1 files changed, 244 insertions, 0 deletions
diff --git a/src/compiler/scala/tools/util/debug/Debug.java b/src/compiler/scala/tools/util/debug/Debug.java
new file mode 100644
index 0000000000..38ee3c7b9a
--- /dev/null
+++ b/src/compiler/scala/tools/util/debug/Debug.java
@@ -0,0 +1,244 @@
+/*     ____ ____  ____ ____  ______                                     *\
+**    / __// __ \/ __// __ \/ ____/    SOcos COmpiles Scala             **
+**  __\_ \/ /_/ / /__/ /_/ /\_ \       (c) 2002, LAMP/EPFL              **
+** /_____/\____/\___/\____/____/                                        **
+\*                                                                      */
+
+// $Id$
+
+package scala.tools.util.debug;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+
+/**
+ * This class is intended to help debugging applications. It provides
+ * functions to abort the application and to turn objects into
+ * strings.
+ *
+ * In order to turn objects into strings, the class maintains a list
+ * of debuggers. An application using this class should configure it
+ * by adding debuggers for its data types (see method "addDebugger").
+ *
+ * Each time an object has to be transformed into a string, the list
+ * of debuggers is searched from the last added one to the first one
+ * for a debugger that is able to make that transformation. The first
+ * that is found, is then used to make the transformation.
+ */
+public class Debug {
+
+    //########################################################################
+    // Private Variables
+
+    /** The list of all available debuggers */
+    private static final ArrayList/*<Debugger>*/ debuggers = new ArrayList();
+
+    static {
+        addDebugger(ObjectDebugger.object);
+        addDebugger(ArrayDebugger.object);
+        addDebugger(ThrowableDebugger.object);
+        addDebugger(new ToStringDebugger(String.class));
+    }
+
+    //########################################################################
+    // Public Methods - Configuring
+
+    /** Adds the specified debugger to the list of debuggers. */
+    public static void addDebugger(Debugger debugger) {
+        debuggers.add(debugger);
+    }
+
+    //########################################################################
+    // Public Methods - Aborting
+
+    /** Aborts the application by throwing an AbortError. */
+    public static Error abort() {
+        throw new AbortError();
+    }
+    public static Error abort(Throwable cause) {
+        throw new AbortError(cause);
+    }
+    public static Error abort(Object object) {
+        return abort(show(object));
+    }
+    public static Error abort(Object object, Throwable cause) {
+        return abort(show(object), cause);
+    }
+    public static Error abort(String message) {
+        throw new AbortError(message);
+    }
+    public static Error abort(String message, Throwable cause) {
+        throw new AbortError(message, cause);
+    }
+    public static Error abort(String message, Object object) {
+        return abort(message + ": " + show(object));
+    }
+    public static Error abort(String message, Object object, Throwable cause) {
+        return abort(message + ": " + show(object), cause);
+    }
+
+    /** Aborts the application by throwing an AbortError. */
+    public static Error abortIllegalCase(int value) {
+        return abort("illegal case: " + value);
+    }
+    public static Error abortIllegalCase(Object object) {
+        return abort("illegal case", object);
+    }
+
+    //########################################################################
+    // Public Methods - Showing
+
+    /**
+     * Makes a string out of the object(s) using for each the first
+     * matching debugger and separating them with dash(es).
+     */
+    public static String show(Object a) {
+        return showAll(new Object[] {a});
+    }
+    public static String show(Object a, Object b) {
+        return showAll(new Object[] {a, b});
+    }
+    public static String show(Object a, Object b, Object c) {
+        return showAll(new Object[] {a, b, c});
+    }
+    public static String show(Object a, Object b, Object c, Object d) {
+        return showAll(new Object[] {a, b, c, d});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e)
+    {
+        return showAll(new Object[] {a, b, c, d, e});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g, Object h)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g, h});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g, Object h, Object i)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g, h, i});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g, Object h, Object i, Object j)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g, Object h, Object i, Object j, Object k)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j, k});
+    }
+    public static String show(Object a, Object b, Object c, Object d, Object e,
+        Object f, Object g, Object h, Object i, Object j, Object k, Object l)
+    {
+        return showAll(new Object[] {a, b, c, d, e, f, g, h, i, j, k, l});
+    }
+
+    /**
+     * Makes a string out of all objects using for each the first
+     * matching debugger and separating them with dashes.
+     */
+    public static String showAll(Object[] objects) {
+        return showAll(objects, " - ");
+    }
+
+    /**
+     * Makes a string out of all objects using for each the first
+     * matching debugger and separating them with the specified
+     * separator if it is non-null and by nothing otherwise.
+     */
+    public static String showAll(Object[] objects, String separator) {
+        StringBuffer buffer = new StringBuffer();
+        appendAll(buffer, objects, separator);
+        return buffer.toString();
+    }
+
+    //########################################################################
+    // Public Methods - Appending
+
+    /**
+     * Appends the object to the buffer using the first matching
+     * debugger.
+     */
+    public static void append(StringBuffer buffer, Object object) {
+        if (object != null) {
+            for (int i = debuggers.size() - 1; i >= 0; i--) {
+                Debugger debugger = (Debugger)debuggers.get(i);
+                if (!debugger.canAppend(object)) continue;
+                debugger.append(buffer, object);
+                return;
+            }
+        }
+        buffer.append(object);
+    }
+
+    /**
+     * Appends all the objects to the buffer using for each the first
+     * matching debugger. The object are separated by the specified
+     * separator if it is non-null and by nothing otherwise.
+     */
+    public static void appendAll(StringBuffer buffer, Object[] objects,
+        String separator)
+    {
+        for (int i = 0; i < objects.length; i++) {
+            if (i > 0 && separator != null) buffer.append(separator);
+            append(buffer, objects[i]);
+        }
+    }
+
+    //########################################################################
+    // Public Methods - Miscellaneous
+
+    /**
+     * Returns the class name of the object. Does some pretty printing
+     * for parameterless pico case classes.
+     */
+    public static String getClassNameOf(Object object) {
+        if (object == null) return "null";
+        Class clasz = object.getClass();
+        String name = clasz.getName();
+        if (!name.endsWith("$$Var")) return name;
+        Class superclass = clasz.getSuperclass();
+        Field[] fields = superclass.getDeclaredFields();
+        for (int i = 0; i < fields.length; i++) {
+            try {
+                Field field = fields[i];
+                if (field.getType() != clasz) continue;
+                if (!Modifier.isStatic(field.getModifiers())) continue;
+                Object value = field.get(null);
+                if (value != object) continue;
+                return name + "[" + field.getName() + "]";
+            } catch (IllegalAccessException exception) {
+                // continue
+            }
+        }
+        return name;
+    }
+
+    /** Returns true iff the object overrides "Object.toString()". */
+    public static boolean overridesToString(Object object) {
+        try {
+            Class clasz = object.getClass();
+            Method toString = clasz.getMethod("toString", new Class[0]);
+            return toString.getDeclaringClass() != Object.class;
+        } catch (NoSuchMethodException exception) {
+            return false;
+        } catch (SecurityException exception) {
+            return false;
+        }
+    }
+
+    //########################################################################
+}