/*
 * Licensed under the GNU Lesser General Public License Version 3
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the license, or
 * (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

// generated automatically - do not change


module gobject.Closure;

private import glib.ConstructionException;
private import glib.Source;
private import gobject.ObjectG;
private import gobject.Value;
private import gobject.c.functions;
public  import gobject.c.types;


/**
 * A #GClosure represents a callback supplied by the programmer. It
 * will generally comprise a function of some kind and a marshaller
 * used to call it. It is the responsibility of the marshaller to
 * convert the arguments for the invocation from #GValues into
 * a suitable form, perform the callback on the converted arguments,
 * and transform the return value back into a #GValue.
 * 
 * In the case of C programs, a closure usually just holds a pointer
 * to a function and maybe a data argument, and the marshaller
 * converts between #GValue and native C types. The GObject
 * library provides the #GCClosure type for this purpose. Bindings for
 * other languages need marshallers which convert between #GValue<!--
 * -->s and suitable representations in the runtime of the language in
 * order to use functions written in that languages as callbacks.
 * 
 * Within GObject, closures play an important role in the
 * implementation of signals. When a signal is registered, the
 * @c_marshaller argument to g_signal_new() specifies the default C
 * marshaller for any closure which is connected to this
 * signal. GObject provides a number of C marshallers for this
 * purpose, see the g_cclosure_marshal_*() functions. Additional C
 * marshallers can be generated with the [glib-genmarshal][glib-genmarshal]
 * utility.  Closures can be explicitly connected to signals with
 * g_signal_connect_closure(), but it usually more convenient to let
 * GObject create a closure automatically by using one of the
 * g_signal_connect_*() functions which take a callback function/user
 * data pair.
 * 
 * Using closures has a number of important advantages over a simple
 * callback function/data pointer combination:
 * 
 * - Closures allow the callee to get the types of the callback parameters,
 * which means that language bindings don't have to write individual glue
 * for each callback type.
 * 
 * - The reference counting of #GClosure makes it easy to handle reentrancy
 * right; if a callback is removed while it is being invoked, the closure
 * and its parameters won't be freed until the invocation finishes.
 * 
 * - g_closure_invalidate() and invalidation notifiers allow callbacks to be
 * automatically removed when the objects they point to go away.
 */
public class Closure
{
	/** the main Gtk struct */
	protected GClosure* gClosure;
	protected bool ownedRef;

	/** Get the main Gtk struct */
	public GClosure* getClosureStruct(bool transferOwnership = false)
	{
		if (transferOwnership)
			ownedRef = false;
		return gClosure;
	}

	/** the main Gtk struct as a void* */
	protected void* getStruct()
	{
		return cast(void*)gClosure;
	}

	/**
	 * Sets our main struct and passes it to the parent class.
	 */
	public this (GClosure* gClosure, bool ownedRef = false)
	{
		this.gClosure = gClosure;
		this.ownedRef = ownedRef;
	}

	~this ()
	{
		if (  ownedRef )
			g_closure_unref(gClosure);
	}


	/** */
	public static GType getType()
	{
		return g_closure_get_type();
	}

	/**
	 * A variant of g_closure_new_simple() which stores @object in the
	 * @data field of the closure and calls g_object_watch_closure() on
	 * @object and the created closure. This function is mainly useful
	 * when implementing new types of closures.
	 *
	 * Params:
	 *     sizeofClosure = the size of the structure to allocate, must be at least
	 *         `sizeof (GClosure)`
	 *     object = a #GObject pointer to store in the @data field of the newly
	 *         allocated #GClosure
	 *
	 * Returns: a newly allocated #GClosure
	 *
	 * Throws: ConstructionException GTK+ fails to create the object.
	 */
	public this(uint sizeofClosure, ObjectG object)
	{
		auto p = g_closure_new_object(sizeofClosure, (object is null) ? null : object.getObjectGStruct());

		if(p is null)
		{
			throw new ConstructionException("null returned by new_object");
		}

