SystemRestart exception to restart the interpreter

src/org/python/util/jython.java

 // Copyright (c) Corporation for National Research Initiatives
 package org.python.util;
 
 import java.io.File;
 import java.io.IOException;
 import java.io.FileInputStream;
 import java.io.InputStream;
 import java.nio.charset.Charset;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
 import org.python.core.Options;
 import org.python.core.Py;
 import org.python.core.PyCode;
 import org.python.core.PyException;
 import org.python.core.PyFile;
 import org.python.core.PyModule;
-import org.python.core.PyObject;
 import org.python.core.PyString;
 import org.python.core.PyStringMap;
 import org.python.core.PySystemState;
 import org.python.core.imp;
 import org.python.core.util.RelativeFile;
+import org.python.modules.thread.thread;
 
 public class jython
 {
     private static final String COPYRIGHT =
             "Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.";
 
     private static final String usage =
         // "usage: jython [option] ... [-c cmd | -m mod | file | -] [arg] ...\n" +
         "usage: jython [option] ... [-c cmd | file | -] [arg] ...\n" +
         "Options and arguments:\n" + //(and corresponding environment variables):\n" +
@@ skipping 17 matching lines @@
         "-v       : verbose (trace import statements)\n" + // (also PYTHONVERBOSE=x)\n" +
         "-V       : print the Python version number and exit (also --version)\n" +
         "-W arg   : warning control (arg is action:message:category:module:lineno)\n" +
         //"-x       : skip first line of source, allowing use of non-Unix forms of #!cmd\n" +
         "file     : program read from script file\n" +
         "-        : program read from stdin (default; interactive mode if a tty)\n" +
         "arg ...  : arguments passed to program in sys.argv[1:]\n" +
         "Other environment variables:\n" +
         "JYTHONPATH: '" + java.io.File.pathSeparator + "'-separated list of directories prefixed to the default module\n" +
         "            search path.  The result is sys.path.";
+
+    private static boolean restart;

[Nicholas Riley, 2008/08/04 02:59:41]

perhaps "shouldRestart"?

 
     public static void runJar(String filename) {
         // TBD: this is kind of gross because a local called `zipfile' just
         // magically shows up in the module's globals.  Either `zipfile'
         // should be called `__zipfile__' or (preferrably, IMO), __run__.py
         // should be imported and a main() function extracted.  This
         // function should be called passing zipfile in as an argument.
         //
         // Probably have to keep this code around for backwards
         // compatibility (?)
@@ skipping 24 matching lines @@
             } finally {
                 file.close();
             }
             Py.runCode(code, locals, locals);
         } catch (IOException e) {
             throw Py.IOError(e);
         }
     }
 
     public static void main(String[] args) {
+        do {
+            restart = false;
+            run(args);
+        } while (restart);
+    }
+
+    public static void run(String[] args) {
         // Parse the command line options
         CommandLineOptions opts = new CommandLineOptions();
         if (!opts.parse(args)) {
             if (opts.version) {
                 PySystemState.determinePlatform(System.getProperties());
                 System.err.println(InteractiveConsole.getDefaultBanner());
                 System.exit(0);
             }
             System.err.println(usage);
             int exitcode = opts.help ? 0 : -1;
             System.exit(exitcode);
         }
 
         // Setup the basic python system state from these options
         PySystemState.initialize(PySystemState.getBaseProperties(),
                                  opts.properties, opts.argv);
 
         // Now create an interpreter
-        InteractiveConsole interp = null;
-        try {
-            String interpClass = PySystemState.registry.getProperty(
-                                    "python.console",
-                                    "org.python.util.InteractiveConsole");
-            interp = (InteractiveConsole)
-                             Class.forName(interpClass).newInstance();
-        } catch (Exception e) {
-            interp = new InteractiveConsole();
-        }
-
-        //System.err.println("interp");
-        PyModule mod = imp.addModule("__main__");
-        interp.setLocals(mod.__dict__);
-        //System.err.println("imp");
+        InteractiveConsole interp = newInterpreter();
 
         for (int i = 0; i < opts.warnoptions.size(); i++) {
             String wopt = (String) opts.warnoptions.elementAt(i);
             PySystemState.warnoptions.append(new PyString(wopt));
         }
 
