user/src/com/google/gwt/core/client/impl/StackTraceCreator.java - gwt - Git at Google

 /*
  * Copyright 2009 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
  * the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations under
  * the License.
  */
 package com.google.gwt.core.client.impl;

 import com.google.gwt.core.client.GWT;
 import com.google.gwt.core.client.JavaScriptException;
 import com.google.gwt.core.client.JavaScriptObject;
 import com.google.gwt.core.client.JsArray;
 import com.google.gwt.core.client.JsArrayString;

 /**
  * Encapsulates logic to create a stack trace. This class should only be used in
  * Production Mode.
  */
 public class StackTraceCreator {

   /**
    * Line number used in a stack trace when it is unknown.
    */
   public static final int LINE_NUMBER_UNKNOWN = -1;

   /**
    * This class acts as a deferred-binding hook point to allow more optimal
    * versions to be substituted. This base version simply crawls
    * <code>arguments.callee.caller</code>.
    */
   static class Collector {
     public native JsArrayString collect() /*-{
       var seen = {};
       var toReturn = [];

       // Ignore the collect() and fillInStackTrace call
       var callee = arguments.callee.caller.caller;
       while (callee) {
         var name = this.@com.google.gwt.core.client.impl.StackTraceCreator.Collector::extractName(Ljava/lang/String;)(callee.toString());
         toReturn.push(name);

         // Avoid infinite loop by associating names to function objects.  We
         // record each caller in the withThisName variable to handle functions
         // with identical names but separate identity (such as 'anonymous')
         var keyName = ':' + name;
         var withThisName = seen[keyName];
         if (withThisName) {
           var i, j;
           for (i = 0, j = withThisName.length; i < j; i++) {
             if (withThisName[i] === callee) {
               return toReturn;
             }
           }
         }

         (withThisName || (seen[keyName] = [])).push(callee);
         callee = callee.caller;
       }
       return toReturn;
     }-*/;

     public void createStackTrace(JavaScriptException e) {
       JsArrayString stack = inferFrom(e.getException());

       StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
       for (int i = 0, j = stackTrace.length; i < j; i++) {
         stackTrace[i] = new StackTraceElement("Unknown", stack.get(i), null,
             LINE_NUMBER_UNKNOWN);
       }
       e.setStackTrace(stackTrace);
     }

     public void fillInStackTrace(Throwable t) {
       JsArrayString stack = StackTraceCreator.createStackTrace();
       StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
       for (int i = 0, j = stackTrace.length; i < j; i++) {
         stackTrace[i] = new StackTraceElement("Unknown", stack.get(i), null,
             LINE_NUMBER_UNKNOWN);
       }
       t.setStackTrace(stackTrace);
     }

     /**
      * Returns the list of properties of an unexpected JavaScript exception.
      */
     public native String getProperties(JavaScriptObject e) /*-{
       var result = "";
       try {
         for (var prop in e) {
           if (prop != "name" && prop != "message" && prop != "toString") {
             try {
               result += "\n " + prop + ": " + e[prop];
             } catch (ignored) {
               // Skip the property if it threw an exception.
             }
           }
         }
       } catch (ignored) {
         // If we can't do "in" on the exception, just return what we have.
       }
       return result;
     }-*/;

     /**
      * Attempt to infer the stack from an unknown JavaScriptObject that had been
      * thrown. The default implementation just returns an empty array.
      *
      * @param e a JavaScriptObject
      */
     public JsArrayString inferFrom(JavaScriptObject e) {
       return JavaScriptObject.createArray().cast();
     }

     /**
      * Extract the name of a function from it's toString() representation.
      * Package-access for testing.
      */
     protected String extractName(String fnToString) {
       return extractNameFromToString(fnToString);
     }

     /**
      * Raise an exception and return it.
      */
     protected native JavaScriptObject makeException() /*-{
       try {
         null.a();
       } catch (e) {
         return e;
       }
     }-*/;
   }

   /**
    * Collaborates with JsStackEmulator.
    */
   static class CollectorEmulated extends Collector {

