[gtk/wip/otte/listview: 27/169] expression: Add the ability to watch an expression
- From: Benjamin Otte <otte src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gtk/wip/otte/listview: 27/169] expression: Add the ability to watch an expression
- Date: Fri, 13 Dec 2019 01:13:12 +0000 (UTC)
commit ae3782e9356402f5070af8f1942e030f52e5f5e4
Author: Benjamin Otte <otte redhat com>
Date: Thu Nov 21 05:53:56 2019 +0100
expression: Add the ability to watch an expression
gtk/gtkexpression.c | 570 +++++++++++++++++++++++++++++++++++++++++++++++++++-
gtk/gtkexpression.h | 21 ++
2 files changed, 588 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkexpression.c b/gtk/gtkexpression.c
index a5ce2f5c31..81afae8ac7 100644
--- a/gtk/gtkexpression.c
+++ b/gtk/gtkexpression.c
@@ -99,15 +99,37 @@ struct _GtkExpression
GtkExpression *owner;
};
+typedef struct _GtkExpressionSubWatch GtkExpressionSubWatch;
+
+struct _GtkExpressionWatch
+{
+ GtkExpression *expression;
+ GObject *this;
+ GDestroyNotify user_destroy;
+ GtkExpressionNotify notify;
+ gpointer user_data;
+ guchar sub[0];
+};
+
struct _GtkExpressionClass
{
gsize struct_size;
const char *type_name;
void (* finalize) (GtkExpression *expr);
+ gboolean (* is_static) (GtkExpression *expr);
gboolean (* evaluate) (GtkExpression *expr,
gpointer this,
GValue *value);
+
+ gsize (* watch_size) (GtkExpression *expr);
+ void (* watch) (GtkExpression *self,
+ GtkExpressionSubWatch *watch,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data);
+ void (* unwatch) (GtkExpression *self,
+ GtkExpressionSubWatch *watch);
};
/**
@@ -143,6 +165,50 @@ gtk_expression_alloc (const GtkExpressionClass *expression_class,
return self;
}
+static gsize
+gtk_expression_watch_size_static (GtkExpression *self)
+{
+ return 0;
+}
+
+static void
+gtk_expression_watch_static (GtkExpression *self,
+ GtkExpressionSubWatch *watch,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data)
+{
+}
+
+static void
+gtk_expression_unwatch_static (GtkExpression *self,
+ GtkExpressionSubWatch *watch)
+{
+}
+
+static gsize
+gtk_expression_watch_size (GtkExpression *self)
+{
+ return self->expression_class->watch_size (self);
+}
+
+static void
+gtk_expression_subwatch_init (GtkExpression *self,
+ GtkExpressionSubWatch *watch,
+ gpointer this,
+ GtkExpressionNotify notify,
+ gpointer user_data)
+{
+ self->expression_class->watch (self, watch, this, notify, user_data);
+}
+
+static void
+gtk_expression_subwatch_finish (GtkExpression *self,
+ GtkExpressionSubWatch *watch)
+{
+ self->expression_class->unwatch (self, watch);
+}
+
/*** CONSTANT ***/
typedef struct _GtkConstantExpression GtkConstantExpression;
@@ -162,6 +228,12 @@ gtk_constant_expression_finalize (GtkExpression *expr)
g_value_unset (&self->value);
}
+static gboolean
+gtk_constant_expression_is_static (GtkExpression *expr)
+{
+ return TRUE;
+}
+
static gboolean
gtk_constant_expression_evaluate (GtkExpression *expr,
gpointer this,
@@ -179,7 +251,11 @@ static const GtkExpressionClass GTK_CONSTANT_EXPRESSION_CLASS =
sizeof (GtkConstantExpression),
"GtkConstantExpression",
gtk_constant_expression_finalize,
+ gtk_constant_expression_is_static,
gtk_constant_expression_evaluate,
+ gtk_expression_watch_size_static,
+ gtk_expression_watch_static,
+ gtk_expression_unwatch_static
};
/**
