Dump table (effil.table -> table) (#134)

implement effil.dump()

README.md

@@ -54,6 +54,7 @@ Requires C++14 compiler compliance. Tested with GCC 4.9+, clang 3.8 and Visual S
       * [effil.rawset()](#tbl--effilrawsettbl-key-value)
       * [effil.rawget()](#value--effilrawgettbl-key)
       * [effil.G](#effilg)
+      * [effil.dump()](#result--effildumpobj)
     * [Channel](#channel)
       * [effil.channel()](#channel--effilchannelcapacity)
       * [channel:push()](#pushed--channelpush)
@@ -422,6 +423,14 @@ effil.thread(job)():wait()
 print(effil.G.key) -- will print "value"
 ```
 
+### `result = effil.dump(obj)`
+Truns `effil.table` into regular Lua table.
+```lua
+tbl = effil.table({})
+effil.type(tbl) -- 'effil.table'
+effil.type(effil.dump(tbl))  -- 'table'
+```
+
 ## Channel
 `effil.channel` is a way to sequentially exchange data between effil threads. It allows to push message from one thread and pop  it from another. Channel's **message** is a set of values of [supported types](#important-notes). All operations with channels are thread safe. See examples of channel usage [here](#examples)
 

src/cpp/function.cpp

@@ -56,7 +56,8 @@ Function::Function(const sol::function& luaObject) {
     sol::stack::pop<sol::object>(state);
 }
 
-sol::object Function::loadFunction(lua_State* state) {
+sol::object Function::convert(lua_State* state, const Converter& clbk) const
+{
     sol::function result = loadString(state, ctx_->function);
     assert(result.valid());
 
@@ -71,11 +72,22 @@ sol::object Function::loadFunction(lua_State* state) {
 #endif // LUA_VERSION_NUM > 501
         assert(ctx_->upvalues[i].get() != nullptr);
 
-        const auto& obj = ctx_->upvalues[i]->unpack(sol::this_state{state});
-        sol::stack::push(state, obj);
+        sol::stack::push(state, clbk(ctx_->upvalues[i]));
         lua_setupvalue(state, -2, i + 1);
     }
     return sol::stack::pop<sol::function>(state);
 }
 
+sol::object Function::loadFunction(lua_State* state) const {
+    return convert(state, [&](const StoredObject& obj){
+        return obj->unpack(sol::this_state{state});
+    });
+}
+
+sol::object Function::convertToLua(lua_State* state, BaseHolder::DumpCache& cache) const {
+    return convert(state, [&](const StoredObject& obj) {
+        return obj->convertToLua(sol::this_state{state}, cache);
+    });
+}
+
 } // namespace effil

src/cpp/function.h

@@ -18,9 +18,13 @@ public:
 
 class Function : public GCObject<FunctionData> {
 public:
-    sol::object loadFunction(lua_State* state);
+    sol::object loadFunction(lua_State* state) const;
+    sol::object convertToLua(lua_State* state, BaseHolder::DumpCache& cache) const;
 
 private:
+    using Converter = std::function<sol::object(const StoredObject&)>;
+    sol::object convert(lua_State* state, const Converter& clbk) const;
+
     explicit Function(const sol::function& luaObject);
     friend class GC;
 };

src/cpp/gc-object.h

@@ -16,7 +16,7 @@ static const GCHandle GCNull = nullptr;
 class BaseGCObject {
 public:
     virtual ~BaseGCObject() = default;
-    virtual GCHandle handle() = 0;
+    virtual GCHandle handle() const = 0;
     virtual size_t instances() const = 0;
     virtual std::unordered_set<GCHandle> refers() const = 0;
 };
@@ -32,7 +32,7 @@ public:
     GCObject& operator=(const GCObject&) = default;
 
     // Unique handle for any copy of GCData in any lua state
-    GCHandle handle() final {
+    GCHandle handle() const final {
         return reinterpret_cast<GCHandle>(ctx_.get());
     }
 

src/cpp/lua-module.cpp

@@ -39,6 +39,19 @@ size_t luaSize(const sol::stack_object& obj) {
                              << luaTypename(obj) << " for effil.size()";
 }
 
+sol::object luaDump(sol::this_state lua, const sol::stack_object& obj) {
+    if (obj.is<SharedTable>()) {
+        BaseHolder::DumpCache cache;
+        return obj.as<SharedTable>().luaDump(lua, cache);
+    }
+    else if (obj.get_type() == sol::type::table) {
+        return obj;
+    }
+
+    throw effil::Exception() << "bad argument #1 to 'effil.dump' (table expected, got "
+                             << luaTypename(obj) << ")";
+}
+
 sol::table luaThreadConfig(sol::this_state state, const sol::stack_object& obj) {
     REQUIRE(obj.valid() && obj.get_type() == sol::type::function)
             << "bad argument #1 to 'effil.thread' (function expected, got "
