Implement redirection for pluggable scripting contexts

examples/jse/ScriptEngineSample.java

@@ -97,7 +97,7 @@ public class ScriptEngineSample {
             		"print(\"string written using 'print'\")\n" +
             		"io.write(\"string written using 'io.write()'\\n\")\n" +
             		"io.stdout:write(\"string written using 'io.stdout:write()'\\n\")\n" +
-            		"io.stderr:write(\"string written using 'io.stderr:write()'\\n\")\n" +
+            		"io.stderr:write(\"string written using 'io.stderr:write(), hit return to continue...'\\n\")\n" +
             		"io.write([[string read using 'io.stdin:read(\"*l\")':]]..io.stdin:read(\"*l\")..\"\\n\")\n";
 
             System.out.println("Evaluating script with redirection set.");
@@ -114,7 +114,7 @@ public class ScriptEngineSample {
             e.getContext().setReader(null);
             e.getContext().setWriter(null);
             e.getContext().setErrorWriter(null);
-            e.eval(script);
+            e.eval(script);  // Will wait for a line from the user at this step!
             System.out.println("output::>"+output+"<::output");
             System.out.println("errors::>"+errors+"<::errors");
 

src/core/org/luaj/vm2/lib/IoLib.java

@@ -111,6 +111,14 @@ public class IoLib extends OneArgFunction {
 		}
 	}
 
+	/** Enumerated value representing stdin */
+	protected static final int FTYPE_STDIN = 0;
+	/** Enumerated value representing stdout */
+	protected static final int FTYPE_STDOUT = 1;
+	/** Enumerated value representing stderr */
+	protected static final int FTYPE_STDERR = 2;
+	/** Enumerated value representing a file type for a named file */
+	protected static final int FTYPE_NAMED = 3;
 
 	/** 
 	 * Wrap the standard input. 
@@ -126,6 +134,13 @@ public class IoLib extends OneArgFunction {
 	 */
 	abstract protected File wrapStdout() throws IOException;
 	
+	/** 
+	 * Wrap the standard error output. 
+	 * @return File 
+	 * @throws IOException
+	 */
+	abstract protected File wrapStderr() throws IOException;
+	
 	/**
 	 * Open a file in a particular mode. 
 	 * @param filename
@@ -295,7 +310,7 @@ public class IoLib extends OneArgFunction {
 	}
 	
 	private File input() {
-		return infile!=null? infile: (infile=ioopenfile("-","r"));
+		return infile!=null? infile: (infile=ioopenfile(FTYPE_STDIN, "-","r"));
 	}
 	
 	//	io.flush() -> bool 
@@ -320,7 +335,7 @@ public class IoLib extends OneArgFunction {
 	//	io.input([file]) -> file
 	public Varargs _io_input(LuaValue file) {
 		infile = file.isnil()? input(): 
-				file.isstring()? ioopenfile(file.checkjstring(),"r"):
+				file.isstring()? ioopenfile(FTYPE_NAMED, file.checkjstring(),"r"):
 				checkfile(file);
 		return infile;
 	}
@@ -328,7 +343,7 @@ public class IoLib extends OneArgFunction {
 	// io.output(filename) -> file
 	public Varargs _io_output(LuaValue filename) {
 		outfile = filename.isnil()? output(): 
-				  filename.isstring()? ioopenfile(filename.checkjstring(),"w"):
+				  filename.isstring()? ioopenfile(FTYPE_NAMED, filename.checkjstring(),"w"):
 				  checkfile(filename);
 		return outfile;
 	}
@@ -348,12 +363,12 @@ public class IoLib extends OneArgFunction {
 
 	//	io.open(filename, [mode]) -> file | nil,err
 	public Varargs _io_open(String filename, String mode) throws IOException {
-		return rawopenfile(filename, mode);
+		return rawopenfile(FTYPE_NAMED, filename, mode);
 	}
 
 	//	io.lines(filename) -> iterator
 	public Varargs _io_lines(String filename) {
-		infile = filename==null? input(): ioopenfile(filename,"r");
+		infile = filename==null? input(): ioopenfile(FTYPE_NAMED, filename,"r");
 		checkopen(infile);
 		return lines(infile);
 	}
@@ -420,16 +435,16 @@ public class IoLib extends OneArgFunction {
 	}
 
 	private File output() {
-		return outfile!=null? outfile: (outfile=ioopenfile("-","w"));
+		return outfile!=null? outfile: (outfile=ioopenfile(FTYPE_STDOUT,"-","w"));
 	}
 	
 	private File errput() {
-		return errfile!=null? errfile: (errfile=ioopenfile("-","w"));
+		return errfile!=null? errfile: (errfile=ioopenfile(FTYPE_STDERR,"-","w"));
 	}
 	
