MEDIUM: lua: "com" signals
This system permits to send signals between lua tasks. A main lua stack can
register the signal in a coprocess. When the coprocess finish his job, it
send a signal, and the associated task is wakes. If the main lua execution
stack stop (with or without errors), the list or pending signals is purged.
diff --git a/include/types/hlua.h b/include/types/hlua.h
index 85d7e81..cfeb767 100644
--- a/include/types/hlua.h
+++ b/include/types/hlua.h
@@ -27,7 +27,16 @@
enum hlua_state state; /* The current execution state. */
struct task *task; /* The task associated with the lua stack execution.
We must wake this task to continue the task execution */
+ struct list com; /* The list head of the signals attached to this task. */
struct ebpt_node node;
};
+struct hlua_com {
+ struct list purge_me; /* Part of the list of signals to be purged in the
+ case of the LUA execution stack crash. */
+ struct list wake_me; /* Part of list of signals to be targeted if an
+ event occurs. */
+ struct task *task; /* The task to be wake if an event occurs. */
+};
+
#endif /* _TYPES_HLUA_H */
diff --git a/src/hlua.c b/src/hlua.c
index 5c59c20..bbbf298 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -9,6 +9,8 @@
#include <types/hlua.h>
#include <types/proxy.h>
+#include <proto/task.h>
+
/* Lua uses longjmp to perform yield or throwing errors. This
* macro is used only for identifying the function that can
* not return because a longjmp is executed.
@@ -23,6 +25,11 @@
/* The main Lua execution context. */
struct hlua gL;
+/* This is the memory pool containing all the signal structs. These
+ * struct are used to store each requiered signal between two tasks.
+ */
+struct pool_head *pool2_hlua_com;
+
/* Store the fast lua context for coroutines. This tree uses the
* Lua stack pointer value as indexed entry, and store the associated
* hlua context.
@@ -134,6 +141,57 @@
return 1;
}
+/* This function register a new signal. "lua" is the current lua
+ * execution context. It contains a pointer to the associated task.
+ * "link" is a list head attached to an other task that must be wake
+ * the lua task if an event occurs. This is useful with external
+ * events like TCP I/O or sleep functions. This funcion allocate
+ * memory for the signal.
+ */
+static int hlua_com_new(struct hlua *lua, struct list *link)
+{
+ struct hlua_com *com = pool_alloc2(pool2_hlua_com);
+ if (!com)
+ return 0;
+ LIST_ADDQ(&lua->com, &com->purge_me);
+ LIST_ADDQ(link, &com->wake_me);
+ com->task = lua->task;
+ return 1;
+}
+
+/* This function purge all the pending signals when the LUA execution
+ * is finished. This prevent than a coprocess try to wake a deleted
+ * task. This function remove the memory associated to the signal.
+ */
+static void hlua_com_purge(struct hlua *lua)
+{
+ struct hlua_com *com, *back;
+
+ /* Delete all pending communication signals. */
+ list_for_each_entry_safe(com, back, &lua->com, purge_me) {
+ LIST_DEL(&com->purge_me);
+ LIST_DEL(&com->wake_me);
+ pool_free2(pool2_hlua_com, com);
+ }
+}
+
+/* This function sends signals. It wakes all the tasks attached
+ * to a list head, and remove the signal, and free the used
+ * memory.
+ */
+static void hlua_com_wake(struct list *wake)
+{
+ struct hlua_com *com, *back;
+
+ /* Wake task and delete all pending communication signals. */
+ list_for_each_entry_safe(com, back, wake, wake_me) {
+ LIST_DEL(&com->purge_me);
+ LIST_DEL(&com->wake_me);
+ task_wakeup(com->task, TASK_WOKEN_MSG);
+ pool_free2(pool2_hlua_com, com);
+ }
+}
+
/*
* The following functions are used to make correspondance between the the
* executed lua pointer and the "struct hlua *" that contain the context.
@@ -172,6 +230,7 @@
{
lua->Mref = LUA_REFNIL;
lua->state = HLUA_STOP;
+ LIST_INIT(&lua->com);
lua->T = lua_newthread(gL.T);
if (!lua->T) {
lua->Tref = LUA_REFNIL;
@@ -192,6 +251,9 @@
/* Remove context. */
hlua_delhlua(lua);
+ /* Purge all the pending signals. */
+ hlua_com_purge(lua);
+
/* The thread is garbage collected by Lua. */
luaL_unref(lua->T, LUA_REGISTRYINDEX, lua->Mref);
luaL_unref(gL.T, LUA_REGISTRYINDEX, lua->Tref);
@@ -347,17 +409,20 @@
break;
case HLUA_E_ERRMSG:
+ hlua_com_purge(lua);
hlua_ctx_renew(lua, 1);
lua->state = HLUA_STOP;
break;
case HLUA_E_ERR:
lua->state = HLUA_STOP;
+ hlua_com_purge(lua);
hlua_ctx_renew(lua, 0);
break;
case HLUA_E_OK:
lua->state = HLUA_STOP;
+ hlua_com_purge(lua);
break;
}
@@ -366,9 +431,13 @@
void hlua_init(void)
{
+ /* Initialise com signals pool session. */
+ pool2_hlua_com = create_pool("hlua_com", sizeof(struct hlua_com), MEM_F_SHARED);
+
/* Init main lua stack. */
gL.Mref = LUA_REFNIL;
gL.state = HLUA_STOP;
+ LIST_INIT(&gL.com);
gL.T = luaL_newstate();
hlua_sethlua(&gL);
gL.Tref = LUA_REFNIL;