--- /dev/null
+/* 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. */
+
+#include "lua_private.h"
+#include "lua_utils.h"
+#include "lua_state_cloner.h"
+#include <lauxlib.h>
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(lua_task, bindings, "Lua bindings (task module)");
+
+#define TASK_MODULE_NAME "simgrid.task"
+
+/* ********************************************************************************* */
+/* simgrid.task API */
+/* ********************************************************************************* */
+
+/**
+ * \brief Ensures that a value in the stack is a valid task and returns it.
+ * \param L a Lua state
+ * \param index an index in the Lua stack
+ * \return the C task corresponding to this Lua task
+ */
+m_task_t sglua_check_task(lua_State* L, int index)
+{
+ 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 ... */
+
+ if (task == NULL) {
+ luaL_error(L, "This task was sent to someone else, you cannot access it anymore");
+ }
+
+ return task;
+}
+
+/**
+ * \brief Creates a new task and leaves it onto the stack.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (string): name of the task
+ * - Argument 2 (number): computation size
+ * - Argument 3 (number): communication size
+ * - Return value (task): the task created
+ *
+ * A Lua task is a regular table with a full userdata inside, and both share
+ * the same metatable. For the regular table, the metatable allows OO-style
+ * writing such as your_task:send(someone).
+ * For the userdata, the metatable is used to check its type.
+ * TODO: make the task name an optional last parameter
+ */
+static int l_task_new(lua_State* L)
+{
+ 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);
+ /* task */
+ luaL_getmetatable(L, TASK_MODULE_NAME);
+ /* task mt */
+ lua_setmetatable(L, -2);
+ /* 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);
+ /* task ctask */
+ lua_setfield(L, -2, "__simgrid_task");
+ /* task */
+ return 1;
+}
+
+/**
+ * \brief Returns the name of a task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (task): a task
+ * - Return value (string): name of the task
+ */
+static int l_task_get_name(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ lua_pushstring(L, MSG_task_get_name(task));
+ return 1;
+}
+
+/**
+ * \brief Returns the computation duration of a task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (task): a task
+ * - Return value (number): computation duration of this task
+ */
+static int l_task_get_computation_duration(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ lua_pushnumber(L, MSG_task_get_compute_duration(task));
+ return 1;
+}
+
+/**
+ * \brief Executes a task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (task): the task to execute
+ * - Return value (nil or string): nil if the task was successfully executed,
+ * or an error string in case of failure, which may be "task canceled" or
+ * "host failure"
+ */
+static int l_task_execute(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ MSG_error_t res = MSG_task_execute(task);
+
+ if (res == MSG_OK) {
+ return 0;
+ }
+ else {
+ lua_pushstring(L, sglua_get_msg_error(res));
+ return 1;
+ }
+}
+
+/**
+ * \brief Pops the Lua task from the stack and registers it so that the
+ * process can retrieve it later knowing the C task.
+ * \param L a lua state
+ */
+void sglua_task_register(lua_State* L) {
+
+ m_task_t task = sglua_check_task(L, -1);
+ /* ... task */
+ /* put in the C task a ref to the lua task so that the receiver finds it */
+ unsigned long ref = luaL_ref(L, LUA_REGISTRYINDEX);
+ /* ... */
+ MSG_task_set_data(task, (void*) ref);
+}
+
+/**
+ * \brief Pushes onto the stack the Lua task corresponding to a C task.
+ *
+ * The Lua task must have been previously registered with task_register so
+ * that it can be retrieved knowing the C task.
+ *
+ * \param L a lua state
+ * \param task a C task
+ */
+void sglua_task_unregister(lua_State* L, m_task_t task) {
+
+ /* ... */
+ /* the task is in my registry, put it onto my stack */
+ unsigned long ref = (unsigned long) MSG_task_get_data(task);
+ lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
+ /* ... task */
+ luaL_unref(L, LUA_REGISTRYINDEX, ref);
+ MSG_task_set_data(task, NULL);
+}
+
+/**
+ * \brief This function is called when a C task has just been copied.
+ *
+ * This callback is used to move the corresponding Lua task from the sender
+ * process to the receiver process.
+ * It is executed in SIMIX kernel mode when the communication finishes,
+ * before both processes are awaken. Thus, this function is thread-safe when
+ * user processes are executed in parallel, though it modifies the Lua
+ * stack of both processes to move the task.
+ * After this function, both Lua stacks are restored in their previous state.
