house-keeping
[chaz/yoink] / src / Moof / Script.hh
1
2 /*******************************************************************************
3
4 Copyright (c) 2009, Charles McGarvey
5 All rights reserved.
6
7 Redistribution and use in source and binary forms, with or without
8 modification, are permitted provided that the following conditions are met:
9
10 * Redistributions of source code must retain the above copyright notice,
11 this list of conditions and the following disclaimer.
12 * Redistributions in binary form must reproduce the above copyright notice,
13 this list of conditions and the following disclaimer in the documentation
14 and/or other materials provided with the distribution.
15
16 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
20 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27 *******************************************************************************/
28
29 #ifndef _MOOF_SCRIPT_HH_
30 #define _MOOF_SCRIPT_HH_
31
32 /**
33 * @file Script.hh
34 * A thin wrapper over Lua. This is not meant as a complicated binding package
35 * between C++ and Lua. It does not try to make the boundary invisible. It
36 * does not hide the concept of the Lua stack, but rather provides that
37 * mechanism with a certain level of abstraction while also providing a cleaner,
38 * more consistent API.
39 */
40
41 #include <list>
42 #include <map>
43 #include <string>
44 #include <vector>
45
46 #include <boost/bind.hpp>
47 #include <boost/function.hpp>
48 #include <boost/shared_ptr.hpp>
49
50 #include <lua.hpp>
51
52 #include <Moof/Log.hh>
53
54
55 namespace Mf {
56
57
58 class Script;
59 typedef boost::shared_ptr<Script> ScriptP;
60
61
62 class Script
63 {
64 public:
65
66 typedef boost::function<int(Script&)> Function;
67
68 enum Type
69 {
70 NONE = LUA_TNONE,
71 NIL = LUA_TNIL,
72 BOOLEAN = LUA_TBOOLEAN,
73 LIGHTUSERDATA = LUA_TLIGHTUSERDATA,
74 NUMBER = LUA_TNUMBER,
75 STRING = LUA_TSTRING,
76 TABLE = LUA_TTABLE,
77 FUNCTION = LUA_TFUNCTION,
78 USERDATA = LUA_TUSERDATA,
79 THREAD = LUA_TTHREAD
80 };
81
82 enum Status
83 {
84 SUCCESS = 0,
85 YIELD = LUA_YIELD,
86 RUNTIME_ERROR = LUA_ERRRUN,
87 SYNTAX_ERROR = LUA_ERRSYNTAX,
88 MEMORY_ERROR = LUA_ERRMEM,
89 HANDLER_ERROR = LUA_ERRERR,
90 FILE_ERROR = LUA_ERRFILE
91 };
92
93 enum PseudoIndex
94 {
95 REGISTRY = LUA_REGISTRYINDEX,
96 ENVIRONMENT = LUA_ENVIRONINDEX,
97 GLOBALS = LUA_GLOBALSINDEX
98 };
99
100 /**
101 * This is the most prominent abstraction on top of the standard Lua API.
102 * A Value object represents a value on the stack. More specifically, it
103 * represents a position on the stack. The distinction is only important
104 * when values are moved around on the stack or if the Value represents a
105 * negative index on the stack (the value of which will change as things are
106 * pushed onto and popped from the stack).
107 */
108
109 struct Value
110 {
111 /**
112 * You have direct access to the index of the value on the stack being
113 * represented.
114 */
115
116 int index;
117
118
119 /**
120 * A default-constructed Value is invalid until a valid Value is
121 * assigned to it. The only method that should be called on such a
122 * Value is isValid(), otherwise chaos may ensue. In this case, the
123 * Value will be invalid even if index is manually changed to a valid
124 * index. You have to index the script itself to get a valid Value.
125 */
126 Value(lua_State* s = 0, int i = 0) :
127 index(i),
128 state(s) {}
129
130 /**
131 * A copied value presently points to the same value, except the real
132 * index is used. That means that if a value that refers to a frame
133 * referenced from the top of the stack will have its normalized index
134 * copied into the new value object.
