8028196: Javac allows timestamps inside rt.jar to affect compilation when using -sourcepath

Added -XXuserPathsFirst to allow user classes to take precedence over boot classes

Reviewed-by: jjg

langtools/src/share/classes/com/sun/tools/javac/jvm/ClassReader.java

@@ -130,6 +130,12 @@ public class ClassReader {
      **/
     public boolean preferSource;
 
+    /**
+     * Switch: Search classpath and sourcepath for classes before the
+     * bootclasspath
+     */
+    public boolean userPathsFirst;
+
     /**
      * The currently selected profile.
      */
@@ -270,6 +276,7 @@ public class ClassReader {
         saveParameterNames = options.isSet("save-parameter-names");
         cacheCompletionFailure = options.isUnset("dev");
         preferSource = "source".equals(options.get("-Xprefer"));
+        userPathsFirst = options.isSet(XXUSERPATHSFIRST);
 
         profile = Profile.instance(context);
 
@@ -2649,7 +2656,7 @@ public class ClassReader {
                 if (c.owner == p)  // it might be an inner class
                     p.members_field.enter(c);
             }
-        } else if (c.classfile != null && (c.flags_field & seen) == 0) {
+        } else if (!preferCurrent && c.classfile != null && (c.flags_field & seen) == 0) {
             // if c.classfile == null, we are currently compiling this class
             // and no further action is necessary.
             // if (c.flags_field & seen) != 0, we have already encountered
@@ -2695,20 +2702,33 @@ public class ClassReader {
 
     private boolean verbosePath = true;
 
+    // Set to true when the currently selected file should be kept
+    private boolean preferCurrent;
+
     /** Load directory of package into members scope.
      */
     private void fillIn(PackageSymbol p) throws IOException {
-        if (p.members_field == null) p.members_field = new Scope(p);
+        if (p.members_field == null)
-        String packageName = p.fullname.toString();
+            p.members_field = new Scope(p);
 
+        preferCurrent = false;
+        if (userPathsFirst) {
+            scanUserPaths(p);
+            preferCurrent = true;
+            scanPlatformPath(p);
+        } else {
+            scanPlatformPath(p);
+            scanUserPaths(p);
+        }
+        verbosePath = false;
+    }
+
+    /**
+     * Scans class path and source path for files in given package.
+     */
+    private void scanUserPaths(PackageSymbol p) throws IOException {
         Set<JavaFileObject.Kind> kinds = getPackageFileKinds();
 
-        fillIn(p, PLATFORM_CLASS_PATH,
-               fileManager.list(PLATFORM_CLASS_PATH,
-                                packageName,
-                                EnumSet.of(JavaFileObject.Kind.CLASS),
-                                false));
-
         Set<JavaFileObject.Kind> classKinds = EnumSet.copyOf(kinds);
         classKinds.remove(JavaFileObject.Kind.SOURCE);
         boolean wantClassFiles = !classKinds.isEmpty();
@@ -2748,6 +2768,7 @@ public class ClassReader {
             }
         }
 
+        String packageName = p.fullname.toString();
         if (wantSourceFiles && !haveSourcePath) {
             fillIn(p, CLASS_PATH,
                    fileManager.list(CLASS_PATH,
@@ -2768,7 +2789,17 @@ public class ClassReader {
                                         sourceKinds,
                                         false));
         }
-        verbosePath = false;
+    }
+
+    /**
+     * Scans platform class path for files in given package.
+     */
+    private void scanPlatformPath(PackageSymbol p) throws IOException {
+        fillIn(p, PLATFORM_CLASS_PATH,
+               fileManager.list(PLATFORM_CLASS_PATH,
+                                p.fullname.toString(),
+                                EnumSet.of(JavaFileObject.Kind.CLASS),
+                                false));
     }
     // where
         private void fillIn(PackageSymbol p,

