com.google.javascript.jscomp.UniqueIdSupplier Maven / Gradle / Ivy
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/*
* Copyright 2016 The Closure Compiler Authors.
*
* 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.javascript.jscomp;
import com.google.common.collect.HashMultiset;
import com.google.common.collect.Multiset;
import java.io.Serializable;
/**
* Generates unique String Ids when requested via a compiler instance.
*
* This supplier provides Ids that are deterministic and unique across all input files given to
* the compiler. The generated ID format is: uniqueId = "fileHashCode$counterForThisFile"
*/
public final class UniqueIdSupplier implements Serializable {
private final Multiset counter;
UniqueIdSupplier() {
counter = HashMultiset.create();
}
/**
* Creates and returns a unique Id across all compiler input source files.
*
* @param input The compiler input for which the unique Id is requested.
* @return unique ID as String
*/
public String getUniqueId(CompilerInput input) {
String filePath = input.getSourceFile().getName();
int fileHashCode = filePath.hashCode();
int id = counter.add(fileHashCode, 1);
String fileHashString = (fileHashCode < 0) ? ("m" + -fileHashCode) : ("" + fileHashCode);
return fileHashString + "$" + id;
}
}