X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/83d441ea28abf1131b70319a5a59f53e59688497..8b30afd41e2c22586e92ecbbfe124403fc861dd6:/src/bindings/lua/simgrid_lua.c

diff --git a/src/bindings/lua/simgrid_lua.c b/src/bindings/lua/simgrid_lua.c
index 330b99a287..76a482e76e 100644
--- a/src/bindings/lua/simgrid_lua.c
+++ b/src/bindings/lua/simgrid_lua.c
@@ -1,624 +1,80 @@
-/* SimGrid Lua bindings                                                     */
-
 /* Copyright (c) 2010. The SimGrid Team.
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
+
+/* SimGrid Lua bindings                                                     */
+
 #include "simgrid_lua.h"
-#include <string.h> // memcpy
+#include "lua_state_cloner.h"
+#include "lua_utils.h"
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(lua, bindings, "Lua Bindings");
 
-static lua_State *lua_maestro_state;
-
-#define TASK_MODULE_NAME "simgrid.Task"
-#define HOST_MODULE_NAME "simgrid.Host"
+#define TASK_MODULE_NAME "simgrid.task"
+#define HOST_MODULE_NAME "simgrid.host"
 // Surf (bypass XML)
-#define LINK_MODULE_NAME "simgrid.Link"
-#define ROUTE_MODULE_NAME "simgrid.Route"
-#define AS_MODULE_NAME "simgrid.AS"
-#define TRACE_MODULE_NAME "simgrid.Trace"
+#define LINK_MODULE_NAME "simgrid.link"
+#define ROUTE_MODULE_NAME "simgrid.route"
+#define PLATF_MODULE_NAME "simgrid.platf"
 