langtools/src/share/classes/com/sun/tools/javac/main/Option.java

@@ -416,6 +416,8 @@ public enum Option {
 
     XPREFER("-Xprefer:", "opt.prefer", EXTENDED, BASIC, ONEOF, "source", "newer"),
 
+    XXUSERPATHSFIRST("-XXuserPathsFirst", "opt.userpathsfirst", HIDDEN, BASIC),
+
     // see enum PkgInfo
     XPKGINFO("-Xpkginfo:", "opt.pkginfo", EXTENDED, BASIC, ONEOF, "always", "legacy", "nonempty"),
 

langtools/src/share/classes/com/sun/tools/javac/resources/javac.properties

@@ -240,6 +240,8 @@ javac.opt.printRounds=\
     Print information about rounds of annotation processing
 javac.opt.printProcessorInfo=\
     Print information about which annotations a processor is asked to process
+javac.opt.userpathsfirst=\
+    Search classpath and sourcepath for classes before the bootclasspath instead of after
 javac.opt.prefer=\
     Specify which file to read when both a source file and class file are found for an implicitly compiled class
 javac.opt.AT=\

langtools/test/tools/javac/options/xprefer/XPreferTest.java

@@ -0,0 +1,385 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @summary Tests which path is used to represent an implicit type given
+ * various xprefer arguments and multiple .class / .java files involved.
+ * @bug 8028196
+ */
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.NoSuchElementException;
+import java.util.Scanner;
+
+import javax.tools.JavaCompiler;
+import javax.tools.JavaCompiler.CompilationTask;
+import javax.tools.ToolProvider;
+
+
+public class XPreferTest {
+
+    enum Dir {
+        SOURCE_PATH("src"),
+        CLASS_PATH("cp"),
+        BOOT_PATH("boot");
+
+        File file;
+        Dir(String dir) {
+            this.file = new File(dir);
+        }
+    }
+
+    enum ImplicitOption {
+        XPREFER_SOURCE("-Xprefer:source"),
+        XPREFER_NEWER("-Xprefer:newer"),
+        XXUSERPATHSFIRST("-XXuserPathsFirst");
+
+        final String optionString;
+        private ImplicitOption(String optionString) {
+            this.optionString = optionString;
+        }
+    }
+
+    final static JavaCompiler comp = ToolProvider.getSystemJavaCompiler();
+    final static File OUTPUT_DIR = new File("out");
+
+    public static void main(String... args) throws Exception {
+
+        // Initialize test-directories
+        OUTPUT_DIR.mkdir();
+        for (Dir dir : Dir.values())
+            dir.file.mkdir();
+
+        int testCaseCounter = 0;
+
+        for (List<Dir> dirSubset : SubseqIter.subseqsOf(Dir.values())) {
+
+            if (dirSubset.isEmpty())
+                continue;
+
+            for (ImplicitOption policy : ImplicitOption.values()) {
+                for (List<Dir> dirOrder : PermutationIterator.permutationsOf(dirSubset)) {
+                    new TestCase(dirOrder, policy, testCaseCounter++).run();
+                }
+            }
+        }
+    }
+
+    static class TestCase {
+
+        String classId;
+        List<Dir> dirs;
+        ImplicitOption option;
+
+        public TestCase(List<Dir> dirs, ImplicitOption option, int testCaseNum) {
+            this.dirs = dirs;
+            this.option = option;
+            this.classId = "XPreferTestImplicit" + testCaseNum;
+        }
+
+        void run() throws Exception {
+
+            System.out.println("Test:");
+            System.out.println("    Class id: " + classId);
+            System.out.println("    Dirs:     " + dirs);
+            System.out.println("    Option:   " + option);
+
+            createTestFiles();
+            String compileOutput = compile();
+            Dir actual = getChosenOrigin(compileOutput);
+            Dir expected = getExpectedOrigin();
+
+            System.out.println("    Expected: " + expected);
+            System.out.println("    Actual:   " + actual);
+
+            if (actual != expected) {
+                throw new RuntimeException(String.format(
+                        "Expected javac to choose %s but %s was chosen",
+                        expected == null ? "<none>" : expected.name(),
