SwfdecAsContext

SwfdecAsContext — the main script engine context

Synopsis


#include <swfdec/swfdec.h>


                    SwfdecAsContext;
void                swfdec_as_context_startup           (SwfdecAsContext *context);
void                swfdec_as_context_abort             (SwfdecAsContext *context,
                                                         const char *reason);
gboolean            swfdec_as_context_is_aborted        (SwfdecAsContext *context);
const char*         swfdec_as_context_get_string        (SwfdecAsContext *context,
                                                         const char *string);
const char*         swfdec_as_context_give_string       (SwfdecAsContext *context,
                                                         char *string);
gboolean            swfdec_as_context_use_mem           (SwfdecAsContext *context,
                                                         gsize bytes);
gboolean            swfdec_as_context_try_use_mem       (SwfdecAsContext *context,
                                                         gsize bytes);
void                swfdec_as_context_unuse_mem         (SwfdecAsContext *context,
                                                         gsize bytes);
void                swfdec_as_context_gc                (SwfdecAsContext *context);
void                swfdec_as_context_maybe_gc          (SwfdecAsContext *context);
void                swfdec_as_context_run               (SwfdecAsContext *context);
void                swfdec_as_context_throw             (SwfdecAsContext *context,
                                                         const SwfdecAsValue *value);
gboolean            swfdec_as_context_catch             (SwfdecAsContext *context,
                                                         SwfdecAsValue *value);
void                swfdec_as_context_eval              (SwfdecAsContext *context,
                                                         SwfdecAsObject *obj,
                                                         const char *str,
                                                         SwfdecAsValue *val);
void                swfdec_as_context_eval_set          (SwfdecAsContext *context,
                                                         SwfdecAsObject *obj,
                                                         const char *str,
                                                         const SwfdecAsValue *val);
void                swfdec_as_context_get_time          (SwfdecAsContext *context,
                                                         GTimeVal *tv);
SwfdecAsFrame*      swfdec_as_context_get_frame         (SwfdecAsContext *context);
gboolean            swfdec_as_context_is_constructing   (SwfdecAsContext *context);

Object Hierarchy


  GObject
   +----SwfdecAsContext
         +----SwfdecPlayer

Properties


  "aborted"                  gboolean              : Read
  "debugger"                 SwfdecAsDebugger      : Read / Write / Construct Only
  "memory-until-gc"          gulong                : Read / Write / Construct
  "random-seed"              guint                 : Write

Signals


  "trace"                                          : Run Last

Description

A SwfdecAsContext provides the main execution environment for Actionscript execution. It provides the objects typically available in ECMAScript and manages script execution, garbage collection etc. SwfdecPlayer is a subclass of the context that implements Flash specific objects on top of it. However, it is possible to use the context for completely different functions where a sandboxed scripting environment is needed. An example is the Swfdec debugger.

Note

The Actionscript engine is similar, but not equal to Javascript. It is not very different, but it is different.

Details

SwfdecAsContext

typedef struct _SwfdecAsContext SwfdecAsContext;

This is the main object ued to hold the state of a script engine. All members are private and should not be accessed.

Subclassing this structure to get scripting support in your own appliation is encouraged.


swfdec_as_context_startup ()

void                swfdec_as_context_startup           (SwfdecAsContext *context);

Starts up the context. This function must be called before any Actionscript is called on context.

context : a SwfdecAsContext

swfdec_as_context_abort ()

void                swfdec_as_context_abort             (SwfdecAsContext *context,
                                                         const char *reason);

Aborts script execution in context. Call this functon if the script engine encountered a fatal error and cannot continue. A possible reason for this is an out-of-memory condition.

context : a SwfdecAsContext
reason : a string describing why execution was aborted

swfdec_as_context_is_aborted ()

gboolean            swfdec_as_context_is_aborted        (SwfdecAsContext *context);

Determines if the given context is aborted. An aborted context is not able to execute any scripts. Aborting can happen if the script engine detects bad scripts that cause excessive memory usage, infinite loops or other problems. In that case the script engine aborts for safety reasons.

context : a SwfdecAsContext
Returns : TRUE if the player is aborted, FALSE if it runs normally.

swfdec_as_context_get_string ()

const char*         swfdec_as_context_get_string        (SwfdecAsContext *context,
                                                         const char *string);

Gets the garbage-collected version of string. You need to call this function for every not garbage-collected string that you want to use in Swfdecs script interpreter.

context : a SwfdecAsContext
string : a sting that is not garbage-collected
Returns : the garbage-collected version of string

swfdec_as_context_give_string ()

const char*         swfdec_as_context_give_string       (SwfdecAsContext *context,
                                                         char *string);

Takes ownership of string and returns a refcounted version of the same string. This function is the same as swfdec_as_context_get_string(), but takes ownership of string.

context : a SwfdecAsContext
string : string to make refcounted
Returns : A refcounted string

swfdec_as_context_use_mem ()

gboolean            swfdec_as_context_use_mem           (SwfdecAsContext *context,
                                                         gsize bytes);

Registers bytes additional bytes as in use by the context. This function keeps track of the memory that script code consumes. If too much memory is in use, this function may decide to stop the script engine with an out of memory error.

context : a SwfdecAsContext
bytes : number of bytes to use
Returns : TRUE if the memory could be allocated. FALSE on OOM.

swfdec_as_context_try_use_mem ()

gboolean            swfdec_as_context_try_use_mem       (SwfdecAsContext *context,
                                                         gsize bytes);

Tries to register bytes additional bytes as in use by the context. This function keeps track of the memory that script code consumes. The scripting engine won't be stopped, even if there wasn't enough memory left.

context : a SwfdecAsContext
bytes : number of bytes to use
Returns : TRUE if the memory could be allocated. FALSE on OOM.

swfdec_as_context_unuse_mem ()

void                swfdec_as_context_unuse_mem         (SwfdecAsContext *context,
                                                         gsize bytes);

Releases a number of bytes previously allocated using swfdec_as_context_use_mem(). See that function for details.

context : a SwfdecAsContext
bytes : number of bytes to release

swfdec_as_context_gc ()

void                swfdec_as_context_gc                (SwfdecAsContext *context);

Calls the Swfdec Gargbage collector and reclaims any unused memory. You should call this function or swfdec_as_context_maybe_gc() regularly.

