Indicate the lex source file in the header of the java source (#371)

regisd · web-flow · commit b9fa958d9edc · 2018-09-28T11:58:35.000+02:00
* Indicate in the source lexFile in the header of the java source
  - Emit in the header of the generated java source the path of the lex file.
  - Do not show the working directory, only the relative path to the working directory.
* Set the source directory in the jflex-maven-plugin

e.g.
```
// DO NOT EDIT
// Generated by JFlex 1.7.1-SNAPSHOT
// source: src/main/jflex/lcalc.flex
```
diff --git a/jflex-maven-plugin/src/main/java/de/jflex/plugin/maven/JFlexMojo.java b/jflex-maven-plugin/src/main/java/de/jflex/plugin/maven/JFlexMojo.java
@@ -215,6 +215,7 @@ private void parseLexFile(File lexFile) throws MojoFailureException, MojoExecuti
     // set options. Very strange that JFlex expects this in a static way.
     Options.setDefaults();
     Options.setDir(generatedFile.getParentFile());
+    Options.setRootDirectory(project.getBasedir());
     Options.dump = dump;
     Options.verbose = verbose;
     Options.unused_warning = unusedWarning;
diff --git a/jflex/src/main/java/jflex/Emitter.java b/jflex/src/main/java/jflex/Emitter.java
@@ -19,6 +19,7 @@
 import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import jflex.io.FileUtil;
 
 /**
  * This class manages the actual code generation, putting the scanner together, filling in skeleton
@@ -406,7 +407,9 @@ private void emitNextInput() {
   }
 
   private void emitHeader() {
-    println("/* The following code was generated by JFlex " + Main.version + " */");
+    println("// DO NOT EDIT");
+    println("// Generated by JFlex " + Main.version);
+    println("// source: " + FileUtil.getRelativePath(Options.getRootDirectory(), inputFile));
     println("");
   }
 
diff --git a/jflex/src/main/java/jflex/Options.java b/jflex/src/main/java/jflex/Options.java
@@ -25,6 +25,12 @@ public class Options {
 
   /** output directory */
   private static File directory;
+  /**
+   * The root source directory.
+   *
+   * <p>In a maven project, this is the directory that contains {@code src} and {@code target}.
+   */
+  private static File rootDirectory;
   /** strict JLex compatibility */
   public static boolean jlex;
   /** don't run minimization algorithm if this is true */
@@ -91,6 +97,18 @@ public static void setDir(File d) {
     directory = d;
   }
 
+  /**
+   * Returns the root directory that contains source code. This is the java working (from system
+   * property {@code user.dir}) by default.
+   */
+  public static File getRootDirectory() {
+    return rootDirectory;
+  }
+
+  public static void setRootDirectory(File rootDir) {
+    rootDirectory = rootDir;
+  }
+
   /** Sets encoding for input files, and check availability of encoding on this JVM. */
   public static void setEncoding(String encodingName) {
     if (Charset.isSupported(encodingName)) {
@@ -104,6 +122,8 @@ public static void setEncoding(String encodingName) {
   /** Sets all options back to default values. */
   public static void setDefaults() {
     directory = null;
+    // System.getProperty("user.dir"), the directory where java was run from.
+    rootDirectory = new File("");
     jlex = false;
     no_minimize = false;
     no_backup = false;
diff --git a/jflex/src/main/java/jflex/io/FileUtil.java b/jflex/src/main/java/jflex/io/FileUtil.java
@@ -0,0 +1,23 @@
+package jflex.io;
+
+import java.io.File;
+import java.io.IOException;
+
+public class FileUtil {
+
+  /** Returns the path of {@code file} relative to {@code rootDirectory}. */
+  public static String getRelativePath(File rootDirectory, File file) {
+    try {
+      String rootDir = rootDirectory.getCanonicalPath() + File.separator;
+      String f = file.getCanonicalPath();
+      if (f.startsWith(rootDir)) {
+        return f.substring(rootDir.length());
+      }
+    } catch (IOException e) {
+      // fall back to file.getPath()
+    }
+    return file.getPath();
+  }
+
+  private FileUtil() {} // utility class
+}
diff --git a/jflex/src/test/java/jflex/io/FileUtilTest.java b/jflex/src/test/java/jflex/io/FileUtilTest.java
@@ -0,0 +1,31 @@
+package jflex.io;
+
+import static org.junit.Assert.*;
+
+import java.io.File;
+import junit.framework.TestCase;
+import org.junit.Test;
+
+public class FileUtilTest extends TestCase {
+
+  @Test
+  public void test_getRelativePath_fileInDir() {
+    File dir = new File("/a/b/c");
+    File f = new File("/a/b/c/d/foo.bar");
+    assertEquals("d/foo.bar", FileUtil.getRelativePath(dir, f));
+  }
+
+  @Test
+  public void test_getRelativePath_fileNotInDir() {
+    File dir = new File("/a/b/c");
+    File f = new File("/d/e/f/foo.bar");
+    assertEquals("/d/e/f/foo.bar", FileUtil.getRelativePath(dir, f));
+  }
+
+  @Test
+  public void test_getRelativePath_sameStart() {
+    File dir = new File("/a/b/c");
+    File f = new File("/a/b/c.txt");
+    assertEquals("/a/b/c.txt", FileUtil.getRelativePath(dir, f));
+  }
+}
