[Bug 467463] [BiDi] Implement contextual base text direction for

StyledText:
(1) Addressed Niraj' comments
(2) Control: updated javadoc to accommodate AUTO direction
(3) Added isAutoDirection to all platforms
(4) win32 TextLayout now returns resolved direction for
back-compatibility reasons.
(5) Class SWT: javadoc for AUTO_TEXT_DIRECTION mentions public API it
can be consumed.

Change-Id: I07ab212d1a8e2bc2b4a54ea6348ee1d97d190ec7

12 files changed, 118 insertions, 73 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/TextLayout.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/TextLayout.java
index 03dee9fc1a..be806db841 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/TextLayout.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/TextLayout.java
@@ -1820,7 +1820,7 @@ public int getLevel (int offset) {
 			return allRuns[i - 1].analysis.s.uBidiLevel;
 		}
 	}
-	return (textDirection & SWT.RIGHT_TO_LEFT) != 0 ? 1 : 0;
+	return (resolveTextDirection() & SWT.RIGHT_TO_LEFT) != 0 ? 1 : 0;
 }
 
 /**
@@ -2439,7 +2439,7 @@ String getSegmentsText() {
 	text.getChars(0, length, oldChars, 0);
 	char[] newChars = new char[length + nSegments];
 	int charCount = 0, segmentCount = 0;
-	char defaultSeparator = (textDirection & SWT.RIGHT_TO_LEFT) != 0 ? RTL_MARK : LTR_MARK;
+	char defaultSeparator = (resolveTextDirection() & SWT.RIGHT_TO_LEFT) != 0 ? RTL_MARK : LTR_MARK;
 	while (charCount < length) {
 		if (segmentCount < nSegments && charCount == segments[segmentCount]) {
 			char separator = segmentsChars != null && segmentsChars.length > segmentCount ? segmentsChars[segmentCount] : defaultSeparator;
@@ -2566,7 +2566,7 @@ public String getText () {
  */
 public int getTextDirection () {
 	checkLayout();
-	return textDirection;
+	return resolveTextDirection();
 }
 
 /**
@@ -2625,7 +2625,7 @@ StyleItem[] itemize () {
 	SCRIPT_STATE scriptState = new SCRIPT_STATE();
 	final int MAX_ITEM = length + 1;
 	
-	if ((textDirection & SWT.RIGHT_TO_LEFT) != 0) {
+	if ((resolveTextDirection() & SWT.RIGHT_TO_LEFT) != 0) {
 		scriptState.uBidiLevel = 1;
 		scriptState.fArabicNumContext = true;
 	}
@@ -2762,6 +2762,15 @@ StyleItem[] merge (long /*int*/ items, int itemCount) {
 }
 
 /* 
+ *  Resolves text direction. If the nominal direction is LTR or RTL, no
+ *  resolution is needed; if the nominal direction is "auto", have BidiUtil
+ *  resolve it according to the first strong bidi character.  
+ */
+int resolveTextDirection () {
+	return textDirection == SWT.AUTO_TEXT_DIRECTION ? BidiUtil.resolveTextDirection (text) : textDirection;
+}
+
+/* 
  *  Reorder the run 
  */
 StyleItem[] reorder (StyleItem[] runs, boolean terminate) {
@@ -3214,7 +3223,8 @@ public void setText (String text) {
 
 /**
  * Sets the text direction of the receiver, which must be one
- * of <code>SWT.LEFT_TO_RIGHT</code> or <code>SWT.RIGHT_TO_LEFT</code>.
+ * of <code>SWT.LEFT_TO_RIGHT</code>, <code>SWT.RIGHT_TO_LEFT</code>
+ * or <code>SWT.AUTO_TEXT_DIRECTION</code>.
  *
  * <p>
  * <b>Warning</b>: This API is currently only implemented on Windows.
@@ -3233,8 +3243,10 @@ public void setTextDirection (int textDirection) {
 	int mask = SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
 	textDirection &= mask;
 	if (textDirection == 0) return;
-	if ((textDirection & SWT.LEFT_TO_RIGHT) != 0) textDirection = SWT.LEFT_TO_RIGHT;
-	if (this.textDirection == textDirection) return;
+	if (textDirection != SWT.AUTO_TEXT_DIRECTION) {
+		if ((textDirection & SWT.LEFT_TO_RIGHT) != 0) textDirection = SWT.LEFT_TO_RIGHT;
+		if (this.textDirection == textDirection) return;
+	}
 	this.textDirection = textDirection;
 	freeRuns();
 }
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/BidiUtil.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/BidiUtil.java
index 7ba1807d4c..9dabebfcdc 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/BidiUtil.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/BidiUtil.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2012 IBM Corporation and others.
+ * Copyright (c) 2000, 2015 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -19,7 +19,9 @@ import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.internal.win32.*;
 import org.eclipse.swt.widgets.*;
 /*
- * Wraps Win32 API used to bidi enable the StyledText widget.
+ * Wraps Win32 API used to bidi enable widgets. Up to 3.104 was used by
+ * StyledText widget exclusively. 3.105 release introduced the method
+ * #resolveTextDirection, which is used by other widgets as well. 
  */
 public class BidiUtil {
 