135 */
136
137 Value(const Value& copy) :
138 index(copy.getRealIndex()),
139 state(copy.state) {}
140
141
142 // check the type of the value
143 bool isBoolean() const { return (bool)lua_isboolean(state, index); }
144 bool isFunction() const { return (bool)lua_isfunction(state, index); }
145 bool isNil() const { return (bool)lua_isnil(state, index); }
146 bool isNone() const { return (bool)lua_isnone(state, index); }
147 bool isValid() const { return state != 0 && !isNone(); }
148 bool isNoneOrNil() const { return (bool)lua_isnoneornil(state, index); }
149 bool isNumber() const { return (bool)lua_isnumber(state, index); }
150 bool isString() const { return (bool)lua_isstring(state, index); }
151 bool isTable() const { return (bool)lua_istable(state, index); }
152 bool isThread() const { return (bool)lua_isthread(state, index); }
153 bool isData() const { return (bool)lua_isuserdata(state, index); }
154 bool isLightData() const { return (bool)lua_islightuserdata(state, index); }
155
156 /**
157 * Check the value and throw an error if its the wrong type. There's a
158 * little caveat: This method never returns because it does a long jump.
159 * Consequently, constructed C++ objects which exist on the stack
160 * between the current frame and some lua function will not be
161 * destructed. That's not a problem for objects that only exist on the
162 * stack, but any objects that allocate memory on the heap (such as
163 * containers or strings) will leak. Therefore, you should only call
164 * this method after cleaning up such objects. The best thing to do for
165 * defining functions is to simply check all the parameters at the
166 * get-go before any C++ objects are even constructed.
167 */
168
169 void requireType(Type type) const
170 {
171 if (type != getType())
172 {
173 luaL_typerror(state, index, lua_typename(state, type));
174 }
175 }
176
177 void throwError(const char* error)
178 {
179 luaL_argerror(state, index, error);
180 }
181
182
183 Value& requireBoolean()
184 {
185 if (!isBoolean()) luaL_typerror(state, index, "boolean");
186 return *this;
187 }
188 Value& requireNumber()
189 {
190 if (!isNumber()) luaL_typerror(state, index, "number");
191 return *this;
192 }
193 Value& requireString()
194 {
195 if (!isString()) luaL_typerror(state, index, "string");
196 return *this;
197 }
198 Value& requireTable()
199 {
200 if (!isTable()) luaL_typerror(state, index, "table");
201 return *this;
202 }
203 Value& requireFunction()
204 {
205 if (!isFunction()) luaL_typerror(state, index, "function");
206 return *this;
207 }
208 Value& requireData()
209 {
210 if (!isData()) luaL_typerror(state, index, "data");
211 return *this;
212 }
213 Value& requireNil()
214 {
215 if (!isNil()) luaL_typerror(state, index, "nil");
216 return *this;
217 }
218 Value& requireThread()
219 {
220 if (!isThread()) luaL_typerror(state, index, "thread");
221 return *this;
222 }
223
224
225 /**
226 * Get the type of the value.
227 */
228
229 Type getType() const
230 {
231 return (Type)lua_type(state, index);
232 }
233
234 /**
235 * Get the name of the type of the value as a string.
236 */
237
238 std::string getTypeName() const
239 {
240 return std::string(luaL_typename(state, index));
241 }
242
243
244 /**
245 * Get the length of the value according to the definition given by Lua.
246 */
247
248 size_t getLength() const
249 {
250 return lua_objlen(state, index);
251 }
252
253 int getRealIndex() const
254 {
255 if (index < 0) return lua_gettop(state) + 1 + index;
256 else return index;
257 }
258
259
260 /**
261 * Get a pointer value (for userdata, tables, threads, and functions).
