fold in Mike Lischke's PR antlr#2065 to make the output directory exa…

…ct if you use a new option `-Xexact-output-dir`. Fixes antlr#1087, Fixes antlr#753, Fixes antlr#638.

tool/src/org/antlr/v4/Tool.java

@@ -115,6 +115,7 @@ public Option(String fieldName, String name, OptionArgType argType, String descr
 	public Map<String, String> grammarOptions = null;
 	public boolean warnings_are_errors = false;
 	public boolean longMessages = false;
+	public boolean exact_output_dir = false;
 
     public static Option[] optionDefs = {
         new Option("outputDirectory",	"-o", OptionArgType.STRING, "specify output directory where all output is generated"),
@@ -134,7 +135,8 @@ public Option(String fieldName, String name, OptionArgType argType, String descr
         new Option("launch_ST_inspector", "-XdbgST", "launch StringTemplate visualizer on generated code"),
 		new Option("ST_inspector_wait_for_close", "-XdbgSTWait", "wait for STViz to close before continuing"),
         new Option("force_atn",			"-Xforce-atn", "use the ATN simulator for all predictions"),
-		new Option("log",   			"-Xlog", "dump lots of logging info to antlr-timestamp.log"),
+	    new Option("log",   			"-Xlog", "dump lots of logging info to antlr-timestamp.log"),
+	    new Option("exact_output_dir",  "-Xexact-output-dir", "all output goes into -o dir regardless of paths/package"),
 	};
 
 	// helper vars for option management
@@ -758,6 +760,61 @@ public File getImportedGrammarFile(Grammar g, String fileName) {
 	 * @param fileNameWithPath path to input source
 	 */
 	public File getOutputDirectory(String fileNameWithPath) {
+		if ( exact_output_dir ) {
+			return new_getOutputDirectory(fileNameWithPath);
+		}
+
+		File outputDir;
+		String fileDirectory;
+
+		// Some files are given to us without a PATH but should should
+		// still be written to the output directory in the relative path of
+		// the output directory. The file directory is either the set of sub directories
+		// or just or the relative path recorded for the parent grammar. This means
+		// that when we write the tokens files, or the .java files for imported grammars
+		// taht we will write them in the correct place.
+		if (fileNameWithPath.lastIndexOf(File.separatorChar) == -1) {
+			// No path is included in the file name, so make the file
+			// directory the same as the parent grammar (which might sitll be just ""
+			// but when it is not, we will write the file in the correct place.
+			fileDirectory = ".";
+
+		}
+		else {
+			fileDirectory = fileNameWithPath.substring(0, fileNameWithPath.lastIndexOf(File.separatorChar));
+		}
+		if ( haveOutputDir ) {
+			// -o /tmp /var/lib/t.g4 => /tmp/T.java
+			// -o subdir/output /usr/lib/t.g4 => subdir/output/T.java
+			// -o . /usr/lib/t.g4 => ./T.java
+			if (fileDirectory != null &&
+				(new File(fileDirectory).isAbsolute() ||
+					fileDirectory.startsWith("~"))) { // isAbsolute doesn't count this :(
+				// somebody set the dir, it takes precendence; write new file there
+				outputDir = new File(outputDirectory);
+			}
+			else {
+				// -o /tmp subdir/t.g4 => /tmp/subdir/T.java
+				if (fileDirectory != null) {
+					outputDir = new File(outputDirectory, fileDirectory);
+				}
+				else {
+					outputDir = new File(outputDirectory);
+				}
+			}
+		}
+		else {
+			// they didn't specify a -o dir so just write to location
+			// where grammar is, absolute or relative, this will only happen
+			// with command line invocation as build tools will always
+			// supply an output directory.
+			outputDir = new File(fileDirectory);
+		}
+		return outputDir;
+	}
+
+	/** @since 4.7.1 in response to -Xexact-output-dir */
+	public File new_getOutputDirectory(String fileNameWithPath) {
 		File outputDir;
 		String fileDirectory;
 
@@ -774,7 +831,7 @@ public File getOutputDirectory(String fileNameWithPath) {
 			// -o /tmp /var/lib/t.g4 => /tmp/T.java
 			// -o subdir/output /usr/lib/t.g4 => subdir/output/T.java
 			// -o . /usr/lib/t.g4 => ./T.java
-			// -o /tmp subdir/t.g4 => /tmp/t.g4
+			// -o /tmp subdir/t.g4 => /tmp/T.java
 			outputDir = new File(outputDirectory);
 		}
 		else {