table support in __index metamethod (#143)

* table support in __index metamethod

* fix after merge

src/cpp/shared-table.cpp

@@ -1,4 +1,5 @@
 #include "shared-table.h"
+#include "function.h"
 
 #include "utils.h"
 
@@ -191,11 +192,34 @@ void SharedTable::luaNewIndex(const sol::stack_object& luaKey, const sol::stack_
     } RETHROW_WITH_PREFIX("effil.table");
 }
 
-sol::object SharedTable::luaIndex(const sol::stack_object& luaKey, sol::this_state state) {
+sol::object SharedTable::luaIndex(const sol::stack_object& luaKey, sol::this_state state) const {
-    DEFFINE_METAMETHOD_CALL("__index", *this, luaKey)
+    REQUIRE(luaKey.valid()) << "Indexing by nil";
     try {
-        return rawGet(luaKey, state);
+        StoredObject key = createStoredObject(luaKey);
+        if (sol::object result = get(key, state)) {
+            return result;
+        }
     } RETHROW_WITH_PREFIX("effil.table");
+
+    SharedLock lock(ctx_->lock);
+    if (ctx_->metatable != GCNull) {
+        const auto tableHolder = GC::instance().get<SharedTable>(ctx_->metatable);
+        lock.unlock();
+
+        SharedLock mt_lock(tableHolder.ctx_->lock);
+        const auto iter = tableHolder.ctx_->entries.find(createStoredObject("__index"));
+        if (iter != tableHolder.ctx_->entries.end()) {
+            if (const auto tbl = storedObjectTo<SharedTable>(iter->second)) {
+                mt_lock.unlock();
+                return tbl->luaIndex(luaKey, state);
+            }
+            else if (const auto func = storedObjectTo<Function>(iter->second)) {
+                mt_lock.unlock();
+                return func->loadFunction(state).as<sol::function>()(*this, luaKey);
+            }
+        }
+    }
+    return sol::nil;
 }
 
 StoredArray SharedTable::luaCall(sol::this_state state, const sol::variadic_args& args) {

src/cpp/shared-table.h

@@ -40,7 +40,7 @@ public:
 
     // These functions are metamethods available in Lua
     void luaNewIndex(const sol::stack_object& luaKey, const sol::stack_object& luaValue, sol::this_state);
-    sol::object luaIndex(const sol::stack_object& key, sol::this_state state);
+    sol::object luaIndex(const sol::stack_object& key, sol::this_state state) const;
     sol::object luaToString(sol::this_state state);
     sol::object luaLength(sol::this_state state);
     PairsIterator luaPairs(sol::this_state);

src/cpp/stored-object.cpp

@@ -250,4 +250,20 @@ sol::optional<std::string> storedObjectToString(const StoredObject& sobj) {
     return getPrimitiveHolderData<std::string>(sobj);
 }
 
+template<>
+sol::optional<SharedTable> storedObjectTo(const StoredObject& obj) {
+    if (const auto ptr = std::dynamic_pointer_cast<SharedTableHolder>(obj)) {
+        return GC::instance().get<SharedTable>(ptr->gcHandle());
+    }
+    return sol::nullopt;
+}
+
+template<>
+sol::optional<Function> storedObjectTo(const StoredObject& obj) {
+    if (const auto ptr = std::dynamic_pointer_cast<FunctionHolder>(obj)) {
+        return GC::instance().get<Function>(ptr->gcHandle());
+    }
+    return sol::nullopt;
+}
+
 } // effil

src/cpp/stored-object.h

@@ -57,4 +57,7 @@ sol::optional<double> storedObjectToDouble(const StoredObject&);
 sol::optional<LUA_INDEX_TYPE> storedObjectToIndexType(const StoredObject&);
 sol::optional<std::string> storedObjectToString(const StoredObject&);
 
+template<typename T>
+sol::optional<T> storedObjectTo(const StoredObject&);
+
 } // effil

tests/lua/metatable.lua

@@ -21,11 +21,11 @@ end
 test.metatable.index_p = function (metatable)
     local share = effil.table()
     metatable.__index = function(t, key)
-        return "mt_" .. effil.rawget(t, key)
+        return "mt_" .. effil.rawget(t, key .. "_origin")
     end
     effil.setmetatable(share, metatable)
 
-    share.table_key = "table_value"
+    share.table_key_origin = "table_value"
     test.equal(share.table_key, "mt_table_value")
 end
 
@@ -164,9 +164,9 @@ test.shared_table_with_metatable.as_shared_table = function()
 
     -- Only __index metamethod
     mt.__index = function(t, key)
-        return "mt_" .. effil.rawget(t, key)
+        return "mt_" .. effil.rawget(t, key .. "_origin")
     end
-    share.table_key = "table_value"
+    share.table_key_origin = "table_value"
     test.equal(share.table_key, "mt_table_value")
 
     -- Both __index and __newindex metamethods
@@ -174,7 +174,7 @@ test.shared_table_with_metatable.as_shared_table = function()
         effil.rawset(t, key, "mt_" .. value)
     end
     share.table_key = "table_value"
-    test.equal(share.table_key, "mt_mt_table_value")
+    test.equal(share.table_key, "mt_table_value")
 
     -- Remove __index, use only __newindex metamethods
     mt.__index = nil
@@ -182,6 +182,26 @@ test.shared_table_with_metatable.as_shared_table = function()
     test.equal(share.table_key, "mt_table_value")
 end
 
+test.shared_table_with_metatable.table_as_index = function()
+    local tbl = effil.table{}
+    local mt = effil.table{ a = 1 }
+    local mt2 = effil.table{ b = 2 }
+    local mt3 = effil.table{ c = 2 }
+
+    effil.setmetatable(tbl, {__index=mt})
+    test.equal(tbl.a, 1)
+    test.equal(tbl.b, nil)
+
+    effil.setmetatable(mt, {__index=mt2})
+    test.equal(tbl.a, 1)
+    test.equal(tbl.b, 2)
+
+    effil.setmetatable(mt2, {__index=mt3})
+    test.equal(tbl.a, 1)
+    test.equal(tbl.b, 2)
+    test.equal(tbl.c, 2)
+end
+
 test.shared_table_with_metatable.next_iterator = function()
     local visited = {a = 1, [2] = 3, [true] = "asd", [2.2] = "qwe"}
     local share = effil.table(visited)