         // Decide if stdin is interactive
         if (!opts.fixInteractive && opts.interactive) {
             opts.interactive = ((PyFile)Py.defaultSystemState.stdin).isatty();
             if (!opts.interactive) {
@@ skipping 54 matching lines @@
                     interp.locals.__setitem__(new PyString("__file__"),
                                               new PyString("<stdin>"));
                     interp.execfile(System.in, "<stdin>");
                 } catch (Throwable t) {
                     Py.printException(t);
                 }
             } else {
                 try {
                    interp.locals.__setitem__(new PyString("__file__"),
                                              new PyString(opts.filename));
-
                    FileInputStream file;
                    try {
                        file = new java.io.FileInputStream(new RelativeFile(opts.filename));
                    } catch (java.io.FileNotFoundException e) {
                        throw Py.IOError(e);
                    }
                    if (imp.load("os").__getattr__("isatty").__call__(Py.java2py(file.getFD())).__nonzero__()) {
                        opts.interactive = true;
                        interp.interact(null, new PyFile(file));
                        System.exit(0);
                    } else {
                        interp.execfile(file, opts.filename);
                    }
                 } catch(Throwable t) {
+                    if (t instanceof PyException &&
+                            Py.matchException((PyException)t, Py.SystemRestart)) {
+                        // Stop current threads...
+                        thread.interruptAllThreads();
+                        // ..reset the state...
+                        Py.setSystemState(new PySystemState());
+                        // ...and start again
+                        restart = true;
+                    } else {
                     Py.printException(t);
                     if (!opts.interactive) {
                         interp.cleanup();
                         System.exit(-1);
                     }
                 }
             }
+        }
         }
         else {
             // if there was no file name on the command line, then "" is
             // the first element on sys.path.  This is here because if
             // there /was/ a filename on the c.l., and say the -i option
             // was given, sys.path[0] will have gotten filled in with the
             // dir of the argument filename.
             Py.getSystemState().path.insert(0, new PyString(""));
 
             if (opts.command != null) {
@@ skipping 21 matching lines @@
             try {
                 interp.interact(null, null);
             } catch (Throwable t) {
                 Py.printException(t);
             }
         }
         interp.cleanup();
         if (opts.fixInteractive || opts.interactive) {
             System.exit(0);
         }
+    }
+
+    /**

[fwierzbicki, 2008/08/04 13:42:57]

I like that this has been broken out into its own method.

+     * @return a new python interpreter, instantiating the right
+     * InteractiveConsole subclass for the configured <tt>python.console</tt>
+     */
+    private static InteractiveConsole newInterpreter() {
+        InteractiveConsole interp = null;
+        try {
+            String interpClass = PySystemState.registry.getProperty(
+                                    "python.console",
+                                    "org.python.util.InteractiveConsole");
+            interp = (InteractiveConsole)
+                             Class.forName(interpClass).newInstance();
+        } catch (Exception e) {
+            interp = new InteractiveConsole();
+}
+
+        //System.err.println("interp");
+        PyModule mod = imp.addModule("__main__");
+        interp.setLocals(mod.__dict__);
+        //System.err.println("imp");
+        return interp;
     }
 }
 
 class CommandLineOptions
 {
     public String filename;
     public boolean jar, interactive, notice;
     public boolean fixInteractive;
     public boolean help, version;
     public String[] argv;
@@ skipping 129 matching lines @@
         else
             argv[0] = "";
 
         for(int i=1; i<n; i++, index++) {
             argv[i] = args[index];
         }
 
         return true;
     }
 }