@@ -107,6 +120,7 @@ int luaopen_effil(lua_State* L) {
             "pairs",        SharedTable::globalLuaPairs,
             "ipairs",       SharedTable::globalLuaIPairs,
             "size",         luaSize,
+            "dump",         luaDump,
             "hardware_threads",        std::thread::hardware_concurrency,
             sol::meta_function::index, luaIndex
     );

src/cpp/shared-table.cpp

@@ -97,6 +97,22 @@ sol::object SharedTable::rawGet(const sol::stack_object& luaKey, sol::this_state
     return get(key, state);
 }
 
+sol::object SharedTable::luaDump(sol::this_state state, BaseHolder::DumpCache& cache) const {
+    const auto iter = cache.find(handle());
+    if (iter == cache.end()) {
+        SharedLock lock(ctx_->lock);
+
+        auto result = sol::table::create(state.L);
+        cache.insert(iter, {handle(), result.registry_index()});
+        for (const auto& pair: ctx_->entries) {
+            result.set(pair.first->convertToLua(state, cache),
+                       pair.second->convertToLua(state, cache));
+        }
+        return result;
+    }
+    return sol::table(state.L, sol::ref_index(iter->second));
+}
+
 /*
  * Lua Meta API methods
  */

src/cpp/shared-table.h

@@ -47,6 +47,8 @@ public:
     PairsIterator luaIPairs(sol::this_state);
     StoredArray luaCall(sol::this_state state, const sol::variadic_args& args);
     sol::object luaUnm(sol::this_state);
+    sol::object luaDump(sol::this_state state, BaseHolder::DumpCache& cache) const;
+
     static sol::object luaAdd(sol::this_state, const sol::stack_object&, const sol::stack_object&);
     static sol::object luaSub(sol::this_state, const sol::stack_object&, const sol::stack_object&);
     static sol::object luaMul(sol::this_state, const sol::stack_object&, const sol::stack_object&);

src/cpp/stored-object.cpp

@@ -94,6 +94,15 @@ protected:
     sol::optional<T> strongRef_;
 };
 
+class SharedTableHolder : public GCObjectHolder<SharedTable> {
+public:
+    using GCObjectHolder<SharedTable>::GCObjectHolder;
+
+    sol::object convertToLua(sol::this_state state, DumpCache& cache) const final {
+        return GC::instance().get<SharedTable>(handle_).luaDump(state, cache);
+    }
+};
+
 class FunctionHolder : public GCObjectHolder<Function> {
 public:
     template <typename SolType>
@@ -103,6 +112,10 @@ public:
     sol::object unpack(sol::this_state state) const final {
         return GC::instance().get<Function>(handle_).loadFunction(state);
     }
+
+    sol::object convertToLua(sol::this_state state, DumpCache& cache) const final {
+        return GC::instance().get<Function>(handle_).convertToLua(state, cache);
+    }
 };
 
 // This class is used as a storage for visited sol::tables
@@ -124,9 +137,9 @@ StoredObject makeStoredObject(sol::object luaObject, SolTableToShared& visited)
             SharedTable table = GC::instance().create<SharedTable>();
             visited.emplace_back(std::make_pair(luaTable, table.handle()));
             dumpTable(&table, luaTable, visited);
-            return std::make_unique<GCObjectHolder<SharedTable>>(table.handle());
+            return std::make_unique<SharedTableHolder>(table.handle());
         } else {
-            return std::make_unique<GCObjectHolder<SharedTable>>(st->second);
+            return std::make_unique<SharedTableHolder>(st->second);
         }
     } else {
         return createStoredObject(luaObject);
@@ -165,7 +178,7 @@ StoredObject fromSolObject(const SolObject& luaObject) {
             return std::make_unique<PrimitiveHolder<void*>>(luaObject);
         case sol::type::userdata:
             if (luaObject.template is<SharedTable>())
-                return std::make_unique<GCObjectHolder<SharedTable>>(luaObject);
+                return std::make_unique<SharedTableHolder>(luaObject);
             else if (luaObject.template is<Channel>())
                 return std::make_unique<GCObjectHolder<Channel>>(luaObject);
             else if (luaObject.template is<Function>())
@@ -191,7 +204,7 @@ StoredObject fromSolObject(const SolObject& luaObject) {
             // SolTableToShared is used to prevent from infinity recursion
             // in recursive tables
             dumpTable(&table, luaTable, visited);
-            return std::make_unique<GCObjectHolder<SharedTable>>(table.handle());
+            return std::make_unique<SharedTableHolder>(table.handle());
