swfdec/swfdec_script.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_script.h"
  25 #include "swfdec_script_internal.h"
  26 #include "swfdec_as_context.h"
  27 #include "swfdec_as_interpret.h"
  28 #include "swfdec_debug.h"
  29
  30 /**
  31  * SwfdecScript:
  32  *
  33  * This is the object used for code to be executed by Swfdec. Scripts are
  34  * independant from the #SwfdecAsContext they are executed in, so you can
  35  * execute the same script in multiple contexts.
  36  */
  37
  38 /* Define this to get SWFDEC_WARN'd about missing properties of objects.
  39  * This can be useful to find out about unimplemented native properties,
  40  * but usually just causes a lot of spam. */
  41 //#define SWFDEC_WARN_MISSING_PROPERTIES
  42
  43 /*** SUPPORT FUNCTIONS ***/
  44
  45 static gboolean
  46 swfdec_script_foreach_internal (SwfdecBits *bits, SwfdecScriptForeachFunc func, gpointer user_data)
  47 {
  48   guint action, len;
  49   const guint8 *data;
  50   gconstpointer bytecode;
  51
  52   bytecode = bits->ptr;
  53   while (swfdec_bits_left (bits) && (action = swfdec_bits_get_u8 (bits))) {
  54     if (action & 0x80) {
  55       len = swfdec_bits_get_u16 (bits);
  56       data = bits->ptr;
  57     } else {
  58       len = 0;
  59       data = NULL;
  60     }
  61     if (swfdec_bits_skip_bytes (bits, len) != len) {
  62       SWFDEC_ERROR ("script too short");
  63       return FALSE;
  64     }
  65     if (!func (bytecode, action, data, len, user_data))
  66       return FALSE;
  67     bytecode = bits->ptr;
  68   }
  69   return TRUE;
  70 }
  71
  72 static gboolean
  73 validate_action (gconstpointer bytecode, guint action, const guint8 *data, guint len, gpointer scriptp)
  74 {
  75   // TODO: get rid of this function
  76   return TRUE;
  77 }
  78
  79 /*** PUBLIC API ***/
  80
  81 gboolean
  82 swfdec_script_foreach (SwfdecScript *script, SwfdecScriptForeachFunc func, gpointer user_data)
  83 {
  84   SwfdecBits bits;
  85
  86   g_return_val_if_fail (script != NULL, FALSE);
  87   g_return_val_if_fail (func != NULL, FALSE);
  88
  89   swfdec_bits_init (&bits, script->buffer);
  90   bits.ptr = script->main;
  91   return swfdec_script_foreach_internal (&bits, func, user_data);
  92 }
  93
  94 /**
  95  * swfdec_script_new:
  96  * @buffer: the #SwfdecBuffer containing the script. This function will take
  97  *          ownership of the passed in buffer.
  98  * @name: name of the script for debugging purposes
  99  * @version: Actionscript version to use in this script
 100  *
 101  * Creates a new script for the actionscript provided in @buffer.
 102  *
 103  * Returns: a new #SwfdecScript for executing the script in @buffer.
 104  **/
 105 SwfdecScript *
 106 swfdec_script_new (SwfdecBuffer *buffer, const char *name, guint version)
 107 {
 108   SwfdecBits bits;
 109   SwfdecScript *script;
 110
 111   g_return_val_if_fail (buffer != NULL, NULL);
 112
 113   swfdec_bits_init (&bits, buffer);
 114   script = swfdec_script_new_from_bits (&bits, name, version);
 115   swfdec_buffer_unref (buffer);
 116   return script;
 117 }
 118
 119 SwfdecScript *
 120 swfdec_script_new_from_bits (SwfdecBits *bits, const char *name, guint version)
 121 {
 122   SwfdecScript *script;
 123   SwfdecBuffer *buffer;
 124   SwfdecBits org;
 125   guint len;
 126
 127   g_return_val_if_fail (bits != NULL, NULL);
 128
 129   org = *bits;
 130   len = swfdec_bits_left (bits) / 8;
 131   script = g_new0 (SwfdecScript, 1);
 132   script->refcount = 1;
 133   script->name = g_strdup (name ? name : "Unnamed script");
 134   script->version = version;
 135   /* by default, a function has 4 registers */
 136   script->n_registers = 5;
 137   /* These flags are the default arguments used by scripts read from a file.
