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/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2007 INRIA, France Telecom
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.mvel2.asm;
/**
* A {@link org.mvel2.asm.ClassVisitor} that generates classes in bytecode form. More
* precisely this visitor generates a byte array conforming to the Java class
* file format. It can be used alone, to generate a Java class "from scratch",
* or with one or more {@link org.mvel2.asm.ClassReader ClassReader} and adapter class visitor
* to generate a modified class from one or more existing Java classes.
*
* @author Eric Bruneton
*/
public class ClassWriter implements ClassVisitor {
/**
* Flag to automatically compute the maximum stack size and the maximum
* number of local variables of methods. If this flag is set, then the
* arguments of the {@link MethodVisitor#visitMaxs visitMaxs} method of the
* {@link MethodVisitor} returned by the {@link #visitMethod visitMethod}
* method will be ignored, and computed automatically from the signature and
* the bytecode of each method.
*
* @see #ClassWriter(int)
*/
public static final int COMPUTE_MAXS = 1;
/**
* Flag to automatically compute the stack map frames of methods from
* scratch. If this flag is set, then the calls to the
* {@link MethodVisitor#visitFrame} method are ignored, and the stack map
* frames are recomputed from the methods bytecode. The arguments of the
* {@link MethodVisitor#visitMaxs visitMaxs} method are also ignored and
* recomputed from the bytecode. In other words, computeFrames implies
* computeMaxs.
*
* @see #ClassWriter(int)
*/
public static final int COMPUTE_FRAMES = 2;
/**
* Pseudo access flag to distinguish between the synthetic attribute and
* the synthetic access flag.
*/
static final int ACC_SYNTHETIC_ATTRIBUTE = 0x40000;
/**
* The type of instructions without any argument.
*/
static final int NOARG_INSN = 0;
/**
* The type of instructions with an signed byte argument.
*/
static final int SBYTE_INSN = 1;
/**
* The type of instructions with an signed short argument.
*/
static final int SHORT_INSN = 2;
/**
* The type of instructions with a local variable index argument.
*/
static final int VAR_INSN = 3;
/**
* The type of instructions with an implicit local variable index argument.
*/
static final int IMPLVAR_INSN = 4;
/**
* The type of instructions with a type descriptor argument.
*/
static final int TYPE_INSN = 5;
/**
* The type of field and method invocations instructions.
*/
static final int FIELDORMETH_INSN = 6;
/**
* The type of the INVOKEINTERFACE/INVOKEDYNAMIC instruction.
*/
static final int ITFDYNMETH_INSN = 7;
/**
* The type of instructions with a 2 bytes bytecode offset label.
*/
static final int LABEL_INSN = 8;
/**
* The type of instructions with a 4 bytes bytecode offset label.
*/
static final int LABELW_INSN = 9;
/**
* The type of the LDC instruction.
*/
static final int LDC_INSN = 10;
/**
* The type of the LDC_W and LDC2_W instructions.
*/
static final int LDCW_INSN = 11;
/**
* The type of the IINC instruction.
*/
static final int IINC_INSN = 12;
/**
* The type of the TABLESWITCH instruction.
*/
static final int TABL_INSN = 13;
/**
* The type of the LOOKUPSWITCH instruction.
*/
static final int LOOK_INSN = 14;
/**
* The type of the MULTIANEWARRAY instruction.
*/
static final int MANA_INSN = 15;
/**
* The type of the WIDE instruction.
*/
static final int WIDE_INSN = 16;
/**
* The instruction types of all JVM opcodes.
*/
static final byte[] TYPE;
/**
* The type of CONSTANT_Class constant pool items.
*/
static final int CLASS = 7;
/**
* The type of CONSTANT_Fieldref constant pool items.
*/
static final int FIELD = 9;
/**
* The type of CONSTANT_Methodref constant pool items.
*/
static final int METH = 10;
/**
* The type of CONSTANT_InterfaceMethodref constant pool items.
*/
static final int IMETH = 11;
/**
* The type of CONSTANT_String constant pool items.
*/
static final int STR = 8;
/**
* The type of CONSTANT_Integer constant pool items.
*/
static final int INT = 3;
/**
* The type of CONSTANT_Float constant pool items.
*/
static final int FLOAT = 4;
/**
* The type of CONSTANT_Long constant pool items.
*/
static final int LONG = 5;
/**
* The type of CONSTANT_Double constant pool items.
*/
static final int DOUBLE = 6;
/**
* The type of CONSTANT_NameAndType constant pool items.
*/
static final int NAME_TYPE = 12;
/**
* The type of CONSTANT_Utf8 constant pool items.