262 */
263
264 const void* getIdentifier() const
265 {
266 return lua_topointer(state, index);
267 }
268
269
270 bool operator == (const Value& rhs) const
271 {
272 return (bool)lua_equal(state, index, rhs.index);
273 }
274 bool operator != (const Value& rhs) const
275 {
276 return !(*this == rhs);
277 }
278 bool operator < (const Value& rhs) const
279 {
280 return (bool)lua_lessthan(state, index, rhs.index);
281 }
282 bool operator <= (const Value& rhs) const
283 {
284 return *this < rhs || *this == rhs;
285 }
286 bool operator > (const Value& rhs) const
287 {
288 return !(*this <= rhs);
289 }
290 bool operator >= (const Value& rhs) const
291 {
292 return !(*this < rhs);
293 }
294 operator bool () const
295 {
296 return (bool)lua_toboolean(state, index);
297 }
298
299 Value& operator = (const Value& rhs)
300 {
301 rhs.pushCopy();
302 replaceWithTop();
303 return *this;
304 }
305
306
307 /**
308 * Convert the underlying value to a C++ type.
309 */
310
311 template <typename T>
312 bool get(T& value) const
313 {
314 if (isNumber())
315 {
316 value = (T)lua_tointeger(state, index);
317 return true;
318 }
319 return false;
320 }
321
322 bool get(float& value) const
323 {
324 if (isNumber())
325 {
326 value = (float)lua_tonumber(state, index);
327 return true;
328 }
329 return false;
330 }
331 bool get(double& value) const
332 {
333 if (isNumber())
334 {
335 value = (double)lua_tonumber(state, index);
336 return true;
337 }
338 return false;
339 }
340
341 bool get(bool& value) const
342 {
343 if (isBoolean())
344 {
345 value = (bool)lua_toboolean(state, index);
346 return true;
347 }
348 return false;
349 }
350
351 bool get(std::string& value) const
352 {
353 if (isString())
354 {
355 size_t size;
356 const char* str = lua_tolstring(state, index, &size);
357 value.assign(str, size);
358 return true;
359 }
360 return false;
361 }
362
363 template <typename T>
364 bool get(std::vector<T>& array) const
365 {
366 if (!isTable()) return false;
367
368 array.clear();
369
370 Value value(state, -1);
371 int realIndex = getRealIndex();
372
373 bool done = false;
374 for (int i = 1; !done; ++i)
375 {
376 lua_rawgeti(state, realIndex, i);
377
378 T v;
379 if (value.get(v)) array.push_back(v);
380 else done = true;
381
382 lua_pop(state, 1);
383 }
384
385 return true;
386 }
387
388 template <typename T>
389 bool get(std::map<std::string,T>& dictionary) const
390 {
391 if (!isTable()) return false;
392
393 dictionary.clear();
394
395 Value key(state, -2);
396 Value value(state, -1);
397 int realIndex = getRealIndex();
398
399 lua_pushnil(state);
400 while (lua_next(state, realIndex) != 0)
401 {
402 std::string k;
403 if (!key.isNumber() && key.get(k))
404 {
405 T v;
406 if (value.get(v)) dictionary[k] = v;
407 }
408 lua_pop(state, 1);
409 }
410 lua_pop(state, 1);
411
412 return true;
413 }
414
415
416
417 /**
418 * Copy the value and push the copy to the stack.
419 */
420
421 void pushCopy() const
422 {
423 lua_pushvalue(state, index);
424 }
425
426 /**
427 * Replace this value with the value at the top of the stack.
428 */
429
430 void replaceWithTop()
431 {
432 lua_replace(state, index);
433 }
434
435 void remove()
436 {
437 lua_remove(state, index);
438 }
439
440 /**
441 * Inserts the top-most value on the stack at position index, shifting other
442 * values as needed.