-/**
- * @brief A chunk of memory.
- *
- * TODO replace this by a dynar
- */
-typedef struct s_buffer {
-  char* data;
-  size_t size;
-  size_t capacity;
-} s_buffer_t, *buffer_t;
-
-static const char* value_tostring(lua_State* L, int index);
-static const char* keyvalue_tostring(lua_State* L, int key_index, int value_index);
-static void stack_dump(const char *msg, lua_State* L);
-static int writer(lua_State* L, const void* source, size_t size, void* userdata);
-static void move_value(lua_State* src, lua_State* dst);
-static void move_value_impl(lua_State* src, lua_State* dst, const char* name);
-static int l_get_from_father(lua_State* L);
-static lua_State *clone_lua_state(lua_State* L);
-static m_task_t check_task(lua_State *L, int index);
-static void register_c_functions(lua_State *L);
-
-/* ********************************************************************************* */
-/*                            helper functions                                       */
-/* ********************************************************************************* */
-
-/**
- * @brief Returns a string representation of a value in the Lua stack.
- *
- * This function is for debugging purposes.
- * It always returns the same pointer.
- *
- * @param L the Lua state
- * @param index index in the stack
- * @return a string representation of the value at this index
- */
-static const char* value_tostring(lua_State* L, int index) {
-
-  static char buff[64];
-
-  switch (lua_type(L, index)) {
-
-    case LUA_TNIL:
-      sprintf(buff, "nil");
-      break;
-
-    case LUA_TNUMBER:
-      sprintf(buff, "%.3f", lua_tonumber(L, index));
-      break;
-
-    case LUA_TBOOLEAN:
-      sprintf(buff, "%s", lua_toboolean(L, index) ? "true" : "false");
-      break;
-
-    case LUA_TSTRING:
-      snprintf(buff, 63, "'%s'", lua_tostring(L, index));
-      break;
-
-    case LUA_TFUNCTION:
-      if (lua_iscfunction(L, index)) {
-        sprintf(buff, "C-function");
-      }
-      else {
-        sprintf(buff, "function");
-      }
-      break;
-
-    case LUA_TTABLE:
-      sprintf(buff, "table(%zu)", lua_objlen(L, index));
-      break;
-
-    case LUA_TLIGHTUSERDATA:
-    case LUA_TUSERDATA:
-      sprintf(buff, "userdata(%p)", lua_touserdata(L, index));
-      break;
-
-    case LUA_TTHREAD:
-      sprintf(buff, "thread");
-      break;
-  }
-  return buff;
-}
-
-/**
- * @brief Returns a string representation of a key-value pair.
- *
- * This function is for debugging purposes.
- * It always returns the same pointer.
- *
- * @param L the Lua state
- * @param key_index index of the key
- * @param value_index index of the value
- * @return a string representation of the key-value pair
- */
-static const char* keyvalue_tostring(lua_State* L, int key_index, int value_index) {
-
-  static char buff[64];
-  /* value_tostring also always returns the same pointer */
-  int len = snprintf(buff, 63, "[%s] -> ", value_tostring(L, key_index));
-  snprintf(buff + len, 63 - len, "%s", value_tostring(L, value_index));
-  return buff;
-}
-
-/**
- * @brief Returns a string composed of the specified number of spaces.
- *
- * This function is for debugging purposes.
- * It always returns the same pointer.
- *
- * @param length length of the string
- * @return a string of this length with only spaces
- */
-static const char* get_spaces(int length) {
-
-  static char spaces[128];
-
-  xbt_assert(length < 128);
-  memset(spaces, ' ', length);
-  spaces[length] = '\0';
-  return spaces;
-}
-
-/**
- * @brief Dumps the Lua stack if debug logs are enabled.
- * @param msg a message to print
- * @param L a Lua state
- */
-static void stack_dump(const char* msg, lua_State* L)
-{
-  if (XBT_LOG_ISENABLED(lua, xbt_log_priority_debug)) {
-    char buff[2048];
-    char* p = buff;
-    int i;
-    int top = lua_gettop(L);
-
-    //if (1) return;
-
-    fflush(stdout);
-
-    p[0] = '\0';
-    for (i = 1; i <= top; i++) {  /* repeat for each level */
-
-      p += sprintf(p, "%s", value_tostring(L, i));
-      p += sprintf(p, " ");       /* put a separator */
-    }
-    XBT_DEBUG("%s%s", msg, buff);
-  }
-}
-
-/**
- * @brief Writes the specified data into a memory buffer.
- *
- * This function is a valid lua_Writer that writes into a memory buffer passed
- * as userdata.
- *
- * @param L a lua state
- * @param source some data
- * @param sz number of bytes of data
- * @param user_data the memory buffer to write
- */
-static int writer(lua_State* L, const void* source, size_t size, void* userdata) {
-
-  buffer_t buffer = (buffer_t) userdata;
-  while (buffer->capacity < buffer->size + size) {
-    buffer->capacity *= 2;
-    buffer->data = xbt_realloc(buffer->data, buffer->capacity);
-  }
-  memcpy(buffer->data + buffer->size, source, size);
-  buffer->size += size;
-
-  return 0;
-}
-
-/**
- * @brief Pops a value from a state and pushes it onto the stack of another
- * state.
- *
- * @param src the source state
- * @param dst the destination state
- */
-static void move_value(lua_State* src, lua_State* dst) {
-
-  if (src != dst) {
-
-    /* create a list of visited tables at index 1 of dst */
-                                  /* src: ... value
-                                     dst: ... */
-    lua_newtable(dst);
-                                  /* dst: ... visited */
-    lua_insert(dst, 1);
-                                  /* dst: visited ... */
-
-    move_value_impl(src, dst, value_tostring(src, -1));
-                                  /* src: ...
-                                     dst: visited ... value */
-    lua_remove(dst, 1);
-                                  /* dst: ... value */
-    stack_dump("src after xmove: ", src);
-    stack_dump("dst after xmove: ", dst);
-  }
-}
-
-/**
- * @brief Pops a value from the stack of a source state and pushes it on the
- * stack of another state.
- *
- * If the value is a table, its content is copied recursively. To avoid cycles,
- * a table of previously visited tables must be present at index 1 of dst.
- * Its keys are pointers to visited tables in src and its values are the tables
- * already built.
- *
- * TODO: add support of closures
- *
- * @param src the source state
- * @param dst the destination state, with a list of visited tables at index 1
- * @param name a name describing the value
- */
-static void move_value_impl(lua_State* src, lua_State *dst, const char* name) {
-
-  luaL_checkany(src, -1);                  /* check the value to copy */
-  luaL_checktype(dst, 1, LUA_TTABLE);      /* check the presence of a table of
-                                              previously visited tables */
-
-  int indent = (lua_gettop(dst) - 1) * 6;
-  XBT_DEBUG("%sCopying data %s", get_spaces(indent), name);
-  indent += 2;
-
-  stack_dump("src before copying a value (should be ... value): ", src);
-  stack_dump("dst before copying a value (should be visited ...): ", dst);
-
-  switch (lua_type(src, -1)) {
-
-    case LUA_TNIL:
-      lua_pushnil(dst);
-      break;
-
-    case LUA_TNUMBER:
-      lua_pushnumber(dst, lua_tonumber(src, -1));
-      break;
-
-    case LUA_TBOOLEAN:
-      lua_pushboolean(dst, lua_toboolean(src, -1));
-      break;
-
-    case LUA_TSTRING:
-      /* no worries about memory: lua_pushstring makes a copy */
-      lua_pushstring(dst, lua_tostring(src, -1));
-      break;
-
-    case LUA_TFUNCTION:
-      /* it's a function that does not exist yet in L2 */
-
-      if (lua_iscfunction(src, -1)) {
-        /* it's a C function: just copy the pointer */
-        lua_CFunction f = lua_tocfunction(src, -1);
-        lua_pushcfunction(dst, f);
-      }
-      else {
-        /* it's a Lua function: dump it from src */
-        XBT_DEBUG("%sDumping Lua function '%s'", get_spaces(indent), name);
-
-        s_buffer_t buffer;
-        buffer.capacity = 64;
-        buffer.size = 0;
-        buffer.data = xbt_new(char, buffer.capacity);
-
-        /* copy the binary chunk from src into a buffer */
-        int error = lua_dump(src, writer, &buffer);
-        xbt_assert(!error, "Failed to dump function '%s' from the source state: error %d",
-              name, error);
-
-        /* load the chunk into dst */
-        error = luaL_loadbuffer(dst, buffer.data, buffer.size, name);
-        xbt_assert(!error, "Failed to load function '%s' into the destination state: %s",
-            name, lua_tostring(dst, -1));
-        XBT_DEBUG("%sFunction '%s' successfully loaded", get_spaces(indent), name);
-      }
-      break;
-
-    case LUA_TTABLE:
-
-      /* see if this table was already visited */
-      lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
-                                  /* dst: visited ... psrctable */
-      lua_gettable(dst, 1);
-                                  /* dst: visited ... table/nil */
-      if (lua_istable(dst, -1)) {
-        XBT_DEBUG("%sNothing to do: table already visited", get_spaces(indent));
-                                  /* dst: visited ... table */
-      }
-      else {
-        XBT_DEBUG("%sFirst visit of this table", get_spaces(indent));
-                                  /* dst: visited ... nil */
-        lua_pop(dst, 1);
-                                  /* dst: visited ... */
-
-        /* first visit: create the new table in dst */
-        lua_newtable(dst);
-                                  /* dst: visited ... table */
-
-        /* mark the table as visited to avoid infinite recursion */
-        lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
-                                  /* dst: visited ... table psrctable */
-        lua_pushvalue(dst, -2);
-                                  /* dst: visited ... table psrctable table */
-        lua_settable(dst, 1);
-                                  /* dst: visited ... table */
-        XBT_DEBUG("%sTable marked as visited", get_spaces(indent));
-
-        stack_dump("dst after marking the table as visited (should be visited ... table): ", dst);
-
-        /* copy the metatable if any */
-        int has_meta_table = lua_getmetatable(src, -1);
-                                  /* src: ... table mt? */
-        if (has_meta_table) {
-          XBT_DEBUG("%sCopying metatable", get_spaces(indent));
-                                  /* src: ... table mt */
-          move_value_impl(src, dst, "metatable");
-                                  /* src: ... table
-                                     dst: visited ... table mt */
-          lua_setmetatable(dst, -2);
-                                  /* dst: visited ... table */
-        }
-        else {
-          XBT_DEBUG("%sNo metatable", get_spaces(indent));
-        }
-
-        stack_dump("src before traversing the table (should be ... table): ", src);
-        stack_dump("dst before traversing the table (should be visited ... table): ", dst);
-
-        /* traverse the table of src and copy each element */
-        lua_pushnil(src);
-                                  /* src: ... table nil */
-        while (lua_next(src, -2) != 0) {
-                                  /* src: ... table key value */
-
-          XBT_DEBUG("%sCopying table element %s", get_spaces(indent), keyvalue_tostring(src, -2, -1));
-
-          stack_dump("src before copying table element (should be ... table key value): ", src);
-          stack_dump("dst before copying table element (should be visited ... table): ", dst);
-
-          /* copy the key */
-          lua_pushvalue(src, -2);
-                                  /* src: ... table key value key */
-          indent += 2;
-          XBT_DEBUG("%sCopying the key part of the table element", get_spaces(indent));
-          move_value_impl(src, dst, value_tostring(src, -1));
-                                  /* src: ... table key value
-                                     dst: visited ... table key */
-          XBT_DEBUG("%sCopied the key part of the table element", get_spaces(indent));
-
-          /* copy the value */
-          XBT_DEBUG("%sCopying the value part of the table element", get_spaces(indent));
-          move_value_impl(src, dst, value_tostring(src, -1));
-                                  /* src: ... table key
-                                     dst: visited ... table key value */
-          XBT_DEBUG("%sCopied the value part of the table element", get_spaces(indent));
-          indent -= 2;
-
-          /* set the table element */
-          lua_settable(dst, -3);
-                                  /* dst: visited ... table */
-
-          /* the key stays on top of src for next iteration */
-          stack_dump("src before next iteration (should be ... table key): ", src);
-          stack_dump("dst before next iteration (should be visited ... table): ", dst);
-
-          XBT_DEBUG("%sTable element copied", get_spaces(indent));
-        }
-        XBT_DEBUG("%sFinished traversing the table", get_spaces(indent));
-      }
-      break;
+static lua_State* sglua_maestro_state;
 
