elemental/src/elemental/json/impl/JsonUtil.java - gwt - Git at Google

 /*
  * Copyright 2010 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 elemental.json.impl;

 import com.google.gwt.regexp.shared.MatchResult;
 import com.google.gwt.regexp.shared.RegExp;

 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;

 import elemental.json.Json;
 import elemental.json.JsonArray;
 import elemental.json.JsonException;
 import elemental.json.JsonObject;
 import elemental.json.JsonValue;
 import elemental.json.impl.JsonContext;

 /**
  * Direct port of json2.js at http://www.json.org/json2.js to GWT.
  */
 public class JsonUtil {

   /**
    * Callback invoked during a RegExp replace for each match. The return value
    * is used as a substitution into the matched string.
    */
   private interface RegExpReplacer {

     String replace(String match);
   }

   private static class StringifyJsonVisitor extends JsonVisitor {

     private static final Set<String> skipKeys;

     static {
       Set<String> toSkip = new HashSet<String>();
       toSkip.add("$H");
       toSkip.add("__gwt_ObjectId");
       skipKeys = Collections.unmodifiableSet(toSkip);
     }

     private String indentLevel;

     private Set<JsonValue> visited;

     private final String indent;

     private final StringBuffer sb;

     private final boolean pretty;

     public StringifyJsonVisitor(String indent, StringBuffer sb,
         boolean pretty) {
       this.indent = indent;
       this.sb = sb;
       this.pretty = pretty;
       indentLevel = "";
       visited = new HashSet<JsonValue>();
     }

     @Override
     public void endVisit(JsonArray array, JsonContext ctx) {
       if (pretty) {
         indentLevel = indentLevel
             .substring(0, indentLevel.length() - indent.length());
         sb.append('\n');
         sb.append(indentLevel);
       }
       sb.append("]");
       visited.remove(array);
     }

     @Override
     public void endVisit(JsonObject object, JsonContext ctx) {
       if (pretty) {
         indentLevel = indentLevel
             .substring(0, indentLevel.length() - indent.length());
         sb.append('\n');
         sb.append(indentLevel);
       }
       sb.append("}");
       visited.remove(object);
       assert !visited.contains(object);
     }

     @Override
     public void visit(double number, JsonContext ctx) {
       sb.append(Double.isInfinite(number) ? "null" : format(number));
     }

     @Override
     public void visit(String string, JsonContext ctx) {
       sb.append(quote(string));
     }

     @Override
     public void visit(boolean bool, JsonContext ctx) {
       sb.append(bool);
     }

     @Override
     public boolean visit(JsonArray array, JsonContext ctx) {
       checkCycle(array);
       sb.append("[");
       if (pretty) {
         sb.append('\n');
         indentLevel += indent;
         sb.append(indentLevel);
       }
       return true;
     }

     @Override
     public boolean visit(JsonObject object, JsonContext ctx) {
       checkCycle(object);
       sb.append("{");
       if (pretty) {
         sb.append('\n');
         indentLevel += indent;
         sb.append(indentLevel);
       }
       return true;
     }

     @Override
     public boolean visitIndex(int index, JsonContext ctx) {
       commaIfNotFirst(ctx);
       return true;
     }

     @Override
     public boolean visitKey(String key, JsonContext ctx) {
       if ("".equals(key)) {
         return true;
       }
       // skip properties injected by GWT runtime on JSOs
       if (skipKeys.contains(key)) {
         return false;
       }
       commaIfNotFirst(ctx);
       sb.append(quote(key) + ":");
       if (pretty) {
         sb.append(' ');
       }
       return true;
     }

     @Override
     public void visitNull(JsonContext ctx) {
       sb.append("null");
     }

     private void checkCycle(JsonValue value) {
       if (visited.contains(value)) {
         throw new JsonException("Cycled detected during stringify");
       } else {
         visited.add(value);
       }
     }

     private void commaIfNotFirst(JsonContext ctx) {
       if (!ctx.isFirst()) {
         sb.append(",");
         if (pretty) {
           sb.append('\n');
           sb.append(indentLevel);
         }
       }
     }

     private String format(double number) {
       String n = String.valueOf(number);
       if (n.endsWith(".0")) {
         n = n.substring(0, n.length() - 2);
       }
       return n;
     }
   }