*/
static final int UTF8 = 1;
/**
* Normal type Item stored in the ClassWriter {@link org.mvel2.asm.ClassWriter#typeTable},
* instead of the constant pool, in order to avoid clashes with normal
* constant pool items in the ClassWriter constant pool's hash table.
*/
static final int TYPE_NORMAL = 13;
/**
* Uninitialized type Item stored in the ClassWriter
* {@link org.mvel2.asm.ClassWriter#typeTable}, instead of the constant pool, in order to
* avoid clashes with normal constant pool items in the ClassWriter constant
* pool's hash table.
*/
static final int TYPE_UNINIT = 14;
/**
* Merged type Item stored in the ClassWriter {@link org.mvel2.asm.ClassWriter#typeTable},
* instead of the constant pool, in order to avoid clashes with normal
* constant pool items in the ClassWriter constant pool's hash table.
*/
static final int TYPE_MERGED = 15;
/**
* The class reader from which this class writer was constructed, if any.
*/
ClassReader cr;
/**
* Minor and major version numbers of the class to be generated.
*/
int version;
/**
* Index of the next item to be added in the constant pool.
*/
int index;
/**
* The constant pool of this class.
*/
final ByteVector pool;
/**
* The constant pool's hash table data.
*/
Item[] items;
/**
* The threshold of the constant pool's hash table.
*/
int threshold;
/**
* A reusable key used to look for items in the {@link #items} hash table.
*/
final Item key;
/**
* A reusable key used to look for items in the {@link #items} hash table.
*/
final Item key2;
/**
* A reusable key used to look for items in the {@link #items} hash table.
*/
final Item key3;
/**
* A type table used to temporarily store internal names that will not
* necessarily be stored in the constant pool. This type table is used by
* the control flow and data flow analysis algorithm used to compute stack
* map frames from scratch. This array associates to each index i
* the Item whose index is i. All Item objects stored in this
* array are also stored in the {@link #items} hash table. These two arrays
* allow to retrieve an Item from its index or, conversely, to get the index
* of an Item from its value. Each Item stores an internal name in its
* {@link Item#strVal1} field.
*/
Item[] typeTable;
/**
* Number of elements in the {@link #typeTable} array.
*/
private short typeCount;
/**
* The access flags of this class.
*/
private int access;
/**
* The constant pool item that contains the internal name of this class.
*/
private int name;
/**
* The internal name of this class.
*/
String thisName;
/**
* The constant pool item that contains the signature of this class.
*/
private int signature;
/**
* The constant pool item that contains the internal name of the super class
* of this class.
*/
private int superName;
/**
* Number of interfaces implemented or extended by this class or interface.
*/
private int interfaceCount;
/**
* The interfaces implemented or extended by this class or interface. More
* precisely, this array contains the indexes of the constant pool items
* that contain the internal names of these interfaces.
*/
private int[] interfaces;
/**
* The index of the constant pool item that contains the name of the source
* file from which this class was compiled.
*/
private int sourceFile;
/**
* The SourceDebug attribute of this class.
*/
private ByteVector sourceDebug;
/**
* The constant pool item that contains the name of the enclosing class of
* this class.
*/
private int enclosingMethodOwner;
/**
* The constant pool item that contains the name and descriptor of the
* enclosing method of this class.
*/
private int enclosingMethod;
/**
* The runtime visible annotations of this class.
*/
private AnnotationWriter anns;
/**
* The runtime invisible annotations of this class.
*/
private AnnotationWriter ianns;
/**
* The non standard attributes of this class.
*/
private Attribute attrs;
/**
* The number of entries in the InnerClasses attribute.
*/
private int innerClassesCount;
/**
* The InnerClasses attribute.
*/
private ByteVector innerClasses;
/**
* The fields of this class. These fields are stored in a linked list of
* {@link FieldWriter} objects, linked to each other by their
* {@link FieldWriter#next} field. This field stores the first element of
* this list.
*/
FieldWriter firstField;
/**
* The fields of this class. These fields are stored in a linked list of
* {@link FieldWriter} objects, linked to each other by their
* {@link FieldWriter#next} field. This field stores the last element of
* this list.
*/
FieldWriter lastField;
/**
* The methods of this class. These methods are stored in a linked list of
* {@link MethodWriter} objects, linked to each other by their
* {@link MethodWriter#next} field. This field stores the first element of
* this list.
*/
MethodWriter firstMethod;
/**
* The methods of this class. These methods are stored in a linked list of
* {@link MethodWriter} objects, linked to each other by their
* {@link MethodWriter#next} field. This field stores the last element of
* this list.
