FbTk::Lua - a class which augments lua::state with additional features

1 files changed, 104 insertions, 0 deletions

diff --git a/src/FbTk/LuaUtil.cc b/src/FbTk/LuaUtil.cc
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+++ b/src/FbTk/LuaUtil.cc
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+// LuaUtil: Various additional functions for working with lua
+// Copyright (C) 2011 Pavel Labath
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "LuaUtil.hh"
+
+namespace {
+    int newindexDenyWrite(lua::state *l) {
+        if(l->isstring(-2))
+            throw std::runtime_error("Cannot modify field '" + l->tostring(-2) + "'.");
+        else
+            throw std::runtime_error("Cannot modify this field.");
+    }
+
+    int newindexDenyModify(lua::state *l) {
+        bool ok = false;
+        l->getmetatable(-1); {
+            l->rawgetfield(-1, "__index"); {
+                l->pushvalue(-4); l->rawget(-2); {
+                    if(l->isnil(-1))
+                        ok = true;
+                } l->pop();
+            } l->pop();
+        } l->pop();
+
+        if(ok) {
+            l->pushvalue(-2);
+            l->pushvalue(-4);
+            l->rawset(-3);
+        } else 
+            newindexDenyWrite(l);
+
+        return 0;
+    }
+}
+
+namespace FbTk {
+
+Lua::InitFunctions Lua::s_init_functions;
+
+Lua::Lua() {
+    InitFunctions::const_iterator it_end = s_init_functions.end();
+    for(InitFunctions::const_iterator it = s_init_functions.begin(); it != it_end; ++it)
+        (**it)(*this);
+}
+
+void Lua::makeReadOnly(int index, bool only_existing_fields) {
+    checkstack(6);
+    lua::stack_sentry s(*this);
+    index = absindex(index);
+
+    newtable(); {
+        newtable(); {
+            pushnil(); while(next(index)) {
+                pushvalue(-2); pushvalue(-2); rawset(-5);
+
+                pop(); pushnil(); rawset(index);
+
+                pushnil();
+            }
+        } rawsetfield(-2, "__index");
+
+        pushfunction(only_existing_fields ? &newindexDenyModify : &newindexDenyWrite);
+        rawsetfield(-2, "__newindex");
+
+        pushboolean(false);
+        rawsetfield(-2, "__metatable");
+    } setmetatable(index);
+}
+
+void Lua::readOnlySet(int index) {
+    checkstack(2);
+    lua::stack_sentry s(*this, -2);
+
+    getmetatable(index); {
+        rawgetfield(-1, "__index"); insert(-4);
+    } pop();
+
+    rawset(-3);
+    pop();
+}
+
+} // namespace FbTk