     @Override
     public JsArrayString collect() {
       JsArrayString toReturn = JsArrayString.createArray().cast();
       JsArray<JavaScriptObject> stack = getStack();
       for (int i = 0, j = getStackDepth(); i < j; i++) {
         String name = stack.get(i) == null ? "anonymous"
             : extractName(stack.get(i).toString());
         // Reverse the order
         toReturn.set(j - i - 1, name);
       }

       return toReturn;
     }

     @Override
     public void createStackTrace(JavaScriptException e) {
       // No-op, relying on initializer call to collect()
     }

     @Override
     public void fillInStackTrace(Throwable t) {
       JsArrayString stack = collect();
       JsArrayString locations = getLocation();
       StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
       for (int i = 0, j = stackTrace.length; i < j; i++) {
         // Locations is also backwards
         String location = locations.get(j - i - 1);
         String fileName = null;
         int lineNumber = LINE_NUMBER_UNKNOWN;
         if (location != null) {
           int idx = location.indexOf(':');
           if (idx != -1) {
             fileName = location.substring(0, idx);
             lineNumber = Integer.parseInt(location.substring(idx + 1));
           } else {
             lineNumber = Integer.parseInt(location);
           }
         }
         stackTrace[i] = new StackTraceElement("Unknown", stack.get(i),
             fileName, lineNumber);
       }
       t.setStackTrace(stackTrace);
     }

     /**
      * When compiler.stackMode = emulated, return an empty string, rather than a
      * list of properties, since the additional information regarding the origin
      * of the JavaScriptException, relative to compiled JavaScript source code,
      * adds no real value, since we have fully emulated stack traces.
      */
     @Override
     public String getProperties(JavaScriptObject e) {
       return "";
     }

     @Override
     public JsArrayString inferFrom(JavaScriptObject e) {
       throw new RuntimeException("Should not reach here");
     }

     private native JsArrayString getLocation()/*-{
       return $location;
     }-*/;

     private native JsArray<JavaScriptObject> getStack()/*-{
       return $stack;
     }-*/;

     private native int getStackDepth() /*-{
       return $stackDepth;
     }-*/;
   }

   /**
    * Mozilla provides a <code>stack</code> property in thrown objects.
    */
   static class CollectorMoz extends Collector {
     /**
      * This implementation doesn't suffer from the limitations of crawling
      * <code>caller</code> since Mozilla provides proper activation records.
      */
     @Override
     public JsArrayString collect() {
       return splice(inferFrom(makeException()), toSplice());
     }

     @Override
     public JsArrayString inferFrom(JavaScriptObject e) {
       JsArrayString stack = getStack(e);
       for (int i = 0, j = stack.length(); i < j; i++) {
         stack.set(i, extractName(stack.get(i)));
       }
       return stack;
     }

     protected native JsArrayString getStack(JavaScriptObject e) /*-{
       return (e && e.stack) ? e.stack.split('\n') : [];
     }-*/;

     protected int toSplice() {
       return 2;
     }
   }

   /**
    * Chrome uses a slightly different format to Mozilla.
    *
    * See http://code.google.com/p/v8/source/browse/branches/bleeding_edge/src/
    * messages.js?r=2340#712 for formatting code.
    *
    * Function calls can be of the four following forms:
    *
    * <pre>
    * at file.js:1:2
    * at functionName (file.js:1:2)
    * at Type.functionName (file.js:1:2)
    * at Type.functionName [as methodName] (file.js:1:2)
    * </pre>
    */
   static class CollectorChrome extends CollectorMoz {

     static {
       increaseChromeStackTraceLimit();
     }

     // TODO(cromwellian) make this a configurable?
     private static native void increaseChromeStackTraceLimit() /*-{
       // 128 seems like a reasonable maximum
       Error.stackTraceLimit = 128;
     }-*/;

     @Override
     public JsArrayString collect() {
       JsArrayString res = super.collect();
       if (res.length() == 0) {
         /*
          * Ensure Safari falls back to default Collector implementation.
          * Remember to remove this method call from the stack:
          */
         res = splice(new Collector().collect(), 1);
       }
       return res;
     }

