SimpleAsyncResult

As of GLib 2.46, gio.simple_async_result.SimpleAsyncResult is deprecated in favor of gio.task.Task, which provides a simpler API.

gio.simple_async_result.SimpleAsyncResult implements gio.async_result.AsyncResult.

gio.simple_async_result.SimpleAsyncResult handles gio.types.AsyncReadyCallbacks, error reporting, operation cancellation and the final state of an operation, completely transparent to the application. Results can be returned as a pointer e.g. for functions that return data that is collected asynchronously, a boolean value for checking the success or failure of an operation, or a gssize for operations which return the number of bytes modified by the operation; all of the simple return cases are covered.

Most of the time, an application will not need to know of the details of this API; it is handled transparently, and any necessary operations are handled by gio.async_result.AsyncResult’s interface. However, if implementing a new GIO module, for writing language bindings, or for complex applications that need better control of how asynchronous operations are completed, it is important to understand this functionality.

gio.simple_async_result.SimpleAsyncResults are tagged with the calling function to ensure that asynchronous functions and their finishing functions are used together correctly.

To create a new gio.simple_async_result.SimpleAsyncResult, call gio.simple_async_result.SimpleAsyncResult.new_. If the result needs to be created for a glib.error.ErrorG, use gio.simple_async_result.SimpleAsyncResult.newFromError or gio.simple_async_result.SimpleAsyncResult.newTakeError. If a glib.error.ErrorG is not available (e.g. the asynchronous operation doesn’t take a glib.error.ErrorG argument), but the result still needs to be created for an error condition, use gio.simple_async_result.SimpleAsyncResult.newError (or gio.simple_async_result.SimpleAsyncResult.setErrorVa if your application or binding requires passing a variable argument list directly), and the error can then be propagated through the use of gio.simple_async_result.SimpleAsyncResult.propagateError.

An asynchronous operation can be made to ignore a cancellation event by calling gio.simple_async_result.SimpleAsyncResult.setHandleCancellation with a gio.simple_async_result.SimpleAsyncResult for the operation and FALSE. This is useful for operations that are dangerous to cancel, such as close (which would cause a leak if cancelled before being run).

gio.simple_async_result.SimpleAsyncResult can integrate into GLib’s event loop, glib.main_loop.MainLoop, or it can use glib.thread.Threads. gio.simple_async_result.SimpleAsyncResult.complete will finish an I/O task directly from the point where it is called. gio.simple_async_result.SimpleAsyncResult.completeInIdle will finish it from an idle handler in the thread-default main context (see glib.main_context.MainContext.pushThreadDefault) where the gio.simple_async_result.SimpleAsyncResult was created. gio.simple_async_result.SimpleAsyncResult.runInThread will run the job in a separate thread and then use gio.simple_async_result.SimpleAsyncResult.completeInIdle to deliver the result.

To set the results of an asynchronous function, gio.simple_async_result.SimpleAsyncResult.setOpResGpointer, gio.simple_async_result.SimpleAsyncResult.setOpResGboolean, and gio.simple_async_result.SimpleAsyncResult.setOpResGssize

are provided, setting the operation's result to a [xlib.types.void*], glib.types.SOURCE_REMOVE, or gssize, respectively.

Likewise, to get the result of an asynchronous function, gio.simple_async_result.SimpleAsyncResult.getOpResGpointer, gio.simple_async_result.SimpleAsyncResult.getOpResGboolean, and gio.simple_async_result.SimpleAsyncResult.getOpResGssize are provided, getting the operation’s result as a [xlib.types.void*], glib.types.SOURCE_REMOVE, and gssize, respectively.

For the details of the requirements implementations must respect, see gio.async_result.AsyncResult. A typical implementation of an asynchronous operation using gio.simple_async_result.SimpleAsyncResult looks something like this:

