com.mycila.maven.plugin.license.header.HeaderSource Maven / Gradle / Ivy

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Maven 2 plugin to check and update license headers in source files
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/*
 * Copyright (C) 2008-2024 Mycila ([email protected])
 *
 * 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
 *
 *         https://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.mycila.maven.plugin.license.header;

import com.mycila.maven.plugin.license.Multi;
import com.mycila.maven.plugin.license.util.FileUtils;
import com.mycila.maven.plugin.license.util.resource.ResourceFinder;
import org.apache.maven.plugin.MojoFailureException;

import java.io.IOException;
import java.nio.charset.Charset;
import java.net.URISyntaxException;
import java.net.URL;

import static com.mycila.maven.plugin.license.Multi.DEFAULT_SEPARATOR;

/**
 * Provides an access to the license template text.
 */
public abstract class HeaderSource {

  /**
   * A {@link HeaderSource} built from a license header template literal.
   */
  public static class LiteralHeaderSource extends HeaderSource {
    public LiteralHeaderSource(String content) {
      super(content, true);
    }

    /**
     * @return always {@code false} because this {@link LiteralHeaderSource} was not loaded from any {@link URL}
     */
    @Override
    public boolean isFromUrl(URL location) {
      return false;
    }

    @Override
    public String toString() {
      return "inline: " + content;
    }

  }

  /**
   * A {@link HeaderSource} loaded from a {@link URL}.
   */
  public static class UrlHeaderSource extends HeaderSource {
    private final URL url;

    public UrlHeaderSource(URL url, Charset encoding) throws IOException, URISyntaxException {
      super(FileUtils.read(url, encoding), false);
      this.url = url;
    }

    @Override
    public boolean isFromUrl(URL location) {
      return this.url.equals(location);
    }

    @Override
    public String toString() {
      return url + ": " + content;
    }

  }

  /**
   * A {@link HeaderSource} built from multiple license header template literals.
   */
  public static class MultiLiteralHeaderSource extends HeaderSource {
    public MultiLiteralHeaderSource(final String preamble, final String[] contents, final String[] separators) {
      super(combineHeaders(preamble, contents, separators), true);
    }

    /**
     * @return always {@code false} because this {@link LiteralHeaderSource} was not loaded from any {@link URL}
     */
    @Override
    public boolean isFromUrl(final URL location) {
      return false;
    }

    @Override
    public String toString() {
      return "inline: " + content;
    }

  }

  /**
   * A {@link HeaderSource} loaded from multiple {@link URL}.
   */
  public static class MultiUrlHeaderSource extends HeaderSource {
    private final URL[] urls;

    public MultiUrlHeaderSource(final String preamble, final URL[] urls, final String[] separators, final Charset encoding) throws IOException, URISyntaxException {
      super(combineHeaders(preamble, FileUtils.read(urls, encoding), separators), false);
      this.urls = urls;
    }

    @Override
    public boolean isFromUrl(final URL location) {
      for (final URL url : urls) {
        if (url.equals(location)) {
          return true;
        }
      }
      return false;
    }

    @Override
    public String toString() {
      final StringBuilder builder = new StringBuilder();
      builder.append('[');
      for (final URL url : urls) {
        if (builder.length() > 1) {
          builder.append(", ");
        }
        builder.append(url);
      }
      builder.append("] : ").append(content);
      return builder.toString();
    }

  }

  private static String combineHeaders(final String preamble, final String[] headers, final String[] separators) {
    final StringBuilder builder = new StringBuilder();

    // preamble
    if (preamble != null) {
      builder.append(preamble);
      if (!preamble.endsWith("\n")) {
        builder.append('\n');
      }
      builder.append('\n');
    }

    for (int i = 0; i < headers.length; i++) {

      // separator
      String separator = null;
      if (i > 0) {
        if (separators == null) {
          separator = DEFAULT_SEPARATOR;
        } else if (separators.length == 1) {
          separator = separators[0];
        } else {
          separator = separators[i - 1];
        }

        if (builder.charAt(builder.length() - 1) != '\n') {
          builder.append('\n');
        }
        builder.append('\n');
        builder.append(separator);
        if (!separator.endsWith("\n")) {
          builder.append('\n');
        }
        builder.append('\n');
      }