+ * The task is moved from the registry of the sender to the registry of the
+ * receiver.
+ *
+ * \param task the task copied
+ * \param src_process the sender
+ * \param dst_process the receiver
+ */
+static void task_copy_callback(m_task_t task, m_process_t src_process,
+ m_process_t dst_process) {
+
+ lua_State* src = MSG_process_get_data(src_process);
+ lua_State* dst = MSG_process_get_data(dst_process);
+
+ /* src: ...
+ dst: ... */
+ sglua_task_unregister(src, task);
+ /* src: ... task */
+ sglua_copy_value(src, dst);
+ /* src: ... task
+ dst: ... task */
+ sglua_task_register(dst); /* dst: ... */
+
+ /* the receiver is now the owner of the task and may destroy it:
+ * make the sender forget the C task so that it doesn't garbage */
+ lua_getfield(src, -1, "__simgrid_task");
+ /* src: ... task ctask */
+ m_task_t* udata = (m_task_t*) luaL_checkudata(src, -1, TASK_MODULE_NAME);
+ *udata = NULL;
+ lua_pop(src, 2);
+ /* src: ... */
+}
+
+/**
+ * \brief Sends a task to a mailbox and waits for its completion.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (task): the task to send
+ * - Argument 2 (string or compatible): mailbox name, as a real string or any
+ * type convertible to string (numbers always are)
+ * - Return values (boolean + string): true if the communication was successful,
+ * or false plus an error string in case of failure, which may be "timeout",
+ * "host failure" or "transfer failure"
+ */
+static int l_task_send(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ const char* mailbox = luaL_checkstring(L, 2);
+ /* task mailbox ... */
+ lua_settop(L, 1);
+ /* task */
+ sglua_task_register(L);
+ /* -- */
+ MSG_error_t res = MSG_task_send(task, mailbox);
+
+ if (res == MSG_OK) {
+ lua_pushboolean(L, 1);
+ /* true */
+ return 1;
+ }
+ else {
+ /* the communication has failed, I'm still the owner of the task */
+ sglua_task_unregister(L, task);
+ /* task */
+ lua_pushboolean(L, 0);
+ /* task false */
+ lua_pushstring(L, sglua_get_msg_error(res));
+ /* task false error */
+ return 2;
+ }
+}
+
+/**
+ * \brief Sends a task on a mailbox.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * This is a non-blocking function: use simgrid.comm.wait() or
+ * simgrid.comm.test() to end the communication.
+ *
+ * - Argument 1 (task): the task to send
+ * - Argument 2 (string or compatible): mailbox name, as a real string or any
+ * type convertible to string (numbers always are)
+ * - Return value (comm): a communication object to be used later with wait or test
+ */
+static int l_task_isend(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ const char* mailbox = luaL_checkstring(L, 2);
+ /* task mailbox ... */
+ lua_settop(L, 1);
+ /* task */
+ sglua_task_register(L);
+ /* -- */
+ msg_comm_t comm = MSG_task_isend(task, mailbox);
+
+ sglua_push_comm(L, comm);
+ /* comm */
+ return 1;
+}
+
+/**
+ * \brief Sends a task on a mailbox on a best effort way (detached send).
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * Like simgrid.task.isend, this is a non-blocking function.
+ * You can use this function if you don't care about when the communication
+ * ends and whether it succeeds.
+ * FIXME: isn't this equivalent to calling simgrid.task.isend() and ignoring
+ * the result?
