Function upvalues implementation (#86)

src/cpp/function.cpp

@@ -0,0 +1,104 @@
+#include "function.h"
+
+namespace effil {
+
+namespace {
+
+bool allowTableUpvalues(const sol::optional<bool>& newValue = sol::nullopt) {
+    static std::atomic_bool value(true);
+
+    if (newValue)
+        return value.exchange(newValue.value());
+    return value;
+}
+
+} // anonymous
+
+sol::object luaAllowTableUpvalues(sol::this_state state, const sol::stack_object& value) {
+    if (value.valid()) {
+        REQUIRE(value.get_type() == sol::type::boolean) << "bad argument #1 to 'effil.allow_table_upvalues' (boolean expected, got " << luaTypename(value) << ")";
+        return sol::make_object(state, allowTableUpvalues(value.template as<bool>()));
+    }
+    else {
+        return sol::make_object(state, allowTableUpvalues());
+    }
+}
+
+void FunctionObject::initialize(const sol::function& luaObject) {
+    assert(luaObject.valid());
+    assert(luaObject.get_type() == sol::type::function);
+
+    lua_State* state = luaObject.lua_state();
+    sol::stack::push(state, luaObject);
+
+    lua_Debug dbgInfo;
+    lua_getinfo(state, ">u", &dbgInfo); // function is popped from stack here
+    sol::stack::push(state, luaObject);
+
+    data_->function = dumpFunction(luaObject);
+    data_->upvalues.resize(dbgInfo.nups);
+#if LUA_VERSION_NUM > 501
+    data_->envUpvaluePos = 0; // means no _ENV upvalue
+#endif // LUA_VERSION_NUM > 501
+
+    for (unsigned char i = 1; i <= dbgInfo.nups; ++i) {
+        const char* valueName = lua_getupvalue(state, -1, i); // push value on stack
+        (void)valueName; // get rid of 'unused' warning for Lua5.1
+        assert(valueName != nullptr);
+
+#if LUA_VERSION_NUM > 501
+        if (strcmp(valueName, "_ENV") == 0) { // do not serialize _ENV
+            sol::stack::pop<sol::object>(state);
+            data_->envUpvaluePos = i;
+            continue;
+        }
+#endif // LUA_VERSION_NUM > 501
+
+        const auto& upvalue = sol::stack::pop<sol::object>(state); // pop from stack
+        if (!allowTableUpvalues() && upvalue.get_type() == sol::type::table) {
+            sol::stack::pop<sol::object>(state);
+            throw effil::Exception() << "bad function upvalue #" << (int)i << " (table is disabled by effil.allow_table_upvalues)";
+        }
+
+        StoredObject storedObject;
+        try {
+            storedObject = createStoredObject(upvalue);
+            assert(storedObject.get() != nullptr);
+        }
+        catch(const std::exception& err) {
+            sol::stack::pop<sol::object>(state);
+            throw effil::Exception() << "bad function upvalue #" << (int)i << " (" << err.what() << ")";
+        }
+
+        if (storedObject->gcHandle() != nullptr) {
+            addReference(storedObject->gcHandle());
+            storedObject->releaseStrongReference();
+        }
+        data_->upvalues[i - 1] = std::move(storedObject);
+    }
+    sol::stack::pop<sol::object>(state);
+}
+
+sol::object FunctionObject::loadFunction(lua_State* state) {
+    sol::function result = loadString(state, data_->function);
+    assert(result.valid());
+
+    sol::stack::push(state, result);
+    for(size_t i = 0; i < data_->upvalues.size(); ++i) {
+#if LUA_VERSION_NUM > 501
+        if (data_->envUpvaluePos == i + 1) {
+            lua_rawgeti(state, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS); // push _ENV to stack
+            lua_setupvalue(state, -2, i + 1); // pop _ENV and set as upvalue
+            continue;
+        }
+#endif // LUA_VERSION_NUM > 501
+        assert(data_->upvalues[i].get() != nullptr);
+
+        const auto& obj = data_->upvalues[i]->unpack(sol::this_state{state});
+        sol::stack::push(state, obj);
+        lua_setupvalue(state, -2, i + 1);
+    }
+    return sol::stack::pop<sol::function>(state);
+}
+
+} // namespace effil

