[StateService] get historical state

src/StateService/README.md

@@ -0,0 +1,64 @@
+# StateService
+
+## RPC API
+
+### GetStateRoot
+#### Params
+|Name|Type|Summary|Required|
+|-|-|-|-|
+|Index|uint|index|true|
+#### Result
+StateRoot Object
+|Name|Type|Summary|
+|-|-|-|
+|version|number|version|
+|index|number|index|
+|roothash|string|version|
+|witness|Object|witness from validators|
+
+### GetProof
+#### Params
+|Name|Type|Summary|Required|
+|-|-|-|-|
+|RootHash|UInt256|state root|true|
+|ScriptHash|UInt160|contract script hash|true|
+|Key|base64 string|key|true|
+#### Result
+Proof in base64 string
+
+### VerifyProof
+#### Params
+|Name|Type|Summary|
+|-|-|-|
+|RootHash|UInt256|state root|true|
+|Proof|base64 string|proof|true|
+#### Result
+Value in base64 string
+
+### GetStateheight
+#### Result
+|Name|Type|Summary|
+|-|-|-|
+|localrootindex|number|root hash index calculated locally|
+|validatedrootindex|number|root hash index verified by validators|
+
+### GetState
+#### Params
+|Name|Type|Summary|Required|
+|-|-|-|-|
+|RootHash|UInt256|specify state|true|
+|ScriptHash|UInt160|contract script hash|true|
+|Key|base64 string|key|true|
+#### Result
+Value in base64 string or `null`
+
+### FindState
+#### Params
+|Name|Type|Summary|Required|
+|-|-|-|-|
+|RootHash|UInt256|specify state|true|
+|ScriptHash|UInt160|contract script hash|true|
+|Prefix|base64 string|key prefix|true|
+|PageNumber|number|page number, default `0`|optional|
+#### Result
+key-value results in array

src/StateService/Settings.cs

@@ -8,6 +8,8 @@ internal class Settings
         public bool FullState { get; }
         public uint Network { get; }
         public bool AutoVerify { get; }
+        public int MaxFindResultItems { get; }
+        public int MaxPageNumber { get; }
 
         public static Settings Default { get; private set; }
 
@@ -17,6 +19,8 @@ private Settings(IConfigurationSection section)
             FullState = section.GetValue("FullState", false);
             Network = section.GetValue("Network", 5195086u);
             AutoVerify = section.GetValue("AutoVerify", false);
+            MaxFindResultItems = section.GetValue("MaxFindResultItems", 100);
+            MaxPageNumber = section.GetValue("MaxPageNumber", 100);
         }
 
         public static void Load(IConfigurationSection section)

src/StateService/StatePlugin.cs

@@ -177,7 +177,9 @@ private string GetProof(UInt256 root_hash, UInt160 script_hash, byte[] key)
                 Id = contract.Id,
                 Key = key,
             };
-            HashSet<byte[]> proof = StateStore.Singleton.GetProof(root_hash, skey);
+            using ISnapshot store = StateStore.Singleton.GetStoreSnapshot();
+            var trie = new MPTTrie<StorageKey, StorageItem>(store, root_hash);
+            var proof = trie.GetProof(skey);
             if (proof is null) throw new RpcException(-100, "Unknown value");
 
             using MemoryStream ms = new MemoryStream();
@@ -239,5 +241,65 @@ public JObject GetStateHeight(JArray _params)
             json["validatedrootindex"] = StateStore.Singleton.ValidatedRootIndex;
             return json;
         }
+
+        private ContractState GetHistoricalContractState(MPTTrie<StorageKey, StorageItem> trie, UInt160 script_hash)
+        {
+            const byte prefix = 8;
+            StorageKey skey = new KeyBuilder(NativeContract.ContractManagement.Id, prefix).Add(script_hash);
+            return trie[skey]?.GetInteroperable<ContractState>();
+        }
+
+        private void PrepareStateParams(JArray _params, out MPTTrie<StorageKey, StorageItem> trie, out StorageKey skey)
+        {
+            var root_hash = UInt256.Parse(_params[0].AsString());
+            var script_hash = UInt160.Parse(_params[1].AsString());
+            var prefix = Convert.FromBase64String(_params[2].AsString());
+            if (!Settings.Default.FullState && StateStore.Singleton.CurrentLocalRootHash != root_hash)
+                throw new RpcException(-100, "Old state not supported");
+            using var store = StateStore.Singleton.GetStoreSnapshot();
+            trie = new MPTTrie<StorageKey, StorageItem>(store, root_hash);
+
+            var contract = GetHistoricalContractState(trie, script_hash);
+            if (contract is null) throw new RpcException(-100, "Unknown contract");
+            skey = new()
+            {
+                Id = contract.Id,
+                Key = prefix,
+            };
+        }
+
+        [RpcMethod]
+        public JObject FindState(JArray _params)
+        {
+            PrepareStateParams(_params, out var trie, out var skey);
+            int pageNumber = 0;
+            if (3 < _params.Count)
+                pageNumber = int.Parse(_params[3].AsString());
+            if (Settings.Default.MaxPageNumber <= pageNumber)
+                throw new RpcException(-100, "Page number exceed limit");
+            var start = Settings.Default.MaxFindResultItems * pageNumber;
+            JArray array = new();
+            int i = 0;
+            foreach (var (ikey, ivalue) in trie.Find(skey.ToArray()))
+            {
+                if (start + Settings.Default.MaxFindResultItems <= i) break;
+                if (start <= i)
+                {
+                    JObject j = new();
+                    j["key"] = Convert.ToBase64String(ikey.Key);
+                    j["value"] = Convert.ToBase64String(ivalue.Value);
+                    array.Add(j);
+                }
+                i++;
+            };
+            return array;
+        }
+
+        [RpcMethod]
+        public JObject GetState(JArray _params)
+        {
+            PrepareStateParams(_params, out var trie, out var skey);
+            return trie[skey]?.Value is null ? null : Convert.ToBase64String(trie[skey].Value);
+        }
     }
 }

src/StateService/StateService/config.json

@@ -3,7 +3,9 @@
     "Path": "Data_MPT_{0}",
     "FullState": false,
     "Network": 860833102,
-    "AutoVerify": false
+    "AutoVerify": false,
+    "MaxFindResultItems": 100,
+    "MaxPageNumber": 100
   },
   "Dependency": [
     "RpcServer"

src/StateService/Storage/StateStore.cs

@@ -55,11 +55,9 @@ public StateSnapshot GetSnapshot()
             return new StateSnapshot(store);
         }
 
-        public HashSet<byte[]> GetProof(UInt256 root, StorageKey skey)
+        public ISnapshot GetStoreSnapshot()
         {
-            using ISnapshot snapshot = store.GetSnapshot();
-            var trie = new MPTTrie<StorageKey, StorageItem>(snapshot, root);
-            return trie.GetProof(skey);
+            return store.GetSnapshot();
         }
 
         protected override void OnReceive(object message)