Support multihash, setMultihash on WNS PublicResolver

contracts/PublicResolver.sol

@@ -15,13 +15,15 @@ contract PublicResolver {
     bytes4 constant ABI_INTERFACE_ID = 0x2203ab56;
     bytes4 constant PUBKEY_INTERFACE_ID = 0xc8690233;
     bytes4 constant TEXT_INTERFACE_ID = 0x59d1d43c;
+    bytes4 constant MULTIHASH_INTERFACE_ID = 0xe89401a1;
 
     event AddrChanged(bytes32 indexed node, address a);
     event ContentChanged(bytes32 indexed node, bytes32 hash);
     event NameChanged(bytes32 indexed node, string name);
     event ABIChanged(bytes32 indexed node, uint256 indexed contentType);
     event PubkeyChanged(bytes32 indexed node, bytes32 x, bytes32 y);
     event TextChanged(bytes32 indexed node, string indexedKey, string key);
+    event MultihashChanged(bytes32 indexed node, bytes hash);
 
     struct PublicKey {
         bytes32 x;
@@ -35,6 +37,7 @@ contract PublicResolver {
         PublicKey pubkey;
         mapping(string=>string) text;
         mapping(uint256=>bytes) abis;
+        bytes multihash;
     }
 
     WNS wns;
@@ -77,6 +80,17 @@ contract PublicResolver {
         records[node].content = hash;
         ContentChanged(node, hash);
     }
+
+    /**
+     * Sets the multihash associated with an WNS node.
+     * May only be called by the owner of that node in the WNS registry.
+     * @param node The node to update.
+     * @param hash The multihash to set
+     */
+    function setMultihash(bytes32 node, bytes hash) public only_owner(node) {
+        records[node].multihash = hash;
+        MultihashChanged(node, hash);
+    }
 
     /**
      * Sets the name associated with an WNS node, for reverse records.
@@ -188,6 +202,15 @@ contract PublicResolver {
         return records[node].content;
     }
 
+    /**
+     * Returns the multihash associated with an WNS node.
+     * @param node The WNS node to query.
+     * @return The associated multihash.
+     */
+    function multihash(bytes32 node) public view returns (bytes) {
+        return records[node].multihash;
+    }
+
     /**
      * Returns the address associated with an WNS node.
      * @param node The WNS node to query.
@@ -209,6 +232,7 @@ contract PublicResolver {
         interfaceID == ABI_INTERFACE_ID ||
         interfaceID == PUBKEY_INTERFACE_ID ||
         interfaceID == TEXT_INTERFACE_ID ||
+        interfaceID == MULTIHASH_INTERFACE_ID ||
         interfaceID == INTERFACE_META_ID;
     }
 }

test/TestPublicResolver.js

@@ -386,4 +386,57 @@ contract('PublicResolver', function (accounts) {
         });
     });
 
+    describe('multihash', async () => {
+
+        it('permits setting multihash by owner', async () => {
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[0]});
+            assert.equal(await resolver.multihash(node), '0x0000000000000000000000000000000000000000000000000000000000000001');
+        });
+
+        it('can overwrite previously set multihash', async () => {
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[0]});
+            assert.equal(await resolver.multihash(node), '0x0000000000000000000000000000000000000000000000000000000000000001');
+
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000002', {from: accounts[0]});
+            assert.equal(await resolver.multihash(node), '0x0000000000000000000000000000000000000000000000000000000000000002');
+        });
+
+        it('can overwrite to same multihash', async () => {
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[0]});
+            assert.equal(await resolver.multihash(node), '0x0000000000000000000000000000000000000000000000000000000000000001');
+
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000002', {from: accounts[0]});
+            assert.equal(await resolver.multihash(node), '0x0000000000000000000000000000000000000000000000000000000000000002');
+        });
+
+        it('forbids setting multihash by non-owners', async () => {
+            try {
+                await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[1]});
+            } catch (error) {
+                return utils.ensureException(error);
+            }
+
+            assert.fail('setting did not fail');
+        });
+
+        it('forbids writing same multihash by non-owners', async () => {
+            await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[0]});
+
+            try {
+                await resolver.setMultihash(node, '0x0000000000000000000000000000000000000000000000000000000000000001', {from: accounts[1]});
+            } catch (error) {
+                return utils.ensureException(error);
+            }
+
+            assert.fail('setting did not fail');
+        });
+
+        it('returns empty when fetching nonexistent multihash', async () => {
+            assert.equal(
+                await resolver.multihash(node),
+                '0x'
+            );
+        });
+    });
+
 });