[feature] add basic decoding support for swarm

Signed-off-by: yenda <eric@status.im>

src/status_im/ethereum/ens.cljs

@@ -105,8 +105,12 @@
     :method "contenthash(bytes32)"
     :params [(namehash ens-name)]
     :on-success
-    (fn [hash]
-      (cb hash))}))
+    (fn [raw-hash]
+      ;; NOTE: it would be better if our abi-spec/decode was able to do that
+      (let [hash (subs raw-hash 130)
+            [cid & hash-and-zeros] (string/split hash "1b20")
+            hash (str "0x" cid "1b20" (subs (apply str hash-and-zeros) 0 64))]
+        (cb hash)))}))
 
 (defn content
   [resolver ens-name cb]

src/status_im/utils/contenthash.cljs

@@ -23,17 +23,36 @@
                             hash))]
       (str "0xe301" (hex/encode (b58/decode b58-hash))))))
 
-(defn decode [hex]
-  (when (and hex (not= hex "0x")
-             (string/starts-with? hex "0xe30101")
-             ;; TODO properly decode the CID
-             ;; extract the content-type using varint ns
-             (= 78 (count hex)))
-    {:namespace :ipfs
-     :hash  (-> hex
-                (subs 10)
-                hex/decode
-                b58/encode)}))
+(defn decode
+  "TODO properly decode the CID
+   extract the content-type using varint ns"
+  [hex]
+  (when (and hex (not= hex "0x"))
+    (cond
+      (and (string/starts-with? hex "0xe40101"))
+      ;; content type can be 2 or 4 bytes
+      ;; we expect 1b20 (hash algorithm and hash length 64)
+      ;; before the hash so we split the contenthash there
+      (when-let [hash (second (string/split hex "1b20"))]
+        (when (= 0x20 (count hash)))
+        {:namespace :swarm
+         :hash hash})
+      (and (= 78 (count hex))
+           (string/starts-with? hex "0xe3010170"))
+      ;; for retrocompatibility with old CIDv0
+      {:namespace :ipfs
+       :hash (-> hex
+                 (subs 10)
+                 hex/decode
+                 b58/encode)}
+      (and (= 78 (count hex))
+           (string/starts-with? hex "0xe30101"))
+      ;; new CIDv1
+      {:namespace :ipfs
+       :hash  (str "z" (-> hex
+                           (subs 6)
+                           hex/decode
+                           b58/encode))})))
 
 (fx/defn cat
   [cofx {:keys [contenthash on-success on-failure]}]

test/cljs/status_im/test/utils/contenthash.cljs

@@ -10,6 +10,10 @@
     (is (= (contenthash/decode "0xe3010170122029f2d17be6139079dc48696d1f582a8530eb9805b561eda517e22a892c7e3f1f")
            {:namespace :ipfs
             :hash "QmRAQB6YaCyidP37UdDnjFY5vQuiBrcqdyoW1CuDgwxkD4"})))
+  (testing "decoding a valid swarm hash"
+    (is (= (contenthash/decode "0xe40101fa011b20d1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162")
+           {:namespace :swarm
+            :hash "d1de9994b4d039f6548d191eb26786769f580809256b4685ef316805265ea162"})))
   (testing "decoding an invalid ipfs hash"
     (is (nil? (contenthash/decode "0xe301122029f2d17be6139079dc48696d1f582a8530eb9805b561eda517e2"))))
   (testing "decoding random garbage"