Bug 480794: [GTK3] TabFolder cannot be traversed with Tab key; TabFolder#getChildren() is empty

Change-Id: Ib9559713fcf327a535b32be3b12de08467eb9c15

4 files changed, 101 insertions, 52 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
index f45c716ef3..23d8dd009a 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
@@ -115,15 +115,8 @@ static int checkStyle (int style) {
 	return style;
 }
 
-//Containers such as Tabfolder have two sets of children,
-//e.g TabItems and actual widget children.
-//thus we need to pass in different parenting handles depending on which children we want.
 Control [] _getChildren () {
 	long /*int*/ parentHandle = parentingHandle ();
-	return _getChildren (parentHandle);
-}
-
-Control [] _getChildren (long /*int*/ parentHandle) {
 	long /*int*/ list = OS.gtk_container_get_children (parentHandle);
 	if (list == 0) return new Control [0];
 	int count = OS.g_list_length (list);
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabFolder.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabFolder.java
index 7b2f4ae1a5..58db9b84a8 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabFolder.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabFolder.java
@@ -48,6 +48,43 @@ import org.eclipse.swt.internal.gtk.*;
  * @noextend This class is not intended to be subclassed by clients.
  */
 public class TabFolder extends Composite {
+	/*
+	 * Implementation note (see bug 454936, bug 480794):
+	 * 
+	 * Architecture Change on GTK3:
+	 * In TabItem#setControl(Control), we reparent the child to be a child of the 'tab'
+	 * rather than tabfolder's parent swtFixed container.
+	 * Note, this reparenting is only on the GTK side, not on the SWT side.
+	 *
+	 * GTK2 and GTK3 child nesting behaviour differs now.
+	 * GTK2:
+	 *   swtFixed
+	 *   |-- GtkNoteBook
+	 *   |   |-- tabLabel1
+	 *   |   |-- tabLabel2
+	 *   |-- swtFixed (child1)  //child is sibling of Notebook
+	 *   |-- swtFixed (child2)
+	 *
+	 * GTK3+:
+	 * 	swtFixed
+	 * 	|--	GtkNoteBook
+	 * 		|-- tabLabel1
+	 * 		|-- tabLabel2
+	 * 		|-- pageHandle (tabItem1)
+	 * 			|-- child1 //child now child of Notebook.pageHandle.
+	 * 		|-- pageHandle (tabItem2)
+	 * 			|-- child1
+	 *
+	 * This changes the hierarchy so that children are beneath gtkNotebook (as oppose to
+	 * being siblings) and thus fixes DND and background color issues.
+	 * In gtk2, reparenting doesn't function properly (tab content appear blank),
+	 * so this is a gtk3-specific behavior.
+	 *
+	 * Note about the reason for reparenting:
+	 * Reparenting (as opposed to adding widget to a tab in the first place) is necessary
+	 * because the SWT API allows situation where you create a child control before you create a TabItem.
+	 */
+
 	TabItem [] items;
 	ImageList imageList;
 
@@ -331,6 +368,49 @@ long /*int*/ eventHandle () {
 	return handle;
 }
 		
+@Override
+Control[] _getChildren() {
+	Control [] directChildren = super._getChildren ();
+	if (OS.GTK3) {
+		int directCount = directChildren.length;
+		int count = items == null ? 0 : items.length;
+		Control [] children = new Control [count + directCount];
+		int i = 0;
+		for (int j = 0; j < count; j++) {
+			TabItem tabItem = items[j];
+			if (tabItem != null) {
+				long /*int*/ parentHandle = tabItem.pageHandle;
+				long /*int*/ list = OS.gtk_container_get_children (parentHandle);
+				if (list != 0) {
+					long /*int*/ handle = OS.g_list_data (list);
+					if (handle != 0) {
+						Widget widget = display.getWidget (handle);
+						if (widget != null && widget != this) {
+							if (widget instanceof Control) {
+								children [i++] = (Control) widget;
+							}
+						}
+					}
+					OS.g_list_free (list);
+				}
+			}
+		}
+		if (i == count + directCount) return children;
+		Control [] newChildren;
+		if (i == count) {
+			newChildren = children;
+		} else {
+			newChildren = new Control [i + directCount];
+			System.arraycopy (children, 0, newChildren, 0, i);
+		}
+		System.arraycopy (directChildren, 0, newChildren, i, directCount);
+		return newChildren;
+		
+	} else {
+		return directChildren;
+	}
+}
+
 /**
  * Returns the item at the given, zero-relative index in the
  * receiver. Throws an exception if the index is out of range.
@@ -536,14 +616,7 @@ public int indexOf (TabItem item) {
 