 138    * DefineFunction and friends override this */
 139   script->flags = SWFDEC_SCRIPT_SUPPRESS_ARGS;
 140
 141   if (!swfdec_script_foreach_internal (bits, validate_action, script)) {
 142     swfdec_script_unref (script);
 143     return NULL;
 144   }
 145   len -= swfdec_bits_left (bits) / 8;
 146   if (len == 0) {
 147     buffer = swfdec_buffer_new (0);
 148   } else {
 149     buffer = swfdec_bits_get_buffer (&org, len);
 150   }
 151
 152   script->main = buffer->data;
 153   script->exit = buffer->data + buffer->length;
 154   script->buffer = swfdec_buffer_ref (swfdec_buffer_get_super (buffer));
 155   swfdec_buffer_unref (buffer);
 156   return script;
 157 }
 158
 159 /**
 160  * swfdec_script_ref:
 161  * @script: a script
 162  *
 163  * Increases the reference count of the given @script by one.
 164  *
 165  * Returns: The @script given as an argument
 166  **/
 167 SwfdecScript *
 168 swfdec_script_ref (SwfdecScript *script)
 169 {
 170   g_return_val_if_fail (script != NULL, NULL);
 171   g_return_val_if_fail (script->refcount > 0, NULL);
 172
 173   script->refcount++;
 174   return script;
 175 }
 176
 177 /**
 178  * swfdec_script_unref:
 179  * @script: a script
 180  *
 181  * Decreases the reference count of the given @script by one. If the count
 182  * reaches zero, it will automatically be destroyed.
 183  **/
 184 void
 185 swfdec_script_unref (SwfdecScript *script)
 186 {
 187   guint i;
 188
 189   g_return_if_fail (script != NULL);
 190   g_return_if_fail (script->refcount > 0);
 191
 192   script->refcount--;
 193   if (script->refcount > 0)
 194     return;
 195
 196   if (script->buffer)
 197     swfdec_buffer_unref (script->buffer);
 198   if (script->constant_pool)
 199     swfdec_buffer_unref (script->constant_pool);
 200   g_free (script->name);
 201   for (i = 0; i < script->n_arguments; i++) {
 202     g_free (script->arguments[i].name);
 203   }
 204   g_free (script->arguments);
 205   g_free (script);
 206 }
 207
 208 /**
 209  * swfdec_script_get_version:
 210  * @script: the script
 211  *
 212  * Queries the Flash version this script was compiled with. Different versions
 213  * result in slightly different behavior in the script interpreter.
 214  *
 215  * Returns: The Flash version this script conforms to
 216  **/
 217 guint
 218 swfdec_script_get_version (SwfdecScript *script)
 219 {
 220   g_return_val_if_fail (script != NULL, 0);
 221
 222   return script->version;
 223 }
 224
 225 /*** UTILITY FUNCTIONS ***/
 226
 227 const char *
 228 swfdec_action_get_name (guint action)
 229 {
 230   g_return_val_if_fail (action < 256, NULL);
 231
 232   return swfdec_as_actions[action].name;
 233 }
 234
 235 guint
 236 swfdec_action_get_from_name (const char *name)
 237 {
 238   guint i;
 239
 240   g_return_val_if_fail (name != NULL, 0);
 241
 242   for (i = 0; i < 256; i++) {
 243     if (swfdec_as_actions[i].name && g_str_equal (name, swfdec_as_actions[i].name))
 244       return i;
 245   }
 246   return 0;
 247 }
 248
 249