terom@203: #include "lua_thread.h"
terom@203: 
terom@203: #include <string.h>
terom@203: #include <assert.h>
terom@203: 
terom@203: #include <lua5.1/lauxlib.h>
terom@203: 
terom@203: 
terom@203: void lua_thread_init (struct lua_thread *thread, struct nexus_lua *lua, lua_thread_cb cb_func, void *cb_arg)
terom@203: {
terom@203:     // zero
terom@203:     memset(thread, 0, sizeof(*thread));
terom@203: 
terom@203:     // store
terom@203:     thread->lua = lua;
terom@203:     thread->cb_func = cb_func;
terom@203:     thread->cb_arg = cb_arg;
terom@203: }
terom@203: 
terom@203: /**
terom@203:  * Thread completed, cleanup and call user callback with given error (NULL for success).
terom@203:  */
terom@203: static void lua_thread_done (lua_State *L, struct lua_thread *thread, error_t *err)
terom@203: {
terom@203:     assert(L == thread->L);
terom@203: 
terom@203:     // remove from registry so thread can be GC'd
terom@203:     lua_pushthread(L);
terom@203:     lua_pushnil(L);
terom@203:     lua_settable(L, LUA_REGISTRYINDEX);
terom@203: 
terom@203:     // drop our ref
terom@203:     thread->L = NULL;
terom@203: 
terom@203:     // call
terom@203:     thread->cb_func(thread, err, thread->cb_arg);
terom@203: }
terom@203: 
terom@203: /**
terom@203:  * Execute the lua_resume with zero arguments, invoking the callback on succesful completion, and returning any
terom@203:  * error.
terom@203:  */
terom@203: static err_t lua_thread_resume (lua_State *L, struct lua_thread *thread, error_t *err)
terom@203: {
terom@203:     int ret;
terom@203: 
terom@203:     // invoke it
terom@203:     switch ((ret = lua_resume(L, 0))) {
terom@203:         case LUA_YIELD:
terom@203:             // ok, running, wait
terom@203:             return SUCCESS;
terom@203: 
terom@203:         case 0:
terom@203:             // done, notify user
terom@203:             lua_thread_done(L, thread, NULL);
terom@203: 
terom@203:             return SUCCESS;
terom@203: 
terom@203:         default:
terom@203:             // let caller handle
terom@203:             // XXX: backtrace...
terom@203:             return nexus_lua_error(L, ret, err);
terom@203:     }
terom@203: }
terom@203: 
terom@203: struct lua_thread_start_ctx {
terom@203:     struct lua_thread *thread;
terom@203:     const char *chunk;
terom@203: };
terom@203: 
terom@203: /**
terom@203:  * Setup the given newthread state, context, and load/run the given chunk
terom@203:  */
terom@203: static int lua_thread_setup (lua_State *L)
terom@203: {
terom@203:     struct lua_thread_start_ctx *ctx;
terom@203:     error_t err;
terom@203: 
terom@203:     // read the ctx argument off the stack
terom@203:     if ((ctx = lua_touserdata(L, 1)) == NULL)
terom@203:         luaL_error(L, "lua_touserdata");
terom@203: 
terom@203:     // push the thread state as the key
terom@203:     lua_pushthread(L);
terom@203: 
terom@203:     // push the lua_thread as the value
terom@203:     lua_pushlightuserdata(L, ctx->thread);
terom@203: 
terom@203:     // store L -> lua_thread mapping in the registry
terom@203:     lua_settable(L, LUA_REGISTRYINDEX);
terom@203: 
terom@203:     // clean up the stack
terom@203:     lua_pop(L, 1);
terom@203:     
terom@203:     // load the chunk as a lua function into the thread's state
terom@203:     if (nexus_lua_error(L, luaL_loadstring(L, ctx->chunk), &err))
terom@203:         luaL_error(L, "%s", error_msg(&err));
terom@203:     
terom@203:     // initial resume on the loaded chunk
terom@203:     if (lua_thread_resume(L, ctx->thread, &err))
terom@203:         luaL_error(L, "%s", error_msg(&err));
terom@203: 
terom@203:     // ok
terom@203:     return 0;
terom@203: }
terom@203: 
terom@203: static int _lua_thread_start (lua_State *L)
terom@203: {
terom@203:     struct lua_thread_start_ctx *ctx;
terom@203:     lua_State *TL;
terom@203:     error_t err;
terom@203: 
terom@203:     // read the ctx argument off the stack
terom@203:     if ((ctx = lua_touserdata(L, 1)) == NULL)
terom@203:         luaL_error(L, "lua_touserdata");
terom@203:     
terom@203:     // create new thread
terom@203:     TL = lua_newthread(L);
terom@203: 
terom@203:     // create thread and do setup on it
terom@203:     if (nexus_lua_error(TL, lua_cpcall(TL, lua_thread_setup, ctx), &err)) {
terom@203:         // cleanup stack (ctx, TL, error message)
terom@203:         lua_pop(L, 3);
terom@203: 
terom@203:         // pass on error
terom@203:         luaL_error(L, "lua_thread_setup: %s", error_msg(&err));
terom@203:     }
terom@203:         
terom@203:     // drop the thread for GC, we don't need it, and also our ctx arg
terom@203:     lua_pop(L, 2);
terom@203:     
terom@203:     // store
terom@203:     ctx->thread->L = TL;
terom@203: 
terom@203:     return 0;
terom@203: }
terom@203: 
terom@203: err_t lua_thread_start (struct lua_thread *thread, const char *chunk, error_t *err)
terom@203: {
terom@203:     struct lua_thread_start_ctx ctx = { thread, chunk };
terom@203: 
terom@203:     // sanity-check
terom@203:     assert(!thread->L);
terom@203: 
terom@203:     // use protected mode to setup
terom@203:     if (nexus_lua_error(thread->lua->st, lua_cpcall(thread->lua->st, _lua_thread_start, &ctx), err))
terom@203:         return ERROR_CODE(err);
terom@203: 
terom@203:     // ok
terom@203:     return SUCCESS;
terom@203: }
terom@203: 
terom@203: void lua_thread_resume_state (lua_State *L)
terom@203: {
terom@203:     struct lua_thread *thread;
terom@203:     error_t err;
terom@203: 
terom@203:     // lookup the thread's context
terom@203:     lua_pushthread(L);
terom@203:     lua_gettable(L, LUA_REGISTRYINDEX);
terom@203: 
terom@203:     // get it as a pointer
terom@203:     if ((thread = lua_touserdata(L, -1)) == NULL)
terom@203:         luaL_error(L, "lua_thread_resume_state: lua_touserdata");
terom@203: 
terom@203:     // handle the resume
terom@203:     if (lua_thread_resume(L, thread, &err))
terom@203:         // notify user
terom@203:         lua_thread_done(thread->L, thread, &err);
terom@203: }
terom@203: