From 9b9501b0fef312da72586299e22d329f00ac5e20 Mon Sep 17 00:00:00 2001
From: Leo Ufimtsev
Date: Tue, 24 Jan 2017 12:23:26 -0500
Subject: Bug 508217 Implement webkit2 support for browser function

(Part 1: JavaScript to call Java) 

This implements Browser.function() on webkit2.
Current implementation allows javascript to reach java, but java doesn't
provide a return vaulue in the callback.

For detailed architecture changes, see: Webkit2JavaCallback() inside
WebKit.java. 
In short, in webkit1 an 'external' object was registered and callJava
was a property of this object.
In webkit2, 'external' object is no longer used and instead a
callback/signal is registered/connected.

With this patch, the following jUnits pass:
test_BrowserFunction_callback
test_BrowserFunction_callback_with_integer
test_BrowserFunction_callback_with_boolean
test_BrowserFunction_callback_with_String
test_BrowserFunction_callback_with_multipleValues
testBrowser4.

The following does not:
test_BrowserFunction_callback_with_javaReturningInt

Patch set 4:
- I noticed that after a page re-load, webkit2 custom functions did not
work. This is because the page-reload mechanism has changed (Bg:510972)
but in the ported webkit2 mechanism functions were not re-registered).
- Added code to re-register custom functions after page reload.

Patch set 7:
- Removed 'protected' modifier.
- Moved comments around.

Change-Id: I94549ed306e0095c735d18389b55a36923c5ec08
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>
---
 .../common/org/eclipse/swt/browser/WebBrowser.java  | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

(limited to 'bundles/org.eclipse.swt/Eclipse SWT Browser')

diff --git a/bundles/org.eclipse.swt/Eclipse SWT Browser/common/org/eclipse/swt/browser/WebBrowser.java b/bundles/org.eclipse.swt/Eclipse SWT Browser/common/org/eclipse/swt/browser/WebBrowser.java
index 5f79e68379..df7f31745e 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT Browser/common/org/eclipse/swt/browser/WebBrowser.java	
+++ b/bundles/org.eclipse.swt/Eclipse SWT Browser/common/org/eclipse/swt/browser/WebBrowser.java	
@@ -346,8 +346,10 @@ public void createFunction (BrowserFunction function) {
 	functionBuffer.append (ERROR_ID.length ());
 	functionBuffer.append (")); throw error;} return result;};"); //$NON-NLS-1$
 
-	StringBuffer buffer = new StringBuffer ("if (!window.callJava) {window.callJava = function callJava(index, token, args) {"); //$NON-NLS-1$
-	buffer.append ("return external.callJava(index,token,args);}};"); //$NON-NLS-1$
+	String javaCallDeclaration = getJavaCallDeclaration();
+
+	StringBuffer buffer = new StringBuffer (); //$NON-NLS-1$
+	buffer.append (javaCallDeclaration); //$NON-NLS-1$
 	if (function.top) {
 		buffer.append (functionBuffer.toString ());
 	}
@@ -375,6 +377,18 @@ public void createFunction (BrowserFunction function) {
 	execute (function.functionString);
 }
 
+/**
+ * Designed to be overriden.
+ * @return javaScrit code that defines the 'callJava' syntax for javascript.
+ */
+String getJavaCallDeclaration() {
+	return    "if (!window.callJava) {\n"
+			+ "		window.callJava = function callJava(index, token, args) {\n"
+			+ "			return external.callJava(index,token,args);\n"
+			+ "		}\n"
+			+ "};\n";
+}
+
 void deregisterFunction (BrowserFunction function) {
 	functions.remove (function.index);
 }
@@ -396,6 +410,9 @@ public Object evaluate (String script, boolean trusted) throws SWTException {
 }
 
 public Object evaluate (String script) throws SWTException {
+	// Developer note:
+	// Webkit1 & Mozilla use this mechanism.
+	// Webkit2 uses a different mechanism. See WebKit:evaluate();
 	BrowserFunction function = new EvaluateFunction (browser, ""); // $NON-NLS-1$
 	int index = getNextFunctionIndex ();
 	function.index = index;
-- 
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