Exemplo n.º 1
0
/*****************************************************************************
 * Decrement an object refcount
 * And destroy the object if its refcount reach zero.
 *****************************************************************************/
void vlc_object_release( vlc_object_t *p_this )
{
    vlc_object_internals_t *internals = vlc_internals( p_this );
    vlc_object_t *parent = NULL;
    bool b_should_destroy;

    vlc_spin_lock( &internals->ref_spin );
    assert( internals->i_refcount > 0 );

    if( internals->i_refcount > 1 )
    {
        /* Fast path */
        /* There are still other references to the object */
        internals->i_refcount--;
        vlc_spin_unlock( &internals->ref_spin );
        return;
    }
    vlc_spin_unlock( &internals->ref_spin );

    /* Slow path */
    /* Remember that we cannot hold the spin while waiting on the mutex */
    libvlc_lock (p_this->p_libvlc);
    /* Take the spin again. Note that another thread may have held the
     * object in the (very short) mean time. */
    vlc_spin_lock( &internals->ref_spin );
    b_should_destroy = --internals->i_refcount == 0;
    vlc_spin_unlock( &internals->ref_spin );

    if( b_should_destroy )
    {
        /* Detach from parent to protect against FIND_CHILDREN */
        parent = p_this->p_parent;
        if (likely(parent))
        {
           /* Unlink */
           if (internals->prev != NULL)
               internals->prev->next = internals->next;
           else
               vlc_internals(parent)->first = internals->next;
           if (internals->next != NULL)
               internals->next->prev = internals->prev;
        }

        /* We have no children */
        assert (internals->first == NULL);
    }
    libvlc_unlock (p_this->p_libvlc);

    if( b_should_destroy )
    {
        int canc;

        canc = vlc_savecancel ();
        vlc_object_destroy( p_this );
        vlc_restorecancel (canc);
        if (parent)
            vlc_object_release (parent);
    }
}
Exemplo n.º 2
0
Arquivo: objects.c Projeto: paa/vlc
/**
 ****************************************************************************
 * detach object from its parent
 *****************************************************************************
 * This function removes all links between an object and its parent.
 *****************************************************************************/
void vlc_object_detach( vlc_object_t *p_this )
{
    vlc_object_t *p_parent;
    if( !p_this ) return;

    libvlc_lock (p_this->p_libvlc);
    p_parent = p_this->p_parent;
    if (p_parent)
        vlc_object_detach_unlocked( p_this );
    libvlc_unlock (p_this->p_libvlc);

    if (p_parent)
        vlc_object_release (p_parent);
}
Exemplo n.º 3
0
Arquivo: objects.c Projeto: paa/vlc
/*****************************************************************************
 * DumpCommand: print the current vlc structure
 *****************************************************************************
 * This function prints either an ASCII tree showing the connections between
 * vlc objects, and additional information such as their refcount, thread ID,
 * etc. (command "tree"), or the same data as a simple list (command "list").
 *****************************************************************************/
static int DumpCommand( vlc_object_t *p_this, char const *psz_cmd,
                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
{
    (void)oldval; (void)p_data;
    vlc_object_t *p_object = NULL;

    if( *newval.psz_string )
    {
        /* try using the object's name to find it */
        p_object = vlc_object_find_name( p_this, newval.psz_string,
                                         FIND_ANYWHERE );
        if( !p_object )
        {
            return VLC_ENOOBJ;
        }
    }

    libvlc_lock (p_this->p_libvlc);
    if( *psz_cmd == 't' )
    {
        char psz_foo[2 * MAX_DUMPSTRUCTURE_DEPTH + 1];

        if( !p_object )
            p_object = VLC_OBJECT(p_this->p_libvlc);

        psz_foo[0] = '|';
        DumpStructure( vlc_internals(p_object), 0, psz_foo );
    }
    else if( *psz_cmd == 'v' )
    {
        if( !p_object )
            p_object = p_this->p_libvlc ? VLC_OBJECT(p_this->p_libvlc) : p_this;