		this(cast(GClosure*) p);
	}

	/**
	 * Allocates a struct of the given size and initializes the initial
	 * part as a #GClosure. This function is mainly useful when
	 * implementing new types of closures.
	 *
	 * |[<!-- language="C" -->
	 * typedef struct _MyClosure MyClosure;
	 * struct _MyClosure
	 * {
	 * GClosure closure;
	 * // extra data goes here
	 * };
	 *
	 * static void
	 * my_closure_finalize (gpointer  notify_data,
	 * GClosure *closure)
	 * {
	 * MyClosure *my_closure = (MyClosure *)closure;
	 *
	 * // free extra data here
	 * }
	 *
	 * MyClosure *my_closure_new (gpointer data)
	 * {
	 * GClosure *closure;
	 * MyClosure *my_closure;
	 *
	 * closure = g_closure_new_simple (sizeof (MyClosure), data);
	 * my_closure = (MyClosure *) closure;
	 *
	 * // initialize extra data here
	 *
	 * g_closure_add_finalize_notifier (closure, notify_data,
	 * my_closure_finalize);
	 * return my_closure;
	 * }
	 * ]|
	 *
	 * Params:
	 *     sizeofClosure = the size of the structure to allocate, must be at least
	 *         `sizeof (GClosure)`
	 *     data = data to store in the @data field of the newly allocated #GClosure
	 *
	 * Returns: a newly allocated #GClosure
	 *
	 * Throws: ConstructionException GTK+ fails to create the object.
	 */
	public this(uint sizeofClosure, void* data)
	{
		auto p = g_closure_new_simple(sizeofClosure, data);

		if(p is null)
		{
			throw new ConstructionException("null returned by new_simple");
		}

		this(cast(GClosure*) p);
	}

	/**
	 * Registers a finalization notifier which will be called when the
	 * reference count of @closure goes down to 0. Multiple finalization
	 * notifiers on a single closure are invoked in unspecified order. If
	 * a single call to g_closure_unref() results in the closure being
	 * both invalidated and finalized, then the invalidate notifiers will
	 * be run before the finalize notifiers.
	 *
	 * Params:
	 *     notifyData = data to pass to @notify_func
	 *     notifyFunc = the callback function to register
	 */
	public void addFinalizeNotifier(void* notifyData, GClosureNotify notifyFunc)
	{
		g_closure_add_finalize_notifier(gClosure, notifyData, notifyFunc);
	}

	/**
	 * Registers an invalidation notifier which will be called when the
	 * @closure is invalidated with g_closure_invalidate(). Invalidation
	 * notifiers are invoked before finalization notifiers, in an
	 * unspecified order.
	 *
	 * Params:
	 *     notifyData = data to pass to @notify_func
	 *     notifyFunc = the callback function to register
	 */
	public void addInvalidateNotifier(void* notifyData, GClosureNotify notifyFunc)
	{
		g_closure_add_invalidate_notifier(gClosure, notifyData, notifyFunc);
	}

	/**
	 * Adds a pair of notifiers which get invoked before and after the
	 * closure callback, respectively. This is typically used to protect
	 * the extra arguments for the duration of the callback. See
	 * g_object_watch_closure() for an example of marshal guards.
	 *
	 * Params:
	 *     preMarshalData = data to pass to @pre_marshal_notify
	 *     preMarshalNotify = a function to call before the closure callback
	 *     postMarshalData = data to pass to @post_marshal_notify
	 *     postMarshalNotify = a function to call after the closure callback
	 */
	public void addMarshalGuards(void* preMarshalData, GClosureNotify preMarshalNotify, void* postMarshalData, GClosureNotify postMarshalNotify)
	{
		g_closure_add_marshal_guards(gClosure, preMarshalData, preMarshalNotify, postMarshalData, postMarshalNotify);
	}