@@ -249,12 +325,20 @@ gtk_constant_expression_new_for_value (const GValue *value)
/*** OBJECT ***/
typedef struct _GtkObjectExpression GtkObjectExpression;
+typedef struct _GtkObjectExpressionWatch GtkObjectExpressionWatch;
struct _GtkObjectExpression
{
GtkExpression parent;
GObject *object;
+ GSList *watches;
+};
+
+struct _GtkObjectExpressionWatch
+{
+ GtkExpressionNotify notify;
+ gpointer user_data;
};
static void
@@ -262,8 +346,16 @@ gtk_object_expression_weak_ref_cb (gpointer data,
GObject *object)
{
GtkObjectExpression *self = (GtkObjectExpression *) data;
+ GSList *l;
self->object = NULL;
+
+ for (l = self->watches; l; l = l->next)
+ {
+ GtkObjectExpressionWatch *owatch = l->data;
+
+ owatch->notify (owatch->user_data);
+ }
}
static void
@@ -273,6 +365,14 @@ gtk_object_expression_finalize (GtkExpression *expr)
if (self->object)
g_object_weak_unref (self->object, gtk_object_expression_weak_ref_cb, self);
+
+ g_assert (self->watches == NULL);
+}
+
+static gboolean
+gtk_object_expression_is_static (GtkExpression *expr)
+{
+ return FALSE;
}
static gboolean
@@ -290,12 +390,46 @@ gtk_object_expression_evaluate (GtkExpression *expr,
return TRUE;
}
+static gsize
+gtk_object_expression_watch_size (GtkExpression *expr)
+{
+ return sizeof (GtkObjectExpressionWatch);
+}
+
+static void
+gtk_object_expression_watch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data)
+{
+ GtkObjectExpression *self = (GtkObjectExpression *) expr;
+ GtkObjectExpressionWatch *owatch = (GtkObjectExpressionWatch *) watch;
+
+ owatch->notify = notify;
+ owatch->user_data = user_data;
+ self->watches = g_slist_prepend (self->watches, owatch);
+}
+
+static void
+gtk_object_expression_unwatch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch)
+{
+ GtkObjectExpression *self = (GtkObjectExpression *) expr;
+
+ self->watches = g_slist_remove (self->watches, watch);
+}
+
static const GtkExpressionClass GTK_OBJECT_EXPRESSION_CLASS =
{
sizeof (GtkObjectExpression),
"GtkObjectExpression",
gtk_object_expression_finalize,
- gtk_object_expression_evaluate
+ gtk_object_expression_is_static,
+ gtk_object_expression_evaluate,
+ gtk_object_expression_watch_size,
+ gtk_object_expression_watch,
+ gtk_object_expression_unwatch
};
/**
@@ -346,6 +480,12 @@ gtk_property_expression_finalize (GtkExpression *expr)
g_clear_pointer (&self->expr, gtk_expression_unref);
}
+static gboolean
+gtk_property_expression_is_static (GtkExpression *expr)
+{
+ return FALSE;
+}
+
static GObject *
gtk_property_expression_get_object (GtkPropertyExpression *self,
gpointer this)
@@ -372,6 +512,8 @@ gtk_property_expression_get_object (GtkPropertyExpression *self,
object = g_value_dup_object (&expr_value);
g_value_unset (&expr_value);
+ if (object == NULL)
+ return NULL;
if (!G_TYPE_CHECK_INSTANCE_TYPE (object, self->pspec->owner_type))
{
@@ -399,12 +541,132 @@ gtk_property_expression_evaluate (GtkExpression *expr,
return TRUE;
}
+typedef struct _GtkPropertyExpressionWatch GtkPropertyExpressionWatch;
+
+struct _GtkPropertyExpressionWatch
+{
+ GtkExpressionNotify notify;
+ gpointer user_data;
+
+ GtkPropertyExpression *expr;
+ gpointer this;
+ GClosure *closure;
+ guchar sub[0];
+};
+
+static void
+gtk_property_expression_watch_destroy_closure (GtkPropertyExpressionWatch *pwatch)
+{
+ if (pwatch->closure == NULL)
+ return;
+
+ g_closure_invalidate (pwatch->closure);