         }
         default:
             throw Exception() << "unable to store object of " << luaTypename(luaObject) << " type";

src/cpp/stored-object.h

@@ -28,6 +28,12 @@ public:
     virtual void releaseStrongReference() { }
     virtual void holdStrongReference() { }
 
+
+    using DumpCache = std::unordered_map<GCHandle, int>;
+    virtual sol::object convertToLua(sol::this_state state, DumpCache&) const {
+        return unpack(state);
+    }
+
 private:
     BaseHolder(const BaseHolder&) = delete;
 };
@@ -46,7 +52,6 @@ StoredObject createStoredObject(const char*);
 StoredObject createStoredObject(const sol::object&);
 StoredObject createStoredObject(const sol::stack_object&);
 
-
 sol::optional<bool> storedObjectToBool(const StoredObject&);
 sol::optional<double> storedObjectToDouble(const StoredObject&);
 sol::optional<LUA_INDEX_TYPE> storedObjectToIndexType(const StoredObject&);

tests/lua/dump_table.lua

@@ -0,0 +1,90 @@
+require "bootstrap-tests"
+
+local function table_included(left, right, path)
+    local path = path or ""
+    if type(left) ~= type(right) then
+        return false, "[" .. path .. "]: " .." got " .. type(right) .. "instead of " .. type(left)
+    end
+
+    for k, v in pairs(left) do
+        local subpath = path .. '.' .. tostring(k)
+        if type(v) == 'table' then
+            local ret, msg = table_included(v, right[k], subpath)
+            if not ret then
+                return false, msg
+            end
+        elseif right[k] ~= v then
+            return false, "[" .. subpath .. "]: got " .. tostring(right[k]) .. " instead of " .. tostring(v)
+        end
+    end
+    return true
+end
+
+local function table_equals(left, right)
+    local ret, msg = table_included(left, right)
+    if not ret then
+        return false, msg
+    end
+    return table_included(right, left)
+end
+
+test.dump_table.tear_down = default_tear_down
+
+test.dump_table.compare_primitives = function()
+    local origin = {
+        1, "str", key = "value",
+        key2 = { 2, [false] = "asd", { [44] = {true} } }
+    }
+
+    local result = effil.dump(effil.table(origin))
+    assert(table_equals(origin, result))
+end
+
+test.dump_table.compare_functions = function()
+    local origin = {
+        func = function(a, b) return a + b end,
+        nested = {
+            [function(a, b) return a - b end] = 2
+        },
+    }
+
+    local result = effil.dump(effil.table(origin))
+    test.equal(origin.func(2, 53), result.func(2, 53))
+    for origin_key, origin_value in pairs(origin.nested) do
+        for res_key, res_value in pairs(result.nested) do
+            test.equal(origin_key(23, 11), res_key(23, 11))
+            test.equal(origin_value, res_value)
+        end
+    end
+end
+
+test.dump_table.reference_loop = function()
+    local origin = {}
+    origin.nested = {1, origin, 2}
+    origin.nested.nested_loop = { [origin] = origin.nested }
+
+    local result = effil.dump(effil.table(origin))
+    test.equal(result.nested[1], 1)
+    test.equal(result.nested[2], result)
+    test.equal(result.nested[3], 2)
+    test.equal(result.nested.nested_loop[result], result.nested)
+end
+
+test.dump_table.regular_table = function()
+    local origin = {}
+    test.equal(origin, effil.dump(origin))
+end
+
+test.dump_table.upvalues_with_loop = function()
+    local origin = {}
+    local function foo()
+        origin.key = "value"
+    end
+    origin.foo = foo
+
+    local result = effil.dump(origin)
+    local name, value = debug.getupvalue(result.foo, 1)
+    test.equal(value, result)
+    result.foo()
+    test.equal(result.key, "value")
+end

tests/lua/run_tests

@@ -16,6 +16,7 @@ require "shared-table"
 require "metatable"
 require "type_mismatch"
 require "upvalues"
+require "dump_table"
 
 if os.getenv("STRESS") then
     require "channel-stress"

tests/lua/type_mismatch.lua

@@ -122,6 +122,11 @@ local function generate_tests()
             --  effil.gc.step
             test.type_mismatch.input_types_mismatch_p(1, "number", "gc.step", type_instance)
         end
+
+        -- effil.dump
+        if typename ~= "table" and typename ~= "effil.table" then
+            test.type_mismatch.input_types_mismatch_p(1, "table", "dump", type_instance)
+        end
     end
 
     -- Below presented tests which support everything except coroutines