*/
MethodWriter lastMethod;
/**
* true if the maximum stack size and number of local variables
* must be automatically computed.
*/
private final boolean computeMaxs;
/**
* true if the stack map frames must be recomputed from scratch.
*/
private final boolean computeFrames;
/**
* true if the stack map tables of this class are invalid. The
* {@link MethodWriter#resizeInstructions} method cannot transform existing
* stack map tables, and so produces potentially invalid classes when it is
* executed. In this case the class is reread and rewritten with the
* {@link #COMPUTE_FRAMES} option (the resizeInstructions method can resize
* stack map tables when this option is used).
*/
boolean invalidFrames;
// ------------------------------------------------------------------------
// Static initializer
// ------------------------------------------------------------------------
/**
* Computes the instruction types of JVM opcodes.
*/
static {
int i;
byte[] b = new byte[220];
String s = "AAAAAAAAAAAAAAAABCKLLDDDDDEEEEEEEEEEEEEEEEEEEEAAAAAAAADD"
+ "DDDEEEEEEEEEEEEEEEEEEEEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
+ "AAAAAAAAAAAAAAAAAMAAAAAAAAAAAAAAAAAAAAIIIIIIIIIIIIIIIIDNOAA"
+ "AAAAGGGGGGGHHFBFAAFFAAQPIIJJIIIIIIIIIIIIIIIIII";
for (i = 0; i < b.length; ++i) {
b[i] = (byte) (s.charAt(i) - 'A');
}
TYPE = b;
// code to generate the above string
//
// // SBYTE_INSN instructions
// b[Constants.NEWARRAY] = SBYTE_INSN;
// b[Constants.BIPUSH] = SBYTE_INSN;
//
// // SHORT_INSN instructions
// b[Constants.SIPUSH] = SHORT_INSN;
//
// // (IMPL)VAR_INSN instructions
// b[Constants.RET] = VAR_INSN;
// for (i = Constants.ILOAD; i <= Constants.ALOAD; ++i) {
// b[i] = VAR_INSN;
// }
// for (i = Constants.ISTORE; i <= Constants.ASTORE; ++i) {
// b[i] = VAR_INSN;
// }
// for (i = 26; i <= 45; ++i) { // ILOAD_0 to ALOAD_3
// b[i] = IMPLVAR_INSN;
// }
// for (i = 59; i <= 78; ++i) { // ISTORE_0 to ASTORE_3
// b[i] = IMPLVAR_INSN;
// }
//
// // TYPE_INSN instructions
// b[Constants.NEW] = TYPE_INSN;
// b[Constants.ANEWARRAY] = TYPE_INSN;
// b[Constants.CHECKCAST] = TYPE_INSN;
// b[Constants.INSTANCEOF] = TYPE_INSN;
//
// // (Set)FIELDORMETH_INSN instructions
// for (i = Constants.GETSTATIC; i <= Constants.INVOKESTATIC; ++i) {
// b[i] = FIELDORMETH_INSN;
// }
// b[Constants.INVOKEINTERFACE] = ITFDYNMETH_INSN;
// b[Constants.INVOKEDYNAMIC] = ITFDYNMETH_INSN;
//
// // LABEL(W)_INSN instructions
// for (i = Constants.IFEQ; i <= Constants.JSR; ++i) {
// b[i] = LABEL_INSN;
// }
// b[Constants.IFNULL] = LABEL_INSN;
// b[Constants.IFNONNULL] = LABEL_INSN;
// b[200] = LABELW_INSN; // GOTO_W
// b[201] = LABELW_INSN; // JSR_W
// // temporary opcodes used internally by ASM - see Label and
// MethodWriter
// for (i = 202; i < 220; ++i) {
// b[i] = LABEL_INSN;
// }
//
// // LDC(_W) instructions
// b[Constants.LDC] = LDC_INSN;
// b[19] = LDCW_INSN; // LDC_W
// b[20] = LDCW_INSN; // LDC2_W
//
// // special instructions
// b[Constants.IINC] = IINC_INSN;
// b[Constants.TABLESWITCH] = TABL_INSN;
// b[Constants.LOOKUPSWITCH] = LOOK_INSN;
// b[Constants.MULTIANEWARRAY] = MANA_INSN;
// b[196] = WIDE_INSN; // WIDE
//
// for (i = 0; i < b.length; ++i) {
// System.err.print((char)('A' + b[i]));
// }
// System.err.println();
}
// ------------------------------------------------------------------------
// Constructor
// ------------------------------------------------------------------------
/**
* Constructs a new {@link org.mvel2.asm.ClassWriter} object.
