--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/agent/make/ClosureFinder.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,254 @@
+/*
+ * Copyright 2003-2004 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+import java.io.*;
+import java.util.*;
+
+
+/**
+<p> This class finds transitive closure of dependencies from a given
+root set of classes. If your project has lots of .class files and you
+want to ship only those .class files which are used (transitively)
+from a root set of classes, then you can use this utility.  </p> <p>
+How does it work?</p>
+
+<p> We walk through all constant pool entries of a given class and
+find all modified UTF-8 entries. Anything that looks like a class name is
+considered as a class and we search for that class in the given
+classpath. If we find a .class of that name, then we add that class to
+list.</p>
+
+<p> We could have used CONSTANT_ClassInfo type constants only. But
+that will miss classes used through Class.forName or xyz.class
+construct.  But, if you refer to a class name in some other string we
+would include it as dependency :(. But this is quite unlikely
+anyway. To look for exact Class.forName argument(s) would involve
+bytecode analysis. Also, we handle only simple reflection. If you
+accept name of a class from externally (for eg properties file or
+command line args for example, this utility will not be able to find
+that dependency. In such cases, include those classes in the root set.
+</p>
+*/
+
+public class ClosureFinder {
+    private Collection roots;            // root class names Collection<String>
+    private Map        visitedClasses;   // set of all dependencies as a Map
+    private String     classPath;        // classpath to look for .class files
+    private String[]   pathComponents;   // classpath components
+    private static final boolean isWindows = File.separatorChar != '/';
+
+    public ClosureFinder(Collection roots, String classPath) {
+        this.roots = roots;
+        this.classPath = classPath;
+        parseClassPath();
+    }
+
+    // parse classPath into pathComponents array
+    private void parseClassPath() {
+        List paths = new ArrayList();
+        StringTokenizer st = new StringTokenizer(classPath, File.pathSeparator);
+        while (st.hasMoreTokens())
+            paths.add(st.nextToken());
+
+        Object[] arr = paths.toArray();
+        pathComponents = new String[arr.length];
+        System.arraycopy(arr, 0, pathComponents, 0, arr.length);
+    }
+
+    // if output is aleady not computed, compute it now
+    // result is a map from class file name to base path where the .class was found
+    public Map find() {
+        if (visitedClasses == null) {
+            visitedClasses = new HashMap();
+            computeClosure();
+        }
+        return visitedClasses;
+    }
+
+    // compute closure for all given root classes
+    private void computeClosure() {
+        for (Iterator rootsItr = roots.iterator(); rootsItr.hasNext();) {
+            String name = (String) rootsItr.next();
+            name = name.substring(0, name.indexOf(".class"));
+            computeClosure(name);
+        }
+    }
+
+
+    // looks up for .class in pathComponents and returns
+    // base path if found, else returns null
+    private String lookupClassFile(String classNameAsPath) {
+        for (int i = 0; i < pathComponents.length; i++) {
+            File f =  new File(pathComponents[i] + File.separator +
+                               classNameAsPath + ".class");
+            if (f.exists()) {
+                if (isWindows) {
+                    String name = f.getName();
+                    // Windows reports special devices AUX,NUL,CON as files
+                    // under any directory. It does not care about file extention :-(
+                    if (name.compareToIgnoreCase("AUX.class") == 0 ||
+                        name.compareToIgnoreCase("NUL.class") == 0 ||
+                        name.compareToIgnoreCase("CON.class") == 0) {
+                        return null;
+                    }
+                }
+                return pathComponents[i];
+            }
+        }
+        return null;
+    }
+
+
+    // from JVM spec. 2'nd edition section 4.4
+    private static final int CONSTANT_Class = 7;
+    private static final int CONSTANT_FieldRef = 9;
+    private static final int CONSTANT_MethodRef = 10;
+    private static final int CONSTANT_InterfaceMethodRef = 11;
+    private static final int CONSTANT_String = 8;
+    private static final int CONSTANT_Integer = 3;
+    private static final int CONSTANT_Float = 4;
+    private static final int CONSTANT_Long = 5;
+    private static final int CONSTANT_Double = 6;
+    private static final int CONSTANT_NameAndType = 12;
+    private static final int CONSTANT_Utf8 = 1;
+
+    // whether a given string may be a class name?