   /**
    * Convert special control characters into unicode escape format.
    */
   public static String escapeControlChars(String text) {
     StringBuffer toReturn = new StringBuffer();
     for (int i = 0; i < text.length(); i++) {
       char c = text.charAt(i);
       if (isControlChar(c)) {
         toReturn.append(escapeStringAsUnicode(String.valueOf(c)));
       } else {
         toReturn.append(c);
       }
     }
     return toReturn.toString();
   }

   public static <T extends JsonValue> T parse(String json) throws JsonException {
     return Json.instance().parse(json);
   }

   /**
    * Safely escape an arbitrary string as a JSON string literal.
    */
   public static String quote(String value) {
     StringBuffer toReturn = new StringBuffer();
     toReturn.append("\"");
     for (int i = 0; i < value.length(); i++) {
       char c = value.charAt(i);

       String toAppend = String.valueOf(c);
       switch (c) {
         case '\b':
           toAppend = "\\b";
           break;
         case '\t':
           toAppend = "\\t";
           break;
         case '\n':
           toAppend = "\\n";
           break;
         case '\f':
           toAppend = "\\f";
           break;
         case '\r':
           toAppend = "\\r";
           break;
         case '"':
           toAppend = "\\\"";
           break;
         case '\\':
           toAppend = "\\\\";
           break;
         default:
           if (isControlChar(c)) {
             toAppend = escapeStringAsUnicode(String.valueOf(c));
           }
       }
       toReturn.append(toAppend);
     }
     toReturn.append("\"");
     return toReturn.toString();
   }

   /**
    * Converts a Json Object to Json format.
    *
    * @param jsonValue  json object to stringify
    * @return json formatted string
    */
   public static String stringify(JsonValue jsonValue) {
     return stringify(jsonValue, 0);
   }

   /**
    * Converts a JSO to Json format.
    *
    * @param jsonValue    json object to stringify
    * @param spaces number of spaces to indent in pretty print mode
    * @return json formatted string
    */
   public static String stringify(JsonValue jsonValue, int spaces) {
     StringBuffer sb = new StringBuffer();
     for (int i = 0; i < spaces; i++) {
       sb.append(' ');
     }
     return stringify(jsonValue, sb.toString());
   }

   /**
    * Converts a Json object to Json formatted String.
    *
    * @param jsonValue    json object to stringify
    * @param indent optional indention prefix for pretty printing
    * @return json formatted string
    */
   public static String stringify(JsonValue jsonValue, final String indent) {
     final StringBuffer sb = new StringBuffer();
     final boolean isPretty = indent != null && !"".equals(indent);

     new StringifyJsonVisitor(indent, sb, isPretty).accept(jsonValue);
     return sb.toString();
   }

   /**
    * Turn a single unicode character into a 32-bit unicode hex literal.
    */
   private static String escapeStringAsUnicode(String match) {
     String hexValue = Integer.toString(match.charAt(0), 16);
     hexValue = hexValue.length() > 4 ? hexValue.substring(hexValue.length() - 4)
         : hexValue;
     return "\\u0000" + hexValue;
   }

   private static boolean isControlChar(char c) {
     return (c >= 0x00 && c <= 0x1f)
         || (c >= 0x7f && c <= 0x9f)
         || c == '\u00ad' || c == '\u070f' || c == '\u17b4' || c == '\u17b5'
         || c == '\ufeff'
         || (c >= '\u0600' && c <= '\u0604')
         || (c >= '\u200c' && c <= '\u200f')
         || (c >= '\u2028' && c <= '\u202f')
         || (c >= '\u2060' && c <= '\u206f')
         || (c >= '\ufff0' && c <= '\uffff');
   }

   /**
    * Execute a regular expression and invoke a callback for each match
    * occurance. The return value of the callback is substituted for the match.
    *
    * @param expression a compiled regular expression
    * @param text       a String on which to perform replacement
    * @param replacer   a callback that maps matched strings into new values
    */
   private static String replace(RegExp expression, String text,
       RegExpReplacer replacer) {
     expression.setLastIndex(0);
     MatchResult mresult = expression.exec(text);
     StringBuffer toReturn = new StringBuffer();
     int lastIndex = 0;
     while (mresult != null) {
       toReturn.append(text.substring(lastIndex, mresult.getIndex()));
       toReturn.append(replacer.replace(mresult.getGroup(0)));
       lastIndex = mresult.getIndex() + 1;
       mresult = expression.exec(text);
     }
     toReturn.append(text.substring(lastIndex));
     return toReturn.toString();
   }
 }
	/*
	* Copyright 2010 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 elemental.json.impl;

	import com.google.gwt.regexp.shared.MatchResult;
	import com.google.gwt.regexp.shared.RegExp;

	import java.util.Collections;
	import java.util.HashSet;
	import java.util.Set;

	import elemental.json.Json;
	import elemental.json.JsonArray;
	import elemental.json.JsonException;
	import elemental.json.JsonObject;
	import elemental.json.JsonValue;
	import elemental.json.impl.JsonContext;