Warning

Calling the GC during execution of code or initialization is not allowed.

context : a SwfdecAsContext

swfdec_as_context_maybe_gc ()

void                swfdec_as_context_maybe_gc          (SwfdecAsContext *context);

Calls the garbage collector if necessary. It's a good idea to call this function regularly instead of swfdec_as_context_gc() as it only does collect garage as needed. For example, SwfdecPlayer calls this function after every frame advancement.

context : a SwfdecAsContext

swfdec_as_context_run ()

void                swfdec_as_context_run               (SwfdecAsContext *context);

Continues running the script engine. Executing code in this engine works in 2 steps: First, you push the frame to be executed onto the stack, then you call this function to execute it. So this function is the single entry point to script execution. This might be helpful when debugging your application.

Note

A lot of convenience functions like swfdec_as_object_run() call this function automatically.

context : a SwfdecAsContext

swfdec_as_context_throw ()

void                swfdec_as_context_throw             (SwfdecAsContext *context,
                                                         const SwfdecAsValue *value);

Throws a new exception in the context using the given value. This function can only be called if the context is not already throwing an exception.

context : a SwfdecAsContext
value : a SwfdecAsValue to be thrown

swfdec_as_context_catch ()

gboolean            swfdec_as_context_catch             (SwfdecAsContext *context,
                                                         SwfdecAsValue *value);

Removes the currently thrown exception from context and sets value to the thrown value

context : a SwfdecAsContext
value : a SwfdecAsValue to be thrown
Returns : TRUE if an exception was catched, FALSE otherwise

swfdec_as_context_eval ()

void                swfdec_as_context_eval              (SwfdecAsContext *context,
                                                         SwfdecAsObject *obj,
                                                         const char *str,
                                                         SwfdecAsValue *val);

This function works like the Actionscript eval function used on obj. It handles both slash-style and dot-style notation. If an error occured during evaluation, the return value will be the undefined value.

context : a SwfdecAsContext
obj : SwfdecAsObject to use as source for evaluating or NULL for the current frame's scope
str : The string to evaluate
val : location for the return value

swfdec_as_context_eval_set ()

void                swfdec_as_context_eval_set          (SwfdecAsContext *context,
                                                         SwfdecAsObject *obj,
                                                         const char *str,
                                                         const SwfdecAsValue *val);

Sets the variable referenced by str to val. If str does not reference a valid property, nothing happens.

context : a SwfdecAsContext
obj : SwfdecAsObject to use as source for evaluating or NULL for the default object.
str : The string to evaluate
val : the value to set the variable to

swfdec_as_context_get_time ()

void                swfdec_as_context_get_time          (SwfdecAsContext *context,
                                                         GTimeVal *tv);

This function queries the time to be used inside this context. By default, this is the same as g_get_current_time(), but it may be overwriten to allow things such as slower or faster playback.

context : a SwfdecAsContext
tv : a GTimeVal to be set to the context's time

swfdec_as_context_get_frame ()

SwfdecAsFrame*      swfdec_as_context_get_frame         (SwfdecAsContext *context);

This is a debugging function. It gets the topmost stack frame that is currently executing. If no function is executing, NULL is returned. You can easily get a backtrace with code like this:

for (frame = swfdec_as_context_get_frame (context); frame != NULL; 
    frame = swfdec_as_frame_get_next (frame)) {
  char *s = swfdec_as_object_get_debug (SWFDEC_AS_OBJECT (frame));
  g_print ("%s\n", s);
  g_free (s);
}

context : a SwfdecAsContext
Returns : the currently executing frame or NULL if none

swfdec_as_context_is_constructing ()

gboolean            swfdec_as_context_is_constructing   (SwfdecAsContext *context);

Determines if the contexxt is currently constructing. This information is used by various constructors to do different things when they are constructing and when they are not. The Boolean, Number and String functions for example setup the newly constructed objects when constructing but only cast the provided argument when being called.

context : a SwfdecAsConstruct
Returns : TRUE if the currently executing frame is a constructor

Property Details

The "aborted" property

  "aborted"                  gboolean              : Read

set when the script engine aborts due to an error.

Default value: FALSE


The "debugger" property

  "debugger"                 SwfdecAsDebugger      : Read / Write / Construct Only

debugger used in this player.


The "memory-until-gc" property

  "memory-until-gc"          gulong                : Read / Write / Construct

amount of bytes that need to be allocated before garbage collection triggers.


The "random-seed" property

  "random-seed"              guint                 : Write

seed used for calculating random numbers.

Default value: 0

Signal Details

The "trace" signal

void                user_function                      (SwfdecAsContext *context,
                                                        gchar           *text,
                                                        gpointer         user_data)      : Run Last

Emits a debugging string while running. The effect of calling any swfdec functions on the emitting context is undefined.

context : the SwfdecAsContext affected
text : the debugging string
user_data : user data set when the signal handler was connected.

See Also

SwfdecPlayer