com.google.googlejavaformat.java.EclipseJavadocFormatter.java Source code

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Here is the source code for com.google.googlejavaformat.java.EclipseJavadocFormatter.java

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/*
 * Copyright 2016 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.googlejavaformat.java;

import com.google.common.collect.ImmutableMap;

import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.formatter.CodeFormatter;
import org.eclipse.jdt.core.formatter.DefaultCodeFormatterConstants;
import org.eclipse.jdt.internal.formatter.DefaultCodeFormatter;
import org.eclipse.jdt.internal.formatter.DefaultCodeFormatterOptions;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.Document;
import org.eclipse.text.edits.TextEdit;

/** Format javadoc comments using eclipse's formatter, for now. */
public class EclipseJavadocFormatter {

    /** An ill-formed Unicode 16-bit string of length 3. */
    private static final String PLACEHOLDER = Character.MIN_HIGH_SURROGATE + Character.MIN_HIGH_SURROGATE + " ";

    private static final String P_TAG = "<p>";

    static String formatJavadoc(String input, int indent, JavaFormatterOptions options) {
        // Eclipse lays out `<p>` tags on separate lines, which we do not want. To hack around this,
        // replace all occurrences of `<p>` in the input with `<p>???`, which will be formatted
        // as:
        //
        // ```
        // paragraph1
        // <p>
        // ???paragraph2
        // ```
        //
        // Finally, delete all `<p>` tags and rewrite `???` back to `<p>`:
        //
        // ```
        // paragraph1
        //
        // <p>paragraph2
        // ```
        //
        // A run of three unpaired surrogate code units is used as the placeholder because it
        // is unlikely to occur naturally in javadoc.

        String preprocessed = input.replace(P_TAG, P_TAG + PLACEHOLDER);
        String output = formatJavadocInternal(preprocessed, indent, options);
        return output.replace(P_TAG, "").replace(PLACEHOLDER, P_TAG);
    }

    private static String formatJavadocInternal(String input, int indent, JavaFormatterOptions options) {

        ImmutableMap.Builder<String, String> optionBuilder = ImmutableMap.<String, String>builder();
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_FORMAT_JAVADOC_COMMENT, "true");
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR, JavaCore.SPACE);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_TAB_SIZE,
                Integer.toString(options.indentationMultiplier()));
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_LINE_LENGTH,
                Integer.toString(options.maxLineLength() - indent));
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_LINE_SPLIT,
                Integer.toString(options.maxLineLength()));
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_INDENT_PARAMETER_DESCRIPTION,
                DefaultCodeFormatterConstants.FALSE);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_INSERT_NEW_LINE_FOR_PARAMETER,
                JavaCore.DO_NOT_INSERT);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_CLEAR_BLANK_LINES_IN_JAVADOC_COMMENT,
                DefaultCodeFormatterConstants.FALSE);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_JOIN_LINES_IN_COMMENTS,
                DefaultCodeFormatterConstants.TRUE);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_JOIN_WRAPPED_LINES,
                DefaultCodeFormatterConstants.TRUE);
        // Disable indenting root tags for now since it indents more than 4 spaces
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_INDENT_ROOT_TAGS,
                DefaultCodeFormatterConstants.FALSE);
        optionBuilder.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_FORMAT_SOURCE,
                DefaultCodeFormatterConstants.FALSE);
        optionBuilder.put(JavaCore.COMPILER_COMPLIANCE, "1.8");
        optionBuilder.put(JavaCore.COMPILER_SOURCE, "1.8");
        optionBuilder.put(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, "1.8");
        DefaultCodeFormatter codeFormatter = new DefaultCodeFormatter(
                new DefaultCodeFormatterOptions(optionBuilder.build()));

        TextEdit edit = codeFormatter.format(CodeFormatter.K_JAVA_DOC, input, /*offset*/ 0, input.length(),
                // eclipse doesn't indent comments reliably, so always request no indent and fix it
                // up later in JavaCommentsHelper
                /*indent*/ 0, /*lineSeparator*/ null);
        if (edit == null) {
            throw new RuntimeException("error formatting javadoc");
        }
        Document document = new Document(input);
        try {
            edit.apply(document);
        } catch (BadLocationException e) {
            throw new RuntimeException("error formatting javadoc", e);
        }
        return document.get();
    }
}