/***
* 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.zbus.common.json.asm;
/**
* A {@link 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 and adapter class visitor to generate a modified class from one or more existing Java classes.
*
* @author Eric Bruneton
*/
public class ClassWriter {
/**
* 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 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 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 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;
/**
* 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 <tt>i</tt> the Item whose index is <tt>i</tt>. 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;
/**
* 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 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 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;
// ------------------------------------------------------------------------
// 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
// ------------------------------------------------------------------------
public ClassWriter(){
this(0);
}
/**
* Constructs a new {@link 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}.
*/
private 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();
}
// ------------------------------------------------------------------------
// Implementation of the ClassVisitor interface
// ------------------------------------------------------------------------
public void visit(final int version, final int access, final String name, final String superName, final String[] interfaces) {
this.version = version;
this.access = access;
this.name = newClass(name);
thisName = name;
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 FieldVisitor visitField(final int access, final String name, final String desc) {
return new FieldWriter(this, access, name, desc);
}
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);
}
// ------------------------------------------------------------------------
// 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;
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);
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 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 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);
}
}
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;
}
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;
}
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;
}
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 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 <tt>true</tt> if <tt>owner</tt> 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 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;
}
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;
}
/**
* 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 <tt>null</tt> 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 <i>must</i> 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);
}
}