From 255d59ed5e2743b97626eff57444f44defc39270 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Mon, 28 Jul 2014 14:47:53 -0300 Subject: [PATCH] some janitorial work (comments, small refactoring) --- loadlib.c | 145 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 98 insertions(+), 47 deletions(-) diff --git a/loadlib.c b/loadlib.c index 08190cb5..c85ef405 100644 --- a/loadlib.c +++ b/loadlib.c @@ -1,5 +1,5 @@ /* -** $Id: loadlib.c,v 1.113 2014/03/12 20:57:40 roberto Exp roberto $ +** $Id: loadlib.c,v 1.114 2014/07/16 13:56:14 roberto Exp roberto $ ** Dynamic library loader for Lua ** See Copyright Notice in lua.h ** @@ -97,20 +97,33 @@ #define LIB_FAIL "open" - -/* error codes for ll_loadfunc */ -#define ERRLIB 1 -#define ERRFUNC 2 - #define setprogdir(L) ((void)0) /* ** system-dependent functions */ -static void ll_unloadlib (void *lib); -static void *ll_load (lua_State *L, const char *path, int seeglb); -static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym); + +/* +** unload library 'lib' +*/ +static void lsys_unloadlib (void *lib); + +/* +** load C library in file 'path'. If 'seeglb', load with all names in +** the library global. +** Returns the library; in case of error, returns NULL plus an +** error string in the stack. +*/ +static void *lsys_load (lua_State *L, const char *path, int seeglb); + +/* +** Try to find a function named 'sym' in library 'lib'. +** Returns the function; in case of error, returns NULL plus an +** error string in the stack. +*/ +static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym); + @@ -126,19 +139,19 @@ static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym); #include -static void ll_unloadlib (void *lib) { +static void lsys_unloadlib (void *lib) { dlclose(lib); } -static void *ll_load (lua_State *L, const char *path, int seeglb) { +static void *lsys_load (lua_State *L, const char *path, int seeglb) { void *lib = dlopen(path, RTLD_NOW | (seeglb ? RTLD_GLOBAL : RTLD_LOCAL)); if (lib == NULL) lua_pushstring(L, dlerror()); return lib; } -static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) { +static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) { lua_CFunction f = (lua_CFunction)dlsym(lib, sym); if (f == NULL) lua_pushstring(L, dlerror()); return f; @@ -190,12 +203,12 @@ static void pusherror (lua_State *L) { lua_pushfstring(L, "system error %d\n", error); } -static void ll_unloadlib (void *lib) { +static void lsys_unloadlib (void *lib) { FreeLibrary((HMODULE)lib); } -static void *ll_load (lua_State *L, const char *path, int seeglb) { +static void *lsys_load (lua_State *L, const char *path, int seeglb) { HMODULE lib = LoadLibraryExA(path, NULL, LUA_LLE_FLAGS); (void)(seeglb); /* not used: symbols are 'global' by default */ if (lib == NULL) pusherror(L); @@ -203,7 +216,7 @@ static void *ll_load (lua_State *L, const char *path, int seeglb) { } -static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) { +static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) { lua_CFunction f = (lua_CFunction)GetProcAddress((HMODULE)lib, sym); if (f == NULL) pusherror(L); return f; @@ -226,19 +239,19 @@ static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) { #define DLMSG "dynamic libraries not enabled; check your Lua installation" -static void ll_unloadlib (void *lib) { +static void lsys_unloadlib (void *lib) { (void)(lib); /* not used */ } -static void *ll_load (lua_State *L, const char *path, int seeglb) { +static void *lsys_load (lua_State *L, const char *path, int seeglb) { (void)(path); (void)(seeglb); /* not used */ lua_pushliteral(L, DLMSG); return NULL; } -static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) { +static lua_CFunction lsys_sym (lua_State *L, void *lib, const char *sym) { (void)(lib); (void)(sym); /* not used */ lua_pushliteral(L, DLMSG); return NULL; @@ -248,7 +261,10 @@ static lua_CFunction ll_sym (lua_State *L, void *lib, const char *sym) { #endif -static void *ll_checkclib (lua_State *L, const char *path) { +/* +** return registry.CLIBS[path] +*/ +static void *checkclib (lua_State *L, const char *path) { void *plib; lua_getfield(L, LUA_REGISTRYINDEX, CLIBS); lua_getfield(L, -1, path); @@ -258,7 +274,11 @@ static void *ll_checkclib (lua_State *L, const char *path) { } -static void ll_addtoclib (lua_State *L, const char *path, void *plib) { +/* +** registry.CLIBS[path] = plib -- for queries +** registry.CLIBS[#CLIBS + 1] = plib -- also keep a list of all libraries +*/ +static void addtoclib (lua_State *L, const char *path, void *plib) { lua_getfield(L, LUA_REGISTRYINDEX, CLIBS); lua_pushlightuserdata(L, plib); lua_pushvalue(L, -1); @@ -269,33 +289,49 @@ static void ll_addtoclib (lua_State *L, const char *path, void *plib) { /* -** __gc tag method for CLIBS table: calls 'll_unloadlib' for all lib +** __gc tag method for CLIBS table: calls 'lsys_unloadlib' for all lib ** handles in list CLIBS */ static int gctm (lua_State *L) { int n = luaL_len(L, 1); for (; n >= 1; n--) { /* for