+                        actual   == null ? "<none>" : actual.name()));
+            }
+        }
+
+        Dir getExpectedOrigin() {
+
+            Dir newest = dirs.get(0);
+
+            switch (option) {
+
+            case XPREFER_NEWER:
+
+                Dir cls = dirs.contains(Dir.BOOT_PATH) ? Dir.BOOT_PATH
+                        : dirs.contains(Dir.CLASS_PATH) ? Dir.CLASS_PATH
+                        : null;
+
+                Dir src = dirs.contains(Dir.SOURCE_PATH) ? Dir.SOURCE_PATH
+                        : null;
+
+                for (Dir dir : dirs)
+                    if (dir == cls || dir == src)
+                        return dir;
+
+                return null;
+
+            case XPREFER_SOURCE:
+                return dirs.contains(Dir.SOURCE_PATH) ? Dir.SOURCE_PATH
+                     : dirs.contains(Dir.BOOT_PATH) ? Dir.BOOT_PATH
+                     : dirs.contains(Dir.CLASS_PATH) ? Dir.CLASS_PATH
+                     : null;
+
+            case XXUSERPATHSFIRST:
+
+                for (Dir dir : dirs)
+                    if (dir == Dir.SOURCE_PATH || dir == Dir.CLASS_PATH)
+                        return dir;
+
+                // Neither SOURCE_PATH nor CLASS_PATH among dirs. Safty check:
+                if (newest != Dir.BOOT_PATH)
+                    throw new AssertionError("Expected to find BOOT_PATH");
+
+                return Dir.BOOT_PATH;
+
+            default:
+                throw new RuntimeException("Unhandled policy case.");
+            }
+        }
+
+        Dir getChosenOrigin(String compilerOutput) {
+            Scanner s = new Scanner(compilerOutput);
+            while (s.hasNextLine()) {
+                String line = s.nextLine();
+                if (line.matches("\\[loading .*\\]"))
+                    for (Dir dir : Dir.values())
+                        if (line.contains(dir.file.getName() + "/" + classId))
+                            return dir;
+            }
+            return null;
+        }
+
+        String compile() throws IOException {
+
+            // Create a class that references classId
+            File explicit = new File("ExplicitClass.java");
+            FileWriter filewriter = new FileWriter(explicit);
+            filewriter.append("class ExplicitClass { " + classId + " implicit; }");
+            filewriter.close();
+
+            StringWriter sw = new StringWriter();
+
+            com.sun.tools.javac.Main.compile(new String[] {
+                    "-verbose",
+                    option.optionString,
+                    "-sourcepath", Dir.SOURCE_PATH.file.getPath(),
+                    "-classpath", Dir.CLASS_PATH.file.getPath(),
+                    "-Xbootclasspath/p:" + Dir.BOOT_PATH.file.getPath(),
+                    "-d", XPreferTest.OUTPUT_DIR.getPath(),
+                    explicit.getPath()
+            }, new PrintWriter(sw));
+
+            return sw.toString();
+        }
+
+        void createTestFiles() throws IOException {
+            long t = 1390927988755L;  // Tue Jan 28 17:53:08 CET 2014
+            for (Dir dir : dirs) {
+                createFile(dir).setLastModified(t);
+                t -= 10000;
+            }
+        }
+
+        File createFile(Dir dir) throws IOException {
+            File src = new File(dir.file, classId + ".java");
+            try (FileWriter w = new FileWriter(src)) {
+                w.append("public class " + classId + " {}");
+            }
+            // If we're after the ".java" representation, we're done...
+            if(dir == Dir.SOURCE_PATH)
+                return src;
+            // ...otherwise compile into a ".class".
+            CompilationTask task = comp.getTask(null, null, null, null, null,
+                    comp.getStandardFileManager(null, null, null).getJavaFileObjects(src));
+            File dest = new File(dir.file, classId + ".class");
+            if(!task.call() || !dest.exists())
+                throw new RuntimeException("Compilation failure.");
+            src.delete();
+            return dest;
+        }
+    }
+}
+
