summaryrefslogtreecommitdiff
path: root/src/script/common/c_internal.cpp
blob: 5c16b88d9d281c8518122f8fd05ed736bef9db6d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "common/c_internal.h"
#include "debug.h"

std::string script_get_backtrace(lua_State *L)
{
	std::string s;
	lua_getfield(L, LUA_GLOBALSINDEX, "debug");
	if(lua_istable(L, -1)){
		lua_getfield(L, -1, "traceback");
		if(lua_isfunction(L, -1)){
			lua_call(L, 0, 1);
			if(lua_isstring(L, -1)){
				s += lua_tostring(L, -1);
			}
			lua_pop(L, 1);
		}
		else{
			lua_pop(L, 1);
		}
	}
	lua_pop(L, 1);
	return s;
}

void script_error(lua_State *L, const char *fmt, ...)
{
	va_list argp;
	va_start(argp, fmt);
	char buf[10000];
	vsnprintf(buf, 10000, fmt, argp);
	va_end(argp);
	throw LuaError(L, buf);
}

// Push the list of callbacks (a lua table).
// Then push nargs arguments.
// Then call this function, which
// - runs the callbacks
// - removes the table and arguments from the lua stack
// - pushes the return value, computed depending on mode
void script_run_callbacks(lua_State *L, int nargs, RunCallbacksMode mode)
{
	// Insert the return value into the lua stack, below the table
	assert(lua_gettop(L) >= nargs + 1);
	lua_pushnil(L);
	lua_insert(L, -(nargs + 1) - 1);
	// Stack now looks like this:
	// ... <return value = nil> <table> <arg#1> <arg#2> ... <arg#n>

	int rv = lua_gettop(L) - nargs - 1;
	int table = rv + 1;
	int arg = table + 1;

	luaL_checktype(L, table, LUA_TTABLE);

	// Foreach
	lua_pushnil(L);
	bool first_loop = true;
	while(lua_next(L, table) != 0){
		// key at index -2 and value at index -1
		luaL_checktype(L, -1, LUA_TFUNCTION);
		// Call function
		for(int i = 0; i < nargs; i++)
			lua_pushvalue(L, arg+i);
		if(lua_pcall(L, nargs, 1, 0))
			script_error(L, "error: %s", lua_tostring(L, -1));

		// Move return value to designated space in stack
		// Or pop it
		if(first_loop){
			// Result of first callback is always moved
			lua_replace(L, rv);
			first_loop = false;
		} else {
			// Otherwise, what happens depends on the mode
			if(mode == RUN_CALLBACKS_MODE_FIRST)
				lua_pop(L, 1);
			else if(mode == RUN_CALLBACKS_MODE_LAST)
				lua_replace(L, rv);
			else if(mode == RUN_CALLBACKS_MODE_AND ||
					mode == RUN_CALLBACKS_MODE_AND_SC){
				if((bool)lua_toboolean(L, rv) == true &&
						(bool)lua_toboolean(L, -1) == false)
					lua_replace(L, rv);
				else
					lua_pop(L, 1);
			}
			else if(mode == RUN_CALLBACKS_MODE_OR ||
					mode == RUN_CALLBACKS_MODE_OR_SC){
				if((bool)lua_toboolean(L, rv) == false &&
						(bool)lua_toboolean(L, -1) == true)
					lua_replace(L, rv);
				else
					lua_pop(L, 1);
			}
			else
				assert(0);
		}

		// Handle short circuit modes
		if(mode == RUN_CALLBACKS_MODE_AND_SC &&
				(bool)lua_toboolean(L, rv) == false)
			break;
		else if(mode == RUN_CALLBACKS_MODE_OR_SC &&
				(bool)lua_toboolean(L, rv) == true)
			break;

		// value removed, keep key for next iteration
	}

	// Remove stuff from stack, leaving only the return value
	lua_settop(L, rv);

	// Fix return value in case no callbacks were called
	if(first_loop){
		if(mode == RUN_CALLBACKS_MODE_AND ||
				mode == RUN_CALLBACKS_MODE_AND_SC){
			lua_pop(L, 1);
			lua_pushboolean(L, true);
		}
		else if(mode == RUN_CALLBACKS_MODE_OR ||
				mode == RUN_CALLBACKS_MODE_OR_SC){
			lua_pop(L, 1);
			lua_pushboolean(L, false);
		}
	}
}