com.envjs.gwt.linker.ServerSingleScriptLinker.java Source code

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Here is the source code for com.envjs.gwt.linker.ServerSingleScriptLinker.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 com.envjs.gwt.linker;

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.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.impl.SelectionScriptLinker;
import com.google.gwt.dev.About;
import com.google.gwt.dev.util.DefaultTextOutput;

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.
 */
@LinkerOrder(Order.PRIMARY)
public class ServerSingleScriptLinker extends SelectionScriptLinker {
    @Override
    public String getDescription() {
        return "Server Single Script";
    }

    @Override
    public ArtifactSet link(TreeLogger logger, LinkerContext context, ArtifactSet artifacts)
            throws UnableToCompleteException {
        ArtifactSet toReturn = new ArtifactSet(artifacts);

        toReturn.add(emitSelectionScript(logger, context, artifacts));

        return toReturn;
    }

    @Override
    protected Collection<EmittedArtifact> doEmitCompilation(TreeLogger logger, LinkerContext context,
            CompilationResult result) throws UnableToCompleteException {
        if (result.getJavaScript().length != 1) {
            logger.branch(TreeLogger.ERROR,
                    "The module must not have multiple fragments when using the " + getDescription() + " Linker.",
                    null);
            throw new UnableToCompleteException();
        }
        return super.doEmitCompilation(logger, context, result);
    }

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

        DefaultTextOutput out = new DefaultTextOutput(true);

        // Emit the selection script.
        // this for 'real browsers' to load the script
        // we don't need this.
        /*
        String bootstrap = generateSelectionScript(logger, context, artifacts);
        bootstrap = context.optimizeJavaScript(logger, bootstrap);
        out.print(bootstrap);
        out.newlineOpt();
        */

        // we need a ref to the top level window
        //  it is referenced in the closure below
        out.print("var $_window = this;");
        out.newlineOpt();

        // this is a hack to make backwards compatible
        out.print("var __defineParser__ = function(){};");
        out.newlineOpt();

        // Emit the module's JS a closure.
        out.newlineOpt();
        out.print("(function () {");
        out.newlineOpt();
        out.print("var $gwt_version = \"" + About.getGwtVersionNum() + "\";");
        out.newlineOpt();
        out.print("var $wnd = $_window;");
        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();

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

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

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

        out.print(js[0]);

        // Generate the call to tell the bootstrap code that we're ready to go.
        out.newlineOpt();

        // the original code setup an "onScriptLoad" event. 
        // Here we just do it
        out.print("gwtOnLoad();");

        out.newlineOpt();
        out.print("})();");
        out.newlineOpt();

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

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

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

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

    @Override
    protected String getSelectionScriptTemplate(TreeLogger logger, LinkerContext context)
            throws UnableToCompleteException {
        throw new UnableToCompleteException();
    }

}