libswfdec/swfdec_as_function.c

   1 /* Swfdec
   2  * Copyright (C) 2007 Benjamin Otte <otte@gnome.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301  USA
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include "swfdec_as_function.h"
  25 #include "swfdec_as_context.h"
  26 #include "swfdec_as_frame_internal.h"
  27 #include "swfdec_as_internal.h"
  28 #include "swfdec_as_stack.h"
  29 #include "swfdec_as_strings.h"
  30 #include "swfdec_debug.h"
  31
  32 G_DEFINE_ABSTRACT_TYPE (SwfdecAsFunction, swfdec_as_function, SWFDEC_TYPE_AS_OBJECT)
  33
  34 /**
  35  * SECTION:SwfdecAsFunction
  36  * @title: SwfdecAsFunction
  37  * @short_description: script objects that can be executed
  38  *
  39  * Functions is the basic object for executing code in the Swfdec script engine.
  40  * There is multiple different variants of functions, such as script-created
  41  * ones and native functions.
  42  *
  43  * If you want to create your own functions, you should create native functions.
  44  * The easiest way to do this is with swfdec_as_object_add_function() or
  45  * swfdec_as_native_function_new().
  46  *
  47  * In Actionscript, every function can be used as a constructor. If you want to
  48  * make a native function be used as a constructor for your own #SwfdecAsObject
  49  * subclass, have a look at swfdec_as_native_function_set_construct_type().
  50  */
  51
  52 /**
  53  * SwfdecAsFunction
  54  *
  55  * This is the base executable object in Swfdec. It is an abstract object. If
  56  * you want to create functions yourself, use #SwfdecAsNativeFunction.
  57  */
  58
  59 static void
  60 swfdec_as_function_class_init (SwfdecAsFunctionClass *klass)
  61 {
  62 }
  63
  64 static void
  65 swfdec_as_function_init (SwfdecAsFunction *function)
  66 {
  67 }
  68
  69 /**
  70  * swfdec_as_function_set_constructor:
  71  * @fun: a #SwfdecAsFunction
  72  *
  73  * Sets the constructor and prototype of @fun. This is a shortcut for calling
  74  * swfdec_as_object_set_constructor() with the right arguments.
  75  **/
  76 void
  77 swfdec_as_function_set_constructor (SwfdecAsFunction *fun)
  78 {
  79   SwfdecAsContext *context;
  80   SwfdecAsObject *object;
  81   SwfdecAsValue val;
  82
  83   g_return_if_fail (SWFDEC_IS_AS_FUNCTION (fun));
  84
  85   object = SWFDEC_AS_OBJECT (fun);
  86   context = object->context;
  87   if (context->Function) {
  88     SWFDEC_AS_VALUE_SET_OBJECT (&val, context->Function);
  89     swfdec_as_object_set_variable (object, SWFDEC_AS_STR_constructor, &val);
  90   }
  91   if (context->Function_prototype) {
  92     SWFDEC_AS_VALUE_SET_OBJECT (&val, context->Function_prototype);
  93     swfdec_as_object_set_variable (object, SWFDEC_AS_STR___proto__, &val);
  94   }
  95 }
  96
  97 /**
  98  * swfdec_as_function_call:
  99  * @function: the #SwfdecAsFunction to call
 100  * @thisp: this argument to use for the call or %NULL for none
 101  * @n_args: number of arguments to pass to the function
 102  * @args: the arguments to pass or %NULL to read the last @n_args stack elements
 103  * @return_value: pointer for return value or %NULL to push the return value to
 104  *                the stack
 105  *
 106  * Calls the given function. This means a #SwfdecAsFrame is created for the
 107  * function and pushed on top of the execution stack. The function is however
 108  * not executed. Call swfdec_as_context_run () to execute it.
 109  **/
 110 void
 111 swfdec_as_function_call (SwfdecAsFunction *function, SwfdecAsObject *thisp, guint n_args,
 112     const SwfdecAsValue *args, SwfdecAsValue *return_value)
 113 {
 114   SwfdecAsContext *context;
 115   SwfdecAsFrame *frame;
 116   SwfdecAsFunctionClass *klass;
 117
 118   g_return_if_fail (SWFDEC_IS_AS_FUNCTION (function));
 119   g_return_if_fail (thisp == NULL || SWFDEC_IS_AS_OBJECT (thisp));
 120
 121   context = SWFDEC_AS_OBJECT (function)->context;
 122   /* just to be sure... */
 123   if (return_value)
 124     SWFDEC_AS_VALUE_SET_UNDEFINED (return_value);
 125
 126   klass = SWFDEC_AS_FUNCTION_GET_CLASS (function);
 127   g_assert (klass->call);
 128   frame = klass->call (function);
 129   /* FIXME: figure out what to do in these situations */
 130   if (frame == NULL)
 131     return;
 132   /* second check especially for super object */
 133   if (thisp != NULL && frame->thisp == NULL)
 134     swfdec_as_frame_set_this (frame, swfdec_as_object_resolve (thisp));
 135   frame->is_local = TRUE;
 136   frame->argc = n_args;
 137   frame->argv = args;
 138   frame->return_value = return_value;
 139   swfdec_as_frame_preload (frame);
 140 }
 141
 142 /*** AS CODE ***/
 143
 144 static void
 145 swfdec_as_function_do_call (SwfdecAsContext *context, SwfdecAsObject *fun,
 146     guint argc, SwfdecAsValue *argv, SwfdecAsValue *ret)
 147 {
 148   SwfdecAsObject *thisp;
 149
 150   if (argc > 0) {
 151     thisp = swfdec_as_value_to_object (context, &argv[0]);
 152     argc -= 1;
 153     argv++;
 154   } else {
 155     thisp = NULL;
 156   }
 157   if (thisp == NULL)
 158     thisp = swfdec_as_object_new_empty (context);
 159   swfdec_as_function_call (SWFDEC_AS_FUNCTION (fun), thisp, argc, argv, ret);
 160   swfdec_as_context_run (context);
 161 }
 162
 163 void
 164 swfdec_as_function_init_context (SwfdecAsContext *context, guint version)
 165 {
 166   SwfdecAsObject *function, *proto;
 167   SwfdecAsValue val;
 168
 169   g_return_if_fail (SWFDEC_IS_AS_CONTEXT (context));
 170
 171   function = SWFDEC_AS_OBJECT (swfdec_as_object_add_function (context->global,
 172       SWFDEC_AS_STR_Function, 0, NULL, 0));
 173   if (!function)
 174     return;
 175   if (version < 6) {
 176     /* deleting it later on is easier than duplicating swfdec_as_object_add_function() */
 177     swfdec_as_object_delete_variable (context->global, SWFDEC_AS_STR_Function);
 178   }
 179   context->Function = function;
 180   SWFDEC_AS_VALUE_SET_OBJECT (&val, function);
 181   swfdec_as_object_set_variable (function, SWFDEC_AS_STR_constructor, &val);
 182   if (version > 5) {
 183     proto = swfdec_as_object_new_empty (context);
 184     if (!proto)
 185       return;
 186     context->Function_prototype = proto;
 187     SWFDEC_AS_VALUE_SET_OBJECT (&val, proto);
 188     swfdec_as_object_set_variable (function, SWFDEC_AS_STR___proto__, &val);
 189     swfdec_as_object_set_variable (function, SWFDEC_AS_STR_prototype, &val);
 190     /* prototype functions */
 191     swfdec_as_object_add_function (proto, SWFDEC_AS_STR_call, SWFDEC_TYPE_AS_FUNCTION,
 192         swfdec_as_function_do_call, 0);
 193   }
 194 }
 195