+// Iterator for iteration over all subsequences of a given list.
+class SubseqIter<T> implements Iterator<List<T>> {
+
+    List<T> elements;
+    boolean[] states;
+
+    public SubseqIter(Collection<T> c) {
+        states = new boolean[c.size()];
+        elements = new ArrayList<T>(c);
+    }
+
+    public static <T> Iterable<List<T>> subseqsOf(final T[] t) {
+        return new Iterable<List<T>>() {
+            @Override
+            public Iterator<List<T>> iterator() {
+                return new SubseqIter<T>(Arrays.asList(t));
+            }
+        };
+    }
+
+    // Roll values in 'states' from index i and forward.
+    // Return true if we wrapped back to zero.
+    private boolean roll(int i) {
+        if (i == states.length)
+            return true;
+        if (!roll(i + 1))
+            return false;
+        states[i] = !states[i];
+        return !states[i];
+    }
+
+    @Override
+    public List<T> next() {
+        if (!hasNext())
+            throw new NoSuchElementException();
+        // Include element i if states[i] is true
+        List<T> next = new ArrayList<T>();
+        for (int i = 0; i < states.length; i++)
+            if (states[i])
+                next.add(elements.get(i));
+        if (roll(0))
+            states = null; // hasNext() == false from now on.
+        return next;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return states != null;
+    }
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+}
+
+class PermutationIterator<T> implements Iterator<List<T>> {
+
+    DirInt head;
+    boolean hasNext = true;
+
+    public PermutationIterator(List<T> toPermute) {
+        ListIterator<T> iter = toPermute.listIterator();
+        if (iter.hasNext())
+            head = new DirInt(iter.nextIndex(), iter.next());
+        DirInt prev = head;
+        while (iter.hasNext()) {
+            DirInt di = new DirInt(iter.nextIndex(), iter.next());
+            di.left = prev;
+            prev.right = di;
+            prev = di;
+        }
+    }
+
+    public static <T> Iterable<List<T>> permutationsOf(final List<T> list) {
+        return new Iterable<List<T>>() {
+            public Iterator<List<T>> iterator() {
+                return new PermutationIterator<>(list);
+            }
+        };
+    }
+
+    @Override
+    public boolean hasNext() {
+        return hasNext;
+    }
+
+    @Override
+    public List<T> next() {
+        // Prep return value based on current state
+        List<T> result = new ArrayList<>();
+        for (DirInt di = head; di != null; di = di.right)
+            result.add(di.object);
+
+        // Step state forward
+        DirInt maxMob = null;
+        for (DirInt di = head; di != null; di = di.right)
+            if (di.isMobile() && (maxMob == null || di.val > maxMob.val))
+                maxMob = di;
+
+        if (maxMob == null) {
+            hasNext = false;
+        } else {
+            maxMob.swapWithAdjacent();
+            for (DirInt di = head; di != null; di = di.right)
+                if (di.val > maxMob.val)
+                    di.facingLeft = !di.facingLeft;
+        }
+        return result;
+    }
+
+    private final class DirInt {
+        int val;
+        T object;
+        DirInt left, right;
+        boolean facingLeft = true;
+
+        public DirInt(int val, T object) {
+            this.val = val;
+            this.object = object;
+        }
+
+        boolean isMobile() {
+            DirInt adjacent = facingLeft ? left : right;
+            return adjacent != null && val > adjacent.val;
+        }
+
+        public void swapWithAdjacent() {
+            DirInt l = facingLeft ? left : this;
+            DirInt r = facingLeft ? this : right;
+            if (head == l) head = r;
+            if (l.left  != null) l.left.right = r;
+            if (r.right != null) r.right.left = l;
+            l.right = r.right;
+            r.left = l.left;
+            r.right = l;
+            l.left = r;
+        }
+    }
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+}