| /* |
| * 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; |
| |
| import java.lang.annotation.Inherited; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| |
| /** |
| * Generates source code for subclasses during deferred binding requests. Subclasses must be |
| * thread-safe. |
| * <p> |
| * If annotated by {@code @RunsLocal}, a generator can minimize its impact on compilation speed. See |
| * {@link RunsLocal} for details. |
| * <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 { |
| |
| /** |
| * An optional annotation indicating that a Generator can be run with local information during |
| * incremental compilation. |
| * <p> |
| * When this annotation is applied, the generator cannot access global level type information |
| * (e.g. {@code JClassType#getSubTypes} or {@code TypeOracle#getTypes}) and also accesses to |
| * property values are restricted to the ones defined by {@link #requiredProperties}. |
| * <p> |
| * This information is used by Generator invocation during incremental compilation to run |
| * Generators as early as possible in the compile tree (and thus as parallelized and cached as |
| * possible). |
| */ |
| @Inherited |
| @Retention(RetentionPolicy.RUNTIME) |
| public @interface RunsLocal { |
| |
| /** |
| * A special value for {@link #requiresProperties} to indicate that any property can affect this |
| * generator's output. While this gives access to any property value, this may slowdown the |
| * compilation speed to precompute all property values. |
| */ |
| String ALL = "%ALL%"; |
| |
| /** |
| * The list of names of properties which will be accessed by this Generator. It is assumed that |
| * any change in the values of these properties will affect the content of Generator output. |
| * <p> |
| * Any Generator that depends on properties will have its execution delayed to the point in the |
| * compile tree where it is known that the properties it cares about have stopped changing. In |
| * general this result of pushing Generator execution towards the root of the tree has negative |
| * performance consequences on incremental compile performance. |
| * <p> |
| * Generators that want to be as fast as possible should strive not to read any properties. |
| * <p> |
| * Can be set to {@code RunsLocal.ALL} to indicate a need to arbitrarily access any property. |
| */ |
| String[] requiresProperties() default {}; |
| } |
| |
| 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; |
| } |