        PrintObject( vlc_internals(p_object), "" );
        vlc_mutex_lock( &vlc_internals( p_object )->var_lock );
        if( vlc_internals( p_object )->var_root == NULL )
            puts( " `-o No variables" );
        else
            twalk( vlc_internals( p_object )->var_root, DumpVariable );
        vlc_mutex_unlock( &vlc_internals( p_object )->var_lock );
    }
    libvlc_unlock (p_this->p_libvlc);

    if( *newval.psz_string )
    {
        vlc_object_release( p_object );
    }
    return VLC_SUCCESS;
}
Exemplo n.º 4
0
Arquivo: objects.c Projeto: paa/vlc
/*****************************************************************************
 * find a typed object and increment its refcount
 *****************************************************************************
 * This function recursively looks for a given object type. i_mode can be one
 * of FIND_PARENT, FIND_CHILD or FIND_ANYWHERE.
 *****************************************************************************/
void * vlc_object_find( vlc_object_t *p_this, int i_type, int i_mode )
{
    vlc_object_t *p_found;

    /* If we are of the requested type ourselves, don't look further */
    if( vlc_internals (p_this)->i_object_type == i_type )
    {
        vlc_object_hold( p_this );
        return p_this;
    }

    /* Otherwise, recursively look for the object */
    if (i_mode == FIND_ANYWHERE)
        return vlc_object_find (VLC_OBJECT(p_this->p_libvlc), i_type, FIND_CHILD);

    switch (i_type)
    {
        case VLC_OBJECT_VOUT:
        case VLC_OBJECT_AOUT:
            break;
        case VLC_OBJECT_INPUT:
            /* input can only be accessed like this from children,
             * otherwise we could not promise that it is initialized */
            if (i_mode != FIND_PARENT)
                return NULL;
            break;
        default:
            return NULL;
    }

    libvlc_lock (p_this->p_libvlc);
    switch (i_mode)
    {
        case FIND_PARENT:
            p_found = FindParent (p_this, i_type);
            break;
        case FIND_CHILD:
            p_found = FindChild (vlc_internals (p_this), i_type);
            break;
        default:
            assert (0);
    }
    libvlc_unlock (p_this->p_libvlc);
    return p_found;
}
Exemplo n.º 5
0
Arquivo: objects.c Projeto: paa/vlc
/**
 ****************************************************************************
 * attach object to a parent object
 *****************************************************************************
 * This function sets p_this as a child of p_parent, and p_parent as a parent
 * of p_this. This link can be undone using vlc_object_detach.
 *****************************************************************************/
void vlc_object_attach( vlc_object_t *p_this, vlc_object_t *p_parent )
{
    if( !p_this ) return;

    vlc_object_internals_t *pap = vlc_internals (p_parent);
    vlc_object_internals_t *priv = vlc_internals (p_this);
    vlc_object_t *p_old_parent;

    priv->prev = NULL;
    vlc_object_hold (p_parent);
    libvlc_lock (p_this->p_libvlc);
#ifndef NDEBUG
    /* Reparenting an object carries a risk of invalid access to the parent,
     * from another thread. This can happen when inheriting a variable, or
     * through any direct access to vlc_object_t.p_parent. Also, reparenting
     * brings a functional bug, whereby the reparented object uses incorrect
     * old values for inherited variables (as the new parent may have different
     * variable values, especially if it is an input).
     * Note that the old parent may be already destroyed.
     * So its pointer must not be dereferenced.
     */
    if (priv->old_parent)
        msg_Info (p_this, "Reparenting an object is dangerous (%p -> %p)!",
                  priv->old_parent, p_parent);
#endif

    p_old_parent = p_this->p_parent;
    if (p_old_parent)
        vlc_object_detach_unlocked (p_this);

    /* Attach the parent to its child */
    p_this->p_parent = p_parent;

