org.chromium.distiller.dev.DistillerScriptLinker.java Source code

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Here is the source code for org.chromium.distiller.dev.DistillerScriptLinker.java

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/*
 * Copyright 2008 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 org.chromium.distiller.dev;

import com.google.gwt.core.ext.LinkerContext;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.linker.Artifact;
import com.google.gwt.core.ext.linker.ArtifactSet;
import com.google.gwt.core.ext.linker.CompilationResult;
import com.google.gwt.core.ext.linker.EmittedArtifact;
import com.google.gwt.core.ext.linker.LinkerOrder;
import com.google.gwt.core.ext.linker.LinkerOrder.Order;
import com.google.gwt.core.ext.linker.Shardable;
import com.google.gwt.core.ext.linker.Transferable;
import com.google.gwt.core.ext.linker.impl.SelectionScriptLinker;
import com.google.gwt.dev.About;
import com.google.gwt.dev.util.DefaultTextOutput;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Set;

/**
 * A Linker for producing a single JavaScript file from a GWT module. The use of
 * this Linker requires that the module has exactly one distinct compilation
 * result. This linker produces less unused boilerplate than the GWT
 * SingleScriptLinker.
 */
@LinkerOrder(Order.PRIMARY)
@Shardable
public class DistillerScriptLinker extends SelectionScriptLinker {
    @Override
    public String getDescription() {
        return "Distiller Script";
    }

    @Transferable
    private static class Script extends Artifact<Script> {
        private final String javaScript;
        private final String strongName;

        public Script(String strongName, String javaScript) {
            super(DistillerScriptLinker.class);
            this.strongName = strongName;
            this.javaScript = javaScript;
        }

        @Override
        public int compareToComparableArtifact(Script that) {
            int res = strongName.compareTo(that.strongName);
            if (res == 0) {
                res = javaScript.compareTo(that.javaScript);
            }
            return res;
        }

        @Override
        public Class<Script> getComparableArtifactType() {
            return Script.class;
        }

        public String getJavaScript() {
            return javaScript;
        }

        public String getStrongName() {
            return strongName;
        }

        @Override
        public int hashCode() {
            return strongName.hashCode() ^ javaScript.hashCode();
        }

        @Override
        public String toString() {
            return "Script " + strongName;
        }
    }

    @Override
    protected Collection<Artifact<?>> doEmitCompilation(TreeLogger logger, LinkerContext context,
            CompilationResult result, ArtifactSet artifacts) throws UnableToCompleteException {

        String[] js = result.getJavaScript();
        if (js.length != 1) {
            logger.branch(TreeLogger.ERROR,
                    "The module must not have multiple fragments when using the " + getDescription() + " Linker.",
                    null);
            throw new UnableToCompleteException();
        }

        Collection<Artifact<?>> toReturn = new ArrayList<Artifact<?>>();
        toReturn.add(new Script(result.getStrongName(), js[0]));
        toReturn.addAll(emitSelectionInformation(result.getStrongName(), result));
        return toReturn;
    }

    @Override
    protected EmittedArtifact emitSelectionScript(TreeLogger logger, LinkerContext context, ArtifactSet artifacts)
            throws UnableToCompleteException {

        // Find the single Script result.
        Set<Script> results = artifacts.find(Script.class);
        if (results.size() != 1) {
            logger.log(TreeLogger.ERROR, "The module must have exactly one distinct"
                    + " permutation when using the " + getDescription() + " Linker; found " + results.size(), null);
            throw new UnableToCompleteException();
        }
        Script result = results.iterator().next();

        DefaultTextOutput out = new DefaultTextOutput(true);

        // Emit the module's JS as a closure.
        out.print("(function () {");
        out.newlineOpt();
        out.print("var $gwt_version = \"" + About.getGwtVersionNum() + "\";");
        out.newlineOpt();
        out.print("var $wnd = window; /* our linker */");
        out.newlineOpt();
        out.print("var $doc = $wnd.document;");
        out.newlineOpt();
        out.print("var $moduleName, $moduleBase;");
        out.newlineOpt();
        out.print("var $stats = $wnd.__gwtStatsEvent ? function(a) {$wnd.__gwtStatsEvent(a)} : null;");
        out.newlineOpt();

        out.print("var $strongName = '" + result.getStrongName() + "';");
        out.newlineOpt();

        out.print(result.getJavaScript());

        out.newlineOpt();
        out.print("gwtOnLoad(undefined, \"" + context.getModuleFunctionName() + "\", \"\", 0);");
        out.newlineOpt();
        out.print("})();");
        out.newlineOpt();

        return emitString(logger, out.toString(), context.getModuleName() + ".nocache.js");
    }

    /**
     * Unimplemented. Normally required by
     * {@link #doEmitCompilation(TreeLogger, LinkerContext, CompilationResult, ArtifactSet)}.
     */
    @Override
    protected String getCompilationExtension(TreeLogger logger, LinkerContext context)
            throws UnableToCompleteException {
        throw new UnableToCompleteException();
    }

    /**
     * Unimplemented. Normally required by
     * {@link #doEmitCompilation(TreeLogger, LinkerContext, CompilationResult, ArtifactSet)}.
     */
    @Override
    protected String getModulePrefix(TreeLogger logger, LinkerContext context, String strongName)
            throws UnableToCompleteException {
        throw new UnableToCompleteException();
    }

    @Override
    protected String getSelectionScriptTemplate(TreeLogger logger, LinkerContext context)
            throws UnableToCompleteException {
        return "com/google/gwt/core/linker/SingleScriptTemplate.js";
    }
}