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  * 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.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * 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

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 package sun.invoke.anon;

 import java.io.IOException;

 import java.io.OutputStream;

 import java.util.Arrays;

 import java.util.HashSet;

 import java.util.IdentityHashMap;

 import java.util.Map;

 import static sun.invoke.anon.ConstantPoolVisitor.*;

 /** A class and its patched constant pool.

  *

  *  This class allow to modify (patch) a constant pool

  *  by changing the value of its entry.

  *  Entry are referenced using index that can be get

  *  by parsing the constant pool using

  *  {@link ConstantPoolParser#parse(ConstantPoolVisitor)}.

  *

  * @see ConstantPoolVisitor

  * @see ConstantPoolParser#createPatch()

  */

 public class ConstantPoolPatch {

     final ConstantPoolParser outer;

     final Object[] patchArray;

     ConstantPoolPatch(ConstantPoolParser outer) {

         this.outer      = outer;

         this.patchArray = new Object[outer.getLength()];

     }

     /** Create a {@link ConstantPoolParser} and

      *  a {@link ConstantPoolPatch} in one step.

      *  Equivalent to {@code new ConstantPoolParser(classFile).createPatch()}.

      *

      * @param classFile an array of bytes containing a class.

      * @see #ConstantPoolParser(Class)

      */

     public ConstantPoolPatch(byte[] classFile) throws InvalidConstantPoolFormatException {

         this(new ConstantPoolParser(classFile));

     }

     /** Create a {@link ConstantPoolParser} and

      *  a {@link ConstantPoolPatch} in one step.

      *  Equivalent to {@code new ConstantPoolParser(templateClass).createPatch()}.

      *

      * @param templateClass the class to parse.

      * @see #ConstantPoolParser(Class)

      */

     public ConstantPoolPatch(Class<?> templateClass) throws IOException, InvalidConstantPoolFormatException {

         this(new ConstantPoolParser(templateClass));

     }

     /** Creates a patch from an existing patch.

      *  All changes are copied from that patch.

      * @param patch a patch

      *

      * @see ConstantPoolParser#createPatch()

      */

     public ConstantPoolPatch(ConstantPoolPatch patch) {

         outer      = patch.outer;

         patchArray = patch.patchArray.clone();

     }

     /** Which parser built this patch? */

     public ConstantPoolParser getParser() {

         return outer;

     }

     /** Report the tag at the given index in the constant pool. */

     public byte getTag(int index) {

         return outer.getTag(index);

     }

     /** Report the current patch at the given index of the constant pool.

      *  Null means no patch will be made.

      *  To observe the unpatched entry at the given index, use

      *  {@link #getParser()}{@code .}@link ConstantPoolParser#parse(ConstantPoolVisitor)}

      */

     public Object getPatch(int index) {

         Object value = patchArray[index];

         if (value == null)  return null;

         switch (getTag(index)) {

         case CONSTANT_Fieldref:

         case CONSTANT_Methodref:

         case CONSTANT_InterfaceMethodref:

             if (value instanceof String)

                 value = stripSemis(2, (String) value);

             break;

         case CONSTANT_NameAndType:

             if (value instanceof String)

                 value = stripSemis(1, (String) value);

             break;

         }

         return value;

     }

     /** Clear all patches. */

     public void clear() {

         Arrays.fill(patchArray, null);

     }

     /** Clear one patch. */

     public void clear(int index) {

         patchArray[index] = null;

     }

     /** Produce the patches as an array. */

     public Object[] getPatches() {

         return patchArray.clone();

     }

     /** Produce the original constant pool as an array. */

     public Object[] getOriginalCP() throws InvalidConstantPoolFormatException {

         return getOriginalCP(0, patchArray.length, -1);

     }

     /** Walk the constant pool, applying patches using the given map.