+ g_closure_unref (pwatch->closure);
+ pwatch->closure = NULL;
+}
+
+static void
+gtk_property_expression_watch_notify_cb (GObject *object,
+ GParamSpec *pspec,
+ GtkPropertyExpressionWatch *pwatch)
+{
+ pwatch->notify (pwatch->user_data);
+}
+
+static void
+gtk_property_expression_watch_create_closure (GtkPropertyExpressionWatch *pwatch)
+{
+ GObject *object;
+
+ object = gtk_property_expression_get_object (pwatch->expr, pwatch->this);
+ if (object == NULL)
+ return;
+
+ pwatch->closure = g_cclosure_new (G_CALLBACK (gtk_property_expression_watch_notify_cb), pwatch, NULL);
+ if (!g_signal_connect_closure_by_id (object,
+ g_signal_lookup ("notify", G_OBJECT_TYPE (object)),
+ g_quark_from_string (pwatch->expr->pspec->name),
+ g_closure_ref (pwatch->closure),
+ FALSE))
+ {
+ g_assert_not_reached ();
+ }
+
+ g_object_unref (object);
+}
+
+static void
+gtk_property_expression_watch_expr_notify_cb (gpointer data)
+{
+ GtkPropertyExpressionWatch *pwatch = data;
+
+ gtk_property_expression_watch_destroy_closure (pwatch);
+ gtk_property_expression_watch_create_closure (pwatch);
+ pwatch->notify (pwatch->user_data);
+}
+
+static gsize
+gtk_property_expression_watch_size (GtkExpression *expr)
+{
+ GtkPropertyExpression *self = (GtkPropertyExpression *) expr;
+ gsize result;
+
+ result = sizeof (GtkPropertyExpressionWatch);
+ if (self->expr)
+ result += gtk_expression_watch_size (self->expr);
+
+ return result;
+}
+
+static void
+gtk_property_expression_watch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data)
+{
+ GtkPropertyExpressionWatch *pwatch = (GtkPropertyExpressionWatch *) watch;
+ GtkPropertyExpression *self = (GtkPropertyExpression *) expr;
+
+ pwatch->notify = notify;
+ pwatch->user_data = user_data;
+ pwatch->expr = self;
+ pwatch->this = this_;
+ if (self->expr && !gtk_expression_is_static (self->expr))
+ {
+ gtk_expression_subwatch_init (self->expr,
+ (GtkExpressionSubWatch *) pwatch->sub,
+ this_,
+ gtk_property_expression_watch_expr_notify_cb,
+ pwatch);
+ }
+
+ gtk_property_expression_watch_create_closure (pwatch);
+}
+
+static void
+gtk_property_expression_unwatch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch)
+{
+ GtkPropertyExpressionWatch *pwatch = (GtkPropertyExpressionWatch *) watch;
+ GtkPropertyExpression *self = (GtkPropertyExpression *) expr;
+
+ gtk_property_expression_watch_destroy_closure (pwatch);
+
+ if (self->expr && !gtk_expression_is_static (self->expr))
+ gtk_expression_subwatch_finish (self->expr, (GtkExpressionSubWatch *) pwatch->sub);
+}
+
static const GtkExpressionClass GTK_PROPERTY_EXPRESSION_CLASS =
{
sizeof (GtkPropertyExpression),
"GtkPropertyExpression",
gtk_property_expression_finalize,
+ gtk_property_expression_is_static,
gtk_property_expression_evaluate,
+ gtk_property_expression_watch_size,
+ gtk_property_expression_watch,
+ gtk_property_expression_unwatch
};
/**
@@ -437,11 +699,15 @@ gtk_property_expression_new (GType this_type,
if (g_type_is_a (this_type, G_TYPE_OBJECT))
{
- pspec = g_object_class_find_property (g_type_class_peek (this_type), property_name);
+ GObjectClass *class = g_type_class_ref (this_type);
+ pspec = g_object_class_find_property (class, property_name);
+ g_type_class_unref (class);
}
else if (g_type_is_a (this_type, G_TYPE_INTERFACE))
{