	/**
	 * Sets a flag on the closure to indicate that its calling
	 * environment has become invalid, and thus causes any future
	 * invocations of g_closure_invoke() on this @closure to be
	 * ignored. Also, invalidation notifiers installed on the closure will
	 * be called at this point. Note that unless you are holding a
	 * reference to the closure yourself, the invalidation notifiers may
	 * unref the closure and cause it to be destroyed, so if you need to
	 * access the closure after calling g_closure_invalidate(), make sure
	 * that you've previously called g_closure_ref().
	 *
	 * Note that g_closure_invalidate() will also be called when the
	 * reference count of a closure drops to zero (unless it has already
	 * been invalidated before).
	 */
	public void invalidate()
	{
		g_closure_invalidate(gClosure);
	}

	/**
	 * Invokes the closure, i.e. executes the callback represented by the @closure.
	 *
	 * Params:
	 *     returnValue = a #GValue to store the return
	 *         value. May be %NULL if the callback of @closure
	 *         doesn't return a value.
	 *     nParamValues = the length of the @param_values array
	 *     paramValues = an array of
	 *         #GValues holding the arguments on which to
	 *         invoke the callback of @closure
	 *     invocationHint = a context-dependent invocation hint
	 */
	public void invoke(Value returnValue, Value[] paramValues, void* invocationHint)
	{
		GValue[] paramValuesArray = new GValue[paramValues.length];
		for ( int i = 0; i < paramValues.length; i++ )
		{
			paramValuesArray[i] = *(paramValues[i].getValueStruct());
		}

		g_closure_invoke(gClosure, (returnValue is null) ? null : returnValue.getValueStruct(), cast(uint)paramValues.length, paramValuesArray.ptr, invocationHint);
	}

	/**
	 * Increments the reference count on a closure to force it staying
	 * alive while the caller holds a pointer to it.
	 *
	 * Returns: The @closure passed in, for convenience
	 */
	public Closure doref()
	{
		auto p = g_closure_ref(gClosure);

		if(p is null)
		{
			return null;
		}

		return ObjectG.getDObject!(Closure)(cast(GClosure*) p);
	}

	/**
	 * Removes a finalization notifier.
	 *
	 * Notice that notifiers are automatically removed after they are run.
	 *
	 * Params:
	 *     notifyData = data which was passed to g_closure_add_finalize_notifier()
	 *         when registering @notify_func
	 *     notifyFunc = the callback function to remove
	 */
	public void removeFinalizeNotifier(void* notifyData, GClosureNotify notifyFunc)
	{
		g_closure_remove_finalize_notifier(gClosure, notifyData, notifyFunc);
	}

	/**
	 * Removes an invalidation notifier.
	 *
	 * Notice that notifiers are automatically removed after they are run.
	 *
	 * Params:
	 *     notifyData = data which was passed to g_closure_add_invalidate_notifier()
	 *         when registering @notify_func
	 *     notifyFunc = the callback function to remove
	 */
	public void removeInvalidateNotifier(void* notifyData, GClosureNotify notifyFunc)
	{
		g_closure_remove_invalidate_notifier(gClosure, notifyData, notifyFunc);
	}

	/**
	 * Sets the marshaller of @closure. The `marshal_data`
	 * of @marshal provides a way for a meta marshaller to provide additional
	 * information to the marshaller. (See g_closure_set_meta_marshal().) For
	 * GObject's C predefined marshallers (the g_cclosure_marshal_*()
	 * functions), what it provides is a callback function to use instead of
	 * @closure->callback.
	 *
	 * Params:
	 *     marshal = a #GClosureMarshal function
	 */
	public void setMarshal(GClosureMarshal marshal)
	{
		g_closure_set_marshal(gClosure, marshal);
	}