      *

      * @param utf8Map Utf8 strings to modify, if encountered

      * @param classMap Classes (or their names) to modify, if encountered

      * @param valueMap Constant values to modify, if encountered

      * @param deleteUsedEntries if true, delete map entries that are used

      */

     public void putPatches(final Map<String,String> utf8Map,

                            final Map<String,Object> classMap,

                            final Map<Object,Object> valueMap,

                            boolean deleteUsedEntries) throws InvalidConstantPoolFormatException {

         final HashSet<String> usedUtf8Keys;

         final HashSet<String> usedClassKeys;

         final HashSet<Object> usedValueKeys;

         if (deleteUsedEntries) {

             usedUtf8Keys  = (utf8Map  == null) ? null : new HashSet<String>();

             usedClassKeys = (classMap == null) ? null : new HashSet<String>();

             usedValueKeys = (valueMap == null) ? null : new HashSet<Object>();

         } else {

             usedUtf8Keys = null;

             usedClassKeys = null;

             usedValueKeys = null;

         }

         outer.parse(new ConstantPoolVisitor() {

             @Override

             public void visitUTF8(int index, byte tag, String utf8) {

                 putUTF8(index, utf8Map.get(utf8));

                 if (usedUtf8Keys != null)  usedUtf8Keys.add(utf8);

             }

             @Override

             public void visitConstantValue(int index, byte tag, Object value) {

                 putConstantValue(index, tag, valueMap.get(value));

                 if (usedValueKeys != null)  usedValueKeys.add(value);

             }

             @Override

             public void visitConstantString(int index, byte tag, String name, int nameIndex) {

                 if (tag == CONSTANT_Class) {

                     putConstantValue(index, tag, classMap.get(name));

                     if (usedClassKeys != null)  usedClassKeys.add(name);

                 } else {

                     assert(tag == CONSTANT_String);

                     visitConstantValue(index, tag, name);

                 }

             }

         });

         if (usedUtf8Keys != null)   utf8Map.keySet().removeAll(usedUtf8Keys);

         if (usedClassKeys != null)  classMap.keySet().removeAll(usedClassKeys);

         if (usedValueKeys != null)  valueMap.keySet().removeAll(usedValueKeys);

     }

     Object[] getOriginalCP(final int startIndex,

                            final int endIndex,

                            final int tagMask) throws InvalidConstantPoolFormatException {

         final Object[] cpArray = new Object[endIndex - startIndex];

         outer.parse(new ConstantPoolVisitor() {

             void show(int index, byte tag, Object value) {

                 if (index < startIndex || index >= endIndex)  return;

                 if (((1 << tag) & tagMask) == 0)  return;

                 cpArray[index - startIndex] = value;

             }

             @Override

             public void visitUTF8(int index, byte tag, String utf8) {

                 show(index, tag, utf8);

             }

             @Override

             public void visitConstantValue(int index, byte tag, Object value) {

                 assert(tag != CONSTANT_String);

                 show(index, tag, value);

             }

             @Override

             public void visitConstantString(int index, byte tag,

                                             String value, int j) {

                 show(index, tag, value);

             }

             @Override

             public void visitMemberRef(int index, byte tag,

                     String className, String memberName,

                     String signature,

                     int j, int k) {

                 show(index, tag, new String[]{ className, memberName, signature });

             }

             @Override

             public void visitDescriptor(int index, byte tag,

                     String memberName, String signature,

                     int j, int k) {

                 show(index, tag, new String[]{ memberName, signature });

             }

         });

         return cpArray;

     }

     /** Write the head (header plus constant pool)

      *  of the patched class file to the indicated stream.

      */

     void writeHead(OutputStream out) throws IOException {

         outer.writePatchedHead(out, patchArray);

     }

     /** Write the tail (everything after the constant pool)

      *  of the patched class file to the indicated stream.

      */

     void writeTail(OutputStream out) throws IOException {

         outer.writeTail(out);

     }

     private void checkConstantTag(byte tag, Object value) {

         if (value == null)

             throw new IllegalArgumentException(

                     "invalid null constant value");

         if (classForTag(tag) != value.getClass())

             throw new IllegalArgumentException(

                     "invalid constant value"

                     + (tag == CONSTANT_None ? ""

                         : " for tag "+tagName(tag))

                     + " of class "+value.getClass());

     }

     private void checkTag(int index, byte putTag) {

         byte tag = outer.tags[index];

         if (tag != putTag)

             throw new IllegalArgumentException(

                 "invalid put operation"

                 + " for " + tagName(putTag)

                 + " at index " + index + " found " + tagName(tag));

     }

     private void checkTagMask(int index, int tagBitMask) {

         byte tag = outer.tags[index];

         int tagBit = ((tag & 0x1F) == tag) ? (1 << tag) : 0;

         if ((tagBit & tagBitMask) == 0)

             throw new IllegalArgumentException(

                 "invalid put operation"

                 + " at index " + index + " found " + tagName(tag));

     }

     private static void checkMemberName(String memberName) {

         if (memberName.indexOf(';') >= 0)

             throw new IllegalArgumentException("memberName " + memberName + " contains a ';'");

     }

     /** Set the entry of the constant pool indexed by index to

      *  a new string.