-    case LUA_TLIGHTUSERDATA:
-      lua_pushlightuserdata(dst, lua_touserdata(src, -1));
-      break;
-
-    case LUA_TUSERDATA:
-    {
-      /* copy the data */
-      size_t size = lua_objlen(src, -1);
-      void* src_block = lua_touserdata(src, -1);
-      void* dst_block = lua_newuserdata(dst, size);
-      memcpy(dst_block, src_block, size);
-
-      /* copy the metatable if any */
-      int has_meta_table = lua_getmetatable(src, -1);
-                                /* src: ... udata mt? */
-      if (has_meta_table) {
-        XBT_DEBUG("%sCopying metatable of userdata", get_spaces(indent));
-                                /* src: ... udata mt */
-        move_value_impl(src, dst, "metatable");
-                                /* src: ... udata
-                                   dst: visited ... udata mt */
-        lua_setmetatable(dst, -2);
-                                /* dst: visited ... udata */
-
-        XBT_DEBUG("%sMetatable of userdata copied", get_spaces(indent));
-      }
-      else {
-        XBT_DEBUG("%sNo metatable for this userdata", get_spaces(indent));
-                                /* src: ... udata */
-      }
-    }
-    break;
-
-    case LUA_TTHREAD:
-      XBT_WARN("Cannot copy a thread from the source state.");
-      lua_pushnil(dst);
-      break;
-  }
-
-  /* pop the value from src */
-  lua_pop(src, 1);
-
-  indent -= 2;
-  XBT_DEBUG("%sData copied", get_spaces(indent));
-
-  stack_dump("src after copying a value (should be ...): ", src);
-  stack_dump("dst after copying a value (should be visited ... value): ", dst);
-}
+static void register_c_functions(lua_State *L);
 
 /**
- * @brief Copies a global value or a registry value from the father state.
- *
- * The state L must have a father, i.e. it should have been created by
- * clone_lua_state().
- * This function is meant to be an __index metamethod.
- * Consequently, it assumes that the stack has two elements:
- * a table (either the environment or the registry of L) and the string key of
- * a value that does not exist yet in this table. It copies the corresponding
- * value from the father state and pushes it on the stack of L.
- * If the value does not exist in the father state either, nil is pushed.
- *
- * TODO: make this function thread safe. If the simulation runs in parallel,
- * several simulated processes may trigger this __index metamethod at the same
- * time and get globals from maestro.
- *
- * @param L the current state
- * @return number of return values pushed (always 1)
+ * \brief Like luaL_checkudata, with additional debug logs.
+ * \param L a lua state
+ * \param ud index of the userdata to check in the stack
+ * \param tname key of the metatable of this userdata in the registry
  */
-static int l_get_from_father(lua_State *L) {
-
-  /* check the arguments */
-  luaL_checktype(L, 1, LUA_TTABLE);
-  const char* key = luaL_checkstring(L, 2);
-                                               /* L:      table key */
-  XBT_DEBUG("__index of '%s' begins", key);
-
-  /* want a global or a registry value? */
-  int pseudo_index;
-  if (lua_equal(L, 1, LUA_REGISTRYINDEX)) {
-    /* registry */
-    pseudo_index = LUA_REGISTRYINDEX;
-    XBT_DEBUG("Will get the value from the registry of the father");
-  }
-  else {
-    /* global */
-    pseudo_index = LUA_GLOBALSINDEX;
-    XBT_DEBUG("Will get the value from the globals of the father");
-  }
-
-  /* get the father */
-  lua_pushstring(L, "simgrid.father_state");
-                                               /* L       table key "simgrid.father_state" */
-  lua_rawget(L, LUA_REGISTRYINDEX);
-                                               /* L       table key father */
-
-  lua_State* father = lua_touserdata(L, -1);
-
-  if (father == NULL) {
-    XBT_WARN("This state has no father");
-    lua_pop(L, 3);
-    lua_pushnil(L);
-    return 1;
+static void* my_checkudata(lua_State* L, int ud, const char* tname) {
+
+  XBT_DEBUG("Checking the userdata: ud = %d", ud);
+  sglua_stack_dump("my_checkudata: ", L);
+  void* p = lua_touserdata(L, ud);
+  lua_getfield(L, LUA_REGISTRYINDEX, tname);
+  const void* correct_mt = lua_topointer(L, -1);
+
+  int has_mt = lua_getmetatable(L, ud);
+  XBT_DEBUG("Checking the userdata: has metatable ? %d", has_mt);
+  const void* actual_mt = NULL;
+  if (has_mt) {
+    actual_mt = lua_topointer(L, -1);
+    lua_pop(L, 1);
   }
+  XBT_DEBUG("Checking the task's metatable: expected %p, found %p", correct_mt, actual_mt);
+  sglua_stack_dump("my_checkudata: ", L);
 