@@ -501,6 +503,66 @@ public static void removeLanguageListener (Control control) {
 	removeLanguageListener(control.handle);
 }
 /**
+ * Determine the base direction for the given text. The direction is derived
+ * from that of the first strong bidirectional character. In case the text
+ * doesn't contain any strong characters, the base direction is to be
+ * derived from a higher-level protocol (e.g. the widget orientation).
+ * <p>
+ * 
+ * @param text
+ *            Text base direction should be resolved for.
+ * @return SWT#LEFT_RIGHT or SWT#RIGHT_TO_LEFT if the text contains strong
+ *         characters and thus the direction can be resolved, SWT#NONE
+ *         otherwise.
+ * @since 3.105
+ */
+public static int resolveTextDirection (String text) {
+	if (text == null) return SWT.NONE;
+	int length = text.length();
+	if (length == 0) return SWT.NONE;
+	char[] rtlProbe = {' ', ' ', '1'};
+	/*
+	 * "Wide" version of win32 API can also run even on non-Unicode Windows,
+	 * hence need for OS.IsUnicode check here. 
+	 */
+	char[] ltrProbe = {'\u202b', 'a', ' '};
+	char[] numberProbe = {'\u05d0', ' ', ' '};
+	GCP_RESULTS result = new GCP_RESULTS();
+	result.lStructSize = GCP_RESULTS.sizeof;
+	int nGlyphs = result.nGlyphs = ltrProbe.length;
+	long /*int*/ hHeap = OS.GetProcessHeap();
+	long /*int*/ lpOrder = result.lpOrder = OS.HeapAlloc(hHeap, OS.HEAP_ZERO_MEMORY, nGlyphs * 4);
+	long /*int*/ hdc = OS.GetDC(0);
+	int[] order = new int[1];
+	int textDirection = SWT.NONE;
+	for (int i = 0; i < length; i++) {
+		char ch = text.charAt(i);
+		rtlProbe[0] = ch;
+		OS.GetCharacterPlacementW(hdc, rtlProbe, rtlProbe.length, 0, result, OS.GCP_REORDER);
+		OS.MoveMemory(order, result.lpOrder, 4);
+		if (order[0] == 2) {
+			textDirection = SWT.RIGHT_TO_LEFT;
+			break;
+		}
+		ltrProbe[2] = ch;
+		OS.GetCharacterPlacementW(hdc, ltrProbe, ltrProbe.length, 0, result, OS.GCP_REORDER);
+		OS.MoveMemory(order, result.lpOrder + 4, 4);
+		if (order[0] == 1) {
+			numberProbe[2] = ch;
+			OS.GetCharacterPlacementW(hdc, numberProbe, numberProbe.length, 0, result, OS.GCP_REORDER);
+			OS.MoveMemory(order, result.lpOrder, 4);
+			if (order[0] == 0) {
+				textDirection = SWT.LEFT_TO_RIGHT;
+				break;
+			}
+		}
+	}
+	OS.ReleaseDC (0, hdc);
+	OS.HeapFree(hHeap, 0, lpOrder);
+	return textDirection;
+
+}
+/**
  * Switch the keyboard language to the specified language type.  We do
  * not distinguish between multiple bidi or multiple non-bidi languages, so
  * set the keyboard to the first language of the given type.
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
index b8385c9674..8273ccaeba 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
@@ -817,7 +817,7 @@ public void removeSelectionListener (SelectionListener listener) {
 
