terom@203: #include "lua_thread.h"
terom@210: #include "log.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:     // 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@204:     thread->cb_func(err, thread->cb_arg);
terom@203: }
terom@203: 
terom@203: /**
terom@204:  * Execute the lua_resume with zero arguments. If the thread finished, this returns zero, if it yielded, >0. For
terom@204:  * errors, returns -err_t.
terom@203:  */
terom@204: static int lua_thread_resume (lua_State *L, struct lua_thread *thread, error_t *err)
terom@203: {
terom@203:     int ret;
terom@203: 
terom@204:     (void) thread;
terom@204:     
terom@203:     // invoke it
terom@203:     switch ((ret = lua_resume(L, 0))) {
terom@203:         case LUA_YIELD:
terom@203:             // ok, running, wait
terom@204:             return 1;
terom@203: 
terom@203:         case 0:
terom@204:             // done
terom@204:             return 0;
terom@203: 
terom@203:         default:
terom@203:             // let caller handle
terom@203:             // XXX: backtrace...
terom@204:             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@204:  * Create a new thread, set it up, and run the initial resume, returning the boolean result of that
terom@204:  * (true for yielded, false for done).
terom@204:  */
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@204:     int ret;
terom@203: 
terom@203:     // read the ctx argument off the stack
terom@203:     if ((ctx = lua_touserdata(L, 1)) == NULL)
terom@204:         return luaL_error(L, "lua_touserdata");
terom@204:     else
terom@204:         lua_pop(L, 1);
terom@203:     
terom@204:     // check
terom@204:     assert(!ctx->thread->L);
terom@204: 
terom@203:     // create new thread
terom@203:     TL = lua_newthread(L);
terom@214:  
terom@214:     // push the lua_thread as the value
terom@214:     lua_pushlightuserdata(L, ctx->thread);
terom@214: 
terom@214:     // store L -> lua_thread mapping in the registry
terom@214:     lua_settable(L, LUA_REGISTRYINDEX);
terom@203: 
terom@204:     // load the chunk as a lua function into the thread's state
terom@204:     if (nexus_lua_error(TL, luaL_loadstring(TL, ctx->chunk), &err))
terom@204:         goto error;
terom@204: 
terom@204:     // initial resume on the loaded chunk
terom@204:     if ((ret = lua_thread_resume(TL, ctx->thread, &err)) < 0)
terom@204:         goto error;
terom@204: 
terom@204:     // yielded?
terom@204:     if (ret) 
terom@204:         // store
terom@204:         ctx->thread->L = TL;
terom@203:     
terom@204:     // pop thread to release for GC
terom@204:     lua_pop(L, 1);
terom@203: 
terom@203:     return 0;
terom@204:         
terom@204: error:
terom@204:     // pop thread to release for GC
terom@204:     lua_pop(L, 1);
terom@204: 
terom@204:     // drop ref
terom@204:     ctx->thread->L = NULL;
terom@204: 
terom@204:     // pass on error
terom@204:     return luaL_error(L, "%s", error_msg(&err));
terom@203: }
terom@203: 
terom@204: int 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@204:         return -ERROR_CODE(err);
terom@203: 
terom@204:     // return true if yielded, false if done
terom@204:     return (thread->L != NULL);
terom@203: }
terom@203: 
terom@210: int lua_thread_yield_state (lua_State *L)
terom@210: {
terom@210:     return lua_yield(L, 0);
terom@210: }
terom@210: 
terom@210: static int _lua_thread_resume_state (lua_State *L)
terom@203: {
terom@203:     struct lua_thread *thread;
terom@203:     error_t err;
terom@204:     int ret;
terom@203: 
terom@210:     // pop irrelevant context arg
terom@210:     lua_pop(L, 1);
terom@210: 
terom@203:     // lookup the thread's context
terom@203:     lua_pushthread(L);
terom@203:     lua_gettable(L, LUA_REGISTRYINDEX);
terom@210:     
terom@210:     // not registered?
terom@210:     if (lua_isnil(L, -1))
terom@210:         return luaL_error(L, "not a registered lua_thread state");
terom@210: 
terom@210:     else if (lua_isboolean(L, -1) && !lua_toboolean(L, -1))
terom@210:         return luaL_error(L, "lua_thread was aborted");
terom@203: 
terom@203:     // get it as a pointer
terom@203:     if ((thread = lua_touserdata(L, -1)) == NULL)
terom@210:         return luaL_error(L, "lua_touserdata");
terom@210:     else
terom@210:         lua_pop(L, 1);
terom@203: 
terom@203:     // handle the resume
terom@204:     if ((ret = lua_thread_resume(L, thread, &err)) < 0)
terom@203:         // notify user
terom@210:         lua_thread_done(thread->L, thread, &err);
terom@204: 
terom@204:     // finished?
terom@210:     else if (ret == 0)
terom@210:         lua_thread_done(thread->L, thread, NULL);
terom@210: 
terom@210:     // ok
terom@210:     return 0;
terom@203: }
terom@203: 
terom@210: void lua_thread_resume_state (lua_State *L)
terom@210: {
terom@210:     error_t err;
terom@210: 
terom@210:     // execute in protected mode
terom@210:     if (nexus_lua_error(L, lua_cpcall(L, _lua_thread_resume_state, NULL), &err))
terom@210:         log_warn_error(&err, "%p", L);
terom@210: }
terom@210: 
terom@210: static int _lua_thread_abort (lua_State *L)
terom@210: {
terom@210:     struct lua_thread *thread;
terom@210: 
terom@210:     // get context arg
terom@210:     if ((thread = lua_touserdata(L, -1)) == NULL)
terom@210:         luaL_error(L, "lua_thread_resume_state: lua_touserdata");
terom@210:     else
terom@210:         lua_pop(L, 1);
terom@210: 
terom@210:     // no mechanism to actually abort the underlying wait yet
terom@210:     (void) thread;
terom@210: 
terom@210:     // invalidate in registry for later lua_thread_resume_state
terom@210:     lua_pushthread(L);
terom@210:     lua_pushboolean(L, false);
terom@210:     lua_settable(L, LUA_REGISTRYINDEX);
terom@210: 
terom@210:     // not much else we can do
terom@210:     return 0;
terom@210: }
terom@210: 
terom@210: void lua_thread_abort (struct lua_thread *thread)
terom@210: {
terom@210:     error_t err;
terom@210: 
terom@210:     if (!thread->L)
terom@210:         // no thread executing
terom@210:         return;
terom@210:     
terom@210:     // use protected mode
terom@210:     if (nexus_lua_error(thread->L, lua_cpcall(thread->L, _lua_thread_abort, thread), &err))
terom@210:         log_warn_error(&err, "_lua_thread_abort");
terom@210: 
terom@210:     // unset
terom@210:     thread->L = NULL;
terom@210: }
terom@210: