revelcGH-30: Handle files that are empty, have an unknown newline, or…

… can't be parsed

pom.xml

@@ -380,6 +380,13 @@
       <plugin>
         <groupId>org.apache.rat</groupId>
         <artifactId>apache-rat-plugin</artifactId>
+        <configuration>
+          <excludes>
+            <exclude>src/test/resources/EmptyFile.java</exclude>
+            <exclude>src/test/resources/FileWithoutNewline.java</exclude>
+            <exclude>src/test/resources/InvalidFile.java</exclude>
+          </excludes>
+        </configuration>
         <executions>
           <execution>
             <id>check-licenses</id>

src/main/java/net/revelc/code/impsort/EmptyFileException.java

@@ -0,0 +1,50 @@
+/*
+ * 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 net.revelc.code.impsort;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+/**
+ * Signals that the file denoted by this path is empty.
+ *
+ * <p>
+ * This exception will be thrown by the {@link ImpSort#parseFile} when it encounters an empty file.
+ * </p>
+ */
+public class EmptyFileException extends IOException {
+  private static final long serialVersionUID = -4202864513494828247L;
+
+  private final Path path;
+
+  /**
+   * Constructs a {@code EmptyFileException} with {@code null} as its error detail message and the
+   * specified path.
+   *
+   * @param path the path
+   */
+  public EmptyFileException(final Path path) {
+    this.path = path;
+  }
+
+  /**
+   * Returns the path.
+   *
+   * @return the path
+   */
+  public Path getPath() {
+    return path;
+  }
+}

src/main/java/net/revelc/code/impsort/ImpSort.java

@@ -45,7 +45,6 @@
 import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.NodeList;
 import com.github.javaparser.ast.PackageDeclaration;
-import com.github.javaparser.ast.body.TypeDeclaration;
 import com.github.javaparser.ast.comments.Comment;
 import com.github.javaparser.ast.comments.JavadocComment;
 import com.github.javaparser.javadoc.Javadoc;
@@ -73,9 +72,17 @@ public ImpSort(final Charset sourceEncoding, final Grouper grouper, final boolea
     this.lineEnding = lineEnding;
   }
 
-  public Result parseFile(final Path path) throws IOException {
-    String file = new String(Files.readAllBytes(path), sourceEncoding);
+  public Result parseFile(final Path path)
+      throws IOException, EmptyFileException, UnknownLineEndingException {
+    byte[] buf = Files.readAllBytes(path);
+    if (buf.length == 0) {
+      throw new EmptyFileException(path);
+    }
+    String file = new String(buf, sourceEncoding);
     LineEnding fileLineEnding = LineEnding.determineLineEnding(file);
+    if (fileLineEnding == LineEnding.UNKNOWN) {
+      throw new UnknownLineEndingException(path);
+    }
     LineEnding impLineEnding;
     if (lineEnding == LineEnding.KEEP) {
       impLineEnding = fileLineEnding;
@@ -84,8 +91,11 @@ public Result parseFile(final Path path) throws IOException {
     }
     List<String> fileLines = Arrays.asList(file.split(fileLineEnding.getChars()));
     ParseResult<CompilationUnit> parseResult = new JavaParser().parse(file);
-    CompilationUnit unit =
-        parseResult.getResult().orElseThrow(() -> new IOException("Unable to parse " + path));
+    Optional<CompilationUnit> unitOptional = parseResult.getResult();
+    if (!parseResult.isSuccessful() || !unitOptional.isPresent()) {
+      throw new IOException("Unable to parse " + path);
+    }
+    CompilationUnit unit = unitOptional.get();
     Position packagePosition =
         unit.getPackageDeclaration().map(p -> p.getEnd().get()).orElse(unit.getBegin().get());
     NodeList<ImportDeclaration> importDeclarations = unit.getImports();

src/main/java/net/revelc/code/impsort/LineEnding.java

@@ -43,10 +43,11 @@ public static LineEnding determineLineEnding(String fileDataString) {
     int crCount = 0;
     int crlfCount = 0;
 
-    for (int i = 0; i < fileDataString.length(); i++) {
-      char c = fileDataString.charAt(i);
+    final int length = fileDataString.length();
+    for (int i = 0; i < length; i++) {
+      final char c = fileDataString.charAt(i);
       if (c == '\r') {
-        if ((i + 1) < fileDataString.length() && fileDataString.charAt(i + 1) == '\n') {
+        if ((i + 1) < length && fileDataString.charAt(i + 1) == '\n') {
           crlfCount++;
           i++;
         } else {

src/main/java/net/revelc/code/impsort/UnknownLineEndingException.java

@@ -0,0 +1,51 @@
+/*
+ * 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 net.revelc.code.impsort;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+/**
+ * Signals that the file denoted by this path has an unknown line ending.
+ *
+ * <p>
+ * This exception will be thrown by the {@link ImpSort#parseFile} when it encounters a file with an
+ * unknown line ending.
+ * </p>
+ */
+public class UnknownLineEndingException extends IOException {
+  private static final long serialVersionUID = 4417291768648259852L;
+
+  private final Path path;
+
+  /**
+   * Constructs a {@code UnknownLineEndingException} with {@code null} as its error detail message
+   * and the specified path.
+   *
+   * @param path the path
+   */
+  public UnknownLineEndingException(final Path path) {
+    this.path = path;
+  }
+
+  /**
+   * Returns the path.
+   *
+   * @return the path
+   */
+  public Path getPath() {
+    return path;
+  }
+}

src/main/java/net/revelc/code/impsort/maven/plugin/AbstractImpSortMojo.java

@@ -34,10 +34,12 @@
 import org.apache.maven.project.MavenProject;
 import org.codehaus.plexus.util.DirectoryScanner;
 
+import net.revelc.code.impsort.EmptyFileException;
 import net.revelc.code.impsort.Grouper;
 import net.revelc.code.impsort.ImpSort;
 import net.revelc.code.impsort.LineEnding;
 import net.revelc.code.impsort.Result;
+import net.revelc.code.impsort.UnknownLineEndingException;
 
 abstract class AbstractImpSortMojo extends AbstractMojo {
 
@@ -233,6 +235,10 @@ public final void execute() throws MojoExecutionException, MojoFailureException
             numProcessed.getAndIncrement();
           }
           processResult(path, result);
+        } catch (EmptyFileException e) {
+          getLog().warn("Skipping empty file " + e.getPath());
+        } catch (UnknownLineEndingException e) {
+          getLog().warn("Skipping file with unknown line ending " + e.getPath());
         } catch (IOException e) {
           fail("Error reading file " + path, e);
         }

src/test/java/net/revelc/code/impsort/FileTest.java

@@ -0,0 +1,63 @@
+/*
+ * 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 net.revelc.code.impsort;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.junit.Test;
+
+/**
+ * Test class for special file cases.
+ */
+public class FileTest {
+
+  private static Grouper eclipseDefaults =
+      new Grouper("java.,javax.,org.,com.", "", false, false, true);
+
+  /**
+   * Test successfully parsing empty (0 byte) file.
+   */
+  @Test(expected = EmptyFileException.class)
+  public void test_empty_file() throws IOException, EmptyFileException, UnknownLineEndingException {
+    Path p =
+        Paths.get(System.getProperty("user.dir"), "src", "test", "resources", "EmptyFile.java");
+    new ImpSort(StandardCharsets.UTF_8, eclipseDefaults, true, true, LineEnding.AUTO).parseFile(p);
+  }
+
+  /**
+   * Test successfully parsing file without any newline.
+   */
+  @Test(expected = UnknownLineEndingException.class)
+  public void test_file_without_newline()
+      throws IOException, EmptyFileException, UnknownLineEndingException {
+    Path p = Paths.get(System.getProperty("user.dir"), "src", "test", "resources",
+        "FileWithoutNewline.java");
+    new ImpSort(StandardCharsets.UTF_8, eclipseDefaults, true, true, LineEnding.AUTO).parseFile(p);
+  }
+
+  /**
+   * Test successfully parsing file that can't be parsed.
+   */
+  @Test(expected = IOException.class)
+  public void test_invalid_file()
+      throws IOException, EmptyFileException, UnknownLineEndingException {
+    Path p =
+        Paths.get(System.getProperty("user.dir"), "src", "test", "resources", "InvalidFile.java");
+    new ImpSort(StandardCharsets.UTF_8, eclipseDefaults, true, true, LineEnding.AUTO).parseFile(p);
+  }
+
+}

src/test/resources/FileWithoutNewline.java

@@ -0,0 +1 @@
+import java.lang.System;public class FileWithoutNewline{public static void main(String[] args){System.out.println("Hello, world!");}}

src/test/resources/InvalidFile.java

@@ -0,0 +1,5 @@
+public class InvalidFile {
+    public static void main(String[] args) {
+        System.out.println("Hello, world!")
+    }
+}