      *

      * @param index an index to a constant pool entry containing a

      *        {@link ConstantPoolVisitor#CONSTANT_Utf8} value.

      * @param utf8 a string

      *

      * @see ConstantPoolVisitor#visitUTF8(int, byte, String)

      */

     public void putUTF8(int index, String utf8) {

         if (utf8 == null) { clear(index); return; }

         checkTag(index, CONSTANT_Utf8);

         patchArray[index] = utf8;

     }

     /** Set the entry of the constant pool indexed by index to

      *  a new value, depending on its dynamic type.

      *

      * @param index an index to a constant pool entry containing a

      *        one of the following structures:

      *        {@link ConstantPoolVisitor#CONSTANT_Integer},

      *        {@link ConstantPoolVisitor#CONSTANT_Float},

      *        {@link ConstantPoolVisitor#CONSTANT_Long},

      *        {@link ConstantPoolVisitor#CONSTANT_Double},

      *        {@link ConstantPoolVisitor#CONSTANT_String}, or

      *        {@link ConstantPoolVisitor#CONSTANT_Class}

      * @param value a boxed int, float, long or double; or a string or class object

      * @throws IllegalArgumentException if the type of the constant does not

      *         match the constant pool entry type,

      *         as reported by {@link #getTag(int)}

      *

      * @see #putConstantValue(int, byte, Object)

      * @see ConstantPoolVisitor#visitConstantValue(int, byte, Object)

      * @see ConstantPoolVisitor#visitConstantString(int, byte, String, int)

      */

     public void putConstantValue(int index, Object value) {

         if (value == null) { clear(index); return; }

         byte tag = tagForConstant(value.getClass());

         checkConstantTag(tag, value);

         checkTag(index, tag);

         patchArray[index] = value;

     }

     /** Set the entry of the constant pool indexed by index to

      *  a new value.

      *

      * @param index an index to a constant pool entry matching the given tag

      * @param tag one of the following values:

      *        {@link ConstantPoolVisitor#CONSTANT_Integer},

      *        {@link ConstantPoolVisitor#CONSTANT_Float},

      *        {@link ConstantPoolVisitor#CONSTANT_Long},

      *        {@link ConstantPoolVisitor#CONSTANT_Double},

      *        {@link ConstantPoolVisitor#CONSTANT_String}, or

      *        {@link ConstantPoolVisitor#CONSTANT_Class}

      * @param value a boxed number, string, or class object

      * @throws IllegalArgumentException if the type of the constant does not

      *         match the constant pool entry type, or if a class name contains

      *         '/' or ';'

      *

      * @see #putConstantValue(int, Object)

      * @see ConstantPoolVisitor#visitConstantValue(int, byte, Object)

      * @see ConstantPoolVisitor#visitConstantString(int, byte, String, int)

      */

     public void putConstantValue(int index, byte tag, Object value) {

         if (value == null) { clear(index); return; }

         checkTag(index, tag);

         if (tag == CONSTANT_Class && value instanceof String) {

             checkClassName((String) value);

         } else if (tag == CONSTANT_String) {

             // the JVM accepts any object as a patch for a string

         } else {

             // make sure the incoming value is the right type

             checkConstantTag(tag, value);

         }

         checkTag(index, tag);

         patchArray[index] = value;

     }

     /** Set the entry of the constant pool indexed by index to

      *  a new {@link ConstantPoolVisitor#CONSTANT_NameAndType} value.

      *

      * @param index an index to a constant pool entry containing a

      *        {@link ConstantPoolVisitor#CONSTANT_NameAndType} value.

      * @param memberName a memberName

      * @param signature a signature

      * @throws IllegalArgumentException if memberName contains the character ';'

      *

      * @see ConstantPoolVisitor#visitDescriptor(int, byte, String, String, int, int)

      */

     public void putDescriptor(int index, String memberName, String signature) {

         checkTag(index, CONSTANT_NameAndType);

         checkMemberName(memberName);

         patchArray[index] = addSemis(memberName, signature);

     }

     /** Set the entry of the constant pool indexed by index to

      *  a new {@link ConstantPoolVisitor#CONSTANT_Fieldref},

      *  {@link ConstantPoolVisitor#CONSTANT_Methodref}, or

      *  {@link ConstantPoolVisitor#CONSTANT_InterfaceMethodref} value.