src/cpp/function.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include "gc-object.h"
+#include "utils.h"
+#include "lua-helpers.h"
+
+namespace effil {
+
+sol::object luaAllowTableUpvalues(sol::this_state state, const sol::stack_object&);
+
+class FunctionObject: public GCObject {
+public:
+    template <typename SolType>
+    FunctionObject(const SolType& luaObject)
+            : data_(std::make_shared<SharedData>()) {
+        initialize(luaObject);
+    }
+
+    sol::object loadFunction(lua_State* state);
+
+private:
+    void initialize(const sol::function& luaObject);
+
+    struct SharedData {
+        std::string function;
+#if LUA_VERSION_NUM > 501
+        unsigned char envUpvaluePos;
+#endif // LUA_VERSION_NUM > 501
+        std::vector<StoredObject> upvalues;
+    };
+
+    std::shared_ptr<SharedData> data_;
+};
+
+} // namespace effil

src/cpp/garbage-collector.cpp

@@ -37,8 +37,8 @@ void GC::collect() {
         }
     }
 
-    DEBUG << "Removing " << (objects_.size() - black.size()) << " out of " << objects_.size() << std::endl;
     // Sweep phase
+    DEBUG << "Removing " << (objects_.size() - black.size()) << " out of " << objects_.size() << std::endl;
     objects_ = std::move(black);
 
     lastCleanup_.store(0);

src/cpp/lua-helpers.cpp

@@ -42,8 +42,9 @@ std::string dumpFunction(const sol::function& f) {
     return result;
 }
 
-sol::function loadString(const sol::state_view& lua, const std::string& str) {
-    int ret = luaL_loadbuffer(lua, str.c_str(), str.size(), nullptr);
+sol::function loadString(const sol::state_view& lua, const std::string& str,
+                         const sol::optional<std::string>& source /* = sol::nullopt*/) {
+    int ret = luaL_loadbuffer(lua, str.c_str(), str.size(), source ? source.value().c_str() : nullptr);
     REQUIRE(ret == LUA_OK) << "Unable to load function from string: " << luaError(ret);
     return sol::stack::pop<sol::function>(lua);
 }

src/cpp/lua-helpers.h

@@ -11,7 +11,8 @@ class Channel;
 class Thread;
 
 std::string dumpFunction(const sol::function& f);
-sol::function loadString(const sol::state_view& lua, const std::string& str);
+sol::function loadString(const sol::state_view& lua, const std::string& str,
+                         const sol::optional<std::string>& source = sol::nullopt);
 std::chrono::milliseconds fromLuaTime(int duration, const sol::optional<std::string>& period);
 
 template <typename SolObject>
@@ -21,7 +22,7 @@ std::string luaTypename(const SolObject& obj) {
             return "effil.table";
         else if (obj.template is<Channel>())
             return "effil.channel";
-        else if (obj.template is<std::shared_ptr<Thread>>())
+        else if (obj.template is<Thread>())
             return "effil.thread";
         else
             return "userdata";

src/cpp/lua-module.cpp

@@ -15,7 +15,7 @@ sol::object createThread(const sol::this_state& lua,
                          int step,
                          const sol::function& function,
                          const sol::variadic_args& args) {
-    return sol::make_object(lua, std::make_shared<Thread>(path, cpath, step, function, args));
+    return sol::make_object(lua, GC::instance().create<Thread>(path, cpath, step, function, args));
 }
 
 sol::object createTable(sol::this_state lua, const sol::optional<sol::object>& tbl) {
@@ -66,7 +66,8 @@ int luaopen_libeffil(lua_State* L) {
             "channel", createChannel,
             "type", getLuaTypename,
             "pairs", SharedTable::globalLuaPairs,
-            "ipairs", SharedTable::globalLuaIPairs
+            "ipairs", SharedTable::globalLuaIPairs,
+            "allow_table_upvalues", luaAllowTableUpvalues
     );
     sol::stack::push(lua, publicApi);
     return 1;

src/cpp/stored-object.cpp

@@ -1,8 +1,8 @@
 #include "stored-object.h"
 #include "channel.h"
-
 #include "threading.h"
 #include "shared-table.h"
+#include "function.h"
 #include "utils.h"
 