	/**
	* Direct port of json2.js at http://www.json.org/json2.js to GWT.
	*/
	public class JsonUtil {

	/**
	* Callback invoked during a RegExp replace for each match. The return value
	* is used as a substitution into the matched string.
	*/
	private interface RegExpReplacer {

	String replace(String match);
	}

	private static class StringifyJsonVisitor extends JsonVisitor {

	private static final Set<String> skipKeys;

	static {
	Set<String> toSkip = new HashSet<String>();
	toSkip.add("$H");
	toSkip.add("__gwt_ObjectId");
	skipKeys = Collections.unmodifiableSet(toSkip);
	}

	private String indentLevel;

	private Set<JsonValue> visited;

	private final String indent;

	private final StringBuffer sb;

	private final boolean pretty;

	public StringifyJsonVisitor(String indent, StringBuffer sb,
	boolean pretty) {
	this.indent = indent;
	this.sb = sb;
	this.pretty = pretty;
	indentLevel = "";
	visited = new HashSet<JsonValue>();
	}

	@Override
	public void endVisit(JsonArray array, JsonContext ctx) {
	if (pretty) {
	indentLevel = indentLevel
	.substring(0, indentLevel.length() - indent.length());
	sb.append('\n');
	sb.append(indentLevel);
	}
	sb.append("]");
	visited.remove(array);
	}

	@Override
	public void endVisit(JsonObject object, JsonContext ctx) {
	if (pretty) {
	indentLevel = indentLevel
	.substring(0, indentLevel.length() - indent.length());
	sb.append('\n');
	sb.append(indentLevel);
	}
	sb.append("}");
	visited.remove(object);
	assert !visited.contains(object);
	}

	@Override
	public void visit(double number, JsonContext ctx) {
	sb.append(Double.isInfinite(number) ? "null" : format(number));
	}

	@Override
	public void visit(String string, JsonContext ctx) {
	sb.append(quote(string));
	}

	@Override
	public void visit(boolean bool, JsonContext ctx) {
	sb.append(bool);
	}

	@Override
	public boolean visit(JsonArray array, JsonContext ctx) {
	checkCycle(array);
	sb.append("[");
	if (pretty) {
	sb.append('\n');
	indentLevel += indent;
	sb.append(indentLevel);
	}
	return true;
	}

	@Override
	public boolean visit(JsonObject object, JsonContext ctx) {
	checkCycle(object);
	sb.append("{");
	if (pretty) {
	sb.append('\n');
	indentLevel += indent;
	sb.append(indentLevel);
	}
	return true;
	}

	@Override
	public boolean visitIndex(int index, JsonContext ctx) {
	commaIfNotFirst(ctx);
	return true;
	}

	@Override
	public boolean visitKey(String key, JsonContext ctx) {
	if ("".equals(key)) {
	return true;
	}
	// skip properties injected by GWT runtime on JSOs
	if (skipKeys.contains(key)) {
	return false;
	}
	commaIfNotFirst(ctx);
	sb.append(quote(key) + ":");
	if (pretty) {
	sb.append(' ');
	}
	return true;
	}

	@Override
	public void visitNull(JsonContext ctx) {
	sb.append("null");
	}

	private void checkCycle(JsonValue value) {
	if (visited.contains(value)) {
	throw new JsonException("Cycled detected during stringify");
	} else {
	visited.add(value);
	}
	}

	private void commaIfNotFirst(JsonContext ctx) {
	if (!ctx.isFirst()) {
	sb.append(",");
	if (pretty) {
	sb.append('\n');
	sb.append(indentLevel);
	}
	}
	}

	private String format(double number) {
	String n = String.valueOf(number);
	if (n.endsWith(".0")) {
	n = n.substring(0, n.length() - 2);
	}
	return n;
	}
	}

