code: /**
   * This file is part of Eclipse Steady.
   *
   * 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.
   *
   * SPDX-License-Identifier: Apache-2.0
   * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
   */
  package org.eclipse.steady.python.sign;
  
  import java.io.File;
  
  import org.apache.logging.log4j.Logger;
  import org.eclipse.steady.Construct;
  import org.eclipse.steady.FileAnalysisException;
  import org.eclipse.steady.FileAnalyzerFactory;
  import org.eclipse.steady.python.Python3FileAnalyzer;
  import org.eclipse.steady.shared.enums.ConstructType;
  import org.eclipse.steady.shared.enums.DigestAlgorithm;
  import org.eclipse.steady.shared.enums.ProgrammingLanguage;
  import org.eclipse.steady.shared.json.model.ConstructId;
  import org.eclipse.steady.sign.Signature;
  import org.eclipse.steady.sign.SignatureChange;
  import org.eclipse.steady.sign.SignatureFactory;
  
  /**
   * Creates construct signatures for several Python constructs. The signature is simply a digest computed over
   * the respective construct body.
   * TODO: Strip comments and the like?
   * TODO: Check the digest algo used by the SW Heritage API
   */
  public class PythonSignatureFactory implements SignatureFactory {
  
    private static final Logger log = org.apache.logging.log4j.LogManager.getLogger();
  
    /**
     * {@inheritDoc}
     *
     * Returns true if the given {@link ConstructId} is of type Java method or Java constructor.
     */
    @Override
    public boolean isSupportedConstructId(ConstructId _id) {
      return _id != null
          && ProgrammingLanguage.PY.equals(_id.getLang())
          && (ConstructType.FUNC.equals(_id.getType())
              || ConstructType.MODU.equals(_id.getType())
              || ConstructType.METH.equals(_id.getType())
              || ConstructType.CONS.equals(_id.getType()));
    }
  
    /** {@inheritDoc} */
    @Override
    public Signature createSignature(Construct _construct) {
      if (_construct != null && _construct.getContent() != null)
        return new PythonConstructDigest(_construct.getContent(), DigestAlgorithm.SHA1);
      else return null;
    }
  
    /** {@inheritDoc} */
    @Override
    public Signature createSignature(ConstructId _cid, File _file) {
      if (!_cid.getLang().equals(ProgrammingLanguage.PY))
        throw new IllegalArgumentException(
            "Programming language [" + _cid.getLang() + "] not supported");
  
      Signature signature = null;
  
      // Compute signature from the entire file
      if (_cid.getType().equals(ConstructType.MODU)) {
        signature = new PythonConstructDigest(_file.toPath(), DigestAlgorithm.SHA1);
      }
      // For all others, parse the file, and compute the digest for the construct body
      else {
        try {
          final Python3FileAnalyzer fa =
              (Python3FileAnalyzer) FileAnalyzerFactory.buildFileAnalyzer(_file, new String[] {"py"});
          final Construct c = fa.getConstruct(_cid);
          if (c == null) {
            throw new IllegalStateException(
                "Construct [" + _cid + "] cannot be found in file [" + _file + "]");
          } else {
            signature = new PythonConstructDigest(c.getContent(), DigestAlgorithm.SHA1);
          }
        } catch (IllegalArgumentException e) {
          log.error(e);
        } catch (FileAnalysisException e) {
          log.error(e);
        }
      }
      return signature;
    }
  
    /** {@inheritDoc} */
    @Override
    public SignatureChange computeChange(Construct _from, Construct _to) {
      // TODO Auto-generated method stub
      return null;
    }
  }
  