-  lua_pop(L, 1);
-                                               /* L:      table key */
-
-  /* get the list of visited tables */
-  lua_pushstring(L, "simgrid.father_visited_tables");
-                                               /* L:      table key "simgrid.father_visited_tables" */
-  lua_rawget(L, LUA_REGISTRYINDEX);
-                                               /* L:      table key visited */
-  lua_insert(L, 1);
-                                               /* L:      visited table key */
-
-  /* get the value from the father */
-  lua_getfield(father, pseudo_index, key);
-                                               /* father: ... value */
-
-  /* push the value onto the stack of L */
-  move_value_impl(father, L, key);
-                                               /* father: ...
-                                                  L:      visited table key value */
-  lua_remove(L, 1);
-                                               /* L:      table key value */
-
-  /* prepare the return value of __index */
-  lua_pushvalue(L, -1);
-                                               /* L:      table key value value */
-  lua_insert(L, 1);
-                                               /* L:      value table key value */
-
-  /* save the copied value in the table for subsequent accesses */
-  lua_settable(L, -3);
-                                               /* L:      value table */
-  lua_settop(L, 1);
-                                               /* L:      value */
-
-  XBT_DEBUG("__index of '%s' returns %s", key, value_tostring(L, -1));
-
-  return 1;
-}
-
-/**
- * @brief Creates a new Lua state and get its environment from an existing state.
- *
- * The state created is independent from the existing one and has its own
- * copies of global variables and functions.
- * However, the global variables and functions are not copied right now from
- * the original state; they are copied only the first time they are accessed.
- * This behavior saves time and memory, and is okay for Simgrid's needs.
- *
- * @param father an existing state
- * @return the state created
- */
-static lua_State* clone_lua_state(lua_State *father) {
-
-  /* create the new state */
-  lua_State *L = luaL_newstate();
-
-  /* set its environment and its registry:
-   * - create a table newenv
-   * - create a metatable mt
-   * - set mt.__index = a function that copies the global from the father state
-   * - set mt as the metatable of the registry
-   * - set mt as the metatable of newenv
-   * - set newenv as the environment of the new state
-   */
-  lua_pushthread(L);                        /* thread */
-  lua_newtable(L);                          /* thread newenv */
-  lua_newtable(L);                          /* thread newenv mt */
-  lua_pushvalue(L, LUA_REGISTRYINDEX);      /* thread newenv mt reg */
-  lua_pushcfunction(L, l_get_from_father);  /* thread newenv mt reg f */
-  lua_setfield(L, -3, "__index");           /* thread newenv mt reg */
-  lua_pushvalue(L, -2);                     /* thread newenv mt reg mt */
-  lua_setmetatable(L, -2);                  /* thread newenv mt reg */
-  lua_pop(L, 1);                            /* thread newenv mt */
-  lua_setmetatable(L, -2);                  /* thread newenv */
-  lua_setfenv(L, -2);                       /* thread */
-  lua_pop(L, 1);                            /* -- */
-
-  /* set a pointer to the father */
-  lua_pushlightuserdata(L, father);         /* father */
-  lua_setfield(L, LUA_REGISTRYINDEX, "simgrid.father_state");
-                                            /* -- */
-
-  lua_getfield(L, LUA_REGISTRYINDEX, "simgrid.father_state"); /* father */
-
-  /* create the table of visited tables from the father */
-  lua_newtable(L);                          /* visited */
-  lua_setfield(L, LUA_REGISTRYINDEX, "simgrid.father_visited_tables");
-                                            /* -- */
-
-  /* open the standard libs (theoretically, this is not necessary as they can
-   * be inherited like any global values, but without a proper support of
-   * closures, iterators like ipairs don't work). */
-  XBT_DEBUG("Metatable of globals and registry set, opening standard libraries now");
-  luaL_openlibs(L);
-
-  XBT_DEBUG("New state created");
-
-  return L;
+  if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
+    luaL_typerror(L, ud, tname);
+  lua_pop(L, 2);
+  return p;
 }
 
 /**
- * @brief Ensures that a userdata on the stack is a task
- * and returns the pointer inside the userdata.
+ * @brief Ensures that a value is a valid task and returns it.
  * @param L a Lua state
  * @param index an index in the Lua stack
  * @return the task at this index
  */
-static m_task_t checkTask(lua_State * L, int index)
+static m_task_t sglua_checktask(lua_State* L, int index)
 {
-  m_task_t *pi, tk;
+  sglua_stack_dump("check task: ", L);
   luaL_checktype(L, index, LUA_TTABLE);
+                                  /* ... task ... */
   lua_getfield(L, index, "__simgrid_task");
+                                  /* ... task ... ctask */
+  m_task_t task = *((m_task_t*) luaL_checkudata(L, -1, TASK_MODULE_NAME));
+  lua_pop(L, 1);
+                                  /* ... task ... */
 