      *

      * @param index an index to a constant pool entry containing a member reference

      * @param className a class name

      * @param memberName a field or method name

      * @param signature a field or method signature

      * @throws IllegalArgumentException if memberName contains the character ';'

      *             or signature is not a correct signature

      *

      * @see ConstantPoolVisitor#visitMemberRef(int, byte, String, String, String, int, int)

      */

     public void putMemberRef(int index, byte tag,

                     String className, String memberName, String signature) {

         checkTagMask(tag, CONSTANT_MemberRef_MASK);

         checkTag(index, tag);

         checkClassName(className);

         checkMemberName(memberName);

         if (signature.startsWith("(") == (tag == CONSTANT_Fieldref))

             throw new IllegalArgumentException("bad signature: "+signature);

         patchArray[index] = addSemis(className, memberName, signature);

     }

     static private final int CONSTANT_MemberRef_MASK =

               CONSTANT_Fieldref

             | CONSTANT_Methodref

             | CONSTANT_InterfaceMethodref;

     private static final Map<Class<?>, Byte> CONSTANT_VALUE_CLASS_TAG

         = new IdentityHashMap<Class<?>, Byte>();

     private static final Class<?>[] CONSTANT_VALUE_CLASS = new Class<?>[16];

     static {

         Object[][] values = {

             {Integer.class, CONSTANT_Integer},

             {Long.class, CONSTANT_Long},

             {Float.class, CONSTANT_Float},

             {Double.class, CONSTANT_Double},

             {String.class, CONSTANT_String},

             {Class.class, CONSTANT_Class}

         };

         for (Object[] value : values) {

             Class<?> cls = (Class<?>)value[0];

             Byte     tag = (Byte) value[1];

             CONSTANT_VALUE_CLASS_TAG.put(cls, tag);

             CONSTANT_VALUE_CLASS[(byte)tag] = cls;

         }

     }

     static Class<?> classForTag(byte tag) {

         if ((tag & 0xFF) >= CONSTANT_VALUE_CLASS.length)

             return null;

         return CONSTANT_VALUE_CLASS[tag];

     }

     static byte tagForConstant(Class<?> cls) {

         Byte tag = CONSTANT_VALUE_CLASS_TAG.get(cls);

         return (tag == null) ? CONSTANT_None : (byte)tag;

     }

     private static void checkClassName(String className) {

         if (className.indexOf('/') >= 0 || className.indexOf(';') >= 0)

             throw new IllegalArgumentException("invalid class name " + className);

     }

     static String addSemis(String name, String... names) {

         StringBuilder buf = new StringBuilder(name.length() * 5);

         buf.append(name);

         for (String name2 : names) {

             buf.append(';').append(name2);

         }

         String res = buf.toString();

         assert(stripSemis(names.length, res)[0].equals(name));

         assert(stripSemis(names.length, res)[1].equals(names[0]));

         assert(names.length == 1 ||

                stripSemis(names.length, res)[2].equals(names[1]));

         return res;

     }

     static String[] stripSemis(int count, String string) {

         String[] res = new String[count+1];

         int pos = 0;

         for (int i = 0; i < count; i++) {

             int pos2 = string.indexOf(';', pos);

             if (pos2 < 0)  pos2 = string.length();  // yuck

             res[i] = string.substring(pos, pos2);

             pos = pos2;

         }

         res[count] = string.substring(pos);

         return res;

     }

     public String toString() {

         StringBuilder buf = new StringBuilder(this.getClass().getName());

         buf.append("{");

         Object[] origCP = null;

         for (int i = 0; i < patchArray.length; i++) {

             if (patchArray[i] == null)  continue;

             if (origCP != null) {

                 buf.append(", ");

             } else {

                 try {

                     origCP = getOriginalCP();

                 } catch (InvalidConstantPoolFormatException ee) {

                     origCP = new Object[0];

                 }

             }

             Object orig = (i < origCP.length) ? origCP[i] : "?";

             buf.append(orig).append("=").append(patchArray[i]);

         }

         buf.append("}");

         return buf.toString();

     }

 }