each handle, in reverse order */ lua_rawgeti(L, 1, n); /* get handle CLIBS[n] */ - ll_unloadlib(lua_touserdata(L, -1)); + lsys_unloadlib(lua_touserdata(L, -1)); lua_pop(L, 1); /* pop handle */ } return 0; } -static int ll_loadfunc (lua_State *L, const char *path, const char *sym) { - void *reg = ll_checkclib(L, path); /* check loaded C libraries */ + +/* error codes for 'lookforfunc' */ +#define ERRLIB 1 +#define ERRFUNC 2 + +/* +** Look for a C function named 'sym' in a dynamically loaded library +** 'path'. +** First, check whether the library is already loaded; if not, try +** to load it. +** Then, if 'sym' is '*', return true (as library has been loaded). +** Otherwise, look for symbol 'sym' in the library and push a +** C function with that symbol. +** Return 0 and 'true' or a function in the stack; in case of +** errors, return an error code and an error message in the stack. +*/ +static int lookforfunc (lua_State *L, const char *path, const char *sym) { + void *reg = checkclib(L, path); /* check loaded C libraries */ if (reg == NULL) { /* must load library? */ - reg = ll_load(L, path, *sym == '*'); + reg = lsys_load(L, path, *sym == '*'); /* global symbols if 'sym'=='*' */ if (reg == NULL) return ERRLIB; /* unable to load library */ - ll_addtoclib(L, path, reg); + addtoclib(L, path, reg); } if (*sym == '*') { /* loading only library (no function)? */ lua_pushboolean(L, 1); /* return 'true' */ return 0; /* no errors */ } else { - lua_CFunction f = ll_sym(L, reg, sym); + lua_CFunction f = lsys_sym(L, reg, sym); if (f == NULL) return ERRFUNC; /* unable to find function */ lua_pushcfunction(L, f); /* else create new function */ @@ -307,7 +343,7 @@ static int ll_loadfunc (lua_State *L, const char *path, const char *sym) { static int ll_loadlib (lua_State *L) { const char *path = luaL_checkstring(L, 1); const char *init = luaL_checkstring(L, 2); - int stat = ll_loadfunc(L, path, init); + int stat = lookforfunc(L, path, init); if (stat == 0) /* no errors? */ return 1; /* return the loaded function */ else { /* error; error message is on stack top */ @@ -416,21 +452,29 @@ static int searcher_Lua (lua_State *L) { } +/* +** Try to find a load function for module 'modname' at file 'filename'. +** First, change '.' to '_' in 'modname'; then, if 'modname' has +** the form X-Y (that is, it has an "ignore mark"), build a function +** name "luaopen_X" and look for it. (For compatibility, if that +** fails, it also tries "luaopen_Y".) If there is no ignore mark, +** look for a function named "luaopen_modname". +*/ static int loadfunc (lua_State *L, const char *filename, const char *modname) { - const char *funcname; + const char *openfunc; const char *mark; modname = luaL_gsub(L, modname, ".", LUA_OFSEP); mark = strchr(modname, *LUA_IGMARK); if (mark) { int stat; - funcname = lua_pushlstring(L, modname, mark - modname); - funcname = lua_pushfstring(L, LUA_POF"%s", funcname); - stat = ll_loadfunc(L, filename, funcname); + openfunc = lua_pushlstring(L, modname, mark - modname); + openfunc = lua_pushfstring(L, LUA_POF"%s", openfunc); + stat = lookforfunc(L, filename, openfunc); if (stat != ERRFUNC) return stat; modname = mark + 1; /* else go ahead and try old-style name */ } - funcname = lua_pushfstring(L, LUA_POF"%s", modname); - return ll_loadfunc(L, filename, funcname); + openfunc = lua_pushfstring(L, LUA_POF"%s", modname); + return lookforfunc(L, filename, openfunc); } @@ -686,24 +730,31 @@ static void createsearcherstable (lua_State *L) { lua_pushcclosure(L, searchers[i], 1); lua_rawseti(L, -2, i+1); } -} - - -LUAMOD_API int luaopen_package (lua_State *L) { - /* create table CLIBS to keep track of loaded C libraries */ - luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS); - lua_createtable(L, 0, 1); /* metatable for CLIBS */ - lua_pushcfunction(L, gctm); - lua_setfield(L, -2, "__gc"); /* set finalizer for CLIBS table */ - lua_setmetatable(L, -2); - /* create `package' table */ - luaL_newlib(L, pk_funcs); - createsearcherstable(L); #if defined(LUA_COMPAT_LOADERS) lua_pushvalue(L, -1); /* make a copy of 'searchers' table */ lua_setfield(L, -3, "loaders"); /* put it in field `loaders' */ #endif lua_setfield(L, -2, "searchers"); /* put it in field 'searchers' */ +} + + +/* +** create table CLIBS to keep track of loaded C libraries, +** setting a finalizer to close all libraries when closing state. +*/ +static void createclibstable (lua_State *L) { + luaL_getsubtable(L, LUA_REGISTRYINDEX, CLIBS); /* create CLIBS table */ + lua_createtable(L, 0, 1); /* create metatable for CLIBS */ + lua_pushcfunction(L, gctm); + lua_setfield(L, -2, "__gc"); /* set finalizer for CLIBS table */ + lua_setmetatable(L, -2); +} + + +LUAMOD_API int luaopen_package (lua_State *L) { + createclibstable(L); + luaL_newlib(L, pk_funcs); /* create `package' table */ + createsearcherstable(L); /* set field 'path' */ setpath(L, "path", LUA_PATHVARVERSION, LUA_PATH_VAR, LUA_PATH_DEFAULT); /* set field 'cpath' */