+    private boolean mayBeClassName(String internalClassName) {
+        int len = internalClassName.length();
+        for (int s = 0; s < len; s++) {
+            char c = internalClassName.charAt(s);
+            if (!Character.isJavaIdentifierPart(c) && c != '/')
+                return false;
+        }
+        return true;
+    }
+
+    // compute closure for a given class
+    private void computeClosure(String className) {
+        if (visitedClasses.get(className) != null) return;
+        String basePath = lookupClassFile(className);
+        if (basePath != null) {
+            visitedClasses.put(className, basePath);
+            try {
+                File classFile = new File(basePath + File.separator + className + ".class");
+                FileInputStream fis = new FileInputStream(classFile);
+                DataInputStream dis = new DataInputStream(fis);
+                // look for .class signature
+                if (dis.readInt() != 0xcafebabe) {
+                    System.err.println(classFile.getAbsolutePath() + " is not a valid .class file");
+                    return;
+                }
+
+                // ignore major and minor version numbers
+                dis.readShort();
+                dis.readShort();
+
+                // read number of constant pool constants
+                int numConsts = (int) dis.readShort();
+                String[] strings = new String[numConsts];
+
+                // zero'th entry is unused
+                for (int cpIndex = 1; cpIndex < numConsts; cpIndex++) {
+                    int constType = (int) dis.readByte();
+                    switch (constType) {
+                    case CONSTANT_Class:
+                    case CONSTANT_String:
+                        dis.readShort(); // string name index;
+                        break;
+
+                    case CONSTANT_FieldRef:
+                    case CONSTANT_MethodRef:
+                    case CONSTANT_InterfaceMethodRef:
+                    case CONSTANT_NameAndType:
+                    case CONSTANT_Integer:
+                    case CONSTANT_Float:
+                        // all these are 4 byte constants
+                        dis.readInt();
+                        break;
+
+                    case CONSTANT_Long:
+                    case CONSTANT_Double:
+                        // 8 byte constants
+                        dis.readLong();
+                        // occupies 2 cp entries
+                        cpIndex++;
+                        break;
+
+
+                    case CONSTANT_Utf8: {
+                        strings[cpIndex] = dis.readUTF();
+                        break;
+                    }
+
+                    default:
+                        System.err.println("invalid constant pool entry");
+                        return;
+                    }
+                }
+
+            // now walk thru the string constants and look for class names
+            for (int s = 0; s < numConsts; s++) {
+                if (strings[s] != null && mayBeClassName(strings[s]))
+                    computeClosure(strings[s].replace('/', File.separatorChar));
+            }
+
+            } catch (IOException exp) {
+                // ignore for now
+            }
+
+        }
+    }
+
+    // a sample main that accepts roots classes in a file and classpath as args
+    public static void main(String[] args) {
+        if (args.length != 2) {
+            System.err.println("Usage: ClosureFinder <root class file> <class path>");
+            System.exit(1);
+        }
+
+        List roots = new ArrayList();
+        try {
+            FileInputStream fis = new FileInputStream(args[0]);
+            DataInputStream dis = new DataInputStream(fis);
+            String line = null;
+            while ((line = dis.readLine()) != null) {
+                if (isWindows) {
+                    line = line.replace('/', File.separatorChar);
+                }
+                roots.add(line);
+            }
+        } catch (IOException exp) {
+            System.err.println(exp.getMessage());
+            System.exit(2);
+        }
+
+        ClosureFinder cf = new ClosureFinder(roots, args[1]);
+        Map out = cf.find();
+        Iterator res = out.keySet().iterator();
+        for(; res.hasNext(); ) {
+            String className = (String) res.next();
+            System.out.println(className + ".class");
+        }
+    }
+}