org.eclipse.xtext.smap.SDEInstaller Maven / Gradle / Ivy
/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.eclipse.xtext.smap;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
//*********************************************************************
// Installation logic (from Robert Field, JSR-045 spec lead)
public class SDEInstaller {
private static final String nameSDE = "SourceDebugExtension";
private byte[] orig;
private byte[] sdeAttr;
private byte[] gen;
private int origPos = 0;
private int genPos = 0;
private int sdeIndex;
private boolean verbose = false;
public SDEInstaller(byte[] original, byte[] sdeAttr) throws IOException {
this.sdeAttr = sdeAttr;
this.orig = original;
gen = new byte[orig.length + sdeAttr.length + 100];
// do it
addSDE();
}
public byte[] getUpdatedByteCode() {
byte[] result = new byte[genPos];
System.arraycopy(gen, 0, result, 0, genPos);
return result;
}
protected void addSDE() throws UnsupportedEncodingException, IOException {
copy(4 + 2 + 2); // magic min/maj version
int constantPoolCountPos = genPos;
int constantPoolCount = readU2();
if (verbose) {
System.out.println("constant pool count: " + constantPoolCount);
}
writeU2(constantPoolCount);
// copy old constant pool return index of SDE symbol, if found
sdeIndex = copyConstantPool(constantPoolCount);
if (sdeIndex < 0) {
// if "SourceDebugExtension" symbol not there add it
writeUtf8ForSDE();
// increment the countantPoolCount
sdeIndex = constantPoolCount;
++constantPoolCount;
randomAccessWriteU2(constantPoolCountPos, constantPoolCount);
if (verbose) {
System.out.println("SourceDebugExtension not found, installed at: " + sdeIndex);
}
} else {
if (verbose) {
System.out.println("SourceDebugExtension found at: " + sdeIndex);
}
}
copy(2 + 2 + 2); // access, this, super
int interfaceCount = readU2();
writeU2(interfaceCount);
if (verbose) {
System.out.println("interfaceCount: " + interfaceCount);
}
copy(interfaceCount * 2);
copyMembers(); // fields
copyMembers(); // methods
int attrCountPos = genPos;
int attrCount = readU2();
writeU2(attrCount);
if (verbose) {
System.out.println("class attrCount: " + attrCount);
}
// copy the class attributes, return true if SDE attr found (not copied)
if (!copyAttrs(attrCount)) {
// we will be adding SDE and it isn't already counted
++attrCount;
randomAccessWriteU2(attrCountPos, attrCount);
if (verbose) {
System.out.println("class attrCount incremented");
}
}
writeAttrForSDE(sdeIndex);
}
protected void copyMembers() {
int count = readU2();
writeU2(count);
if (verbose) {
System.out.println("members count: " + count);
}
for (int i = 0; i < count; ++i) {
copy(6); // access, name, descriptor
int attrCount = readU2();
writeU2(attrCount);
if (verbose) {
System.out.println("member attr count: " + attrCount);
}
copyAttrs(attrCount);
}
}
protected boolean copyAttrs(int attrCount) {
boolean sdeFound = false;
for (int i = 0; i < attrCount; ++i) {
int nameIndex = readU2();
// don't write old SDE
if (nameIndex == sdeIndex) {
sdeFound = true;
if (verbose) {
System.out.println("SDE attr found");
}
} else {
writeU2(nameIndex); // name
int len = readU4();
writeU4(len);
copy(len);
if (verbose) {
System.out.println("attr len: " + len);
}
}
}
return sdeFound;
}
protected void writeAttrForSDE(int index) {
writeU2(index);
writeU4(sdeAttr.length);
for (int i = 0; i < sdeAttr.length; ++i) {
writeU1(sdeAttr[i]);
}
}
protected void randomAccessWriteU2(int pos, int val) {
int savePos = genPos;
genPos = pos;
writeU2(val);
genPos = savePos;
}
protected int readU1() {
return orig[origPos++] & 0xFF;
}
protected int readU2() {
int res = readU1();
return (res << 8) + readU1();
}
protected int readU4() {
int res = readU2();
return (res << 16) + readU2();
}
protected void writeU1(int val) {
gen[genPos++] = (byte) val;
}
protected void writeU2(int val) {
writeU1(val >> 8);
writeU1(val & 0xFF);
}
protected void writeU4(int val) {
writeU2(val >> 16);
writeU2(val & 0xFFFF);
}
protected void copy(int count) {
for (int i = 0; i < count; ++i) {
gen[genPos++] = orig[origPos++];
}
}
protected byte[] readBytes(int count) {
byte[] bytes = new byte[count];
for (int i = 0; i < count; ++i) {
bytes[i] = orig[origPos++];
}
return bytes;
}
protected void writeBytes(byte[] bytes) {
for (int i = 0; i < bytes.length; ++i) {
gen[genPos++] = bytes[i];
}
}
protected int copyConstantPool(int constantPoolCount) throws UnsupportedEncodingException, IOException {
int sdeIndex = -1;
// copy const pool index zero not in class file
for (int i = 1; i < constantPoolCount; ++i) {
int tag = readU1();
writeU1(tag);
switch (tag) {
case 7: // Class
case 8: // String
if (verbose) {
System.out.println(i + " copying 2 bytes");
}
copy(2);
break;
case 9: // Field
case 10: // Method
case 11: // InterfaceMethod
case 3: // Integer
case 4: // Float
case 12: // NameAndType
if (verbose) {
System.out.println(i + " copying 4 bytes");
}
copy(4);
break;
case 5: // Long
case 6: // Double
if (verbose) {
System.out.println(i + " copying 8 bytes");
}
copy(8);
i++;
break;
case 1: // Utf8
int len = readU2();
writeU2(len);
byte[] utf8 = readBytes(len);
String str = new String(utf8, "UTF-8");
if (verbose) {
System.out.println(i + " read class attr -- '" + str + "'");
}
if (str.equals(nameSDE)) {
sdeIndex = i;
}
writeBytes(utf8);
break;
default:
throw new IOException("unexpected tag: " + tag);
}
}
return sdeIndex;
}
protected void writeUtf8ForSDE() {
int len = nameSDE.length();
writeU1(1); // Utf8 tag
writeU2(len);
for (int i = 0; i < len; ++i) {
writeU1(nameSDE.charAt(i));
}
}
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