Bug 489640 [GTK3] setting a lot of items to combobox is extremely slow

(Bug fix).

Setting wrap causes O(n^2) performance regression because after
every insert the drop-down list size is re-computed.

Solution:
1) Turn off wrap during insert (to fix bulk insert, e.g setItems(...))
2) Delay enabling (so that multiple single-insert calls [e.g add(.)] are
not delayed if called in a loop.

Tests:
- Attached snippets:
  Before fix: Gtk3: 1000ms
  After fix:  Gtk3:   10ms  (event faster than gtk2's 23ms).

- Child eclipse works well.
- All SWT jUnits pass.
- Combo box looks same as before.

Patchset 4:
- Implemented similar logic for removing items to fix performance.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=4896403
Change-Id: Ibf14b35712277e068bc719d073a482ab5c04fb7f
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>

4 files changed, 33 insertions, 0 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
index 674d32688d..cd4875fa87 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
@@ -5391,6 +5391,18 @@ JNIEXPORT jintLong JNICALL GTK_NATIVE(_1gtk_1combo_1box_1get_1model)
 }
 #endif
 
+#ifndef NO__1gtk_1combo_1box_1get_1wrap_1width
+JNIEXPORT jint JNICALL GTK_NATIVE(_1gtk_1combo_1box_1get_1wrap_1width)
+	(JNIEnv *env, jclass that, jintLong arg0)
+{
+	jint rc = 0;
+	GTK_NATIVE_ENTER(env, that, _1gtk_1combo_1box_1get_1wrap_1width_FUNC);
+	rc = (jint)gtk_combo_box_get_wrap_width((GtkComboBox *)arg0);
+	GTK_NATIVE_EXIT(env, that, _1gtk_1combo_1box_1get_1wrap_1width_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO__1gtk_1combo_1box_1popdown
 JNIEXPORT void JNICALL GTK_NATIVE(_1gtk_1combo_1box_1popdown)
 	(JNIEnv *env, jclass that, jintLong arg0)
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
index 1bd6a98e1f..c4c943401b 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
@@ -403,6 +403,7 @@ char * GTK_nativeFunctionNames[] = {
 	"_1gtk_1color_1selection_1set_1has_1palette",
 	"_1gtk_1combo_1box_1get_1active",
 	"_1gtk_1combo_1box_1get_1model",
+	"_1gtk_1combo_1box_1get_1wrap_1width",
 	"_1gtk_1combo_1box_1popdown",
 	"_1gtk_1combo_1box_1popup",
 	"_1gtk_1combo_1box_1set_1active",
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
index c999193244..9bd4eb22c9 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
@@ -401,6 +401,7 @@ typedef enum {
 	_1gtk_1color_1selection_1set_1has_1palette_FUNC,
 	_1gtk_1combo_1box_1get_1active_FUNC,
 	_1gtk_1combo_1box_1get_1model_FUNC,
+	_1gtk_1combo_1box_1get_1wrap_1width_FUNC,
 	_1gtk_1combo_1box_1popdown_FUNC,
 	_1gtk_1combo_1box_1popup_FUNC,
 	_1gtk_1combo_1box_1set_1active_FUNC,
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/GTK.java b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/GTK.java
index ef0023c904..855d78da93 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/GTK.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/GTK.java
@@ -1540,6 +1540,7 @@ public class GTK extends OS {
 	}
 	/** @method flags=dynamic */
 	public static final native void _gtk_combo_box_text_insert(long /*int*/ combo_box, int position, byte[] id, byte[] text);
+	/** Do not call directly, instead use Combo.gtk_combo_box_insert(..) */
 	public static final void gtk_combo_box_text_insert(long /*int*/ combo_box, int position, byte[] id, byte[] text) {
 		lock.lock();
 		try {
@@ -1574,6 +1575,7 @@ public class GTK extends OS {
 	}
 	/** @method flags=dynamic */
 	public static final native void _gtk_combo_box_text_remove_all(long /*int*/ combo_box);
+	/** Do not call directly. Call Combo.gtk_combo_box_text_remove_all(..) instead). */
 	public static final void gtk_combo_box_text_remove_all(long /*int*/ combo_box) {
 		lock.lock();
 		try {
@@ -1624,6 +1626,9 @@ public class GTK extends OS {
 	 * @param width cast=(gint)
 	 */
 	public static final native void _gtk_combo_box_set_wrap_width(long /*int*/ combo_box, int width);
+	/**
+	 * Do not use directly. Instead use Combo.gtk_combo_box_toggle_wrap(..)
+	 */
 	public static final void gtk_combo_box_set_wrap_width(long /*int*/ combo_box, int width) {
 		lock.lock();
 		try {
@@ -1632,6 +1637,20 @@ public class GTK extends OS {
 			lock.unlock();
 		}
 	}
+
+	/**
+	 * @param combo_box cast=(GtkComboBox *)
+	 * @return cast=(gint)
+	 */
+	public static final native int _gtk_combo_box_get_wrap_width(long /*int*/ combo_box);
+	public static final int gtk_combo_box_get_wrap_width(long /*int*/ combo_box) {
+		lock.lock();
+		try {
+			return _gtk_combo_box_get_wrap_width(combo_box);
+		} finally {
+			lock.unlock();
+		}
+	}
 	/**
 	* @param combo_box cast=(GtkComboBox *)
 	*/