com.google.gwt.dev.js.JsPrettyNamer Maven / Gradle / Ivy
/*
* Copyright 2007 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.dev.js;
import com.google.gwt.dev.cfg.ConfigProps;
import com.google.gwt.dev.js.ast.JsName;
import com.google.gwt.dev.js.ast.JsProgram;
import com.google.gwt.dev.js.ast.JsScope;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;
/**
* A namer that keeps the short ("pretty") identifier wherever possible.
*/
public class JsPrettyNamer extends JsNamer {
public static void exec(JsProgram program, ConfigProps config) throws IllegalNameException {
new JsPrettyNamer(program, config).execImpl();
}
public JsPrettyNamer(JsProgram program, ConfigProps config) {
super(program, config);
}
@Override
protected void reset() {
}
@Override
protected void visit(JsScope scope) {
changeNames(scope);
}
/**
* Does a minimal fixup on the short names in the given scope and all its descendants.
* Unobfuscatable names map to their full name and any names that conflict with a previous
* idenitifier or any child scope's identifier are renamed. Otherwise the short name is
* left as-is.
* @return all names used in the given scope and any of its descendants (after renaming).
*/
private Set changeNames(JsScope scope) {
// First, change the names in all the child scopes and remember that they're taken.
Set taken = new HashSet();
for (JsScope child : scope.getChildren()) {
taken.addAll(changeNames(child));
}
// The next integer to try as an identifier suffix.
HashMap suffixCounters = new HashMap();
for (JsName name : scope.getAllNames()) {
if (!referenced.contains(name)) {
// Don't allocate idents for non-referenced names.
continue;
}
rename(name, scope, taken, suffixCounters);
taken.add(name.getShortIdent());
}
return taken;
}
/**
* Changes the short identifier of one JsName.
* @param taken the set of short identifiers that are already used (read-only)
* @param suffixCounters contains the next suffix to use for each prefix (updated).
*/
private void rename(JsName name, JsScope scope, Set taken,
HashMap suffixCounters) {
if (!name.isObfuscatable()) {
// We must use the full name.
name.setShortIdent(name.getIdent());
return;
}
String prefix = name.getShortIdent();
if (prefix.contains("-")) {
// Fixes package-info.java classes.
prefix = prefix.replace("-", "_");
name.setShortIdent(prefix);
}
if (!isAvailable(prefix, scope, taken)) {
// Start searching using a suffix hint stored in the scope.
// We still do a search in case there is a collision with
// a user-provided identifier
Integer suffixOrNull = suffixCounters.get(prefix);
int suffix = (suffixOrNull == null) ? 0 : suffixOrNull;
String candidate;
do {
candidate = prefix + "_" + suffix++;
} while (!isAvailable(candidate, scope, taken));
suffixCounters.put(prefix, suffix);
name.setShortIdent(candidate);
}
// otherwise the short name is already good
}
/**
* Returns true if a candidate identifier is available in a scope.
* @param taken the set of names that we've already used.
*/
private boolean isAvailable(String candidate, JsScope scope, Set taken) {
if (!reserved.isAvailable(candidate)) {
return false;
}
if (taken.contains(candidate)) {
return false;
}
/*
* Never obfuscate a name into an identifier that conflicts with an existing
* unobfuscatable name! It's okay if it conflicts with an existing
* obfuscatable name; that name will get obfuscated out of the way.
*/
return (scope.findExistingUnobfuscatableName(candidate) == null);
}
}