	/**
	* Convert special control characters into unicode escape format.
	*/
	public static String escapeControlChars(String text) {
	StringBuffer toReturn = new StringBuffer();
	for (int i = 0; i < text.length(); i++) {
	char c = text.charAt(i);
	if (isControlChar(c)) {
	toReturn.append(escapeStringAsUnicode(String.valueOf(c)));
	} else {
	toReturn.append(c);
	}
	}
	return toReturn.toString();
	}

	public static <T extends JsonValue> T parse(String json) throws JsonException {
	return Json.instance().parse(json);
	}

	/**
	* Safely escape an arbitrary string as a JSON string literal.
	*/
	public static String quote(String value) {
	StringBuffer toReturn = new StringBuffer();
	toReturn.append("\"");
	for (int i = 0; i < value.length(); i++) {
	char c = value.charAt(i);

	String toAppend = String.valueOf(c);
	switch (c) {
	case '\b':
	toAppend = "\\b";
	break;
	case '\t':
	toAppend = "\\t";
	break;
	case '\n':
	toAppend = "\\n";
	break;
	case '\f':
	toAppend = "\\f";
	break;
	case '\r':
	toAppend = "\\r";
	break;
	case '"':
	toAppend = "\\\"";
	break;
	case '\\':
	toAppend = "\\\\";
	break;
	default:
	if (isControlChar(c)) {
	toAppend = escapeStringAsUnicode(String.valueOf(c));
	}
	}
	toReturn.append(toAppend);
	}
	toReturn.append("\"");
	return toReturn.toString();
	}

	/**
	* Converts a Json Object to Json format.
	*
	* @param jsonValue json object to stringify
	* @return json formatted string
	*/
	public static String stringify(JsonValue jsonValue) {
	return stringify(jsonValue, 0);
	}

	/**
	* Converts a JSO to Json format.
	*
	* @param jsonValue json object to stringify
	* @param spaces number of spaces to indent in pretty print mode
	* @return json formatted string
	*/
	public static String stringify(JsonValue jsonValue, int spaces) {
	StringBuffer sb = new StringBuffer();
	for (int i = 0; i < spaces; i++) {
	sb.append(' ');
	}
	return stringify(jsonValue, sb.toString());
	}

	/**
	* Converts a Json object to Json formatted String.
	*
	* @param jsonValue json object to stringify
	* @param indent optional indention prefix for pretty printing
	* @return json formatted string
	*/
	public static String stringify(JsonValue jsonValue, final String indent) {
	final StringBuffer sb = new StringBuffer();
	final boolean isPretty = indent != null && !"".equals(indent);

	new StringifyJsonVisitor(indent, sb, isPretty).accept(jsonValue);
	return sb.toString();
	}

	/**
	* Turn a single unicode character into a 32-bit unicode hex literal.
	*/
	private static String escapeStringAsUnicode(String match) {
	String hexValue = Integer.toString(match.charAt(0), 16);
	hexValue = hexValue.length() > 4 ? hexValue.substring(hexValue.length() - 4)
	: hexValue;
	return "\\u0000" + hexValue;
	}

	private static boolean isControlChar(char c) {
	return (c >= 0x00 && c <= 0x1f)
	\|\| (c >= 0x7f && c <= 0x9f)
	\|\| c == '\u00ad' \|\| c == '\u070f' \|\| c == '\u17b4' \|\| c == '\u17b5'
	\|\| c == '\ufeff'
	\|\| (c >= '\u0600' && c <= '\u0604')
	\|\| (c >= '\u200c' && c <= '\u200f')
	\|\| (c >= '\u2028' && c <= '\u202f')
	\|\| (c >= '\u2060' && c <= '\u206f')
	\|\| (c >= '\ufff0' && c <= '\uffff');
	}

	/**
	* Execute a regular expression and invoke a callback for each match
	* occurance. The return value of the callback is substituted for the match.
	*
	* @param expression a compiled regular expression
	* @param text a String on which to perform replacement
	* @param replacer a callback that maps matched strings into new values
	*/
	private static String replace(RegExp expression, String text,
	RegExpReplacer replacer) {
	expression.setLastIndex(0);
	MatchResult mresult = expression.exec(text);
	StringBuffer toReturn = new StringBuffer();
	int lastIndex = 0;
	while (mresult != null) {
	toReturn.append(text.substring(lastIndex, mresult.getIndex()));
	toReturn.append(replacer.replace(mresult.getGroup(0)));
	lastIndex = mresult.getIndex() + 1;
	mresult = expression.exec(text);
	}
	toReturn.append(text.substring(lastIndex));
	return toReturn.toString();
	}
	}