*
* @param flags option flags that can be used to modify the default behavior
* of this class. See {@link #COMPUTE_MAXS}, {@link #COMPUTE_FRAMES}.
*/
public ClassWriter(final int flags) {
index = 1;
pool = new ByteVector();
items = new Item[256];
threshold = (int) (0.75d * items.length);
key = new Item();
key2 = new Item();
key3 = new Item();
this.computeMaxs = (flags & COMPUTE_MAXS) != 0;
this.computeFrames = (flags & COMPUTE_FRAMES) != 0;
}
/**
* Constructs a new {@link org.mvel2.asm.ClassWriter} object and enables optimizations for
* "mostly add" bytecode transformations. These optimizations are the
* following:
*
* - The constant pool from the original class is copied as is in
* the new class, which saves time. New constant pool entries will be added
* at the end if necessary, but unused constant pool entries won't be
* removed.
- Methods that are not transformed are copied as
* is in the new class, directly from the original class bytecode (i.e.
* without emitting visit events for all the method instructions), which
* saves a lot of time. Untransformed methods are detected by the
* fact that the {@link org.mvel2.asm.ClassReader} receives {@link MethodVisitor} objects
* that come from a {@link org.mvel2.asm.ClassWriter} (and not from a custom
* {@link org.mvel2.asm.ClassAdapter} or any other {@link org.mvel2.asm.ClassVisitor} instance).
*
*
* @param classReader the {@link org.mvel2.asm.ClassReader} used to read the original
* class. It will be used to copy the entire constant pool from the
* original class and also to copy other fragments of original
* bytecode where applicable.
* @param flags option flags that can be used to modify the default behavior
* of this class. These option flags do not affect methods that
* are copied as is in the new class. This means that the maximum
* stack size nor the stack frames will be computed for these
* methods. See {@link #COMPUTE_MAXS}, {@link #COMPUTE_FRAMES}.
*/
public ClassWriter(final ClassReader classReader, final int flags) {
this(flags);
classReader.copyPool(this);
this.cr = classReader;
}
// ------------------------------------------------------------------------
// Implementation of the ClassVisitor interface
// ------------------------------------------------------------------------
public void visit(
final int version,
final int access,
final String name,
final String signature,
final String superName,
final String[] interfaces)
{
this.version = version;
this.access = access;
this.name = newClass(name);
thisName = name;
if (ClassReader.SIGNATURES && signature != null) {
this.signature = newUTF8(signature);
}
this.superName = superName == null ? 0 : newClass(superName);
if (interfaces != null && interfaces.length > 0) {
interfaceCount = interfaces.length;
this.interfaces = new int[interfaceCount];
for (int i = 0; i < interfaceCount; ++i) {
this.interfaces[i] = newClass(interfaces[i]);
}
}
}
public void visitSource(final String file, final String debug) {
if (file != null) {
sourceFile = newUTF8(file);
}
if (debug != null) {
sourceDebug = new ByteVector().putUTF8(debug);
}
}
public void visitOuterClass(
final String owner,
final String name,
final String desc)
{
enclosingMethodOwner = newClass(owner);
if (name != null && desc != null) {
enclosingMethod = newNameType(name, desc);
}
}
public AnnotationVisitor visitAnnotation(
final String desc,
final boolean visible)
{
if (!ClassReader.ANNOTATIONS) {
return null;
}
ByteVector bv = new ByteVector();
// write type, and reserve space for values count
bv.putShort(newUTF8(desc)).putShort(0);
AnnotationWriter aw = new AnnotationWriter(this, true, bv, bv, 2);
if (visible) {
aw.next = anns;
anns = aw;
} else {
aw.next = ianns;
ianns = aw;
}
return aw;
}
public void visitAttribute(final Attribute attr) {
attr.next = attrs;
attrs = attr;
}
public void visitInnerClass(
final String name,
final String outerName,
final String innerName,
final int access)
{
if (innerClasses == null) {
innerClasses = new ByteVector();
}
++innerClassesCount;
innerClasses.putShort(name == null ? 0 : newClass(name));
innerClasses.putShort(outerName == null ? 0 : newClass(outerName));
innerClasses.putShort(innerName == null ? 0 : newUTF8(innerName));
innerClasses.putShort(access);
}
public FieldVisitor visitField(
final int access,
final String name,
final String desc,
final String signature,
final Object value)
{
return new FieldWriter(this, access, name, desc, signature, value);
}
public MethodVisitor visitMethod(
final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions)
{
return new MethodWriter(this,
access,
name,
desc,
signature,
exceptions,
computeMaxs,
computeFrames);
}
public void visitEnd() {
}
// ------------------------------------------------------------------------
// Other public methods
// ------------------------------------------------------------------------
/**
* Returns the bytecode of the class that was build with this class writer.
