/***
* 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 com.alibaba.fastjson.asm;
/**
*
* @author Eric Bruneton
*/
public class ClassWriter {
/**
* 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;
// ------------------------------------------------------------------------
// Constructor
// ------------------------------------------------------------------------
public ClassWriter(){
this(0);
}
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 = newClassItem(name).index;
thisName = name;
this.superName = superName == null ? 0 : newClassItem(superName).index;
if (interfaces != null && interfaces.length > 0) {
interfaceCount = interfaces.length;
this.interfaces = new int[interfaceCount];
for (int i = 0; i < interfaceCount; ++i) {
this.interfaces[i] = newClassItem(interfaces[i]).index;
}
}
}
// ------------------------------------------------------------------------
// 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 = 393216; // 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);
key.set(val);
Item result = get(key);
if (result == null) {
pool.putByte(3 /* INT */ ).putInt(val);
result = new Item(index++, key);
put(result);
}
return result;
} else if (cst instanceof String) {
return newString((String) cst);
} else if (cst instanceof Type) {
Type t = (Type) cst;
return newClassItem(t.sort == 10 /*Type.OBJECT*/ ? t.getInternalName() : t.getDescriptor());
} else {
throw new IllegalArgumentException("value " + cst);
}
}
public int newUTF8(final String value) {
key.set(1 /* UTF8 */, value, null, null);
Item result = get(key);
if (result == null) {
pool.putByte(1 /* UTF8 */).putUTF8(value);
result = new Item(index++, key);
put(result);
}
return result.index;
}
public Item newClassItem(final String value) {
key2.set(7 /* CLASS */, value, null, null);
Item result = get(key2);
if (result == null) {
pool.put12(7 /* CLASS */, newUTF8(value));
result = new Item(index++, key2);
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.
*
* @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(9 /* FIELD */, owner, name, desc);
Item result = get(key3);
if (result == null) {
// put122(9 /* FIELD */, newClassItem(owner).index, newNameTypeItem(name, desc).index);
int s1 = newClassItem(owner).index, s2 = newNameTypeItem(name, desc).index;
pool.put12(9 /* FIELD */, s1).putShort(s2);
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 ? 11 /* IMETH */ : 10 /* METH */;
key3.set(type, owner, name, desc);
Item result = get(key3);
if (result == null) {
// put122(type, newClassItem(owner).index, newNameTypeItem(name, desc).index);
int s1 = newClassItem(owner).index, s2 = newNameTypeItem(name, desc).index;
pool.put12(type, s1).putShort(s2);
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(8 /* STR */, value, null, null);
Item result = get(key2);
if (result == null) {
pool.put12(8 /*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.
*
* @param name a name.
* @param desc a type descriptor.
* @return a new or already existing name and type item.
*/
public Item newNameTypeItem(final String name, final String desc) {
key2.set(12 /* NAME_TYPE */, name, desc, null);
Item result = get(key2);
if (result == null) {
//put122(12 /* NAME_TYPE */, newUTF8(name), newUTF8(desc));
int s1 = newUTF8(name), s2 = newUTF8(desc);
pool.put12(12 /* NAME_TYPE */, s1).putShort(s2);
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;
}
// private void put122(final int b, final int s1, final int s2) {
// pool.put12(b, s1).putShort(s2);
// }
}