    /* Attach the child to its parent */
    priv->next = pap->first;
    if (priv->next != NULL)
        priv->next->prev = priv;
    pap->first = priv;
    libvlc_unlock (p_this->p_libvlc);

    if (p_old_parent)
        vlc_object_release (p_old_parent);
}
Exemplo n.º 6
0
Arquivo: objects.c Projeto: paa/vlc
/**
 * Gets the list of children of an objects, and increment their reference
 * count.
 * @return a list (possibly empty) or NULL in case of error.
 */
vlc_list_t *vlc_list_children( vlc_object_t *obj )
{
    vlc_list_t *l;
    vlc_object_internals_t *priv;
    unsigned count = 0;

    libvlc_lock (obj->p_libvlc);
    for (priv = vlc_internals (obj)->first; priv; priv = priv->next)
         count++;
    l = NewList (count);
    if (likely(l != NULL))
    {
        unsigned i = 0;

        for (priv = vlc_internals (obj)->first; priv; priv = priv->next)
            l->p_values[i++].p_object = vlc_object_hold (vlc_externals (priv));
    }
    libvlc_unlock (obj->p_libvlc);
    return l;
}
Exemplo n.º 7
0
/**
 ****************************************************************************
 * attach object to a parent object
 *****************************************************************************
 * This function sets p_this as a child of p_parent, and p_parent as a parent
 * of p_this.
 *****************************************************************************/
void vlc_object_attach( vlc_object_t *p_this, vlc_object_t *p_parent )
{
    if( !p_this ) return;

    vlc_object_internals_t *pap = vlc_internals (p_parent);
    vlc_object_internals_t *priv = vlc_internals (p_this);

    priv->prev = NULL;
    vlc_object_hold (p_parent);
    libvlc_lock (p_this->p_libvlc);

    /* Attach the parent to its child */
    assert (p_this->p_parent == NULL);
    p_this->p_parent = p_parent;

    /* Attach the child to its parent */
    priv->next = pap->first;
    if (priv->next != NULL)
        priv->next->prev = priv;
    pap->first = priv;
    libvlc_unlock (p_this->p_libvlc);
}
Exemplo n.º 8
0
Arquivo: objects.c Projeto: paa/vlc
/**
 * Finds a named object and increment its reference count.
 * Beware that objects found in this manner can be "owned" by another thread,
 * be of _any_ type, and be attached to any module (if any). With such an
 * object reference, you can set or get object variables, emit log messages,
 * and read write-once object parameters (psz_object_type, etc).
 * You CANNOT cast the object to a more specific object type, and you
 * definitely cannot invoke object type-specific callbacks with this.
 *
 * @param p_this object to search from
 * @param psz_name name of the object to search for
 * @param i_mode search direction: FIND_PARENT, FIND_CHILD or FIND_ANYWHERE.
 *
 * @return a matching object (must be released by the caller),
 * or NULL on error.
 */
vlc_object_t *vlc_object_find_name( vlc_object_t *p_this,
                                    const char *psz_name, int i_mode )
{
    vlc_object_t *p_found;

    /* Reading psz_object_name from a separate inhibits thread-safety.
     * Use a libvlc address variable instead for that sort of things! */
    msg_Warn( p_this, "%s(%s) is not safe!", __func__, psz_name );
    /* If have the requested name ourselves, don't look further */
    if( !objnamecmp(p_this, psz_name) )
    {
        vlc_object_hold( p_this );
        return p_this;
    }

    /* Otherwise, recursively look for the object */
    if (i_mode == FIND_ANYWHERE)
        return vlc_object_find_name (VLC_OBJECT(p_this->p_libvlc), psz_name,
                                     FIND_CHILD);

    libvlc_lock (p_this->p_libvlc);
    vlc_mutex_lock (&name_lock);
    switch (i_mode)
    {
        case FIND_PARENT:
            p_found = FindParentName (p_this, psz_name);
            break;
        case FIND_CHILD:
            p_found = FindChildName (vlc_internals (p_this), psz_name);
            break;
        default:
            assert (0);
    }
    vlc_mutex_unlock (&name_lock);
    libvlc_unlock (p_this->p_libvlc);
    return p_found;
}