*
* @return the bytecode of the class that was build with this class writer.
*/
public byte[] toByteArray() {
// computes the real size of the bytecode of this class
int size = 24 + 2 * interfaceCount;
int nbFields = 0;
FieldWriter fb = firstField;
while (fb != null) {
++nbFields;
size += fb.getSize();
fb = fb.next;
}
int nbMethods = 0;
MethodWriter mb = firstMethod;
while (mb != null) {
++nbMethods;
size += mb.getSize();
mb = mb.next;
}
int attributeCount = 0;
if (ClassReader.SIGNATURES && signature != 0) {
++attributeCount;
size += 8;
newUTF8("Signature");
}
if (sourceFile != 0) {
++attributeCount;
size += 8;
newUTF8("SourceFile");
}
if (sourceDebug != null) {
++attributeCount;
size += sourceDebug.length + 4;
newUTF8("SourceDebugExtension");
}
if (enclosingMethodOwner != 0) {
++attributeCount;
size += 10;
newUTF8("EnclosingMethod");
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
++attributeCount;
size += 6;
newUTF8("Deprecated");
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& ((version & 0xFFFF) < Opcodes.V1_5 || (access & ACC_SYNTHETIC_ATTRIBUTE) != 0))
{
++attributeCount;
size += 6;
newUTF8("Synthetic");
}
if (innerClasses != null) {
++attributeCount;
size += 8 + innerClasses.length;
newUTF8("InnerClasses");
}
if (ClassReader.ANNOTATIONS && anns != null) {
++attributeCount;
size += 8 + anns.getSize();
newUTF8("RuntimeVisibleAnnotations");
}
if (ClassReader.ANNOTATIONS && ianns != null) {
++attributeCount;
size += 8 + ianns.getSize();
newUTF8("RuntimeInvisibleAnnotations");
}
if (attrs != null) {
attributeCount += attrs.getCount();
size += attrs.getSize(this, null, 0, -1, -1);
}
size += pool.length;
// allocates a byte vector of this size, in order to avoid unnecessary
// arraycopy operations in the ByteVector.enlarge() method
ByteVector out = new ByteVector(size);
out.putInt(0xCAFEBABE).putInt(version);
out.putShort(index).putByteArray(pool.data, 0, pool.length);
int mask = Opcodes.ACC_DEPRECATED
| ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
| ((access & ClassWriter.ACC_SYNTHETIC_ATTRIBUTE) / (ClassWriter.ACC_SYNTHETIC_ATTRIBUTE / Opcodes.ACC_SYNTHETIC));
out.putShort(access & ~mask).putShort(name).putShort(superName);
out.putShort(interfaceCount);
for (int i = 0; i < interfaceCount; ++i) {
out.putShort(interfaces[i]);
}
out.putShort(nbFields);
fb = firstField;
while (fb != null) {
fb.put(out);
fb = fb.next;
}
out.putShort(nbMethods);
mb = firstMethod;
while (mb != null) {
mb.put(out);
mb = mb.next;
}
out.putShort(attributeCount);
if (ClassReader.SIGNATURES && signature != 0) {
out.putShort(newUTF8("Signature")).putInt(2).putShort(signature);
}
if (sourceFile != 0) {
out.putShort(newUTF8("SourceFile")).putInt(2).putShort(sourceFile);
}
if (sourceDebug != null) {
int len = sourceDebug.length - 2;
out.putShort(newUTF8("SourceDebugExtension")).putInt(len);
out.putByteArray(sourceDebug.data, 2, len);
}
if (enclosingMethodOwner != 0) {
out.putShort(newUTF8("EnclosingMethod")).putInt(4);
out.putShort(enclosingMethodOwner).putShort(enclosingMethod);
}
if ((access & Opcodes.ACC_DEPRECATED) != 0) {
out.putShort(newUTF8("Deprecated")).putInt(0);
}
if ((access & Opcodes.ACC_SYNTHETIC) != 0
&& ((version & 0xFFFF) < Opcodes.V1_5 || (access & ACC_SYNTHETIC_ATTRIBUTE) != 0))
{
out.putShort(newUTF8("Synthetic")).putInt(0);
}
if (innerClasses != null) {
out.putShort(newUTF8("InnerClasses"));
out.putInt(innerClasses.length + 2).putShort(innerClassesCount);
out.putByteArray(innerClasses.data, 0, innerClasses.length);
}
if (ClassReader.ANNOTATIONS && anns != null) {
out.putShort(newUTF8("RuntimeVisibleAnnotations"));
anns.put(out);
}
if (ClassReader.ANNOTATIONS && ianns != null) {
out.putShort(newUTF8("RuntimeInvisibleAnnotations"));
ianns.put(out);
}
if (attrs != null) {
attrs.put(this, null, 0, -1, -1, out);
}
if (invalidFrames) {
ClassWriter cw = new ClassWriter(COMPUTE_FRAMES);
new ClassReader(out.data).accept(cw, ClassReader.SKIP_FRAMES);
return cw.toByteArray();
}
return out.data;
}
// ------------------------------------------------------------------------
// Utility methods: constant pool management
// ------------------------------------------------------------------------
/**
* Adds a number or string constant to the constant pool of the class being
* build. Does nothing if the constant pool already contains a similar item.