     @Override
     public void createStackTrace(JavaScriptException e) {
       JsArrayString stack = inferFrom(e.getException());
       parseStackTrace(e, stack);
     }

     @Override
     public void fillInStackTrace(Throwable t) {
       JsArrayString stack = StackTraceCreator.createStackTrace();
       parseStackTrace(t, stack);
     }

     @Override
     public JsArrayString inferFrom(JavaScriptObject e) {
       JsArrayString stack = super.inferFrom(e);
       if (stack.length() == 0) {
         // Safari should fall back to default Collector:
         return new Collector().inferFrom(e);
       } else {
         // Chrome contains the error itself as the first line of the stack:
         return splice(stack, 1);
       }
     }

     @Override
     protected String extractName(String fnToString) {
       String extractedName = "anonymous";
       String location = "";

       if (fnToString.length() == 0) {
         return extractedName;
       }

       String toReturn = fnToString.trim();

       // Strip the "at " prefix:
       if (toReturn.startsWith("at ")) {
         toReturn = toReturn.substring(3);
       }

       // Strip square bracketed items from the end:
       int index = toReturn.indexOf("[");
       if (index != -1) {
         toReturn = toReturn.substring(0, index).trim() +
             toReturn.substring(toReturn.indexOf("]", index) + 1).trim();
       }

       index = toReturn.indexOf("(");
       if (index == -1) {
         // No bracketed items found, hence no function name available
         location = toReturn;
         toReturn = "";
       } else {
         // Bracketed items found: strip them off, parse location info
         int closeParen = toReturn.indexOf(")", index);
         location = toReturn.substring(index + 1, closeParen);
         toReturn = toReturn.substring(0, index).trim();
       }

       // Strip the Type off t
       index = toReturn.indexOf('.');
       if (index != -1) {
         toReturn = toReturn.substring(index + 1);
       }
       return (toReturn.length() > 0 ? toReturn : "anonymous") + "@@" + location;
     }

     protected int replaceIfNoSourceMap(int line) {
          return line;
     }

     @Override
     protected int toSplice() {
       return 3;
     }

     private void parseStackTrace(Throwable e, JsArrayString stack) {
       StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
       for (int i = 0, j = stackTrace.length; i < j; i++) {
         String stackElements[] = stack.get(i).split("@@");

         int line = LINE_NUMBER_UNKNOWN;
         int col = -1;
         String fileName = "Unknown";
         if (stackElements.length == 2 && stackElements[1] != null) {
           String location = stackElements[1];
           // colon between line and column
           int lastColon = location.lastIndexOf(':');
           // colon between file url and line number
           int endFileUrl = location.lastIndexOf(':', lastColon - 1);
           fileName = location.substring(0, endFileUrl);

           if (lastColon != -1 && endFileUrl != -1) {
               line = parseInt(location.substring(endFileUrl + 1, lastColon));
               col = parseInt(location.substring(lastColon + 1));
           }
         }
         stackTrace[i] = new StackTraceElement("Unknown", stackElements[0], fileName + "@" + col,
             replaceIfNoSourceMap(line < 0 ? -1 : line));
       }
       e.setStackTrace(stackTrace);
     }
   }

   /**
    * Subclass that forces reported line numbers to -1 (fetch from symbolMap) if source maps are
    * disabled.
    */
   static class CollectorChromeNoSourceMap extends CollectorChrome {
     protected int replaceIfNoSourceMap(int line) {
       return -1;
     }
   }

   private static native int parseInt(String number) /*-{
     return parseInt(number) || -1;
   }-*/;

   /**
    * Opera encodes stack trace information in the error's message.
    */
   static class CollectorOpera extends CollectorMoz {
     /**
      * We have much a much simpler format to work with.
      */
     @Override
     protected String extractName(String fnToString) {
       return fnToString.length() == 0 ? "anonymous" : fnToString;
     }