      // header
      final String header = headers[i];
      builder.append(header);
    }

    return builder.toString();
  }

  public static HeaderSource of(String headerPath, Charset encoding, ResourceFinder finder) {
    return of(null, encoding, finder);
  }

  /**
   * Checking the params left to right, returns the first available {@link HeaderSource} that can be created. If
   * {@code inlineHeader} is not {@code null} returns a new {@link LiteralHeaderSource}. Otherwise attempts to create a
   * new {@link UrlHeaderSource} out of {@code headerPath} and {@code encoding}.
   *
   * @param multi        container for multi license, or null if single license
   * @param inlineHeader the text of a license header template
   * @param headerPath   a path resolvable by the {@code finder}
   * @param encoding     the encoding to use when reading {@code headerPath}
   * @param finder       the {@link ResourceFinder} to use to resolve {@code headerPath}
   * @return a new {@link HeaderSource}
   */
  public static HeaderSource of(Multi multi, String inlineHeader, String headerPath, Charset encoding, ResourceFinder finder) {
    if (multi != null) {
      if (multi.getInlineHeaders() != null && multi.getInlineHeaders().length > 0) {
        return new MultiLiteralHeaderSource(multi.getPreamble(), multi.getInlineHeaders(), multi.getSeparators());
      } else if (multi.getHeaders() == null || multi.getHeaders().length == 0) {
        throw new IllegalArgumentException("Either multi/inlineHeader or multi/header path needs to be specified");
      } else {
        final URL[] headerUrls = new URL[multi.getHeaders().length];
        for (int i = 0; i < multi.getHeaders().length; i++) {
          try {
            headerPath = multi.getHeaders()[i];
            final URL headerUrl = finder.findResource(headerPath);
            headerUrls[i] = headerUrl;
          } catch (final MojoFailureException e) {
            throw new IllegalArgumentException(
                "Cannot read header document " + headerPath + ". Cause: " + e.getMessage(), e);
          }
        }
        try {
          return new MultiUrlHeaderSource(multi.getPreamble(), headerUrls, multi.getSeparators(), encoding);
        } catch (final IOException | URISyntaxException e) {
          throw new IllegalArgumentException(
              "Cannot read multi header documents. Cause: " + e.getMessage(), e);
        }
      }
    } else {
      if (inlineHeader != null && !inlineHeader.isEmpty()) {
        return new LiteralHeaderSource(inlineHeader);
      } else if (headerPath == null) {
        throw new IllegalArgumentException("Either inlineHeader or header path needs to be specified");
      } else {
        try {
          final URL headerUrl = finder.findResource(headerPath);
          return new UrlHeaderSource(headerUrl, encoding);
        } catch (Exception e) {
          throw new IllegalArgumentException(
              "Cannot read header document " + headerPath + ". Cause: " + e.getMessage(), e);
        }
      }
    }
  }

  protected final String content;
  private final boolean inline;

  protected HeaderSource(String content, boolean inline) {
    super();
    this.content = content;
    this.inline = inline;
  }

  /**
   * @return the text of the license template
   */
  public String getContent() {
    return content;
  }

  /**
   * @return {@code true} if this {@link HeaderSource} was created from a string rather by loading the bits from an
   * URL; {@code false} otherwise
   */
  public boolean isInline() {
    return inline;
  }

  /**
   * Retuns {@code true} if this {@link HeaderSource} was loaded from the URL given in the {@code location} parameter
   * or {@code false} otherwise.
   *
   * @param location the URL to tell if this {@link HeaderSource} was loaded from it
   * @return {@code true} if this {@link HeaderSource} was loaded from the URL given in the {@code location} parameter
   * or {@code false} otherwise
   */
  public abstract boolean isFromUrl(URL location);

}