[gnome-boxes/wip/props-ui-files: 81/96] Add DeferredChange class

[Zeeshan Ali <zeeshanak src gnome org>]

commit 73a772a5a9c0ff4b757fed4d7307242d52818d24
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Wed Jun 1 20:07:51 2016 +0100

    Add DeferredChange class
    
    Add a class to represent a deferred change in properties view.

 src/Makefile.am          |    1 +
 src/deferred-change.vala |   44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 48a2bea..adfc8ed 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -105,6 +105,7 @@ gnome_boxes_SOURCES =                               \
        collection.vala                         \
        collection-filter-switcher.vala         \
        collection-toolbar.vala                 \
+       deferred-change.vala                    \
        display-page.vala                       \
        display-toolbar.vala                    \
        display.vala                            \
diff --git a/src/deferred-change.vala b/src/deferred-change.vala
new file mode 100644
index 0000000..58087c7
--- /dev/null
+++ b/src/deferred-change.vala
@@ -0,0 +1,44 @@
+// This file is part of GNOME Boxes. License: LGPLv2+
+
+private class DeferredChange {
+    public signal void flushed ();
+
+    public string id { get; private set; }
+    public SourceFunc func;
+    public uint interval { get; private set; } // In seconds
+
+    private uint timeout_id;
+
+    public DeferredChange (string id, owned SourceFunc func, uint interval = 0) {
+        this.id = id;
+        this.func = (owned) func;
+        this.interval = interval;
+
+        if (interval == 0)
+            return;
+
+        timeout_id = Timeout.add_seconds (interval, () => {
+            flush ();
+
+            return false;
+        });
+    }
+
+    public void flush () {
+        if (func == null)
+            return;
+
+        func ();
+        func = null;
+
+        unschedule ();
+
+        flushed ();
+    }
+
+    public void unschedule () {
+        if (timeout_id > 0)
+            Source.remove (timeout_id);
+        timeout_id = 0;
+    }
+}