     /**
      * Opera has the function name on every-other line.
      */
     @Override
     protected JsArrayString getStack(JavaScriptObject e) {
       JsArrayString toReturn = getMessage(e);
       assert toReturn.length() % 2 == 0 : "Expecting an even number of lines";

       int i, i2, j;
       for (i = 0, i2 = 0, j = toReturn.length(); i2 < j; i++, i2 += 2) {
         int idx = toReturn.get(i2).lastIndexOf("function ");
         if (idx == -1) {
           toReturn.set(i, "");
         } else {
           toReturn.set(i, toReturn.get(i2).substring(idx + 9).trim());
         }
       }
       setLength(toReturn, i);

       return toReturn;
     }

     @Override
     protected int toSplice() {
       return 3;
     }

     private native JsArrayString getMessage(JavaScriptObject e) /*-{
       return (e && e.message) ? e.message.split('\n') : [];
     }-*/;

     private native void setLength(JsArrayString obj, int length) /*-{
       obj.length = length;
     }-*/;
   }

   /**
    * When compiler.stackMode = strip, we stub out the collector.
    */
   static class CollectorNull extends Collector {
     @Override
     public  JsArrayString collect() {
       return JsArrayString.createArray().cast();
     }

     @Override
     public void createStackTrace(JavaScriptException e) {
       // empty, since Throwable.getStackTrace() properly handles null
     }

     @Override
     public void fillInStackTrace(Throwable t) {
       // empty, since Throwable.getStackTrace() properly handles null
     }
   }

   /**
    * Create a stack trace based on a JavaScriptException. This method should
    * only be called in Production Mode.
    */
   public static void createStackTrace(JavaScriptException e) {
     if (!GWT.isScript()) {
       throw new RuntimeException(
           "StackTraceCreator should only be called in Production Mode");
     }

     GWT.<Collector> create(Collector.class).createStackTrace(e);
   }

   /**
    * Fill in a stack trace based on the current execution stack. This method
    * should only be called in Production Mode.
    */
   public static void fillInStackTrace(Throwable t) {
     if (!GWT.isScript()) {
       throw new RuntimeException(
           "StackTraceCreator should only be called in Production Mode");
     }

     GWT.<Collector> create(Collector.class).fillInStackTrace(t);
   }

   /**
    * Returns the list of properties of an unexpected JavaScript exception,
    * unless compiler.stackMode = emulated, in which case the empty string is
    * returned. This method should only be called in Production Mode.
    */
   public static String getProperties(JavaScriptObject e) {
     if (!GWT.isScript()) {
       throw new RuntimeException(
           "StackTraceCreator should only be called in Production Mode");
     }

     return GWT.<Collector> create(Collector.class).getProperties(e);
   }

   /**
    * Create a stack trace based on the current execution stack. This method
    * should only be called in Production Mode.
    */
   static JsArrayString createStackTrace() {
     if (!GWT.isScript()) {
       throw new RuntimeException(
           "StackTraceCreator should only be called in Production Mode");
     }

     return GWT.<Collector> create(Collector.class).collect();
   }

   static String extractNameFromToString(String fnToString) {
     String toReturn = "";
     fnToString = fnToString.trim();
     int index = fnToString.indexOf("(");
     int start = fnToString.startsWith("function") ? 8 : 0;
     if (index == -1) {
       // Firefox 14 does not include parenthesis and uses '@' symbol instead to terminate symbol
       index = fnToString.indexOf('@');
       /**
        * Firefox 14 doesn't return strings like 'function()' for anonymous methods, so
        * we assert a space must trail 'function' keyword for a method named 'functionName', e.g.
        * functionName:file.js:2 won't accidentally strip off the 'function' prefix which is part
        * of the name.
        */
       start = fnToString.startsWith("function ") ? 9 : 0;
     }
     if (index != -1) {
       toReturn = fnToString.substring(start, index).trim();
     }
     return toReturn.length() > 0 ? toReturn : "anonymous";
   }

   private static native JsArrayString splice(JsArrayString arr, int length) /*-{
     (arr.length >= length) && arr.splice(0, length);
     return arr;
   }-*/;
 }
	/*
	* Copyright 2009 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may not
	* use this file except in compliance with the License. You may obtain a copy of
	* the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations under
	* the License.
	*/
	package com.google.gwt.core.client.impl;

	import com.google.gwt.core.client.GWT;
	import com.google.gwt.core.client.JavaScriptException;
	import com.google.gwt.core.client.JavaScriptObject;
	import com.google.gwt.core.client.JsArray;
	import com.google.gwt.core.client.JsArrayString;