 @Override
 int resolveTextDirection() {
-	return (style & SWT.ARROW) != 0 ? SWT.NONE : resolveTextDirection(text);
+	return (style & SWT.ARROW) != 0 ? SWT.NONE : BidiUtil.resolveTextDirection(text);
 }
 
 void selectRadio () {
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Combo.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Combo.java
index af4e97841a..4d9120f2e7 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Combo.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Combo.java
@@ -1235,7 +1235,7 @@ Event getSegments (String string) {
 		}
 	}
 	if ((state & HAS_AUTO_DIRECTION) != 0) {
-		int direction = resolveTextDirection(string);
+		int direction = BidiUtil.resolveTextDirection(string);
 		if (direction == SWT.NONE) {
 			/*
 			 * Force adding a UCC even when no strong characters are found.
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
index a5cf242700..ab8aabb610 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
@@ -3716,10 +3716,7 @@ boolean setTabItemFocus () {
 /**
  * Sets the base text direction (a.k.a. "paragraph direction") of the receiver,
  * which must be one of the constants <code>SWT.LEFT_TO_RIGHT</code>,
- * <code>SWT.RIGHT_TO_LEFT</code>, or a bitwise disjunction 
- * <code>SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT</code>. The latter stands for an
- * "auto" direction, which implies that a control containing text derives the
- * direction from the directionality of the first strong bidi character.
+ * <code>SWT.RIGHT_TO_LEFT</code>, or <code>SWT.AUTO_TEXT_DIRECTION</code>.
  * <p>
  * <code>setOrientation</code> would override this value with the text direction
  * that is consistent with the new orientation.
@@ -3738,6 +3735,7 @@ boolean setTabItemFocus () {
  * 
  * @see SWT#LEFT_TO_RIGHT
  * @see SWT#RIGHT_TO_LEFT
+ * @see SWT#AUTO_TEXT_DIRECTION
  * @see SWT#FLIP_TEXT_DIRECTION
  * 
  * @since 3.102
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Group.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Group.java
index 4ce38746fb..28884de6a2 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Group.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Group.java
@@ -11,6 +11,7 @@
 package org.eclipse.swt.widgets;
 
 
+import org.eclipse.swt.internal.BidiUtil;
 import org.eclipse.swt.internal.win32.*;
 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
@@ -377,7 +378,7 @@ void releaseWidget () {
 
 @Override
 int resolveTextDirection () {
-	return resolveTextDirection (text);
+	return BidiUtil.resolveTextDirection (text);
 }
 
 @Override
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Label.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Label.java
index 970b510a9b..17d91e9806 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Label.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Label.java
@@ -11,9 +11,10 @@
 package org.eclipse.swt.widgets;
 
 
-import org.eclipse.swt.internal.win32.*;
 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.internal.BidiUtil;
+import org.eclipse.swt.internal.win32.*;
 
 /**
  * Instances of this class represent a non-selectable
@@ -300,7 +301,7 @@ void releaseWidget () {
 
 @Override
 int resolveTextDirection() {
-	return (style & SWT.SEPARATOR) != 0 ? SWT.NONE : resolveTextDirection(text);
+	return (style & SWT.SEPARATOR) != 0 ? SWT.NONE : BidiUtil.resolveTextDirection (text);
 }
 
 /**
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Link.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Link.java
index 1e84e903e3..97cf652bfb 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Link.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Link.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2013 IBM Corporation and others.
+ * Copyright (c) 2000, 2015 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.swt.widgets;
 
+import org.eclipse.swt.internal.BidiUtil;
 import org.eclipse.swt.internal.win32.*;
 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
@@ -762,7 +763,7 @@ public void setText (String string) {
 
 @Override
 int resolveTextDirection() {
-	return resolveTextDirection(text);
+	return BidiUtil.resolveTextDirection(text);
 }
 
 @Override
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/List.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/List.java
index 3f16621bcd..f3c60c26f9 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/List.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/List.java
@@ -11,10 +11,11 @@
 package org.eclipse.swt.widgets;
 
 
-import org.eclipse.swt.internal.win32.*;
 import org.eclipse.swt.*;
-import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.events.*;
+import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.internal.BidiUtil;
+import org.eclipse.swt.internal.win32.*;
 
 /** 
  * Instances of this class represent a selectable user interface
@@ -1638,7 +1639,7 @@ long /*int*/ windowProc (long /*int*/ hwnd, int msg, long /*int*/ wParam, long /
 				TCHAR buffer = new TCHAR (cp, length);
 				OS.MoveMemory (buffer, lParam, buffer.length () * TCHAR.sizeof);
 				String string = buffer.toString (0, length);
-				int direction = resolveTextDirection (string);
+				int direction = BidiUtil.resolveTextDirection (string);
 				if (direction == SWT.NONE) {
 					/*
 					 * Force adding a UCC even when no strong characters are found.
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
index e2dd3c3e5c..66c9e94930 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
@@ -6932,7 +6932,7 @@ LRESULT wmNotifyChild (NMHDR hdr, long /*int*/ wParam, long /*int*/ lParam) {
 						length = 1;
 					}
 					if (length > 1 && (state & HAS_AUTO_DIRECTION) != 0) {
-						switch (resolveTextDirection(string)) {
+						switch (BidiUtil.resolveTextDirection(string)) {
 							case SWT.LEFT_TO_RIGHT:
 								string = LRE + string;
 								length++;
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
index 6ddb901dd1..34137bf398 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
@@ -14,6 +14,7 @@ package org.eclipse.swt.widgets;
 import org.eclipse.swt.*;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.internal.BidiUtil;
 import org.eclipse.swt.internal.win32.*;
 