 #include <map>
@@ -45,29 +45,6 @@ private:
     StoredType data_;
 };
 
-class FunctionHolder : public BaseHolder {
-public:
-    template <typename SolObject>
-    FunctionHolder(SolObject luaObject) noexcept {
-        sol::state_view lua(luaObject.lua_state());
-        function_ = dumpFunction(luaObject);
-    }
-
-    bool rawCompare(const BaseHolder* other) const noexcept final {
-        return function_ < static_cast<const FunctionHolder*>(other)->function_;
-    }
-
-    sol::object unpack(sol::this_state state) const final {
-        sol::function result = loadString(state, function_);
-        // The result of restaring always is valid function.
-        assert(result.valid());
-        return sol::make_object(state, result);
-    }
-
-private:
-    std::string function_;
-};
-
 template<typename T>
 class GCObjectHolder : public BaseHolder {
 public:
@@ -87,7 +64,7 @@ public:
         return handle_ < static_cast<const GCObjectHolder<T>*>(other)->handle_;
     }
 
-    sol::object unpack(sol::this_state state) const final {
+    sol::object unpack(sol::this_state state) const override {
         return sol::make_object(state, GC::instance().get<T>(handle_));
     }
 
@@ -103,11 +80,22 @@ public:
         }
     }
 
-private:
+protected:
     GCObjectHandle handle_;
     sol::optional<T> strongRef_;
 };
 
+class FunctionHolder : public GCObjectHolder<FunctionObject> {
+public:
+    template <typename SolType>
+    FunctionHolder(const SolType& luaObject) : GCObjectHolder<FunctionObject>(luaObject) {}
+    FunctionHolder(GCObjectHandle handle) : GCObjectHolder(handle) {}
+
+    sol::object unpack(sol::this_state state) const final {
+        return GC::instance().get<FunctionObject>(handle_).loadFunction(state);
+    }
+};
+
 // This class is used as a storage for visited sol::tables
 // TODO: try to use map or unordered map instead of linear search in vector
 // TODO: Trick is - sol::object has only operator==:/
@@ -171,12 +159,16 @@ StoredObject fromSolObject(const SolObject& luaObject) {
                 return std::make_unique<GCObjectHolder<SharedTable>>(luaObject);
             else if (luaObject.template is<Channel>())
                 return std::make_unique<GCObjectHolder<Channel>>(luaObject);
-            else if (luaObject.template is<std::shared_ptr<Thread>>())
-                return std::make_unique<PrimitiveHolder<std::shared_ptr<Thread>>>(luaObject);
+            else if (luaObject.template is<FunctionObject>())
+                return std::make_unique<FunctionHolder>(luaObject);
+            else if (luaObject.template is<Thread>())
+                return std::make_unique<GCObjectHolder<Thread>>(luaObject);
             else
                 throw Exception() << "Unable to store userdata object\n";
-        case sol::type::function:
-            return std::make_unique<FunctionHolder>(luaObject);
+        case sol::type::function: {
+            FunctionObject func = GC::instance().create<FunctionObject>(luaObject);
+            return std::make_unique<FunctionHolder>(func.handle());
+        }
         case sol::type::table: {
             sol::table luaTable = luaObject;
             // Tables pool is used to store tables.

src/cpp/threading.cpp

@@ -163,43 +163,46 @@ void luaHook(lua_State*, lua_Debug*) {
     }
 }
 
-void runThread(std::shared_ptr<ThreadHandle> handle,
-               std::string strFunction,
+} // namespace
+
+void Thread::runThread(Thread thread,
+               FunctionObject function,
                effil::StoredArray arguments) {
-    assert(handle);
-    thisThreadHandle = handle.get();
+    thisThreadHandle = thread.handle_.get();
+    assert(thisThreadHandle != nullptr);
 