*
* @param cst the value of the constant to be added to the constant pool.
* This parameter must be an {@link Integer}, a {@link Float}, a
* {@link Long}, a {@link Double}, a {@link String} or a
* {@link org.mvel2.asm.Type}.
* @return a new or already existing constant item with the given value.
*/
Item newConstItem(final Object cst) {
if (cst instanceof Integer) {
int val = ((Integer) cst).intValue();
return newInteger(val);
} else if (cst instanceof Byte) {
int val = ((Byte) cst).intValue();
return newInteger(val);
} else if (cst instanceof Character) {
int val = ((Character) cst).charValue();
return newInteger(val);
} else if (cst instanceof Short) {
int val = ((Short) cst).intValue();
return newInteger(val);
} else if (cst instanceof Boolean) {
int val = ((Boolean) cst).booleanValue() ? 1 : 0;
return newInteger(val);
} else if (cst instanceof Float) {
float val = ((Float) cst).floatValue();
return newFloat(val);
} else if (cst instanceof Long) {
long val = ((Long) cst).longValue();
return newLong(val);
} else if (cst instanceof Double) {
double val = ((Double) cst).doubleValue();
return newDouble(val);
} else if (cst instanceof String) {
return newString((String) cst);
} else if (cst instanceof Type) {
Type t = (Type) cst;
return newClassItem(t.getSort() == Type.OBJECT
? t.getInternalName()
: t.getDescriptor());
} else {
throw new IllegalArgumentException("value " + cst);
}
}
/**
* Adds a number or string constant to the constant pool of the class being
* build. Does nothing if the constant pool already contains a similar item.
* This method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param cst the value of the constant to be added to the constant pool.
* This parameter must be an {@link Integer}, a {@link Float}, a
* {@link Long}, a {@link Double} or a {@link String}.
* @return the index of a new or already existing constant item with the
* given value.
*/
public int newConst(final Object cst) {
return newConstItem(cst).index;
}
/**
* Adds an UTF8 string to the constant pool of the class being build. Does
* nothing if the constant pool already contains a similar item. This
* method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is normally not
* needed by class generators or adapters.
*
* @param value the String value.
* @return the index of a new or already existing UTF8 item.
*/
public int newUTF8(final String value) {
key.set(UTF8, value, null, null);
Item result = get(key);
if (result == null) {
pool.putByte(UTF8).putUTF8(value);
result = new Item(index++, key);
put(result);
}
return result.index;
}
/**
* Adds a class reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
* This method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param value the internal name of the class.
* @return a new or already existing class reference item.
*/
Item newClassItem(final String value) {
key2.set(CLASS, value, null, null);
Item result = get(key2);
if (result == null) {
pool.put12(CLASS, newUTF8(value));
result = new Item(index++, key2);
put(result);
}
return result;
}
/**
* Adds a class reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
* This method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param value the internal name of the class.
* @return the index of a new or already existing class reference item.
*/
public int newClass(final String value) {
return newClassItem(value).index;
}
/**
* Adds a field reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
*
* @param owner the internal name of the field's owner class.
* @param name the field's name.
* @param desc the field's descriptor.
* @return a new or already existing field reference item.
*/
Item newFieldItem(final String owner, final String name, final String desc)
{
key3.set(FIELD, owner, name, desc);
Item result = get(key3);
if (result == null) {
put122(FIELD, newClass(owner), newNameType(name, desc));
result = new Item(index++, key3);
put(result);
}
return result;
}
/**
* Adds a field reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
* This method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param owner the internal name of the field's owner class.
* @param name the field's name.
* @param desc the field's descriptor.
* @return the index of a new or already existing field reference item.