-  pi = (m_task_t *) luaL_checkudata(L, -1, TASK_MODULE_NAME);
+  if (task == NULL) {
+    luaL_error(L, "This task was sent to someone else, you cannot access it anymore");
+  }
 
-  if (pi == NULL)
-    luaL_typerror(L, index, TASK_MODULE_NAME);
-  tk = *pi;
-  if (!tk)
-    luaL_error(L, "null Task");
-  lua_pop(L, 1);
-  return tk;
+  return task;
 }
 
 /* ********************************************************************************* */
@@ -626,91 +82,86 @@ static m_task_t checkTask(lua_State * L, int index)
 /* ********************************************************************************* */
 
 /**
- * A task is either something to compute somewhere, or something to exchange between two hosts (or both).
- * It is defined by a computing amount and a message size.
- *
- */
-
-/* *              * *
- * * Constructors * *
- * *              * */
-
-/**
- * @brief Constructs a new task with the specified processing amount and amount
- * of data needed.
- *
- * @param name	Task's name
+ * \brief Creates a new task and leaves it onto the stack.
  *
- * @param computeDuration 	A value of the processing amount (in flop) needed to process the task.
- *				If 0, then it cannot be executed with the execute() method.
- *				This value has to be >= 0.
- *
- * @param messageSize		A value of amount of data (in bytes) needed to transfert this task.
- *				If 0, then it cannot be transfered with the get() and put() methods.
- *				This value has to be >= 0.
+ * Lua arguments:
+ * - task name (string)
+ * - computation size (integer)
+ * - communication size (integer)
  */
-static int Task_new(lua_State * L)
+static int l_task_new(lua_State* L)
 {
-  XBT_DEBUG("Task new...");
-  const char *name = luaL_checkstring(L, 1);
+  XBT_DEBUG("Task new");
+  const char* name = luaL_checkstring(L, 1);
   int comp_size = luaL_checkint(L, 2);
   int msg_size = luaL_checkint(L, 3);
+                                  /* name comp comm */
+  lua_settop(L, 0);
+                                  /* -- */
   m_task_t msg_task = MSG_task_create(name, comp_size, msg_size, NULL);
-  lua_newtable(L);              /* create a table, put the userdata on top of it */
-  m_task_t *lua_task = (m_task_t *) lua_newuserdata(L, sizeof(m_task_t));
+
+  lua_newtable(L);
+                                  /* task */
+  m_task_t* lua_task = (m_task_t*) lua_newuserdata(L, sizeof(m_task_t));
+                                  /* task ctask */
   *lua_task = msg_task;
   luaL_getmetatable(L, TASK_MODULE_NAME);
+                                  /* task ctask mt */
   lua_setmetatable(L, -2);
-  lua_setfield(L, -2, "__simgrid_task");        /* put the userdata as field of the table */
-  /* remove the args from the stack */
-  lua_remove(L, 1);
-  lua_remove(L, 1);
-  lua_remove(L, 1);
+                                  /* task ctask */
+  lua_setfield(L, -2, "__simgrid_task");
+                                  /* task */
   return 1;
 }
 
-static int Task_get_name(lua_State * L)
+static int l_task_get_name(lua_State* L)
 {
-  m_task_t tk = checkTask(L, -1);
-  lua_pushstring(L, MSG_task_get_name(tk));
+  m_task_t task = sglua_checktask(L, 1);
+  lua_pushstring(L, MSG_task_get_name(task));
   return 1;
 }
 
-static int Task_computation_duration(lua_State * L)
+static int l_task_computation_duration(lua_State* L)
 {
-  m_task_t tk = checkTask(L, -1);
-  lua_pushnumber(L, MSG_task_get_compute_duration(tk));
+  m_task_t task = sglua_checktask(L, 1);
+  lua_pushnumber(L, MSG_task_get_compute_duration(task));
   return 1;
 }
 
-static int Task_execute(lua_State * L)
+static int l_task_execute(lua_State* L)
 {
-  m_task_t tk = checkTask(L, -1);
-  int res = MSG_task_execute(tk);
+  m_task_t task = sglua_checktask(L, 1);
+  int res = MSG_task_execute(task);
   lua_pushnumber(L, res);
   return 1;
 }
 
-static int Task_destroy(lua_State * L)
+static int l_task_send(lua_State* L)
 {
-  m_task_t tk = checkTask(L, -1);
-  int res = MSG_task_destroy(tk);
-  lua_pushnumber(L, res);
-  return 1;
-}
+  m_task_t task = sglua_checktask(L, 1);
+  const char* mailbox = luaL_checkstring(L, 2);
+                                  /* task mailbox */
+  lua_settop(L, 1);
+                                  /* task */
+  /* copy my stack into the task, so that the receiver can copy the lua task */
+  MSG_task_set_data(task, L);
+  MSG_error_t res = MSG_task_send(task, mailbox);
+  while (MSG_task_get_data(task) != NULL) {
+    /* don't mess up with my stack: the receiver didn't copy the data yet */
+    MSG_process_sleep(0);
+  }
 
-static int Task_send(lua_State * L)
-{
-  //stack_dump("send ", L);
-  m_task_t tk = checkTask(L, 1);
-  const char *mailbox = luaL_checkstring(L, 2);
-  lua_pop(L, 1);                // remove the string so that the task is on top of it
-  MSG_task_set_data(tk, L);     // Copy my stack into the task, so that the receiver can copy the lua task directly
-  MSG_error_t res = MSG_task_send(tk, mailbox);
-  while (MSG_task_get_data(tk) != NULL) // Don't mess up with my stack: the receiver didn't copy the data yet
-    MSG_process_sleep(0);       // yield
-
-  if (res != MSG_OK)
+  if (res == MSG_OK) {
+    /* the receiver is the owner of the task and may destroy it:
+     * remove the C task on my side so that I don't garbage collect it */
+    lua_getfield(L, 1, "__simgrid_task");
+                                  /* task ctask */
+    m_task_t* udata = (m_task_t*) luaL_checkudata(L, -1, TASK_MODULE_NAME);
+    *udata = NULL;
+    lua_pop(L, 1);
+                                  /* task */
+  }
+  else {
     switch (res) {
     case MSG_TIMEOUT:
       XBT_DEBUG("MSG_task_send failed : Timeout");
@@ -726,28 +177,26 @@ static int Task_send(lua_State * L)
           ("MSG_task_send failed : Unexpected error , please report this bug");
       break;
     }
+  }
   return 0;
 }
 
