shithub: lu9-p9

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p9: implement non-throwing error reporting

--- a/fs.c

+++ b/fs.c

@@ -8,7 +8,7 @@

 	file = luaL_checkstring(L, 1);

 	mode = luaL_checkinteger(L, 2);

 	if((fd = open(file, mode)) == -1)

-		lerror(L, "open");

+		return error(L, "open: %r");

 	lua_pushinteger(L, fd);

 	return 1;

 }

@@ -24,7 +24,7 @@

 	mode = luaL_checkinteger(L, 2);

 	perm = luaL_checkinteger(L, 3);

 	if((fd = create(file, mode, perm)) == -1)

-		lerror(L, "create");

+		return error(L, "create: %r");

 	lua_pushinteger(L, fd);

 	return 1;

 }

@@ -33,7 +33,7 @@

 p9_close(lua_State *L)

 {

 	if(close(luaL_checkinteger(L, 1)) == -1)

-		lerror(L, "close");

+		return error(L, "close: %r");

 	return 0;

 }

@@ -53,7 +53,7 @@

 	else

 		n = pread(fd, buf, nbytes, offset);

 	if(n == -1)

-		lerror(L, "read");

+		return error(L, "read: %r");

 	lua_pushlstring(L, buf, n);

 	return 1;

 }

@@ -75,7 +75,7 @@

 	else

 		n = pwrite(fd, buf, nbytes, offset);

 	if(n != nbytes)

-		lerror(L, "write");

+		return error(L, "write: %r");

 	lua_pushinteger(L, n);

 	return 1;

 }

@@ -90,7 +90,7 @@

 	n = luaL_checkinteger(L, 2);

 	type = luaL_checkinteger(L, 3);

 	if((off = seek(fd, n, type)) == -1)

-		lerror(L, "seek");

+		return error(L, "seek: %r");

 	lua_pushinteger(L, off);

 	return 1;

 }

@@ -102,7 +102,7 @@

 	file = luaL_checkstring(L, 1);

 	if(remove(file) == -1)

-		lerror(L, "remove");

+		return error(L, "remove: %r");

 	lua_pushboolean(L, 1);

 	return 1;

 }

@@ -116,7 +116,7 @@

 	fd = luaL_checkinteger(L, 1);

 	buf = getbuffer(L, 8192);

 	if(fd2path(fd, buf, 8192) != 0)

-		lerror(L, "fd2path");

+		return error(L, "fd2path: %r");

 	lua_pushstring(L, buf);

 	return 1;

 }

@@ -198,12 +198,8 @@

 	case LUA_TNUMBER:

 		d = dirfstat(lua_tonumber(L, 1)); break;

 	}

-	if(d == nil){

-		lua_pushnil(L);

-		seterror(L, "stat: %r");

-		pusherror(L);

-		return 2;

-	}

+	if(d == nil)

+		return error(L, "stat: %r");

 	createdirtable(L, d);

 	free(d);

 	return 1;

@@ -220,54 +216,51 @@

 {

 	static int p9_walkout(lua_State*);

 	static int p9_walknext(lua_State*);

-	int nargs;

+	int nargs, wstate;

 	Dir *d;

 	Walk *w;

 	nargs = lua_gettop(L);

 	w = lua_newuserdatauv(L, sizeof(Walk), 1);

+	wstate = nargs + 1;

 	w->fd = -1;

 	w->nleft = 0;

 	w->dirs = w->p = nil;

 	luaL_setmetatable(L, "p9-Walk");

 	if(nargs == 2){

-		lua_insert(L, 2);

-		lua_setiuservalue(L, -2, 1);

+		lua_pushvalue(L, 2);

+		lua_setiuservalue(L, wstate, 1);

 	}

 	if(lua_isnumber(L, 1))

 		w->fd = lua_tointeger(L, 1);

 	else{

 		if((w->fd = open(luaL_checkstring(L, 1), OREAD|OCEXEC)) == -1){

-			seterror(L, "open: %r");