*/
public int newField(final String owner, final String name, final String desc)
{
return newFieldItem(owner, name, desc).index;
}
/**
* Adds a method reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
*
* @param owner the internal name of the method's owner class.
* @param name the method's name.
* @param desc the method's descriptor.
* @param itf true if owner is an interface.
* @return a new or already existing method reference item.
*/
Item newMethodItem(
final String owner,
final String name,
final String desc,
final boolean itf)
{
int type = itf ? IMETH : METH;
key3.set(type, owner, name, desc);
Item result = get(key3);
if (result == null) {
put122(type, newClass(owner), newNameType(name, desc));
result = new Item(index++, key3);
put(result);
}
return result;
}
/**
* Adds a method reference to the constant pool of the class being build.
* Does nothing if the constant pool already contains a similar item.
* This method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is
* normally not needed by class generators or adapters.
*
* @param owner the internal name of the method's owner class.
* @param name the method's name.
* @param desc the method's descriptor.
* @param itf true if owner is an interface.
* @return the index of a new or already existing method reference item.
*/
public int newMethod(
final String owner,
final String name,
final String desc,
final boolean itf)
{
return newMethodItem(owner, name, desc, itf).index;
}
/**
* Adds an integer to the constant pool of the class being build. Does
* nothing if the constant pool already contains a similar item.
*
* @param value the int value.
* @return a new or already existing int item.
*/
Item newInteger(final int value) {
key.set(value);
Item result = get(key);
if (result == null) {
pool.putByte(INT).putInt(value);
result = new Item(index++, key);
put(result);
}
return result;
}
/**
* Adds a float to the constant pool of the class being build. Does nothing
* if the constant pool already contains a similar item.
*
* @param value the float value.
* @return a new or already existing float item.
*/
Item newFloat(final float value) {
key.set(value);
Item result = get(key);
if (result == null) {
pool.putByte(FLOAT).putInt(key.intVal);
result = new Item(index++, key);
put(result);
}
return result;
}
/**
* Adds a long to the constant pool of the class being build. Does nothing
* if the constant pool already contains a similar item.
*
* @param value the long value.
* @return a new or already existing long item.
*/
Item newLong(final long value) {
key.set(value);
Item result = get(key);
if (result == null) {
pool.putByte(LONG).putLong(value);
result = new Item(index, key);
put(result);
index += 2;
}
return result;
}
/**
* Adds a double to the constant pool of the class being build. Does nothing
* if the constant pool already contains a similar item.
*
* @param value the double value.
* @return a new or already existing double item.
*/
Item newDouble(final double value) {
key.set(value);
Item result = get(key);
if (result == null) {
pool.putByte(DOUBLE).putLong(key.longVal);
result = new Item(index, key);
put(result);
index += 2;
}
return result;
}
/**
* Adds a string to the constant pool of the class being build. Does nothing
* if the constant pool already contains a similar item.
*
* @param value the String value.
* @return a new or already existing string item.
*/
private Item newString(final String value) {
key2.set(STR, value, null, null);
Item result = get(key2);
if (result == null) {
pool.put12(STR, newUTF8(value));
result = new Item(index++, key2);
put(result);
}
return result;
}
/**
* Adds a name and type to the constant pool of the class being build. Does
* nothing if the constant pool already contains a similar item. This
* method is intended for {@link org.mvel2.asm.Attribute} sub classes, and is normally not
* needed by class generators or adapters.
*
* @param name a name.
* @param desc a type descriptor.
* @return the index of a new or already existing name and type item.
*/
public int newNameType(final String name, final String desc) {
return newNameTypeItem(name, desc).index;
}
/**
* Adds a name and type to the constant pool of the class being build. Does
* nothing if the constant pool already contains a similar item.
*
* @param name a name.
* @param desc a type descriptor.
* @return a new or already existing name and type item.
*/
Item newNameTypeItem(final String name, final String desc) {
key2.set(NAME_TYPE, name, desc, null);
Item result = get(key2);
if (result == null) {
put122(NAME_TYPE, newUTF8(name), newUTF8(desc));
result = new Item(index++, key2);
put(result);
}
return result;
}
/**
* Adds the given internal name to {@link #typeTable} and returns its index.
* Does nothing if the type table already contains this internal name.
*
* @param type the internal name to be added to the type table.
* @return the index of this internal name in the type table.
*/
int addType(final String type) {
key.set(TYPE_NORMAL, type, null, null);
Item result = get(key);
if (result == null) {
result = addType(key);
}
return result.index;
}
/**
* Adds the given "uninitialized" type to {@link #typeTable} and returns its
* index. This method is used for UNINITIALIZED types, made of an internal
* name and a bytecode offset.