 @Override
 Point minimumSize (int wHint, int hHint, boolean flushCache) {
-	Control [] children;
-	if (OS.GTK3) {
-		//We want the 'Tabcontents' rather than
-		//what's nested under the main swtFixed.
-		children = _getChildren (clientHandle ());
-	} else {
-		children = _getChildren ();
-	}
+	Control [] children = _getChildren ();
 	int width = 0, height = 0;
 	for (int i=0; i<children.length; i++) {
 		Control child = children [i];
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabItem.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabItem.java
index 87b8fe5ead..90e28ee79f 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabItem.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/TabItem.java
@@ -12,9 +12,9 @@ package org.eclipse.swt.widgets;
 
 
 import org.eclipse.swt.*;
+import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.internal.*;
 import org.eclipse.swt.internal.gtk.*;
-import org.eclipse.swt.graphics.*;
 
 /**
  * Instances of this class represent a selectable user interface object
@@ -288,42 +288,7 @@ public void setControl (Control control) {
 	}
 
 	if (control != null && OS.GTK3) {
-		/*
-		* Bug 454936 (see also other 454936 references in TabFolder)
-		* Architecture Fix:
-		*  We reparent the child to be a child of the 'tab' rather than tabfolder's parent swtFixed container.
-		*  Note, this reparenting is only on the GTK side, not on the SWT side.
-		*
-		*  Note, GTK2 and GTK3 child nesting behaviour is different now.
-		*  GTK2:
-		*    swtFixed
-		*    |-- GtkNoteBook
-		*    |   |-- tabLabel1
-		*    |   |-- tabLabel2
-		*    |-- swtFixed (child1)  //child is sibling of Notebook
-		*    |-- swtFixed (child2)
-		*
-		*  GTK3+:
-		*  	swtFixed
-		*  	|--	GtkNoteBook
-		*  		|-- tabLabel1
-		*  		|-- tabLabel2
-		*  		|-- swtFixed (child1) //child now child of Notebook.
-		*  		|-- swtFixed (child2)
-		*
-		*  This corrects the hierarchy so that children are beneath gtkNotebook (as oppose to
-		*  being siblings) and thus fixes DND and background color issues.
-		*  In gtk2, reparenting doesn't function properly (tab content appear blank),
-		*  so this is a gtk3-specific behavior.
-		*
-		*  Note about the reason for reparenting:
-		*   Reparenting (as oppose to adding widget to a tab in the first place) is neccessary
-		*   because you can have a situation where you create a widget before you create a tab. e.g
-		*     TabFolder tabFolder = new TabFolder(shell, 0);
-		*     Composite composite = new Composite(tabFolder, 0);
-		*     TabItem tabItem = new TabItem(tabFolder, 0);
-		*     tabitem.setControl(composite);
-		*/
+		// See implementation note about bug 454936 at the start of TabFolder.
 		OS.gtk_widget_reparent (control.topHandle (), pageHandle);
 	}
 
diff --git a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_TabFolder.java b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_TabFolder.java
index 01f32c71cb..33986fc34e 100644
--- a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_TabFolder.java
+++ b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_TabFolder.java
@@ -16,6 +16,8 @@ import java.util.Vector;
 
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Button;
+import org.eclipse.swt.widgets.Control;
+import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.TabFolder;
 import org.eclipse.swt.widgets.TabItem;
 import org.eclipse.swt.widgets.Text;
@@ -55,6 +57,22 @@ public void test_computeSizeIIZ() {
 public void test_computeTrimIIII() {
 }
 
+public void test_TabFolder_getChildren() {
+	ArrayList<Control> children = new ArrayList<Control>();
+	for (int i = 0; i < 6; i++) {
+		TabItem item = new TabItem(tabFolder, SWT.NONE);
+		item.setText("TabItem " + i);
+		Button button = new Button(tabFolder, SWT.PUSH);
+		button.setText("Page " + i);
+		item.setControl(button);
+		children.add(button);
+	}
+	Label label = new Label(tabFolder, SWT.NONE);
+	label.setText("Unused Child");
+	children.add(label);
+	assertArrayEquals(children.toArray(), tabFolder.getChildren());
+}
+
 @Override
 public void test_getClientArea() {
 }