     try {
         {
-            ScopeGuard reportComplete([handle, &arguments](){
-                DEBUG << "Finished " << std::endl;
+            ScopeGuard reportComplete([thread, &arguments](){
                 // Let's destroy accociated state
                 // to release all resources as soon as possible
                 arguments.clear();
-                handle->destroyLua();
+                thread.handle_->destroyLua();
             });
-            sol::function userFuncObj = loadString(handle->lua(), strFunction);
+            sol::function userFuncObj = function.loadFunction(thread.handle_->lua());
             sol::function_result results = userFuncObj(std::move(arguments));
             (void)results; // just leave all returns on the stack
-            sol::variadic_args args(handle->lua(), -lua_gettop(handle->lua()));
+            sol::variadic_args args(thread.handle_->lua(), -lua_gettop(thread.handle_->lua()));
             for (const auto& iter : args) {
                 StoredObject store = createStoredObject(iter.get<sol::object>());
-                handle->result().emplace_back(std::move(store));
+                if (store->gcHandle() != nullptr)
+                {
+                    thread.addReference(store->gcHandle());
+                    store->releaseStrongReference();
+                }
+                thread.handle_->result().emplace_back(std::move(store));
             }
         }
-        handle->changeStatus(Status::Completed);
+        thread.handle_->changeStatus(Status::Completed);
     } catch (const LuaHookStopException&) {
-        handle->changeStatus(Status::Canceled);
+        thread.handle_->changeStatus(Status::Canceled);
     } catch (const sol::error& err) {
         DEBUG << "Failed with msg: " << err.what() << std::endl;
-        handle->result().emplace_back(createStoredObject(err.what()));
-        handle->changeStatus(Status::Failed);
+        thread.handle_->result().emplace_back(createStoredObject(err.what()));
+        thread.handle_->changeStatus(Status::Failed);
     }
 }
 
-} // namespace
-
-
 std::string threadId() {
     std::stringstream ss;
     ss << std::this_thread::get_id();
@@ -233,6 +236,11 @@ Thread::Thread(const std::string& path,
        const sol::variadic_args& variadicArgs)
         : handle_(std::make_shared<ThreadHandle>()) {
 
+    sol::optional<FunctionObject> functionObj;
+    try {
+        functionObj = FunctionObject(function);
+    } RETHROW_WITH_PREFIX("effil.thread");
+
     handle_->lua()["package"]["path"] = path;
     handle_->lua()["package"]["cpath"] = cpath;
     handle_->lua().script("require 'effil'");
@@ -240,20 +248,20 @@ Thread::Thread(const std::string& path,
     if (step != 0)
         lua_sethook(handle_->lua(), luaHook, LUA_MASKCOUNT, step);
 
-    std::string strFunction = dumpFunction(function);
-
     effil::StoredArray arguments;
     try {
         for (const auto& arg : variadicArgs) {
-            arguments.emplace_back(createStoredObject(arg.get<sol::object>()));
+            const auto& storedObj = createStoredObject(arg.get<sol::object>());
+            addReference(storedObj->gcHandle());
+            storedObj->releaseStrongReference();
+            arguments.emplace_back(storedObj);
         }
     } RETHROW_WITH_PREFIX("effil.thread");
 
-    std::thread thr(&runThread,
-                    handle_,
-                    std::move(strFunction),
+    std::thread thr(&Thread::runThread,
+                    *this,
+                    functionObj.value(),
                     std::move(arguments));
-    DEBUG << "Created " << thr.get_id() << std::endl;
     thr.detach();
 }
 

src/cpp/threading.h

@@ -2,6 +2,7 @@
 
 #include <sol.hpp>
 #include "lua-helpers.h"
+#include "function.h"
 
 namespace effil {
 
@@ -12,7 +13,7 @@ void sleep(const sol::stack_object& duration, const sol::stack_object& metric);
 
 class ThreadHandle;
 
-class Thread {
+class Thread : public GCObject {
 public:
     Thread(const std::string& path,
            const std::string& cpath,
@@ -37,11 +38,9 @@ public:
     void resume();
 
 private:
-    std::shared_ptr<ThreadHandle> handle_;
+    static void runThread(Thread, FunctionObject, effil::StoredArray);
 