+			error(L, "open: %r");

 			goto Error;

 		}

 	}

 	if((d = dirfstat(w->fd)) == nil){

-		seterror(L, "stat: %r");

+		error(L, "stat: %r");

 		goto Error;

 	}

 	int isdir = d->mode & DMDIR;

 	free(d);

 	if(!isdir){

-		seterror(L, "walk in a non-directory");

+		error(L, "walk in a non-directory");

 		goto Error;

 	}

 	/* return p9_walknext, p9-Walk, nil, p9-Walk */

-	int i = lua_gettop(L);

 	lua_pushcfunction(L, p9_walknext);

-	lua_pushvalue(L, i);

+	lua_pushvalue(L, wstate);

 	lua_pushnil(L);

-	lua_pushvalue(L, i);

+	lua_pushvalue(L, wstate);

 	return 4;

 Error:

-	lua_getiuservalue(L, -1, 1);

-	if(lua_istable(L, -1)){

-		pusherror(L);

-		lua_setfield(L, -2, "error");

+	if(nargs == 2){

+		lua_setfield(L, 2, "error");

 		lua_pushcfunction(L, p9_walkout);

 		return 1;

 	}

-	pusherror(L);

 	return lua_error(L);

 }

@@ -290,7 +283,7 @@

 			w->dirs = nil;

 		}

 		if((w->nleft = dirread(w->fd, &w->dirs)) == -1){

-			seterror(L, "dirread: %r");

+			error(L, "dirread: %r");

 			goto Error;

 		}

 		w->p = w->dirs;

@@ -302,13 +295,14 @@

 	createdirtable(L, d);

 	return 1;

 Error:

-	pusherror(L);

-	if(lua_istable(L, lua_upvalueindex(1))){

-		lua_setfield(L, lua_upvalueindex(1), "error");

+	if(lua_getiuservalue(L, 1, 1) == LUA_TTABLE){

+		lua_pushvalue(L, -2);

+		lua_setfield(L, -2, "error");

 		lua_pushnil(L);

 		return 1;

 	}

-	return lua_error(L);

+	lua_pop(L, 1);

+	return 2;

 }

 static int

@@ -317,10 +311,14 @@

 	Walk *w;

 	w = luaL_checkudata(L, 1, "p9-Walk");

-	free(w->dirs);

-	w->dirs = nil;

-	close(w->fd);

-	w->fd = -1;

+	if(w->dirs != nil){

+		free(w->dirs);

+		w->dirs = nil;

+	}

+	if(w->fd != -1){

+		close(w->fd);

+		w->fd = -1;

+	}

 	return 0;

 }

--- a/mod/init.lua

+++ b/mod/init.lua

@@ -413,41 +413,4 @@

 	end,

 })

-

-

-

--- Lethal API

--- p9.lethal() returns a proxy table that is just like the

--- regular p9 module table, except that each function field

--- is wrapped such that any error raised during a call

--- results in program termination. An error is printed to

--- fd 2 and the same error is used for the program's exit status.

--- Note that this only mechanism only works for the fields

--- of the p9 module, like the p9.open and friends.

--- In particular, it doesn't apply to methods of File objects

--- nor to the p9.env object.

--- This limitation should be removed in the future.

-

-local lethalproxy = setmetatable({}, {

-	__index = function(_, key)

-		if type(p9[key]) ~= "function" then

-			return p9[key]

-		end

-		return function(...)

-			local res = table.pack(pcall(p9[key], ...))