443 */
444
445 void insertTopHere()
446 {
447 lua_insert(state, index);
448 }
449
450
451 void pushMetatable() const
452 {
453 lua_getmetatable(state, index);
454 }
455
456 void pushField() const
457 {
458 lua_gettable(state, index);
459 }
460
461 void pushField(const std::string& name) const
462 {
463 lua_getfield(state, index, name.c_str());
464 }
465
466
467 private:
468
469 lua_State* state;
470 };
471
472
473 Script() :
474 mState(luaL_newstate())
475 {
476 lua_pushlightuserdata(mState, this);
477 lua_setfield(mState, LUA_REGISTRYINDEX, "_script_obj");
478 }
479
480 ~Script()
481 {
482 if (mIsMainThread) lua_close(mState);
483 }
484
485
486 static ScriptP alloc()
487 {
488 return ScriptP(new Script);
489 }
490
491
492 void importStandardLibraries()
493 {
494 luaL_openlibs(mState);
495 }
496
497 void importFunction(const std::string& name, const Function& function)
498 {
499 push(function);
500 lua_setglobal(mState, name.c_str());
501 }
502
503
504 Status doString(const std::string& commands)
505 {
506 return (Status)luaL_dostring(mState, commands.c_str());
507 }
508
509 Status doFile(const std::string& file)
510 {
511 return (Status)luaL_dofile(mState, file.c_str());
512 }
513
514
515 /**
516 * Thread-handling methods.
517 */
518
519 Script pushNewThread()
520 {
521 return Script(mState);
522 }
523
524 void pushThread()
525 {
526 lua_pushthread(mState);
527 }
528
529 Status resume(int nargs)
530 {
531 return (Status)lua_resume(mState, nargs);
532 }
533
534 Status getStatus() const
535 {
536 return (Status)lua_status(mState);
537 }
538
539 int yield(int results)
540 {
541 return lua_yield(mState, results);
542 }
543
544 bool isMainThread() const
545 {
546 return mIsMainThread;
547 }
548
549
550 /**
551 * Throw an error with the value at the top of the stack. This method never
552 * returns because it does a long jump. Consequently, constructed C++
553 * objects which exist on the stack between the current frame and some lua
554 * function will not be destructed. That's not a problem for objects that
555 * only exist on the stack, but any objects that allocate memory on the heap
556 * (such as containers or strings) will leak. Therefore, you should only
557 * call this method after cleaning up such objects.
558 */
559
560 void throwError()
561 {
562 lua_error(mState);
563 }
564
565
566 /**
567 * Get significant values.
568 */
569
570 Value getGlobalTable() const
571 {
572 return Value(mState, GLOBALS);
573 }
574
575 Value getRegistryTable() const
576 {
577 return Value(mState, REGISTRY);
578 }
579
580 Value getEnvironmentTable() const
581 {
582 return Value(mState, ENVIRONMENT);
583 }
584
585 Value getTop() const
586 {
587 return Value(mState, lua_gettop(mState));
588 }
589
590 /**
591 * Get the size of the stack; this is also the index of the top-most value.
592 */
593
594 int getSize() const
595 {
596 return lua_gettop(mState);
597 }
598
599 void setSize(int size)
600 {
601 lua_settop(mState, size);
602 }
603
604 void clear()
605 {
606 setSize(0);
607 }
608
609
610 /**
611 * Makes sure there is at least extra more places on the stack. Returns
612 * false if space couldn't be created. Just like with the regular Lua API,
613 * you are responsible to make sure the stack is big enough to hold whatever
614 * you want to push on it. This is usually only an issue if you're pushing
615 * stuff in a loop.
616 */
617
618 bool checkStack(int extra)
619 {
620 return (bool)lua_checkstack(mState, extra);
621 }
622
623
624 /**
625 * Concatenates the top-most n values on the stack.
626 */
627
628 void concat(int n)
629 {
630 lua_concat(mState, n);
631 }
632
633
634 /**
635 * Push some values onto the stack.