 /**
@@ -1747,9 +1748,9 @@ int resolveTextDirection() {
 		OS.GetWindowText (handle, buffer, length + 1);
 		if (segments != null) {
 			buffer = deprocessText (buffer, 0, -1, false);
-			textDirection = resolveTextDirection(buffer.toString ());
+			textDirection = BidiUtil.resolveTextDirection(buffer.toString ());
 		} else {
-			textDirection = resolveTextDirection(buffer.toString (0, length));
+			textDirection = BidiUtil.resolveTextDirection(buffer.toString (0, length));
 		}
 		if (textDirection == SWT.NONE) {
 			/*
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Widget.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Widget.java
index a70f10b242..01ecd025e7 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Widget.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Widget.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2013 IBM Corporation and others.
+ * Copyright (c) 2000, 2015 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -699,6 +699,20 @@ boolean hooks (int eventType) {
 }
 
 /**
+ * Returns <code>true</code> if the widget has auto text direction,
+ * and <code>false</code> otherwise.
+ *
+ * @return <code>true</code> when the widget has auto direction and <code>false</code> otherwise
+ * 
+ * @see #HAS_AUTO_DIRECTION
+ * 
+ * @since 3.105
+ */
+public boolean isAutoDirection () {
+	return (state & HAS_AUTO_DIRECTION) != 0;
+}
+
+/**
  * Returns <code>true</code> if the widget has been disposed,
  * and <code>false</code> otherwise.
  * <p>
@@ -1039,52 +1053,6 @@ void reskinWidget() {
 	}
 }
 
-static int resolveTextDirection(String text) {
-	if (text == null) return SWT.NONE;
-	int length = text.length();
-	if (length == 0) return SWT.NONE;
-	char[] rtlProbe = {' ', ' ', '1'};
-	/*
-	 * "Wide" version of win32 API can also run even on non-Unicode Windows,
-	 * hence need for OS.IsUnicode check here. 
-	 */
-	char[] ltrProbe = {RLE, 'a', ' '};
-	char[] numberProbe = {'\u05d0', ' ', ' '};
-	GCP_RESULTS result = new GCP_RESULTS();
-	result.lStructSize = GCP_RESULTS.sizeof;
-	int nGlyphs = result.nGlyphs = ltrProbe.length;
-	long /*int*/ hHeap = OS.GetProcessHeap();
-	long /*int*/ lpOrder = result.lpOrder = OS.HeapAlloc(hHeap, OS.HEAP_ZERO_MEMORY, nGlyphs * 4);
-	long /*int*/ hdc = OS.GetDC(0);
-	int[] order = new int[1];
-	int textDirection = SWT.NONE;
-	for (int i = 0; i < length; i++) {
-		char ch = text.charAt(i);
-		rtlProbe[0] = ch;
-		OS.GetCharacterPlacementW(hdc, rtlProbe, rtlProbe.length, 0, result, OS.GCP_REORDER);
-		OS.MoveMemory(order, result.lpOrder, 4);
-		if (order[0] == 2) {
-			textDirection = SWT.RIGHT_TO_LEFT;
-			break;
-		}
-		ltrProbe[2] = ch;
-		OS.GetCharacterPlacementW(hdc, ltrProbe, ltrProbe.length, 0, result, OS.GCP_REORDER);
-		OS.MoveMemory(order, result.lpOrder + 4, 4);
-		if (order[0] == 1) {
-			numberProbe[2] = ch;
-			OS.GetCharacterPlacementW(hdc, numberProbe, numberProbe.length, 0, result, OS.GCP_REORDER);
-			OS.MoveMemory(order, result.lpOrder, 4);
-			if (order[0] == 0) {
-				textDirection = SWT.LEFT_TO_RIGHT;
-				break;
-			}
-		}
-	}
-	OS.ReleaseDC (0, hdc);
-	OS.HeapFree(hHeap, 0, lpOrder);
-	return textDirection;
-}
-
 boolean sendDragEvent (int button, int x, int y) {
 	Event event = new Event ();
 	event.button = button;