-static int Task_recv_with_timeout(lua_State *L)
+static int l_task_recv_with_timeout(lua_State *L)
 {
-  m_task_t tk = NULL;
-  const char *mailbox = luaL_checkstring(L, -2);
-  int timeout = luaL_checknumber(L, -1);
-  MSG_error_t res = MSG_task_receive_with_timeout(&tk, mailbox, timeout);
+  m_task_t task = NULL;
+  const char* mailbox = luaL_checkstring(L, 1);
+  int timeout = luaL_checknumber(L, 2);
+                                  /* mailbox timeout */
+  lua_settop(L, 0);
+                                  /* -- */
+  MSG_error_t res = MSG_task_receive_with_timeout(&task, mailbox, timeout);
 
   if (res == MSG_OK) {
-    lua_State *sender_stack = MSG_task_get_data(tk);
-
-    stack_dump("sender before moving data: ", sender_stack);
-    stack_dump("receiver before moving data: ", L);
-
-    move_value(sender_stack, L);        // copy the data directly from sender's stack
-
-    stack_dump("sender after moving data: ", sender_stack);
-    stack_dump("receiver after moving data: ", L);
-
-    MSG_task_set_data(tk, NULL);
+    /* copy the data directly from sender's stack */
+    lua_State* sender_stack = MSG_task_get_data(task);
+    sglua_copy_value(sender_stack, L);
+                                  /* task */
+    MSG_task_set_data(task, NULL);
   }
   else {
     switch (res) {
@@ -765,57 +214,62 @@ static int Task_recv_with_timeout(lua_State *L)
       break;
     }
     lua_pushnil(L);
+                                  /* nil */
   }
+                                  /* task/nil */
   return 1;
 }
 
-static int Task_recv(lua_State * L)
+static int l_task_recv(lua_State * L)
 {
   lua_pushnumber(L, -1.0);
-  return Task_recv_with_timeout(L);
+  return l_task_recv_with_timeout(L);
 }
 
-static const luaL_reg Task_methods[] = {
-  {"new", Task_new},
-  {"name", Task_get_name},
-  {"computation_duration", Task_computation_duration},
-  {"execute", Task_execute},
-  {"destroy", Task_destroy},
-  {"send", Task_send},
-  {"recv", Task_recv},
-  {"recv_timeout", Task_recv_with_timeout},
+static const luaL_reg task_functions[] = {
+  {"new", l_task_new},
+  {"name", l_task_get_name},
+  {"computation_duration", l_task_computation_duration},
+  {"execute", l_task_execute},
+  {"send", l_task_send},
+  {"recv", l_task_recv},
+  {"recv_timeout", l_task_recv_with_timeout},
   {NULL, NULL}
 };
 
-static int Task_gc(lua_State * L)
+static int l_task_gc(lua_State* L)
 {
-  m_task_t tk = checkTask(L, -1);
-  if (tk)
-    MSG_task_destroy(tk);
+                                  /* ctask */
+  m_task_t task = *((m_task_t*) luaL_checkudata(L, 1, TASK_MODULE_NAME));
+  /* the task is NULL if I sent it to someone else */
+  if (task != NULL) {
+    MSG_task_destroy(task);
+  }
   return 0;
 }
 
-static int Task_tostring(lua_State * L)
+static int l_task_tostring(lua_State* L)
 {
-  lua_pushfstring(L, "Task :%p", lua_touserdata(L, 1));
+  m_task_t task = sglua_checktask(L, 1);
+  lua_pushfstring(L, "Task: %p", task);
   return 1;
 }
 
-static const luaL_reg Task_meta[] = {
-  {"__gc", Task_gc},
-  {"__tostring", Task_tostring},
+static const luaL_reg task_meta[] = {
+  {"__gc", l_task_gc},
+  {"__tostring", l_task_tostring},
   {NULL, NULL}
 };
 
 /**
  * Host
  */
-static m_host_t checkHost(lua_State * L, int index)
+static m_host_t sglua_checkhost(lua_State * L, int index)
 {
   m_host_t *pi, ht;
   luaL_checktype(L, index, LUA_TTABLE);
   lua_getfield(L, index, "__simgrid_host");
-  pi = (m_host_t *) luaL_checkudata(L, -1, HOST_MODULE_NAME);
+  pi = (m_host_t *) luaL_checkudata(L, lua_gettop(L), HOST_MODULE_NAME);
   if (pi == NULL)
     luaL_typerror(L, index, HOST_MODULE_NAME);
   ht = *pi;
@@ -825,7 +279,7 @@ static m_host_t checkHost(lua_State * L, int index)
   return ht;
 }
 
-static int Host_get_by_name(lua_State * L)
+static int l_host_get_by_name(lua_State * L)
 {
   const char *name = luaL_checkstring(L, 1);
   XBT_DEBUG("Getting Host from name...");
@@ -844,20 +298,20 @@ static int Host_get_by_name(lua_State * L)
   return 1;
 }
 
-static int Host_get_name(lua_State * L)
+static int l_host_get_name(lua_State * L)
 {
-  m_host_t ht = checkHost(L, -1);
+  m_host_t ht = sglua_checkhost(L, -1);
   lua_pushstring(L, MSG_host_get_name(ht));
   return 1;
 }
 
-static int Host_number(lua_State * L)
+static int l_host_number(lua_State * L)
 {
   lua_pushnumber(L, MSG_get_host_number());
   return 1;
 }
 