- pspec = g_object_interface_find_property (g_type_default_interface_peek (this_type), property_name);
+ GTypeInterface *iface = g_type_default_interface_ref (this_type);
+ pspec = g_object_interface_find_property (iface, property_name);
+ g_type_default_interface_unref (iface);
}
else
{
@@ -491,6 +757,21 @@ gtk_closure_expression_finalize (GtkExpression *expr)
g_closure_unref (self->closure);
}
+static gboolean
+gtk_closure_expression_is_static (GtkExpression *expr)
+{
+ GtkClosureExpression *self = (GtkClosureExpression *) expr;
+ guint i;
+
+ for (i = 0; i < self->n_params; i++)
+ {
+ if (!gtk_expression_is_static (self->params[i]))
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
static gboolean
gtk_closure_expression_evaluate (GtkExpression *expr,
gpointer this,
@@ -528,12 +809,104 @@ out:
return result;
}
+typedef struct _GtkClosureExpressionWatch GtkClosureExpressionWatch;
+struct _GtkClosureExpressionWatch
+{
+ GtkExpressionNotify notify;
+ gpointer user_data;
+
+ guchar sub[0];
+};
+
+static void
+gtk_closure_expression_watch_notify_cb (gpointer data)
+{
+ GtkClosureExpressionWatch *cwatch = data;
+
+ cwatch->notify (cwatch->user_data);
+}
+
+static gsize
+gtk_closure_expression_watch_size (GtkExpression *expr)
+{
+ GtkClosureExpression *self = (GtkClosureExpression *) expr;
+ gsize size;
+ guint i;
+
+ size = sizeof (GtkClosureExpressionWatch);
+
+ for (i = 0; i < self->n_params; i++)
+ {
+ if (gtk_expression_is_static (self->params[i]))
+ continue;
+
+ size += gtk_expression_watch_size (self->params[i]);
+ }
+
+ return size;
+}
+
+static void
+gtk_closure_expression_watch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data)
+{
+ GtkClosureExpressionWatch *cwatch = (GtkClosureExpressionWatch *) watch;
+ GtkClosureExpression *self = (GtkClosureExpression *) expr;
+ guchar *sub;
+ guint i;
+
+ cwatch->notify = notify;
+ cwatch->user_data = user_data;
+
+ sub = cwatch->sub;
+ for (i = 0; i < self->n_params; i++)
+ {
+ if (gtk_expression_is_static (self->params[i]))
+ continue;
+
+ gtk_expression_subwatch_init (self->params[i],
+ (GtkExpressionSubWatch *) sub,
+ this_,
+ gtk_closure_expression_watch_notify_cb,
+ watch);
+ sub += gtk_expression_watch_size (self->params[i]);
+ }
+}
+
+static void
+gtk_closure_expression_unwatch (GtkExpression *expr,
+ GtkExpressionSubWatch *watch)
+{
+ GtkClosureExpressionWatch *cwatch = (GtkClosureExpressionWatch *) watch;
+ GtkClosureExpression *self = (GtkClosureExpression *) expr;
+ guchar *sub;
+ guint i;
+
+ sub = cwatch->sub;
+ for (i = 0; i < self->n_params; i++)
+ {
+ if (gtk_expression_is_static (self->params[i]))
+ continue;
+
+ gtk_expression_subwatch_finish (self->params[i],
+ (GtkExpressionSubWatch *) sub);
+ sub += gtk_expression_watch_size (self->params[i]);
+ }
+}
+
static const GtkExpressionClass GTK_CLOSURE_EXPRESSION_CLASS =
{
sizeof (GtkClosureExpression),
"GtkClosureExpression",
gtk_closure_expression_finalize,
+ gtk_closure_expression_is_static,
gtk_closure_expression_evaluate,
+ gtk_closure_expression_watch_size,
+ gtk_closure_expression_watch,
+ gtk_closure_expression_unwatch
};
/**
@@ -692,3 +1065,194 @@ gtk_expression_evaluate (GtkExpression *self,
return self->expression_class->evaluate (self, this_, value);
}
+/**
+ * gtk_expression_is_static:
+ * @self: a #GtkExpression
+ *
+ * Checks if the expression is static.