	/**
	 * Sets the meta marshaller of @closure.  A meta marshaller wraps
	 * @closure->marshal and modifies the way it is called in some
	 * fashion. The most common use of this facility is for C callbacks.
	 * The same marshallers (generated by [glib-genmarshal][glib-genmarshal]),
	 * are used everywhere, but the way that we get the callback function
	 * differs. In most cases we want to use @closure->callback, but in
	 * other cases we want to use some different technique to retrieve the
	 * callback function.
	 *
	 * For example, class closures for signals (see
	 * g_signal_type_cclosure_new()) retrieve the callback function from a
	 * fixed offset in the class structure.  The meta marshaller retrieves
	 * the right callback and passes it to the marshaller as the
	 * @marshal_data argument.
	 *
	 * Params:
	 *     marshalData = context-dependent data to pass to @meta_marshal
	 *     metaMarshal = a #GClosureMarshal function
	 */
	public void setMetaMarshal(void* marshalData, GClosureMarshal metaMarshal)
	{
		g_closure_set_meta_marshal(gClosure, marshalData, metaMarshal);
	}

	/**
	 * Takes over the initial ownership of a closure.  Each closure is
	 * initially created in a "floating" state, which means that the initial
	 * reference count is not owned by any caller. g_closure_sink() checks
	 * to see if the object is still floating, and if so, unsets the
	 * floating state and decreases the reference count. If the closure
	 * is not floating, g_closure_sink() does nothing. The reason for the
	 * existence of the floating state is to prevent cumbersome code
	 * sequences like:
	 * |[<!-- language="C" -->
	 * closure = g_cclosure_new (cb_func, cb_data);
	 * g_source_set_closure (source, closure);
	 * g_closure_unref (closure); // GObject doesn't really need this
	 * ]|
	 * Because g_source_set_closure() (and similar functions) take ownership of the
	 * initial reference count, if it is unowned, we instead can write:
	 * |[<!-- language="C" -->
	 * g_source_set_closure (source, g_cclosure_new (cb_func, cb_data));
	 * ]|
	 *
	 * Generally, this function is used together with g_closure_ref(). Ane example
	 * of storing a closure for later notification looks like:
	 * |[<!-- language="C" -->
	 * static GClosure *notify_closure = NULL;
	 * void
	 * foo_notify_set_closure (GClosure *closure)
	 * {
	 * if (notify_closure)
	 * g_closure_unref (notify_closure);
	 * notify_closure = closure;
	 * if (notify_closure)
	 * {
	 * g_closure_ref (notify_closure);
	 * g_closure_sink (notify_closure);
	 * }
	 * }
	 * ]|
	 *
	 * Because g_closure_sink() may decrement the reference count of a closure
	 * (if it hasn't been called on @closure yet) just like g_closure_unref(),
	 * g_closure_ref() should be called prior to this function.
	 */
	public void sink()
	{
		g_closure_sink(gClosure);
	}

	/**
	 * Decrements the reference count of a closure after it was previously
	 * incremented by the same caller. If no other callers are using the
	 * closure, then the closure will be destroyed and freed.
	 */
	public void unref()
	{
		g_closure_unref(gClosure);
	}

	/**
	 * Set the callback for a source as a #GClosure.
	 *
	 * If the source is not one of the standard GLib types, the @closure_callback
	 * and @closure_marshal fields of the #GSourceFuncs structure must have been
	 * filled in with pointers to appropriate functions.
	 *
	 * Params:
	 *     source = the source
	 *     closure = a #GClosure
	 */
	public static void sourceSetClosure(Source source, Closure closure)
	{
		g_source_set_closure((source is null) ? null : source.getSourceStruct(), (closure is null) ? null : closure.getClosureStruct());
	}

	/**
	 * Sets a dummy callback for @source. The callback will do nothing, and
	 * if the source expects a #gboolean return value, it will return %TRUE.
	 * (If the source expects any other type of return value, it will return
	 * a 0/%NULL value; whatever g_value_init() initializes a #GValue to for
	 * that type.)
	 *
	 * If the source is not one of the standard GLib types, the
	 * @closure_callback and @closure_marshal fields of the #GSourceFuncs
	 * structure must have been filled in with pointers to appropriate
	 * functions.
	 *
	 * Params:
	 *     source = the source
	 */
	public static void sourceSetDummyCallback(Source source)
	{
		g_source_set_dummy_callback((source is null) ? null : source.getSourceStruct());
	}
}