com.google.javascript.jscomp.deps.ClosureBundler.java Source code

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Here is the source code for com.google.javascript.jscomp.deps.ClosureBundler.java

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/*
 * Copyright 2014 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.deps;

import com.google.common.io.CharSource;
import com.google.common.io.Files;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;

/**
 * A utility class to assist in creating JS bundle files.
 */
public final class ClosureBundler {
    private boolean useEval = false;
    private String sourceUrl = null;

    public ClosureBundler() {
    }

    public final ClosureBundler useEval(boolean useEval) {
        this.useEval = useEval;
        return this;
    }

    public final ClosureBundler withSourceUrl(String sourceUrl) {
        this.sourceUrl = sourceUrl;
        return this;
    }

    /** Append the contents of the string to the supplied appendable. */
    public static void appendInput(Appendable out, DependencyInfo info, String contents) throws IOException {
        new ClosureBundler().appendTo(out, info, contents);
    }

    /** Append the contents of the string to the supplied appendable. */
    public void appendTo(Appendable out, DependencyInfo info, String content) throws IOException {
        appendTo(out, info, CharSource.wrap(content));
    }

    /** Append the contents of the file to the supplied appendable. */
    public void appendTo(Appendable out, DependencyInfo info, File content, Charset contentCharset)
            throws IOException {
        appendTo(out, info, Files.asCharSource(content, contentCharset));
    }

    /** Append the contents of the CharSource to the supplied appendable. */
    private void appendTo(Appendable out, DependencyInfo info, CharSource content) throws IOException {
        if (info.isModule()) {
            appendGoogModule(out, content);
        } else {
            appendTraditional(out, content);
        }
    }

    private void appendTraditional(Appendable out, CharSource contents) throws IOException {
        if (useEval) {
            out.append("(0,eval(\"");
            append(out, Mode.ESCAPED, contents);
            appendSourceUrl(out, Mode.ESCAPED);
            out.append("\"));");
        } else {
            out.append(contents.read());
            appendSourceUrl(out, Mode.NORMAL);
        }
    }

    private void appendGoogModule(Appendable out, CharSource contents) throws IOException {
        if (useEval) {
            out.append("goog.loadModule(\"");
            append(out, Mode.ESCAPED, contents);
            appendSourceUrl(out, Mode.ESCAPED);
            out.append("\");");
        } else {
            // add the prefix on the first line so the line numbers aren't affected.
            out.append("goog.loadModule(function(exports) {" + "'use strict';");
            append(out, Mode.NORMAL, contents);
            out.append("\n" // terminate any trailing single line comment.
                    + ";" // terminate any trailing expression.
                    + "return exports;});\n");
            appendSourceUrl(out, Mode.NORMAL);
        }
    }

    private enum Mode {
        ESCAPED, NORMAL,
    }

    private void appendEscaped(Appendable out, String s) throws IOException {
        out.append(SourceCodeEscapers.javascriptEscaper().escape(s));
    }

    private void append(Appendable out, Mode mode, String s) throws IOException {
        if (mode == Mode.ESCAPED) {
            appendEscaped(out, s);
        } else {
            out.append(s);
        }
    }

    private void append(Appendable out, Mode mode, CharSource cs) throws IOException {
        append(out, mode, cs.read());
    }

    private void appendSourceUrl(Appendable out, Mode mode) throws IOException {
        if (sourceUrl != null) {
            append(out, mode, "\n//# sourceURL=");
            append(out, mode, sourceUrl);
            append(out, mode, "\n");
        }
    }
}