	/**
	* Encapsulates logic to create a stack trace. This class should only be used in
	* Production Mode.
	*/
	public class StackTraceCreator {

	/**
	* Line number used in a stack trace when it is unknown.
	*/
	public static final int LINE_NUMBER_UNKNOWN = -1;

	/**
	* This class acts as a deferred-binding hook point to allow more optimal
	* versions to be substituted. This base version simply crawls
	* <code>arguments.callee.caller</code>.
	*/
	static class Collector {
	public native JsArrayString collect() /*-{
	var seen = {};
	var toReturn = [];

	// Ignore the collect() and fillInStackTrace call
	var callee = arguments.callee.caller.caller;
	while (callee) {
	var name = this.@com.google.gwt.core.client.impl.StackTraceCreator.Collector::extractName(Ljava/lang/String;)(callee.toString());
	toReturn.push(name);

	// Avoid infinite loop by associating names to function objects. We
	// record each caller in the withThisName variable to handle functions
	// with identical names but separate identity (such as 'anonymous')
	var keyName = ':' + name;
	var withThisName = seen[keyName];
	if (withThisName) {
	var i, j;
	for (i = 0, j = withThisName.length; i < j; i++) {
	if (withThisName[i] === callee) {
	return toReturn;
	}
	}
	}

	(withThisName \|\| (seen[keyName] = [])).push(callee);
	callee = callee.caller;
	}
	return toReturn;
	}-*/;

	public void createStackTrace(JavaScriptException e) {
	JsArrayString stack = inferFrom(e.getException());

	StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
	for (int i = 0, j = stackTrace.length; i < j; i++) {
	stackTrace[i] = new StackTraceElement("Unknown", stack.get(i), null,
	LINE_NUMBER_UNKNOWN);
	}
	e.setStackTrace(stackTrace);
	}

	public void fillInStackTrace(Throwable t) {
	JsArrayString stack = StackTraceCreator.createStackTrace();
	StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
	for (int i = 0, j = stackTrace.length; i < j; i++) {
	stackTrace[i] = new StackTraceElement("Unknown", stack.get(i), null,
	LINE_NUMBER_UNKNOWN);
	}
	t.setStackTrace(stackTrace);
	}

	/**
	* Returns the list of properties of an unexpected JavaScript exception.
	*/
	public native String getProperties(JavaScriptObject e) /*-{
	var result = "";
	try {
	for (var prop in e) {
	if (prop != "name" && prop != "message" && prop != "toString") {
	try {
	result += "\n " + prop + ": " + e[prop];
	} catch (ignored) {
	// Skip the property if it threw an exception.
	}
	}
	}
	} catch (ignored) {
	// If we can't do "in" on the exception, just return what we have.
	}
	return result;
	}-*/;

	/**
	* Attempt to infer the stack from an unknown JavaScriptObject that had been
	* thrown. The default implementation just returns an empty array.
	*
	* @param e a JavaScriptObject
	*/
	public JsArrayString inferFrom(JavaScriptObject e) {
	return JavaScriptObject.createArray().cast();
	}

	/**
	* Extract the name of a function from it's toString() representation.
	* Package-access for testing.
	*/
	protected String extractName(String fnToString) {
	return extractNameFromToString(fnToString);
	}

	/**
	* Raise an exception and return it.
	*/
	protected native JavaScriptObject makeException() /*-{
	try {
	null.a();
	} catch (e) {
	return e;
	}
	}-*/;
	}

	/**
	* Collaborates with JsStackEmulator.
	*/
	static class CollectorEmulated extends Collector {