*
* @param type the internal name to be added to the type table.
* @param offset the bytecode offset of the NEW instruction that created
* this UNINITIALIZED type value.
* @return the index of this internal name in the type table.
*/
int addUninitializedType(final String type, final int offset) {
key.type = TYPE_UNINIT;
key.intVal = offset;
key.strVal1 = type;
key.hashCode = 0x7FFFFFFF & (TYPE_UNINIT + type.hashCode() + offset);
Item result = get(key);
if (result == null) {
result = addType(key);
}
return result.index;
}
/**
* Adds the given Item to {@link #typeTable}.
*
* @param item the value to be added to the type table.
* @return the added Item, which a new Item instance with the same value as
* the given Item.
*/
private Item addType(final Item item) {
++typeCount;
Item result = new Item(typeCount, key);
put(result);
if (typeTable == null) {
typeTable = new Item[16];
}
if (typeCount == typeTable.length) {
Item[] newTable = new Item[2 * typeTable.length];
System.arraycopy(typeTable, 0, newTable, 0, typeTable.length);
typeTable = newTable;
}
typeTable[typeCount] = result;
return result;
}
/**
* Returns the index of the common super type of the two given types. This
* method calls {@link #getCommonSuperClass} and caches the result in the
* {@link #items} hash table to speedup future calls with the same
* parameters.
*
* @param type1 index of an internal name in {@link #typeTable}.
* @param type2 index of an internal name in {@link #typeTable}.
* @return the index of the common super type of the two given types.
*/
int getMergedType(final int type1, final int type2) {
key2.type = TYPE_MERGED;
key2.longVal = type1 | (((long) type2) << 32);
key2.hashCode = 0x7FFFFFFF & (TYPE_MERGED + type1 + type2);
Item result = get(key2);
if (result == null) {
String t = typeTable[type1].strVal1;
String u = typeTable[type2].strVal1;
key2.intVal = addType(getCommonSuperClass(t, u));
result = new Item((short) 0, key2);
put(result);
}
return result.intVal;
}
/**
* Returns the common super type of the two given types. The default
* implementation of this method loads the two given classes and uses
* the java.lang.Class methods to find the common super class. It can be
* overridden to compute this common super type in other ways, in particular
* without actually loading any class, or to take into account the class
* that is currently being generated by this ClassWriter, which can of
* course not be loaded since it is under construction.
*
* @param type1 the internal name of a class.
* @param type2 the internal name of another class.
* @return the internal name of the common super class of the two given
* classes.
*/
protected String getCommonSuperClass(final String type1, final String type2)
{
Class c, d;
try {
c = Class.forName(type1.replace('/', '.'));
d = Class.forName(type2.replace('/', '.'));
} catch (Exception e) {
throw new RuntimeException(e.toString());
}
if (c.isAssignableFrom(d)) {
return type1;
}
if (d.isAssignableFrom(c)) {
return type2;
}
if (c.isInterface() || d.isInterface()) {
return "java/lang/Object";
} else {
do {
c = c.getSuperclass();
} while (!c.isAssignableFrom(d));
return c.getName().replace('.', '/');
}
}
/**
* Returns the constant pool's hash table item which is equal to the given
* item.
*
* @param key a constant pool item.
* @return the constant pool's hash table item which is equal to the given
* item, or null if there is no such item.
*/
private Item get(final Item key) {
Item i = items[key.hashCode % items.length];
while (i != null && (i.type != key.type || !key.isEqualTo(i))) {
i = i.next;
}
return i;
}
/**
* Puts the given item in the constant pool's hash table. The hash table
* must not already contains this item.
*
* @param i the item to be added to the constant pool's hash table.
*/
private void put(final Item i) {
if (index > threshold) {
int ll = items.length;
int nl = ll * 2 + 1;
Item[] newItems = new Item[nl];
for (int l = ll - 1; l >= 0; --l) {
Item j = items[l];
while (j != null) {
int index = j.hashCode % newItems.length;
Item k = j.next;
j.next = newItems[index];
newItems[index] = j;
j = k;
}
}
items = newItems;
threshold = (int) (nl * 0.75);
}
int index = i.hashCode % items.length;
i.next = items[index];
items[index] = i;
}
/**
* Puts one byte and two shorts into the constant pool.
*
* @param b a byte.
* @param s1 a short.
* @param s2 another short.
*/
private void put122(final int b, final int s1, final int s2) {
pool.put12(b, s1).putShort(s2);
}
}