-static int Host_at(lua_State * L)
+static int l_host_at(lua_State * L)
 {
   int index = luaL_checkinteger(L, 1);
   m_host_t host = MSG_get_host_table()[index - 1];      // lua indexing start by 1 (lua[1] <=> C[0])
@@ -871,36 +325,42 @@ static int Host_at(lua_State * L)
 
 }
 
-static int Host_self(lua_State * L)
+static int l_host_self(lua_State * L)
 {
+                                  /* -- */
   m_host_t host = MSG_host_self();
   lua_newtable(L);
-  m_host_t *lua_host =(m_host_t *)lua_newuserdata(L,sizeof(m_host_t));
+                                  /* table */
+  m_host_t* lua_host = (m_host_t*) lua_newuserdata(L, sizeof(m_host_t));
+                                  /* table ud */
   *lua_host = host;
   luaL_getmetatable(L, HOST_MODULE_NAME);
+                                  /* table ud mt */
   lua_setmetatable(L, -2);
+                                  /* table ud */
   lua_setfield(L, -2, "__simgrid_host");
+                                  /* table */
   return 1;
 }
 
-static int Host_get_property_value(lua_State * L)
+static int l_host_get_property_value(lua_State * L)
 {
-  m_host_t ht = checkHost(L, -2);
+  m_host_t ht = sglua_checkhost(L, -2);
   const char *prop = luaL_checkstring(L, -1);
   lua_pushstring(L,MSG_host_get_property_value(ht,prop));
   return 1;
 }
 
-static int Host_sleep(lua_State *L)
+static int l_host_sleep(lua_State *L)
 {
   int time = luaL_checknumber(L, -1);
   MSG_process_sleep(time);
   return 1;
 }
 
-static int Host_destroy(lua_State *L)
+static int l_host_destroy(lua_State *L)
 {
-  m_host_t ht = checkHost(L, -1);
+  m_host_t ht = sglua_checkhost(L, -1);
   __MSG_host_destroy(ht);
   return 1;
 }
@@ -974,101 +434,51 @@ static int gras_generate(lua_State * L)
   return 0;
 }
 
-/***********************************
- * 	Tracing
- **********************************/
-static int trace_start(lua_State *L)
-{
-#ifdef HAVE_TRACING
-  TRACE_start();
-#endif
-  return 1;
-}
-
-static int trace_category(lua_State * L)
-{
-#ifdef HAVE_TRACING
-  TRACE_category(luaL_checkstring(L, 1));
-#endif
-  return 1;
-}
-
-static int trace_set_task_category(lua_State *L)
-{
-#ifdef HAVE_TRACING
-  TRACE_msg_set_task_category(checkTask(L, -2), luaL_checkstring(L, -1));
-#endif
-  return 1;
-}
-
-static int trace_end(lua_State *L)
-{
-#ifdef HAVE_TRACING
-  TRACE_end();
-#endif
-  return 1;
-}
 
 // *********** Register Methods ******************************************* //
 
 /*
  * Host Methods
  */
-static const luaL_reg Host_methods[] = {
-  {"getByName", Host_get_by_name},
-  {"name", Host_get_name},
-  {"number", Host_number},
-  {"at", Host_at},
-  {"self", Host_self},
-  {"getPropValue", Host_get_property_value},
-  {"sleep", Host_sleep},
-  {"destroy", Host_destroy},
+static const luaL_reg host_functions[] = {
+  {"get_by_name", l_host_get_by_name},
+  {"name", l_host_get_name},
+  {"number", l_host_number},
+  {"at", l_host_at},
+  {"self", l_host_self},
+  {"get_prop_value", l_host_get_property_value},
+  {"sleep", l_host_sleep},
+  {"destroy", l_host_destroy},
   // Bypass XML Methods
-  {"setFunction", console_set_function},
-  {"setProperty", console_host_set_property},
+  {"set_function", console_set_function},
+  {"set_property", console_host_set_property},
   {NULL, NULL}
 };
 
-static int Host_gc(lua_State * L)
-{
-  m_host_t ht = checkHost(L, -1);
-  if (ht)
-    ht = NULL;
-  return 0;
-}
-
-static int Host_tostring(lua_State * L)
+static int l_host_tostring(lua_State * L)
 {
   lua_pushfstring(L, "Host :%p", lua_touserdata(L, 1));
   return 1;
 }
 
-static const luaL_reg Host_meta[] = {
-  {"__gc", Host_gc},
-  {"__tostring", Host_tostring},
+static const luaL_reg host_meta[] = {
+  {"__tostring", l_host_tostring},
   {0, 0}
 };
 
 /*
  * AS Methods
  */
-static const luaL_reg AS_methods[] = {
-  {"new", console_add_AS},
-  {"addHost", console_add_host},
-  {"addLink", console_add_link},
-  {"addRoute", console_add_route},
-  {NULL, NULL}
-};
-
-/**
- * Tracing Functions
- */
-static const luaL_reg Trace_methods[] = {
-  {"start", trace_start},
-  {"category", trace_category},
-  {"setTaskCategory", trace_set_task_category},
-  {"finish", trace_end},
-  {NULL, NULL}
+static const luaL_reg platf_functions[] = {
+    {"open", console_open},
+    {"close", console_close},
+    {"AS_open", console_AS_open},
+    {"AS_close", console_AS_close},
+    {"host_new", console_add_host},
+    {"link_new", console_add_link},
+    {"router_new", console_add_router},
+    {"route_new", console_add_route},
+    {NULL, NULL}
 };
 
 /*
@@ -1085,7 +495,7 @@ static int run_lua_code(int argc, char **argv)
 {
   XBT_DEBUG("Run lua code %s", argv[0]);
 
-  lua_State *L = clone_lua_state(lua_maestro_state);
+  lua_State *L = sglua_clone_maestro();
   int res = 1;
 
   /* start the function */
@@ -1099,7 +509,7 @@ static int run_lua_code(int argc, char **argv)
     lua_pushstring(L, argv[i]);
 