+ *
+ * A static expression will never change its result when
+ * gtk_expression_evaluate() is called on it with the same arguments.
+ *
+ * That means a call to gtk_expression_watch() is not necessary because
+ * it will never trigger a notify.
+ *
+ * Returns: %TRUE if the expression is static
+ **/
+gboolean
+gtk_expression_is_static (GtkExpression *self)
+{
+ return self->expression_class->is_static (self);
+}
+
+static gboolean
+gtk_expression_watch_is_watching (GtkExpressionWatch *watch)
+{
+ return watch->expression != NULL;
+}
+
+static void
+gtk_expression_watch_this_cb (gpointer data,
+ GObject *this)
+{
+ GtkExpressionWatch *watch = data;
+
+ watch->this = NULL;
+
+ watch->notify (watch->user_data);
+ gtk_expression_watch_unwatch (watch);
+}
+
+static void
+gtk_expression_watch_cb (gpointer data)
+{
+ GtkExpressionWatch *watch = data;
+
+ if (!gtk_expression_watch_is_watching (watch))
+ return;
+
+ watch->notify (watch->user_data);
+}
+
+/**
+ * gtk_expression_watch:
+ * @self: a #GtkExpression
+ * @this_: (transfer none) (type GObject) (nullable): the this argument to
+ * watch
+ * @notify: (closure user_data): callback to invoke when the
+ * expression changes
+ * @user_data: user data to pass to @notify callback
+ * @user_destroy: destroy notify for @user_data
+ *
+ * Installs a watch for the given @expression that calls the @notify function
+ * whenever the evaluation of @self may have changed.
+ *
+ * GTK cannot guarantee that the evaluation did indeed change when the @notify
+ * gets invoked, but it guarantees the opposite: When it did in fact change,
+ * the @notify will be invoked.
+ *
+ * Returns: (transfer none): The newly installed watch. Note that the only
+ * reference held to the watch will be released when the watch is unwatched
+ * which can happen automatically, and not just via
+ * gtk_expression_watch_unwatch(). You should call gtk_expression_watch_ref()
+ * if you want to keep the watch around.
+ **/
+GtkExpressionWatch *
+gtk_expression_watch (GtkExpression *self,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data,
+ GDestroyNotify user_destroy)
+{
+ GtkExpressionWatch *watch;
+
+ g_return_val_if_fail (self != NULL, NULL);
+ g_return_val_if_fail (this_ == NULL || G_IS_OBJECT (this_), NULL);
+ g_return_val_if_fail (notify != NULL, NULL);
+
+ watch = g_atomic_rc_box_alloc0 (sizeof (GtkExpressionWatch) + gtk_expression_watch_size (self));
+
+ watch->expression = gtk_expression_ref (self);
+ watch->this = this_;
+ if (this_)
+ g_object_weak_ref (this_, gtk_expression_watch_this_cb, watch);
+ watch->notify = notify;
+ watch->user_data = user_data;
+ watch->user_destroy = user_destroy;
+
+ gtk_expression_subwatch_init (self,
+ (GtkExpressionSubWatch *) watch->sub,
+ this_,
+ gtk_expression_watch_cb,
+ watch);
+
+ return watch;
+}
+
+/**
+ * gtk_expression_watch_ref:
+ * @self: (allow-none): a #GtkExpressionWatch
+ *
+ * Acquires a reference on the given #GtkExpressionWatch.
+ *
+ * Returns: (transfer none): the #GtkExpression with an additional reference
+ */
+GtkExpressionWatch *
+gtk_expression_watch_ref (GtkExpressionWatch *self)
+{
+ return g_atomic_rc_box_acquire (self);
+}
+
+static void
+gtk_expression_watch_finalize (gpointer data)
+{
+ GtkExpressionWatch *watch = data;
+
+ g_assert (!gtk_expression_watch_is_watching (watch));
+}
+
+/**
+ * gtk_expression_watch_unref:
+ * @self: (allow-none): a #GtkExpressionWatch
+ *
+ * Releases a reference on the given #GtkExpressionWatch.