1 static void
2 baked_cb (Cake    *cake,
3           gpointer user_data)
4 {
5   // In this example, this callback is not given a reference to the cake,
6   // so the GSimpleAsyncResult has to take a reference to it.
7   GSimpleAsyncResult *result = user_data;
8 
9   if (cake == NULL)
10     g_simple_async_result_set_error (result,
11                                      BAKER_ERRORS,
12                                      BAKER_ERROR_NO_FLOUR,
13                                      "Go to the supermarket");
14   else
15     g_simple_async_result_set_op_res_gpointer (result,
16                                                g_object_ref (cake),
17                                                g_object_unref);
18 
19 
20   // In this example, we assume that baked_cb is called as a callback from
21   // the mainloop, so it's safe to complete the operation synchronously here.
22   // If, however, _baker_prepare_cake () might call its callback without
23   // first returning to the mainloop — inadvisable, but some APIs do so —
24   // we would need to use g_simple_async_result_complete_in_idle().
25   g_simple_async_result_complete (result);
26   g_object_unref (result);
27 }
28 
29 void
30 baker_bake_cake_async (Baker              *self,
31                        guint               radius,
32                        GAsyncReadyCallback callback,
33                        gpointer            user_data)
34 {
35   GSimpleAsyncResult *simple;
36   Cake               *cake;
37 
38   if (radius < 3)
39     {
40       g_simple_async_report_error_in_idle (G_OBJECT (self),
41                                            callback,
42                                            user_data,
43                                            BAKER_ERRORS,
44                                            BAKER_ERROR_TOO_SMALL,
45                                            "%ucm radius cakes are silly",
46                                            radius);
47       return;
48     }
49 
50   simple = g_simple_async_result_new (G_OBJECT (self),
51                                       callback,
52                                       user_data,
53                                       baker_bake_cake_async);
54   cake = _baker_get_cached_cake (self, radius);
55 
56   if (cake != NULL)
57     {
58       g_simple_async_result_set_op_res_gpointer (simple,
59                                                  g_object_ref (cake),
60                                                  g_object_unref);
61       g_simple_async_result_complete_in_idle (simple);
62       g_object_unref (simple);
63       // Drop the reference returned by _baker_get_cached_cake();
64       // the GSimpleAsyncResult has taken its own reference.
65       g_object_unref (cake);
66       return;
67     }
68 
69   _baker_prepare_cake (self, radius, baked_cb, simple);
70 }
71 
72 Cake *
73 baker_bake_cake_finish (Baker        *self,
74                         GAsyncResult *result,
75                         GError      **error)
76 {
77   GSimpleAsyncResult *simple;
78   Cake               *cake;
79 
80   g_return_val_if_fail (g_simple_async_result_is_valid (result,
81                                                         G_OBJECT (self),
82                                                         baker_bake_cake_async),
83                         NULL);
84 
85   simple = (GSimpleAsyncResult *) result;
86 
87   if (g_simple_async_result_propagate_error (simple, error))
88     return NULL;
89 
90   cake = CAKE (g_simple_async_result_get_op_res_gpointer (simple));
91   return g_object_ref (cake);
92 }

class SimpleAsyncResult : ObjectG , AsyncResult {

this(gobject.object.ObjectG sourceObject, gio.types.AsyncReadyCallback callback, void* sourceTag);

static gio.simple_async_result.SimpleAsyncResult newFromError(gobject.object.ObjectG sourceObject, gio.types.AsyncReadyCallback callback, glib.error.ErrorG error);

static bool isValid(gio.async_result.AsyncResult result, gobject.object.ObjectG source, void* sourceTag);

void complete();

void completeInIdle();

bool getOpResGboolean();

ptrdiff_t getOpResGssize();

bool propagateError();

void setCheckCancellable(gio.cancellable.Cancellable checkCancellable);

void setFromError(glib.error.ErrorG error);

void setHandleCancellation(bool handleCancellation);

void setOpResGboolean(bool opRes);

void setOpResGssize(ptrdiff_t opRes);

}

Constructors

this this(gobject.object.ObjectG sourceObject, gio.types.AsyncReadyCallback callback, void* sourceTag): Creates a #GSimpleAsyncResult.

Members

Functions

complete void complete(): Completes an asynchronous I/O job immediately. Must be called in the thread where the asynchronous result was to be delivered, as it invokes the callback directly. If you are in a different thread use gio.simple_async_result.SimpleAsyncResult.completeInIdle.
completeInIdle void completeInIdle(): Completes an asynchronous function in an idle handler in the [thread-default main context][g-main-context-push-thread-default] of the thread that simple was initially created in (and re-pushes that context around the invocation of the callback).
getOpResGboolean bool getOpResGboolean(): Gets the operation result boolean from within the asynchronous result.
getOpResGssize ptrdiff_t getOpResGssize(): Gets a gssize from the asynchronous result.
propagateError bool propagateError(): Propagates an error from within the simple asynchronous result to a given destination.
setCheckCancellable void setCheckCancellable(gio.cancellable.Cancellable checkCancellable): Sets a #GCancellable to check before dispatching results.
setFromError void setFromError(glib.error.ErrorG error): Sets the result from a #GError.
setHandleCancellation void setHandleCancellation(bool handleCancellation): Sets whether to handle cancellation within the asynchronous operation.
setOpResGboolean void setOpResGboolean(bool opRes): Sets the operation result to a boolean within the asynchronous result.
setOpResGssize void setOpResGssize(ptrdiff_t opRes): Sets the operation result within the asynchronous result to the given op_res.

Static functions

isValid bool isValid(gio.async_result.AsyncResult result, gobject.object.ObjectG source, void* sourceTag): Ensures that the data passed to the _finish function of an async operation is consistent. Three checks are performed.
newFromError gio.simple_async_result.SimpleAsyncResult newFromError(gobject.object.ObjectG sourceObject, gio.types.AsyncReadyCallback callback, glib.error.ErrorG error): Creates a #GSimpleAsyncResult from an error condition.