-			if not res[1] then

-				p9.write(2, string.format("%s: %s\n", arg[0] or "lua", res[2]))

-				os.exit(res[2])

-			end

-			table.remove(res, 1)

-			return table.unpack(res)

-		end

-	end

-})

-

---- lethal() -> p9{}

-function p9.lethal()

-	return lethalproxy

-end

-

 return p9

--- a/ns.c

+++ b/ns.c

@@ -9,7 +9,7 @@

 	over = luaL_checkstring(L, 2);

 	flag = luaL_checkinteger(L, 3);

 	if((r = bind(this, over, flag)) == -1)

-		lerror(L, "bind");

+		return error(L, "bind: %r");

 	lua_pushinteger(L, r);

 	return 1;

 }

@@ -26,7 +26,7 @@

 	flag = luaL_checkinteger(L, 4);

 	aname = luaL_checkstring(L, 5);

 	if((r = mount(fd, afd, over, flag, aname)) == -1)

-		lerror(L, "mount");

+		return error(L, "mount: %r");

 	lua_pushinteger(L, r);

 	return 1;

 }

@@ -40,7 +40,7 @@

 	name = luaL_optstring(L, 1, nil);

 	over = luaL_checkstring(L, 2);

 	if((r = unmount(name, over)) == -1)

-		lerror(L, "unmount");

+		return error(L, "unmount: %r");

 	lua_pushinteger(L, r);

 	return 1;

 }

--- a/p9.c

+++ b/p9.c

@@ -5,8 +5,8 @@

 #include <lua.h>

 #include <lauxlib.h>

-static void

-seterror(lua_State *L, char *fmt, ...)

+static int

+error(lua_State *L, char *fmt, ...)

 {

 	va_list varg;

 	int n;

@@ -13,29 +13,13 @@

 	char *buf;

 	luaL_Buffer b;

+	lua_pushnil(L);

 	buf = luaL_buffinitsize(L, &b, 512);

 	va_start(varg, fmt);

 	n = vsnprint(buf, 512, fmt, varg);

 	va_end(varg);

 	luaL_pushresultsize(&b, n);

-	lua_setfield(L, LUA_REGISTRYINDEX, "p9-error");

-}

-

-static const char*

-pusherror(lua_State *L)

-{

-	lua_getfield(L, LUA_REGISTRYINDEX, "p9-error");

-	return lua_tostring(L, -1);

-}

-

-static void

-lerror(lua_State *L, char *call)

-{

-	char err[ERRMAX];

-	

-	rerrstr(err, sizeof err);

-	lua_pushfstring(L, "%s: %s", call, err);

-	lua_error(L);

+	return 2;

 }

 /* Memory allocator associated with Lua state */

--- a/proc.c

+++ b/proc.c

@@ -6,7 +6,7 @@

 	flags = luaL_checkinteger(L, 1);

 	if((r = rfork(flags)) == -1)

-		lerror(L, "rfork");

+		return error(L, "rfork %r");

 	lua_pushinteger(L, r);

 	return 1;

 }

--- a/test.lua

+++ b/test.lua

@@ -75,7 +75,7 @@

 	local f <close> = p9.createfile(tmp())

 	fd = f.fd

 end

-assert(pcall(p9.seek, fd, 0) == false)

+assert(p9.seek(fd, 0) == nil)

 -- Make sure it's not closed

 local fd

 do

@@ -82,7 +82,7 @@

 	local f = p9.createfile(tmp())

 	fd = f.fd

 end

-assert(pcall(p9.seek, fd, 0) == true)

+assert(p9.seek(fd, 0))

 p9.close(fd)

 -- Basic operations. These are the same as regular

@@ -173,18 +173,18 @@

 -- Namespaces

 -- bind and unmount work

-assert(pcall(function()

+assert(function()

 	local f

-	p9.bind("#|", "/n/pipe")

-	f = p9.openfile("/n/pipe/data")

-	p9.unmount("/n/pipe")

-	assert(pcall(p9.openfile, "/n/pipe/data") == false)

-end))

+	assert(p9.bind("#|", "/n/pipe"))

+	f = assert(p9.openfile("/n/pipe/data"))

+	assert(p9.unmount("/n/pipe"))

+	assert(p9.openfile("/n/pipe/data") == nil)

+end)

 -- mount works

-assert(pcall(function()

+assert(function()

 	assert(p9.mount(p9.open("/srv/cwfs", "rw"), nil, "/n/test"))

 	assert(p9.openfile("/n/test/lib/glass"))

-end))

+end)

 -- Process control