From ef60ec40c3d2bb8dd847c0d6cc0218cfb9955262 Mon Sep 17 00:00:00 2001
From: Chris Marsh <chris@discordapp.com>
Date: Fri, 28 Jul 2017 10:03:05 -0700
Subject: [PATCH] Do/wrap error checking around json reading

---
 src/discord-rpc.cpp    | 36 ++++++++++++++++++------------------
 src/rpc_connection.cpp |  5 ++---
 src/serialization.h    | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+), 21 deletions(-)

diff --git a/src/discord-rpc.cpp b/src/discord-rpc.cpp
index a91123f..d667cf8 100644
--- a/src/discord-rpc.cpp
+++ b/src/discord-rpc.cpp
@@ -100,20 +100,16 @@ extern "C" void Discord_UpdateConnection()
                 break;
             }
 
-            const char* evtName = nullptr;
-            auto evt = message.FindMember("evt");
-            if (evt != message.MemberEnd() && evt->value.IsString()) {
-                evtName = evt->value.GetString();
-            }
+            const char* evtName = GetStrMember(&message, "evt");
+            const char* nonce = GetStrMember(&message, "nonce");
 
-            auto nonce = message.FindMember("nonce");
-            if (nonce != message.MemberEnd() && nonce->value.IsString()) {
+            if (nonce) {
                 // in responses only -- should use to match up response when needed.
 
                 if (evtName && strcmp(evtName, "ERROR") == 0) {
-                    auto data = message.FindMember("data");
-                    LastErrorCode = data->value["code"].GetInt();
-                    StringCopy(LastErrorMessage, data->value["message"].GetString());
+                    auto data = GetObjMember(&message, "data");
+                    LastErrorCode = GetIntMember(data, "code");
+                    StringCopy(LastErrorMessage, GetStrMember(data, "message", ""));
                     GotErrorMessage.store(true);
                 }
             }
@@ -124,16 +120,20 @@ extern "C" void Discord_UpdateConnection()
                 }
 
                 if (strcmp(evtName, "GAME_JOIN") == 0) {
-                    auto data = message.FindMember("data");
-                    auto secret = data->value["secret"].GetString();
-                    StringCopy(JoinGameSecret, secret);
-                    WasJoinGame.store(true);
+                    auto data = GetObjMember(&message, "data");
+                    auto secret = GetStrMember(data, "secret");
+                    if (secret) {
+                        StringCopy(JoinGameSecret, secret);
+                        WasJoinGame.store(true);
+                    }
                 }
                 else if (strcmp(evtName, "GAME_SPECTATE") == 0) {
-                    auto data = message.FindMember("data");
-                    auto secret = data->value["secret"].GetString();
-                    StringCopy(SpectateGameSecret, secret);
-                    WasSpectateGame.store(true);
+                    auto data = GetObjMember(&message, "data");
+                    auto secret = GetStrMember(data, "secret");
+                    if (secret) {
+                        StringCopy(SpectateGameSecret, secret);
+                        WasSpectateGame.store(true);
+                    }
                 }
             }
         }
diff --git a/src/rpc_connection.cpp b/src/rpc_connection.cpp
index b10269b..1ff2d3b 100644
--- a/src/rpc_connection.cpp
+++ b/src/rpc_connection.cpp
@@ -114,9 +114,8 @@ bool RpcConnection::Read(JsonDocument& message)
         switch (readFrame.opcode) {
         case Opcode::Close: {
             message.ParseInsitu(readFrame.message);
-            lastErrorCode = message["code"].GetInt();
-            const auto& m = message["message"];
-            StringCopy(lastErrorMessage, m.GetString());
+            lastErrorCode = GetIntMember(&message, "code");
+            StringCopy(lastErrorMessage, GetStrMember(&message, "message", ""));
             Close();
             return false;
         }
diff --git a/src/serialization.h b/src/serialization.h
index f155b66..172b67b 100644
--- a/src/serialization.h
+++ b/src/serialization.h
@@ -142,3 +142,40 @@ public:
     {
     }
 };
+
+using JsonValue = rapidjson::GenericValue<UTF8, PoolAllocator>;
+
+inline JsonValue* GetObjMember(JsonValue* obj, const char* name)
+{
+    if (obj) {
+        auto member = obj->FindMember(name);
+        if (member != obj->MemberEnd() && member->value.IsObject()) {
+            return &member->value;
+        }
+    }
+    return nullptr;
+}
+
+inline int GetIntMember(JsonValue* obj, const char* name, int notFoundDefault = 0)
+{
+    if (obj) {
+        auto member = obj->FindMember(name);
+        if (member != obj->MemberEnd() && member->value.IsInt()) {
+            return member->value.GetInt();
+        }
+    }
+    return notFoundDefault;
+}
+
+inline const char* GetStrMember(JsonValue* obj,
+                                const char* name,
+                                const char* notFoundDefault = nullptr)
+{
+    if (obj) {
+        auto member = obj->FindMember(name);
+        if (member != obj->MemberEnd() && member->value.IsString()) {
+            return member->value.GetString();
+        }
+    }
+    return notFoundDefault;
+}