   /* call the function */
-  int err;
+  _XBT_GNUC_UNUSED int err;
   err = lua_pcall(L, argc - 1, 1, 0);
   xbt_assert(err == 0, "error running function `%s': %s", argv[0],
               lua_tostring(L, -1));
@@ -1167,9 +577,8 @@ static int clean(lua_State * L)
 static int msg_register_platform(lua_State * L)
 {
   /* Tell Simgrid we dont wanna use its parser */
-  surf_parse = console_parse_platform;
+  //surf_parse = console_parse_platform;
   surf_parse_reset_callbacks();
-  surf_config_models_setup(NULL);
   MSG_create_environment(NULL);
   return 0;
 }
@@ -1180,9 +589,8 @@ static int msg_register_platform(lua_State * L)
 
 static int sd_register_platform(lua_State * L)
 {
-  surf_parse = console_parse_platform_wsL07;
+  //surf_parse = console_parse_platform_wsL07;
   surf_parse_reset_callbacks();
-  surf_config_models_setup(NULL);
   SD_create_environment(NULL);
   return 0;
 }
@@ -1192,10 +600,8 @@ static int sd_register_platform(lua_State * L)
  */
 static int gras_register_platform(lua_State * L)
 {
-  /* Tell Simgrid we dont wanna use surf parser */
-  surf_parse = console_parse_platform;
+  //surf_parse = console_parse_platform;
   surf_parse_reset_callbacks();
-  surf_config_models_setup(NULL);
   gras_create_environment(NULL);
   return 0;
 }
@@ -1206,7 +612,7 @@ static int gras_register_platform(lua_State * L)
 static int msg_register_application(lua_State * L)
 {
   MSG_function_register_default(run_lua_code);
-  surf_parse = console_parse_application;
+  //surf_parse = console_parse_application;
   MSG_launch_application(NULL);
   return 0;
 }
@@ -1217,12 +623,12 @@ static int msg_register_application(lua_State * L)
 static int gras_register_application(lua_State * L)
 {
   gras_function_register_default(run_lua_code);
-  surf_parse = console_parse_application;
+  //surf_parse = console_parse_application;
   gras_launch_application(NULL);
   return 0;
 }
 
-static const luaL_Reg simgrid_funcs[] = {
+static const luaL_Reg simgrid_functions[] = {
   {"create_environment", create_environment},
   {"launch_application", launch_application},
   {"debug", debug},
@@ -1297,13 +703,34 @@ int luaopen_simgrid(lua_State *L)
   }
 
   /* Keep the context mechanism informed of our lua world today */
-  lua_maestro_state = L;
+  sglua_maestro_state = L;
+
+  /* initialize access to my tables by children Lua states */
+  lua_newtable(L);
+  lua_setfield(L, LUA_REGISTRYINDEX, "simgrid.maestro_tables");
 
   register_c_functions(L);
 
   return 1;
 }
 
+/**
+ * @brief Returns whether a Lua state is the maestro state.
+ * @param L a Lua state
+ * @return true if this is maestro
+ */
+int sglua_is_maestro(lua_State* L) {
+  return L == sglua_maestro_state;
+}
+
+/**
+ * @brief Returns the maestro state.
+ * @return true the maestro Lua state
+ */
+lua_State* sglua_get_maestro(void) {
+  return sglua_maestro_state;
+}
+
 /**
  * Makes the appropriate Simgrid functions available to the Lua world.
  * @param L a Lua world
@@ -1311,24 +738,24 @@ int luaopen_simgrid(lua_State *L)
 void register_c_functions(lua_State *L) {
 
   /* register the core C functions to lua */
-  luaL_register(L, "simgrid", simgrid_funcs);
+  luaL_register(L, "simgrid", simgrid_functions);
 
   /* register the task methods to lua */
-  luaL_openlib(L, TASK_MODULE_NAME, Task_methods, 0);   // create methods table, add it to the globals
+  luaL_openlib(L, TASK_MODULE_NAME, task_functions, 0);   // create methods table, add it to the globals
   luaL_newmetatable(L, TASK_MODULE_NAME);       // create metatable for Task, add it to the Lua registry
-  luaL_openlib(L, 0, Task_meta, 0);     // fill metatable
+  luaL_openlib(L, 0, task_meta, 0);     // fill metatable
   lua_pushliteral(L, "__index");
   lua_pushvalue(L, -3);         // dup methods table
-  lua_rawset(L, -3);            // matatable.__index = methods
+  lua_rawset(L, -3);            // metatable.__index = methods
   lua_pushliteral(L, "__metatable");
   lua_pushvalue(L, -3);         // dup methods table
   lua_rawset(L, -3);            // hide metatable:metatable.__metatable = methods
   lua_pop(L, 1);                // drop metatable
 
   /* register the hosts methods to lua */
-  luaL_openlib(L, HOST_MODULE_NAME, Host_methods, 0);
+  luaL_openlib(L, HOST_MODULE_NAME, host_functions, 0);
   luaL_newmetatable(L, HOST_MODULE_NAME);
-  luaL_openlib(L, 0, Host_meta, 0);
+  luaL_openlib(L, 0, host_meta, 0);
   lua_pushliteral(L, "__index");
   lua_pushvalue(L, -3);
   lua_rawset(L, -3);
@@ -1337,13 +764,8 @@ void register_c_functions(lua_State *L) {
   lua_rawset(L, -3);
   lua_pop(L, 1);
 
-  /* register the links methods to lua */
-  luaL_openlib(L, AS_MODULE_NAME, AS_methods, 0);
-  luaL_newmetatable(L, AS_MODULE_NAME);
-  lua_pop(L, 1);
-
-  /* register the Tracing functions to lua */
-  luaL_openlib(L, TRACE_MODULE_NAME, Trace_methods, 0);
-  luaL_newmetatable(L, TRACE_MODULE_NAME);
+  /* register the platform methods to lua */
+  luaL_openlib(L, PLATF_MODULE_NAME, platf_functions, 0);
+  luaL_newmetatable(L, PLATF_MODULE_NAME);
   lua_pop(L, 1);
 }