-	private File ioopenfile(String filename, String mode) {
+	private File ioopenfile(int filetype, String filename, String mode) {
 		try {
-			return rawopenfile(filename, mode);
+			return rawopenfile(filetype, filename, mode);
 		} catch ( Exception e ) {
 			error("io error: "+e.getMessage());
 			return null;
@@ -517,15 +532,14 @@ public class IoLib extends OneArgFunction {
 			error("attempt to use a closed file");
 		return file;
 	}
-	
+
-	private File rawopenfile(String filename, String mode) throws IOException {
+	private File rawopenfile(int filetype, String filename, String mode) throws IOException {
-		boolean isstdfile = "-".equals(filename);
+		switch (filetype) {
-		boolean isreadmode = mode.startsWith("r");
+		case FTYPE_STDIN: return wrapStdin();
-		if ( isstdfile ) {
+		case FTYPE_STDOUT: return wrapStdout();
-			return isreadmode? 
+		case FTYPE_STDERR: return wrapStderr();
-				wrapStdin():
-				wrapStdout();
 		}
+		boolean isreadmode = mode.startsWith("r");
 		boolean isappend = mode.startsWith("a");
 		boolean isupdate = mode.indexOf("+") > 0;
 		boolean isbinary = mode.endsWith("b");

src/jme/org/luaj/vm2/lib/jme/JmeIoLib.java

@@ -75,6 +75,10 @@ public class JmeIoLib extends IoLib {
 		return new FileImpl(globals.STDOUT);
 	}
 	
+	protected File wrapStderr() throws IOException {
+		return new FileImpl(globals.STDERR);
+	}
+	
 	protected File openFile( String filename, boolean readMode, boolean appendMode, boolean updateMode, boolean binaryMode ) throws IOException {
 		String url = "file:///" + filename;
 		int mode  = readMode? Connector.READ: Connector.READ_WRITE;

src/jse/org/luaj/vm2/lib/jse/JseIoLib.java

@@ -23,9 +23,11 @@ package org.luaj.vm2.lib.jse;
 
 
 import java.io.BufferedInputStream;
+import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.PrintStream;
 import java.io.RandomAccessFile;
 
 import org.luaj.vm2.LuaError;
@@ -68,11 +70,15 @@ import org.luaj.vm2.lib.LibFunction;
 public class JseIoLib extends IoLib {
 
 	protected File wrapStdin() throws IOException {
-		return new FileImpl(globals.STDIN);
+		return new StdinFile();
 	}
 	
 	protected File wrapStdout() throws IOException {
-		return new FileImpl(globals.STDOUT);
+		return new StdoutFile(FTYPE_STDOUT);
+	}
+	
+	protected File wrapStderr() throws IOException {
+		return new StdoutFile(FTYPE_STDERR);
 	}
 	
 	protected File openFile( String filename, boolean readMode, boolean appendMode, boolean updateMode, boolean binaryMode ) throws IOException {
@@ -103,6 +109,7 @@ public class JseIoLib extends IoLib {
 		throw new LuaError("not implemented");
 	}
 	
+
 	private final class FileImpl extends File {
 		private final RandomAccessFile file;
 		private final InputStream is;
@@ -215,4 +222,120 @@ public class JseIoLib extends IoLib {
 			return length;
 		}
 	}
+
+	private final class StdoutFile extends File {
+		private final int file_type;
+
+		private StdoutFile(int file_type) {
+			this.file_type = file_type;
+		}
+
+		public String tojstring() {
+			return "file ("+this.hashCode()+")";
+		}
+
+		private final PrintStream getPrintStream() {
+			return file_type == FTYPE_STDERR?
+					globals.STDERR:
+					globals.STDOUT;
+		}
+
+		public void write(LuaString string) throws IOException {
+			getPrintStream().write(string.m_bytes, string.m_offset, string.m_length);
+		}
+
+		public void flush() throws IOException {
+			getPrintStream().flush();
+		}
+
+		public boolean isstdfile() {
+			return true;
+		}
+
+		public void close() throws IOException {
+			// do not close std files.
+		}
+
+		public boolean isclosed() {
+			return false;
+		}
+
+		public int seek(String option, int bytecount) throws IOException {
+			return 0;
+		}
+
+		public void setvbuf(String mode, int size) {
+		}
+
+		public int remaining() throws IOException {
+			return 0;
+		}
+
+		public int peek() throws IOException, EOFException {
+			return 0;
+		}
+
+		public int read() throws IOException, EOFException {
+			return 0;
+		}
+
+		public int read(byte[] bytes, int offset, int length)
+				throws IOException {
+			return 0;
+		}
+	}
+
+	private final class StdinFile extends File {
+		private StdinFile() {
+		}
+
+		public String tojstring() {
+			return "file ("+this.hashCode()+")";
+		}
+
+		public void write(LuaString string) throws IOException {
+		}
+
+		public void flush() throws IOException {
+		}
+
+		public boolean isstdfile() {
+			return true;
+		}
+
+		public void close() throws IOException {
+			// do not close std files.
+		}
+
+		public boolean isclosed() {
+			return false;
+		}
+
+		public int seek(String option, int bytecount) throws IOException {
+			return 0;
+		}
+
+		public void setvbuf(String mode, int size) {
+		}
+
+		public int remaining() throws IOException {
+			return 0;
+		}
+
+		public int peek() throws IOException, EOFException {
+			globals.STDIN.mark(1);
+			int c = globals.STDIN.read();
+			globals.STDIN.reset();
+			return c;
+		}
+
+		public int read() throws IOException, EOFException {
+			return globals.STDIN.read();
+		}
+
+		public int read(byte[] bytes, int offset, int length)
+				throws IOException {
+			return globals.STDIN.read(bytes, offset, length);
+		}
+	}
 }