	@Override
	public JsArrayString collect() {
	JsArrayString toReturn = JsArrayString.createArray().cast();
	JsArray<JavaScriptObject> stack = getStack();
	for (int i = 0, j = getStackDepth(); i < j; i++) {
	String name = stack.get(i) == null ? "anonymous"
	: extractName(stack.get(i).toString());
	// Reverse the order
	toReturn.set(j - i - 1, name);
	}

	return toReturn;
	}

	@Override
	public void createStackTrace(JavaScriptException e) {
	// No-op, relying on initializer call to collect()
	}

	@Override
	public void fillInStackTrace(Throwable t) {
	JsArrayString stack = collect();
	JsArrayString locations = getLocation();
	StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
	for (int i = 0, j = stackTrace.length; i < j; i++) {
	// Locations is also backwards
	String location = locations.get(j - i - 1);
	String fileName = null;
	int lineNumber = LINE_NUMBER_UNKNOWN;
	if (location != null) {
	int idx = location.indexOf(':');
	if (idx != -1) {
	fileName = location.substring(0, idx);
	lineNumber = Integer.parseInt(location.substring(idx + 1));
	} else {
	lineNumber = Integer.parseInt(location);
	}
	}
	stackTrace[i] = new StackTraceElement("Unknown", stack.get(i),
	fileName, lineNumber);
	}
	t.setStackTrace(stackTrace);
	}

	/**
	* When compiler.stackMode = emulated, return an empty string, rather than a
	* list of properties, since the additional information regarding the origin
	* of the JavaScriptException, relative to compiled JavaScript source code,
	* adds no real value, since we have fully emulated stack traces.
	*/
	@Override
	public String getProperties(JavaScriptObject e) {
	return "";
	}

	@Override
	public JsArrayString inferFrom(JavaScriptObject e) {
	throw new RuntimeException("Should not reach here");
	}

	private native JsArrayString getLocation()/*-{
	return $location;
	}-*/;

	private native JsArray<JavaScriptObject> getStack()/*-{
	return $stack;
	}-*/;

	private native int getStackDepth() /*-{
	return $stackDepth;
	}-*/;
	}

	/**
	* Mozilla provides a <code>stack</code> property in thrown objects.
	*/
	static class CollectorMoz extends Collector {
	/**
	* This implementation doesn't suffer from the limitations of crawling
	* <code>caller</code> since Mozilla provides proper activation records.
	*/
	@Override
	public JsArrayString collect() {
	return splice(inferFrom(makeException()), toSplice());
	}

	@Override
	public JsArrayString inferFrom(JavaScriptObject e) {
	JsArrayString stack = getStack(e);
	for (int i = 0, j = stack.length(); i < j; i++) {
	stack.set(i, extractName(stack.get(i)));
	}
	return stack;
	}

	protected native JsArrayString getStack(JavaScriptObject e) /*-{
	return (e && e.stack) ? e.stack.split('\n') : [];
	}-*/;

	protected int toSplice() {
	return 2;
	}
	}

	/**
	* Chrome uses a slightly different format to Mozilla.
	*
	* See http://code.google.com/p/v8/source/browse/branches/bleeding_edge/src/
	* messages.js?r=2340#712 for formatting code.
	*
	* Function calls can be of the four following forms:
	*
	* <pre>
	* at file.js:1:2
	* at functionName (file.js:1:2)
	* at Type.functionName (file.js:1:2)
	* at Type.functionName [as methodName] (file.js:1:2)
	* </pre>
	*/
	static class CollectorChrome extends CollectorMoz {

	static {
	increaseChromeStackTraceLimit();
	}

	// TODO(cromwellian) make this a configurable?
	private static native void increaseChromeStackTraceLimit() /*-{
	// 128 seems like a reasonable maximum
	Error.stackTraceLimit = 128;
	}-*/;

	@Override
	public JsArrayString collect() {
	JsArrayString res = super.collect();
	if (res.length() == 0) {
	/*
	* Ensure Safari falls back to default Collector implementation.
	* Remember to remove this method call from the stack:
	*/
	res = splice(new Collector().collect(), 1);
	}
	return res;
	}

