1)
+      node3.addNodeLink('2', node2)
+
+      pull(
+        pull.values([
+          node1,
+          node2,
+          node3
+        ]),
+        resolver.putStream(done)
+      )
+    })
+
+    it('root path (same as get)', (done) => {
+      resolver.resolve(node1.cid(), '/', (err, result) => {
+        expect(err).to.not.exist
+        expect(result.cid()).to.eql(node1.cid())
+        done()
+      })
+    })
+
+    it('value within 1st node scope', (done) => {
+      resolver.resolve(node1.cid(), 'data', (err, result) => {
+        expect(err).to.not.exist
+        expect(result).to.eql(new Buffer('I am 1'))
+        done()
+      })
+    })
+
+    it('value within nested scope (1 level)', (done) => {
+      resolver.resolve(node2.cid(), 'links/0/data', (err, result) => {
+        expect(err).to.not.exist
+        expect(result).to.eql(new Buffer('I am 1'))
+        done()
+      })
+    })
+
+    it('value within nested scope (2 levels)', (done) => {
+      resolver.resolve(node3.cid(), 'links/1/links/0/data', (err, result) => {
+        expect(err).to.not.exist
+        expect(result).to.eql(new Buffer('I am 1'))
+        done()
+      })
+    })
   })
 }