+ *
+ * - Argument 1 (task): the task to send
+ * - Argument 2 (string or compatible): mailbox name, as a real string or any
+ * type convertible to string (numbers always are)
+ */
+static int l_task_dsend(lua_State* L)
+{
+ m_task_t task = sglua_check_task(L, 1);
+ const char* mailbox = luaL_checkstring(L, 2);
+ /* task mailbox ... */
+ lua_settop(L, 1);
+ /* task */
+ sglua_task_register(L);
+ /* -- */
+ MSG_task_dsend(task, mailbox, NULL);
+ return 0;
+}
+
+/**
+ * \brief Receives a task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (string or compatible): mailbox name, as a real string or any
+ * type convertible to string (numbers always are)
+ * - Argument 2 (number, optional): timeout (default is no timeout)
+ * - Return values (task or nil + string): the task received, or nil plus an
+ * error message if the communication has failed
+ */
+static int l_task_recv(lua_State* L)
+{
+ m_task_t task = NULL;
+ const char* mailbox = luaL_checkstring(L, 1);
+ int timeout;
+ if (lua_gettop(L) >= 2) {
+ /* mailbox timeout ... */
+ timeout = luaL_checknumber(L, 2);
+ }
+ else {
+ /* mailbox */
+ timeout = -1;
+ /* no timeout by default */
+ }
+ /* mailbox ... */
+ MSG_error_t res = MSG_task_receive_with_timeout(&task, mailbox, timeout);
+
+ if (res == MSG_OK) {
+ sglua_task_unregister(L, task);
+ /* mailbox ... task */
+ return 1;
+ }
+ else {
+ lua_pushnil(L);
+ /* mailbox ... nil */
+ lua_pushstring(L, sglua_get_msg_error(res));
+ /* mailbox ... nil error */
+ return 2;
+ }
+}
+
+/**
+ * \brief Asynchronously receives a task on a mailbox.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * This is a non-blocking function: use simgrid.comm.wait() or
+ * simgrid.comm.test() to end the communication and get the task in case of
+ * success.
+ *
+ * - Argument 1 (string or compatible): mailbox name, as a real string or any
+ * type convertible to string (numbers always are)
+ * - Return value (comm): a communication object to be used later with wait or test
+ */
+
+static int l_task_irecv(lua_State* L)
+{
+ const char* mailbox = luaL_checkstring(L, 1);
+ /* mailbox ... */
+ m_task_t* task = xbt_new0(m_task_t, 1); // FIXME fix this leak
+ msg_comm_t comm = MSG_task_irecv(task, mailbox);
+ sglua_push_comm(L, comm);
+ /* mailbox ... comm */
+ return 1;
+}
+
+static const luaL_reg task_functions[] = {
+ {"new", l_task_new},
+ {"get_name", l_task_get_name},
+ {"get_computation_duration", l_task_get_computation_duration},
+ {"execute", l_task_execute},
+ {"send", l_task_send},
+ {"isend", l_task_isend},
+ {"dsend", l_task_dsend},
+ {"recv", l_task_recv},
+ {"irecv", l_task_irecv},
+ {NULL, NULL}
+};
+
+/**
+ * \brief Finalizes the userdata of a task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (userdata): a C task, possibly NULL if it was sent to another
+ * Lua state
+ */
+static int l_task_gc(lua_State* L)
+{
+ /* 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;
+}
+
+/**
+ * \brief Returns a string representation of a C task.
+ * \param L a Lua state
+ * \return number of values returned to Lua
+ *
+ * - Argument 1 (userdata): a task
+ * - Return value (string): a string describing this task
+ */
+static int l_task_tostring(lua_State* L)
+{
+ m_task_t task = *((m_task_t*) luaL_checkudata(L, 1, TASK_MODULE_NAME));
+ lua_pushfstring(L, "Task: %p", task);
+ return 1;
+}
+
+/**
+ * \brief Metamethods of both a task table and the userdata inside it.
+ */
+static const luaL_reg task_meta[] = {
+ {"__gc", l_task_gc}, /* will be called only for userdata */
+ {"__tostring", l_task_tostring},
+ {NULL, NULL}
+};
+
+/**
+ * \brief Registers the task functions into the table simgrid.task.
+ *
+ * Also initialize the metatable of the task userdata type.
+ *
+ * \param L a lua state
+ */
+void sglua_register_task_functions(lua_State* L)
+{
+ /* create a table simgrid.task and fill it with task functions */
+ luaL_openlib(L, TASK_MODULE_NAME, task_functions, 0);
+ /* simgrid.task */
+
+ /* create the metatable for tasks, add it to the Lua registry */
+ luaL_newmetatable(L, TASK_MODULE_NAME);
+ /* simgrid.task mt */
+ /* fill the metatable */
+ luaL_openlib(L, NULL, task_meta, 0);
+ /* simgrid.task mt */
+ lua_pushvalue(L, -2);
+ /* simgrid.task mt simgrid.task */
+ /* metatable.__index = simgrid.task
+ * we put the task functions inside the task itself:
+ * this allows to write my_task:method(args) for
+ * simgrid.task.method(my_task, args) */
+ lua_setfield(L, -2, "__index");
+ /* simgrid.task mt */
+ lua_pop(L, 2);
+ /* -- */
+
+ /* set up MSG to copy Lua tasks between states */
+ MSG_task_set_copy_callback(task_copy_callback);
+}
+