-private:
-    Thread(const Thread&) = delete;
-    Thread& operator=(const Thread&) = delete;
+    std::shared_ptr<ThreadHandle> handle_;
 };
 
 } // effil

src/lua/effil.lua

@@ -15,7 +15,8 @@ local api = {
     channel = capi.channel,
     type = capi.type,
     pairs = capi.pairs,
-    ipairs = capi.ipairs
+    ipairs = capi.ipairs,
+    allow_table_upvalues = capi.allow_table_upvalues
 }
 
 api.size = function (something)

tests/lua/bootstrap-tests.lua

@@ -9,6 +9,13 @@ function default_tear_down()
     effil.gc.collect()
     -- effil.G is always present
     -- thus, gc has one object
+    if effil.gc.count() ~= 1 then
+        print "Not all bojects were removed, gonna sleep for 2 seconds"
+        effil.sleep(2)
+
+        collectgarbage()
+        effil.gc.collect()
+    end
     test.equal(effil.gc.count(), 1)
 end
 

tests/lua/gc-stress.lua

@@ -34,6 +34,4 @@ test.gc_stress.create_and_collect_in_parallel = function ()
     for i = 1, thread_num do
         test.equal(threads[i]:wait(), "completed")
     end
-
-    test.equal(effil.gc.count(), 1)
 end

tests/lua/metatable.lua

@@ -9,7 +9,7 @@ test.metatable.tear_down = function (metatable)
     if type(metatable) == "table" then
         test.equal(effil.gc.count(), 1)
     else
-        test.equal(effil.gc.count(), 2)
+        test.equal(effil.gc.count(), 3)
     end
 end
 

tests/lua/run_tests

@@ -14,6 +14,7 @@ require "thread"
 require "shared-table"
 require "metatable"
 require "type_mismatch"
+require "upvalues"
 
 if os.getenv("STRESS") then
     require "channel-stress"

tests/lua/thread.lua

@@ -98,6 +98,7 @@ test.thread.cancel = function ()
     test.is_true(thread:cancel())
     test.equal(thread:status(), "canceled")
 end
+
 test.thread.async_cancel = function ()
     local thread_runner = effil.thread(
         function()
@@ -213,9 +214,6 @@ test.thread.returns = function ()
 
     test.is_function(returns[5])
     test.equal(returns[5](11, 89), 100)
-
-    -- Workaround to get child thread free all return values
-    effil.sleep(2)
 end
 
 test.thread.timed_cancel = function ()

tests/lua/type.lua

@@ -1,9 +1,16 @@
 require "bootstrap-tests"
 
-test.type = function()
+test.type.tear_down = default_tear_down
+
+test.type.check_all_types = function()
     test.equal(effil.type(1), "number")
     test.equal(effil.type("string"), "string")
+    test.equal(effil.type(true), "boolean")
+    test.equal(effil.type(nil), "nil")
+    test.equal(effil.type(function()end), "function")
     test.equal(effil.type(effil.table()), "effil.table")
     test.equal(effil.type(effil.channel()), "effil.channel")
-    test.equal(effil.type(effil.thread(function() end)()), "effil.thread")
+    local thr = effil.thread(function() end)()
+    test.equal(effil.type(thr), "effil.thread")
+    thr:wait()
 end

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
+
+        if typename ~= "boolean" then
+            -- effil.allow_table_upvalue
+            test.type_mismatch.input_types_mismatch_p(1, "boolean", "allow_table_upvalues", type_instance)
+        end
     end
 
     -- Below presented tests which support everything except coroutines
@@ -149,8 +154,7 @@ end
 -- Put it to function to limit the lifetime of objects
 generate_tests()
 
-test.type_mismatch.gc_checks_after_tests = function ()
-    collectgarbage()
-    effil.gc.collect()
-    test.equal(effil.gc.count(), 1)
+test.type_mismatch.gc_checks_after_tests = function()
+    effil.allow_table_upvalues(true)
+    default_tear_down()
 end

tests/lua/upvalues.lua

@@ -0,0 +1,119 @@
+require "bootstrap-tests"
+
+test.upvalues.tear_down = default_tear_down
+
+test.upvalues.check_single_upvalue_p = function(type_creator, type_checker)
+    local obj = type_creator()
+    local thread_worker = function(checker) return require("effil").type(obj) .. ": " .. checker(obj) end
+    local ret = effil.thread(thread_worker)(type_checker):get()
+
+    print("Returned: " .. ret)
+    test.equal(ret, effil.type(obj) .. ": " .. type_checker(obj))
+end
+
+local foo = function() return 22 end
+
+test.upvalues.check_single_upvalue_p(function() return 1488 end,
+                                   function() return "1488" end)
+
+test.upvalues.check_single_upvalue_p(function() return "awesome" end,
+                                   function() return "awesome" end)
+
+test.upvalues.check_single_upvalue_p(function() return true end,
+                                   function() return "true" end)
+
+test.upvalues.check_single_upvalue_p(function() return nil end,
+                                   function() return "nil" end)
+
+test.upvalues.check_single_upvalue_p(function() return foo end,
+                                   function(f) return f() end)
+
+test.upvalues.check_single_upvalue_p(function() return effil.table({key = 44}) end,
+                                   function(t) return t.key end)
+
+test.upvalues.check_single_upvalue_p(function() local c = effil.channel() c:push(33) c:push(33) return c end,
+                                   function(c) return c:pop() end)
+
+test.upvalues.check_single_upvalue_p(function() return effil.thread(foo)() end,
+                                   function(t) return t:get() end)
+
+test.upvalues.check_invalid_coroutine = function()
+    local obj = coroutine.create(foo)
+    local thread_worker = function() return tostring(obj) end
+    local ret, err = pcall(effil.thread(thread_worker))
+    if ret then
+        ret:wait()
+    end
+    test.is_false(ret)
+    print("Returned: " .. err)
+    upvalue_num = LUA_VERSION > 51 and 2 or 1
+    test.equal(err, "effil.thread: bad function upvalue #" .. upvalue_num ..
+          " (unable to store object of thread type)")
+end
+
+test.upvalues.check_table = function()
+    local obj = { key = "value" }
+    local thread_worker = function() return require("effil").type(obj) .. ": " .. obj.key end
+    local ret = effil.thread(thread_worker)():get()
+
+    print("Returned: " .. ret)
+    test.equal(ret, "effil.table: value")
+end
+
+test.upvalues.check_env = function()
+    local obj1 = 13 -- local
+    obj2 = { key = "origin" } -- global
+    local obj3 = 79 -- local
+
+    local function foo() -- _ENV is 2nd upvalue
+        return obj1, obj2.key, obj3
+    end
+
+    local function thread_worker(func)
+        obj1 = 31 -- global
+        obj2 = { key = "local" } -- global
+        obj3 = 97 -- global
+        return table.concat({func()}, ", ")
+    end
+
+    local ret = effil.thread(thread_worker)(foo):get()
+    print("Returned: " .. ret)
+    test.equal(ret, "13, local, 79")
+end
+
+local function check_works(should_work)
+    local obj = { key = "value"}
+    local function worker()
+        return obj.key
+    end
+
+    local ret, err = pcall(effil.thread(worker))
+    if ret then
+        err:wait()
+    end
+    test.equal(ret, should_work)
+    if not should_work then
+        test.equal(err, "effil.thread: bad function upvalue #1 (table is disabled by effil.allow_table_upvalues)")
+    end
+end
+
+test.upvalues_table.tear_down = function()
+    effil.allow_table_upvalues(true)
+    default_tear_down()
+end
+
+test.upvalues_table.disabling_table_upvalues = function()
+    test.equal(effil.allow_table_upvalues(), true)
+    -- works by default
+    check_works(true)
+
+    -- disable
+    test.equal(effil.allow_table_upvalues(false), true)
+    check_works(false)
+    test.equal(effil.allow_table_upvalues(), false)
+
+    -- enable back
+    test.equal(effil.allow_table_upvalues(true), false)
+    check_works(true)
+    test.equal(effil.allow_table_upvalues(), true)
+end