From b038636ff558b4ee8e4fd423a1610d8974f09b01 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Wed, 27 Nov 2013 15:14:26 -0800
Subject: [PATCH] refactor(util/script_state): remove unsafe unguarded_apply

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
---
 src/util/script_state.cpp | 69 +++++++++++++++++++--------------------
 src/util/script_state.h   | 13 +-------
 2 files changed, 34 insertions(+), 48 deletions(-)

diff --git a/src/util/script_state.cpp b/src/util/script_state.cpp
index 28dff8d4b..a4dc5d05a 100644
--- a/src/util/script_state.cpp
+++ b/src/util/script_state.cpp
@@ -301,9 +301,8 @@ class data_channel {
     std::condition_variable m_cv;
 public:
     data_channel() {
-        m_channel.unguarded_apply([&](lua_State * channel) {
-                m_ini = lua_gettop(channel);
-            });
+        lua_State * channel = m_channel.m_ptr->m_state;
+        m_ini = lua_gettop(channel);
     }
 
     /**
@@ -316,12 +315,11 @@ public:
         if (last < first)
             return;
         std::lock_guard<std::mutex> lock(m_mutex);
-        m_channel.unguarded_apply([&](lua_State * channel) {
-                bool was_empty = lua_gettop(channel) == m_ini;
-                copy_values(src, first, last, channel);
-                if (was_empty)
-                    m_cv.notify_one();
-            });
+        lua_State * channel = m_channel.m_ptr->m_state;
+        bool was_empty = lua_gettop(channel) == m_ini;
+        copy_values(src, first, last, channel);
+        if (was_empty)
+            m_cv.notify_one();
     }
 
     /**
@@ -330,33 +328,32 @@ public:
     */
     int read(lua_State * tgt, int i) {
         std::unique_lock<std::mutex> lock(m_mutex);
-        return m_channel.unguarded_apply([&](lua_State * channel) {
-                if (i > 0) {
-                    // i is the position of the timeout argument
-                    std::chrono::milliseconds dura(luaL_checkinteger(tgt, i));
-                    if (lua_gettop(channel) == m_ini)
-                        m_cv.wait_for(lock, dura);
-                    if (lua_gettop(channel) == m_ini) {
-                        // timeout...
-                        lua_pushboolean(tgt, false);
-                        lua_pushnil(tgt);
-                        return 2;
-                    } else {
-                        lua_pushboolean(tgt, true);
-                        copy_values(channel, m_ini + 1, m_ini + 1, tgt);
-                        lua_remove(channel, m_ini + 1);
-                        return 2;
-                    }
-                } else {
-                    while (lua_gettop(channel) == m_ini) {
-                        check_interrupted();
-                        m_cv.wait_for(lock, g_small_delay);
-                    }
-                    copy_values(channel, m_ini + 1, m_ini + 1, tgt);
-                    lua_remove(channel, m_ini + 1);
-                    return 1;
-                }
-            });
+        lua_State * channel = m_channel.m_ptr->m_state;
+        if (i > 0) {
+            // i is the position of the timeout argument
+            std::chrono::milliseconds dura(luaL_checkinteger(tgt, i));
+            if (lua_gettop(channel) == m_ini)
+                m_cv.wait_for(lock, dura);
+            if (lua_gettop(channel) == m_ini) {
+                // timeout...
+                lua_pushboolean(tgt, false);
+                lua_pushnil(tgt);
+                return 2;
+            } else {
+                lua_pushboolean(tgt, true);
+                copy_values(channel, m_ini + 1, m_ini + 1, tgt);
+                lua_remove(channel, m_ini + 1);
+                return 2;
+            }
+        } else {
+            while (lua_gettop(channel) == m_ini) {
+                check_interrupted();
+                m_cv.wait_for(lock, g_small_delay);
+            }
+            copy_values(channel, m_ini + 1, m_ini + 1, tgt);
+            lua_remove(channel, m_ini + 1);
+            return 1;
+        }
     }
 };
 
diff --git a/src/util/script_state.h b/src/util/script_state.h
index b41cabf78..67a9b3c70 100644
--- a/src/util/script_state.h
+++ b/src/util/script_state.h
@@ -22,6 +22,7 @@ private:
     friend script_state to_script_state(lua_State * L);
     std::recursive_mutex & get_mutex();
     lua_State * get_state();
+    friend class data_channel;
 public:
     script_state();
     virtual ~script_state();
@@ -46,18 +47,6 @@ public:
         return f(get_state());
     }
 
-    /**
-       \brief Similar to \c apply, but a lock is not used to guarantee
-       exclusive access to the lua_State object.
-
-       \warning It is the caller resposability to guarantee that the object is not being
-       concurrently accessed.
-    */
-    template<typename F>
-    typename std::result_of<F(lua_State * L)>::type unguarded_apply(F && f) {
-        return f(get_state());
-    }
-
     typedef void (*reg_fn)(lua_State *); // NOLINT
     static void register_module(reg_fn f);