+ *
+ * If the reference was the last, the resources associated to @self are
+ * freed.
+ */
+void
+gtk_expression_watch_unref (GtkExpressionWatch *self)
+{
+ g_atomic_rc_box_release_full (self, gtk_expression_watch_finalize);
+}
+
+/**
+ * gtk_expression_watch_unwatch:
+ * @watch: (transfer none): watch to release
+ *
+ * Stops watching an expression that was established via gtk_expression_watch().
+ **/
+void
+gtk_expression_watch_unwatch (GtkExpressionWatch *watch)
+{
+ if (!gtk_expression_watch_is_watching (watch))
+ return;
+
+ gtk_expression_subwatch_finish (watch->expression, (GtkExpressionSubWatch *) watch->sub);
+
+ if (watch->this)
+ g_object_weak_unref (watch->this, gtk_expression_watch_this_cb, watch);
+
+ if (watch->user_destroy)
+ watch->user_destroy (watch->user_data);
+
+ g_clear_pointer (&watch->expression, gtk_expression_unref);
+
+ gtk_expression_watch_unref (watch);
+}
+
+/**
+ * gtk_expression_watch_evaluate:
+ * @watch: a #GtkExpressionWatch
+ * @value: an empty #GValue to be set
+ *
+ * Evaluates the watched expression and on success stores the result
+ * in @value.
+ *
+ * This is equivalent to calling gtk_expression_evaluate() with the
+ * expression and this pointer originally used to create @watch.
+ *
+ * Returns: %TRUE if the expression could be evaluated and @value was set
+ **/
+gboolean
+gtk_expression_watch_evaluate (GtkExpressionWatch *watch,
+ GValue *value)
+{
+ g_return_val_if_fail (watch != NULL, FALSE);
+
+ if (!gtk_expression_watch_is_watching (watch))
+ return FALSE;
+
+ return gtk_expression_evaluate (watch->expression, watch->this, value);
+}
+
diff --git a/gtk/gtkexpression.h b/gtk/gtkexpression.h
index ebcc586b1f..0ffde58aaf 100644
--- a/gtk/gtkexpression.h
+++ b/gtk/gtkexpression.h
@@ -26,6 +26,9 @@
G_BEGIN_DECLS
typedef struct _GtkExpression GtkExpression;
+typedef struct _GtkExpressionWatch GtkExpressionWatch;
+
+typedef void (* GtkExpressionNotify) (gpointer user_data);
#define GTK_IS_EXPRESSION(expr) ((expr) != NULL)
@@ -42,9 +45,27 @@ void gtk_expression_unref (GtkExpression
GDK_AVAILABLE_IN_ALL
GType gtk_expression_get_value_type (GtkExpression *self);
GDK_AVAILABLE_IN_ALL
+gboolean gtk_expression_is_static (GtkExpression *self);
+GDK_AVAILABLE_IN_ALL
gboolean gtk_expression_evaluate (GtkExpression *self,
gpointer this_,
GValue *value);
+GDK_AVAILABLE_IN_ALL
+GtkExpressionWatch * gtk_expression_watch (GtkExpression *self,
+ gpointer this_,
+ GtkExpressionNotify notify,
+ gpointer user_data,
+ GDestroyNotify
user_destroy);
+
+GDK_AVAILABLE_IN_ALL
+GtkExpressionWatch * gtk_expression_watch_ref (GtkExpressionWatch *watch);
+GDK_AVAILABLE_IN_ALL
+void gtk_expression_watch_unref (GtkExpressionWatch *watch);
+GDK_AVAILABLE_IN_ALL
+gboolean gtk_expression_watch_evaluate (GtkExpressionWatch *watch,
+ GValue *value);
+GDK_AVAILABLE_IN_ALL
+void gtk_expression_watch_unwatch (GtkExpressionWatch *watch);
GDK_AVAILABLE_IN_ALL
GtkExpression * gtk_property_expression_new (GType this_type,
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