mirror of
https://github.com/jart/cosmopolitan.git
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89 lines
4.7 KiB
C
89 lines
4.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.internal.h"
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#include "third_party/lua/cosmo.h"
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#include "third_party/lua/lauxlib.h"
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// this is called with the error objects/string at -1
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// and returns the stringified error object at -1
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// @param L is main Lua interpreter
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void expanderr(lua_State *L) {
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if (lua_tostring(L, -1) == NULL) { // is error object not a string?
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if (luaL_callmeta(L, -1, "__tostring")) { // is there a metamethod?
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if (lua_type(L, -1) != LUA_TSTRING) { // returns not a string?
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lua_pushfstring(L, "(error object returned a %s value)",
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luaL_typename(L, -1));
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lua_remove(L, -2); // remove non-string value from __tostring
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}
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} else {
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lua_pushfstring(L, "(error object is a %s value)",
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luaL_typename(L, -1));
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}
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lua_remove(L, -2); // remove the error object
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}
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}
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// calling convention for lua stack of L is:
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// -2 is function
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// -1 is is argument (assuming nargs == 1)
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// L will have this after the call
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// -1 is error or result (assuming nres == 1)
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// @param L is main Lua interpreter
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// @note this needs to be reentrant
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int LuaCallWithTrace(lua_State *L, int nargs, int nres, lua_State *C) {
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int nresults, status;
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bool canyield = !!C; // allow yield if coroutine is provided
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if (!C) C = lua_newthread(L); // create a new coroutine if not passed
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// move coroutine to the bottom of the stack (including one that is passed)
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lua_insert(L, 1);
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// make sure that there is enough stack space
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if (!lua_checkstack(C, 1 + nargs)) {
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lua_pushliteral(L, "too many arguments to resume");
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return LUA_ERRRUN; /* error flag */
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}
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// move the function (and arguments) to the top of the coro stack
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lua_xmove(L, C, 1 + nargs);
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// resume the coroutine thus executing the function
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status = lua_resume(C, L, nargs, &nresults);
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// remove coroutine (still) at the bottom, but only if not yielding
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// keep it when yielding to anchor, so it's not GC-collected
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// it's going to be removed at the beginning of the request handling
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if (!canyield) lua_remove(L, 1);
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if (status != LUA_OK && status != LUA_YIELD) {
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lua_xmove(C, L, 1); // move the error message
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expanderr(L); // handle non-string error objects
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// replace the error with the traceback on failure
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luaL_traceback2(L, C, lua_tostring(L, -1), 0);
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lua_remove(L, -2); // remove the error message
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} else {
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if (!lua_checkstack(L, MAX(nresults, nres))) {
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lua_pop(C, nresults); // remove results anyway
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lua_pushliteral(L, "too many results to resume");
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return LUA_ERRRUN; // error flag
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}
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lua_xmove(C, L, nresults); // move results to the main stack
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// grow the stack in case returned fewer results
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// than the caller expects, as lua_resume
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// doesn't adjust the stack for needed results
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for (; nresults < nres; nresults++) lua_pushnil(L);
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if (!canyield) status = LUA_OK; // treat LUA_YIELD the same as LUA_OK
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}
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return status;
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}
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