Mixed In Members

From `mixin AsyncResultT!()`

getSourceObject gobject.object.ObjectG getSourceObject(): Gets the source object from a #GAsyncResult.
getUserData void* getUserData(): Gets the user data from a #GAsyncResult.
isTagged bool isTagged(void* sourceTag): Checks if res has the given source_tag (generally a function pointer indicating the function res was created by).
legacyPropagateError bool legacyPropagateError(): If res is a #GSimpleAsyncResult, this is equivalent to gio.simple_async_result.SimpleAsyncResult.propagateError. Otherwise it returns false.

Inherited Members

From ObjectG

setGObject void setGObject(void* cObj, Flag!"Take" take): Set the GObject of a D ObjectG wrapper.
cPtr void* cPtr(Flag!"Dup" dup): Get a pointer to the underlying C object.
ref_ void* ref_(void* gObj): Calls g_object_ref() on a GObject.
unref unref(void* gObj): Calls g_object_unref() on a GObject.
getType GType getType(): Get the GType of an object.
gType GType gType [@property getter]: GObject GType property.
self ObjectG self(): Convenience method to return this cast to a type. For use in D with statements.
getDObject T getDObject(void* cptr, Flag!"Take" take): Template to get the D object from a C GObject and cast it to the given D object type.
connectSignalClosure ulong connectSignalClosure(string signalDetail, DClosure closure, Flag!"After" after): Connect a D closure to an object signal.
setProperty void setProperty(string propertyName, T val): Template for setting a GObject property.
getProperty T getProperty(string propertyName): Template for getting a GObject property.
compatControl size_t compatControl(size_t what, void* data)
bindProperty gobject.binding.Binding bindProperty(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags): Creates a binding between source_property on source and target_property on target.
bindPropertyFull gobject.binding.Binding bindPropertyFull(string sourceProperty, gobject.object.ObjectG target, string targetProperty, gobject.types.BindingFlags flags, gobject.closure.Closure transformTo, gobject.closure.Closure transformFrom): Creates a binding between source_property on source and target_property on target, allowing you to set the transformation functions to be used by the binding.
forceFloating void forceFloating(): This function is intended for #GObject implementations to re-enforce a floating[floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling gobject.object.ObjectG.refSink.
freezeNotify void freezeNotify(): Increases the freeze count on object. If the freeze count is non-zero, the emission of "notify" signals on object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen.
getData void* getData(string key): Gets a named field from the objects table of associations (see gobject.object.ObjectG.setData).
getProperty void getProperty(string propertyName, gobject.value.Value value): Gets a property of an object.
getQdata void* getQdata(glib.types.Quark quark): This function gets back user data pointers stored via gobject.object.ObjectG.setQdata.
getv void getv(string[] names, gobject.value.Value[] values): Gets n_properties properties for an object. Obtained properties will be set to values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.
isFloating bool isFloating(): Checks whether object has a floating[floating-ref] reference.
notify void notify(string propertyName): Emits a "notify" signal for the property property_name on object.
notifyByPspec void notifyByPspec(gobject.param_spec.ParamSpec pspec): Emits a "notify" signal for the property specified by pspec on object.
refSink gobject.object.ObjectG refSink(): Increase the reference count of object, and possibly remove the floating[floating-ref] reference, if object has a floating reference.
runDispose void runDispose(): Releases all references to other objects. This can be used to break reference cycles.
setData void setData(string key, void* data): Each object carries around a table of associations from strings to pointers. This function lets you set an association.
setProperty void setProperty(string propertyName, gobject.value.Value value): Sets a property on an object.
stealData void* stealData(string key): Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
stealQdata void* stealQdata(glib.types.Quark quark): This function gets back user data pointers stored via gobject.object.ObjectG.setQdata and removes the data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example:
thawNotify void thawNotify(): Reverts the effect of a previous call to gobject.object.ObjectG.freezeNotify. The freeze count is decreased on object and when it reaches zero, queued "notify" signals are emitted.
watchClosure void watchClosure(gobject.closure.Closure closure): This function essentially limits the life time of the closure to the life time of the object. That is, when the object is finalized, the closure is invalidated by calling gobject.closure.Closure.invalidate on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, gobject.object.ObjectG.ref_ and gobject.object.ObjectG.unref are added as marshal guards to the closure, to ensure that an extra reference count is held on object during invocation of the closure. Usually, this function will be called on closures that use this object as closure data.
connectNotify ulong connectNotify(string detail, T callback, Flag!"After" after): Connect to Notify signal.

From AsyncResult

getSourceObject gobject.object.ObjectG getSourceObject(): Gets the source object from a #GAsyncResult.
getUserData void* getUserData(): Gets the user data from a #GAsyncResult.
isTagged bool isTagged(void* sourceTag): Checks if res has the given source_tag (generally a function pointer indicating the function res was created by).
legacyPropagateError bool legacyPropagateError(): If res is a #GSimpleAsyncResult, this is equivalent to gio.simple_async_result.SimpleAsyncResult.propagateError. Otherwise it returns false.

gio simple_async_result classes

SimpleAsyncResult

SimpleAsyncResult

From mixin AsyncResultT!()

From `mixin AsyncResultT!()`