	@Override
	public void createStackTrace(JavaScriptException e) {
	JsArrayString stack = inferFrom(e.getException());
	parseStackTrace(e, stack);
	}

	@Override
	public void fillInStackTrace(Throwable t) {
	JsArrayString stack = StackTraceCreator.createStackTrace();
	parseStackTrace(t, stack);
	}

	@Override
	public JsArrayString inferFrom(JavaScriptObject e) {
	JsArrayString stack = super.inferFrom(e);
	if (stack.length() == 0) {
	// Safari should fall back to default Collector:
	return new Collector().inferFrom(e);
	} else {
	// Chrome contains the error itself as the first line of the stack:
	return splice(stack, 1);
	}
	}

	@Override
	protected String extractName(String fnToString) {
	String extractedName = "anonymous";
	String location = "";

	if (fnToString.length() == 0) {
	return extractedName;
	}

	String toReturn = fnToString.trim();

	// Strip the "at " prefix:
	if (toReturn.startsWith("at ")) {
	toReturn = toReturn.substring(3);
	}

	// Strip square bracketed items from the end:
	int index = toReturn.indexOf("[");
	if (index != -1) {
	toReturn = toReturn.substring(0, index).trim() +
	toReturn.substring(toReturn.indexOf("]", index) + 1).trim();
	}

	index = toReturn.indexOf("(");
	if (index == -1) {
	// No bracketed items found, hence no function name available
	location = toReturn;
	toReturn = "";
	} else {
	// Bracketed items found: strip them off, parse location info
	int closeParen = toReturn.indexOf(")", index);
	location = toReturn.substring(index + 1, closeParen);
	toReturn = toReturn.substring(0, index).trim();
	}

	// Strip the Type off t
	index = toReturn.indexOf('.');
	if (index != -1) {
	toReturn = toReturn.substring(index + 1);
	}
	return (toReturn.length() > 0 ? toReturn : "anonymous") + "@@" + location;
	}

	protected int replaceIfNoSourceMap(int line) {
	return line;
	}

	@Override
	protected int toSplice() {
	return 3;
	}

	private void parseStackTrace(Throwable e, JsArrayString stack) {
	StackTraceElement[] stackTrace = new StackTraceElement[stack.length()];
	for (int i = 0, j = stackTrace.length; i < j; i++) {
	String stackElements[] = stack.get(i).split("@@");

	int line = LINE_NUMBER_UNKNOWN;
	int col = -1;
	String fileName = "Unknown";
	if (stackElements.length == 2 && stackElements[1] != null) {
	String location = stackElements[1];
	// colon between line and column
	int lastColon = location.lastIndexOf(':');
	// colon between file url and line number
	int endFileUrl = location.lastIndexOf(':', lastColon - 1);
	fileName = location.substring(0, endFileUrl);

	if (lastColon != -1 && endFileUrl != -1) {
	line = parseInt(location.substring(endFileUrl + 1, lastColon));
	col = parseInt(location.substring(lastColon + 1));
	}
	}
	stackTrace[i] = new StackTraceElement("Unknown", stackElements[0], fileName + "@" + col,
	replaceIfNoSourceMap(line < 0 ? -1 : line));
	}
	e.setStackTrace(stackTrace);
	}
	}

	/**
	* Subclass that forces reported line numbers to -1 (fetch from symbolMap) if source maps are
	* disabled.
	*/
	static class CollectorChromeNoSourceMap extends CollectorChrome {
	protected int replaceIfNoSourceMap(int line) {
	return -1;
	}
	}

	private static native int parseInt(String number) /*-{
	return parseInt(number) \|\| -1;
	}-*/;

	/**
	* Opera encodes stack trace information in the error's message.
	*/
	static class CollectorOpera extends CollectorMoz {
	/**
	* We have much a much simpler format to work with.
	*/
	@Override
	protected String extractName(String fnToString) {
	return fnToString.length() == 0 ? "anonymous" : fnToString;
	}

