| /* |
| * Copyright 2006 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.ext; |
| |
| import com.google.gwt.thirdparty.guava.common.base.Strings; |
| |
| /** |
| * Generates source code for subclasses during deferred binding requests. Subclasses must be |
| * thread-safe. |
| * <p> |
| * Resource reading should be done through the ResourceOracle in the provided GeneratorContext (not |
| * via ClassLoader.getResource(), File, or URL) so that Generator Resource dependencies can be |
| * detected and used to facilitate fast incremental recompiles. |
| */ |
| public abstract class Generator { |
| |
| private static final int MAX_SIXTEEN_BIT_NUMBER_STRING_LENGTH = 5; |
| |
| /** |
| * Escapes string content to be a valid string literal. |
| * |
| * @return an escaped version of <code>unescaped</code>, suitable for being enclosed in double |
| * quotes in Java source |
| */ |
| public static String escape(String unescaped) { |
| int extra = 0; |
| for (int in = 0, n = unescaped.length(); in < n; ++in) { |
| switch (unescaped.charAt(in)) { |
| case '\0': |
| case '\n': |
| case '\r': |
| case '\"': |
| case '\\': |
| ++extra; |
| break; |
| } |
| } |
| |
| if (extra == 0) { |
| return unescaped; |
| } |
| |
| char[] oldChars = unescaped.toCharArray(); |
| char[] newChars = new char[oldChars.length + extra]; |
| for (int in = 0, out = 0, n = oldChars.length; in < n; ++in, ++out) { |
| char c = oldChars[in]; |
| switch (c) { |
| case '\0': |
| newChars[out++] = '\\'; |
| c = '0'; |
| break; |
| case '\n': |
| newChars[out++] = '\\'; |
| c = 'n'; |
| break; |
| case '\r': |
| newChars[out++] = '\\'; |
| c = 'r'; |
| break; |
| case '\"': |
| newChars[out++] = '\\'; |
| c = '"'; |
| break; |
| case '\\': |
| newChars[out++] = '\\'; |
| c = '\\'; |
| break; |
| } |
| newChars[out] = c; |
| } |
| |
| return String.valueOf(newChars); |
| } |
| |
| /** |
| * Returns an escaped version of a String that is valid as a Java class name.<br /> |
| * |
| * Illegal characters become "_" + the character integer padded to 5 digits like "_01234". The |
| * padding prevents collisions like the following "_" + "123" + "4" = "_" + "1234". The "_" escape |
| * character is escaped to "__". |
| */ |
| public static String escapeClassName(String unescapedString) { |
| char[] unescapedCharacters = unescapedString.toCharArray(); |
| StringBuilder escapedCharacters = new StringBuilder(); |
| |
| boolean firstCharacter = true; |
| for (char unescapedCharacter : unescapedCharacters) { |
| if (firstCharacter && !Character.isJavaIdentifierStart(unescapedCharacter)) { |
| // Escape characters that can't be the first in a class name. |
| escapeAndAppendCharacter(escapedCharacters, unescapedCharacter); |
| } else if (!Character.isJavaIdentifierPart(unescapedCharacter)) { |
| // Escape characters that can't be in a class name. |
| escapeAndAppendCharacter(escapedCharacters, unescapedCharacter); |
| } else if (unescapedCharacter == '_') { |
| // Escape the escape character. |
| escapedCharacters.append("__"); |
| } else { |
| // Leave valid characters alone. |
| escapedCharacters.append(unescapedCharacter); |
| } |
| |
| firstCharacter = false; |
| } |
| |
| return escapedCharacters.toString(); |
| } |
| |
| private static void escapeAndAppendCharacter( |
| StringBuilder escapedCharacters, char unescapedCharacter) { |
| String numberString = Integer.toString(unescapedCharacter); |
| numberString = Strings.padStart(numberString, MAX_SIXTEEN_BIT_NUMBER_STRING_LENGTH, '0'); |
| escapedCharacters.append("_" + numberString); |
| } |
| |
| /** |
| * Generate a default constructible subclass of the requested type. The generator throws |
| * <code>UnableToCompleteException</code> if for any reason it cannot provide a substitute class |
| * |
| * @return the name of a subclass to substitute for the requested class, or return |
| * <code>null</code> to cause the requested type itself to be used |
| */ |
| public abstract String generate(TreeLogger logger, GeneratorContext context, String typeName) |
| throws UnableToCompleteException; |
| } |