636 */
637
638 template <typename T>
639 void push(T value)
640 {
641 lua_pushinteger(mState, lua_Integer(value));
642 }
643
644 void push(bool value)
645 {
646 lua_pushboolean(mState, int(value));
647 }
648
649 void push(float value)
650 {
651 lua_pushnumber(mState, (lua_Number)value);
652 }
653 void push(double value)
654 {
655 lua_pushnumber(mState, (lua_Number)value);
656 }
657
658 void push(const std::string& value)
659 {
660 lua_pushlstring(mState, value.c_str(), value.length());
661 }
662 void push(const char* value)
663 {
664 lua_pushstring(mState, value);
665 }
666 void push(const char* value, size_t length)
667 {
668 lua_pushlstring(mState, value, length);
669 }
670
671 void push(const Function& function)
672 {
673 mFunctions.push_back(function);
674
675 lua_pushlightuserdata(mState, (void*)&mFunctions.back());
676 lua_pushcclosure(mState, dispatchCall, 1);
677 }
678
679 void push(void* data)
680 {
681 lua_pushlightuserdata(mState, data);
682 }
683
684 void pushNil()
685 {
686 lua_pushnil(mState);
687 }
688
689 void pushFromThread(Script& thread, int n)
690 {
691 lua_xmove(thread.mState, mState, n);
692 }
693
694 Status pushCode(const std::string& filename)
695 {
696 return (Status)luaL_loadfile(mState, filename.c_str());
697 }
698
699 Status pushCode(const std::string& name, const char* buffer, size_t size)
700 {
701 return (Status)luaL_loadbuffer(mState, buffer, size, name.c_str());
702 }
703
704 void* pushNewData(size_t size)
705 {
706 return lua_newuserdata(mState, size);
707 }
708
709 void pushNewTable()
710 {
711 lua_newtable(mState);
712 }
713
714
715 /**
716 * Call a function on the stack. The correct procedure is to push a
717 * function onto the stack followed by nargs arguments. This method will
718 * pop them off upon return, leaving up to nresults return values (default
719 * is any number of return values, depending on the callee).
720 */
721
722 Status call(int nargs, int nresults = LUA_MULTRET)
723 {
724 return (Status)lua_pcall(mState, nargs, nresults, 0);
725 }
726
727
728 /**
729 * Pops n values from the top of the stack.
730 */
731
732 void pop(int n = 1)
733 {
734 lua_pop(mState, n);
735 }
736
737
738 /**
739 * Index into the stack to get a Value.
740 */
741
742 Value operator [] (int index) const
743 {
744 return Value(mState, index);
745 }
746
747
748 /**
749 * Getting and setting fields of a table.
750 */
751
752 void get(const std::string& field, int index = GLOBALS) const
753 {
754 lua_getfield(mState, index, field.c_str());
755 }
756
757 void set(const std::string& field, int index = GLOBALS)
758 {
759 lua_setfield(mState, index, field.c_str());
760 }
761
762
763 /**
764 * Control over the garbage collection process.
765 */
766
767 void collectAll()
768 {
769 lua_gc(mState, LUA_GCCOLLECT, 0);
770 }
771
772 void stopCollector()
773 {
774 lua_gc(mState, LUA_GCSTOP, 0);
775 }
776
777 void restartCollector()
778 {
779 lua_gc(mState, LUA_GCRESTART, 0);
780 }
781
782 int getUsedMemory() const
783 {
784 // in kilobytes
785 return lua_gc(mState, LUA_GCCOUNT, 0);
786 }
787
788 void collectStep(int step)
789 {
790 lua_gc(mState, LUA_GCSTEP, step);
791 }
792
793 void tuneCollector(int pause, int step)
794 {
795 lua_gc(mState, LUA_GCSETPAUSE, pause);
796 lua_gc(mState, LUA_GCSETSTEPMUL, step);
797 }
798
799
800 private:
801
802 Script(lua_State* state) :
803 mState(lua_newthread(state)),
804 mIsMainThread(false) {}
805
806 static int dispatchCall(lua_State* state)
807 {
808 const Function* function = (const Function*)lua_touserdata(state,
809 lua_upvalueindex(1));
810
811 lua_getfield(state, LUA_REGISTRYINDEX, "_script_obj");
812 Script* script = (Script*)lua_touserdata(state, -1);
813 lua_pop(state, 1);
814
815 return (*function)(*script);
816 }
817
818 lua_State* mState;
819 bool mIsMainThread;
820 std::list<Function> mFunctions;
821 };
822
823
824 } // namespace Mf
825
826 #endif // _MOOF_SCRIPT_HH_
827
828 /** vim: set ts=4 sw=4 tw=80: *************************************************/
829
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