	/**
	* Opera has the function name on every-other line.
	*/
	@Override
	protected JsArrayString getStack(JavaScriptObject e) {
	JsArrayString toReturn = getMessage(e);
	assert toReturn.length() % 2 == 0 : "Expecting an even number of lines";

	int i, i2, j;
	for (i = 0, i2 = 0, j = toReturn.length(); i2 < j; i++, i2 += 2) {
	int idx = toReturn.get(i2).lastIndexOf("function ");
	if (idx == -1) {
	toReturn.set(i, "");
	} else {
	toReturn.set(i, toReturn.get(i2).substring(idx + 9).trim());
	}
	}
	setLength(toReturn, i);

	return toReturn;
	}

	@Override
	protected int toSplice() {
	return 3;
	}

	private native JsArrayString getMessage(JavaScriptObject e) /*-{
	return (e && e.message) ? e.message.split('\n') : [];
	}-*/;

	private native void setLength(JsArrayString obj, int length) /*-{
	obj.length = length;
	}-*/;
	}

	/**
	* When compiler.stackMode = strip, we stub out the collector.
	*/
	static class CollectorNull extends Collector {
	@Override
	public JsArrayString collect() {
	return JsArrayString.createArray().cast();
	}

	@Override
	public void createStackTrace(JavaScriptException e) {
	// empty, since Throwable.getStackTrace() properly handles null
	}

	@Override
	public void fillInStackTrace(Throwable t) {
	// empty, since Throwable.getStackTrace() properly handles null
	}
	}

	/**
	* Create a stack trace based on a JavaScriptException. This method should
	* only be called in Production Mode.
	*/
	public static void createStackTrace(JavaScriptException e) {
	if (!GWT.isScript()) {
	throw new RuntimeException(
	"StackTraceCreator should only be called in Production Mode");
	}

	GWT.<Collector> create(Collector.class).createStackTrace(e);
	}

	/**
	* Fill in a stack trace based on the current execution stack. This method
	* should only be called in Production Mode.
	*/
	public static void fillInStackTrace(Throwable t) {
	if (!GWT.isScript()) {
	throw new RuntimeException(
	"StackTraceCreator should only be called in Production Mode");
	}

	GWT.<Collector> create(Collector.class).fillInStackTrace(t);
	}

	/**
	* Returns the list of properties of an unexpected JavaScript exception,
	* unless compiler.stackMode = emulated, in which case the empty string is
	* returned. This method should only be called in Production Mode.
	*/
	public static String getProperties(JavaScriptObject e) {
	if (!GWT.isScript()) {
	throw new RuntimeException(
	"StackTraceCreator should only be called in Production Mode");
	}

	return GWT.<Collector> create(Collector.class).getProperties(e);
	}

	/**
	* Create a stack trace based on the current execution stack. This method
	* should only be called in Production Mode.
	*/
	static JsArrayString createStackTrace() {
	if (!GWT.isScript()) {
	throw new RuntimeException(
	"StackTraceCreator should only be called in Production Mode");
	}

	return GWT.<Collector> create(Collector.class).collect();
	}

	static String extractNameFromToString(String fnToString) {
	String toReturn = "";
	fnToString = fnToString.trim();
	int index = fnToString.indexOf("(");
	int start = fnToString.startsWith("function") ? 8 : 0;
	if (index == -1) {
	// Firefox 14 does not include parenthesis and uses '@' symbol instead to terminate symbol
	index = fnToString.indexOf('@');
	/**
	* Firefox 14 doesn't return strings like 'function()' for anonymous methods, so
	* we assert a space must trail 'function' keyword for a method named 'functionName', e.g.
	* functionName:file.js:2 won't accidentally strip off the 'function' prefix which is part
	* of the name.
	*/
	start = fnToString.startsWith("function ") ? 9 : 0;
	}
	if (index != -1) {
	toReturn = fnToString.substring(start, index).trim();
	}
	return toReturn.length() > 0 ? toReturn : "anonymous";
	}

	private static native JsArrayString splice(JsArrayString arr, int length) /*-{
	(arr.length >= length) && arr.splice(0, length);
	return arr;
	}-*/;
	}