org.apache.commons.compress.harmony.unpack200.SegmentConstantPool Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.compress.harmony.unpack200;
import java.util.List;
import org.apache.commons.compress.harmony.pack200.Pack200Exception;
import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
import org.apache.commons.compress.harmony.unpack200.bytecode.ConstantPoolEntry;
/**
* SegmentConstantPool manages the constant pool used for re-creating class files.
*/
public class SegmentConstantPool {
private final CpBands bands;
private final SegmentConstantPoolArrayCache arrayCache = new SegmentConstantPoolArrayCache();
/**
* @param bands TODO
*/
public SegmentConstantPool(final CpBands bands) {
this.bands = bands;
}
// define in archive order
public static final int ALL = 0;
public static final int UTF_8 = 1;
public static final int CP_INT = 2;
public static final int CP_FLOAT = 3;
public static final int CP_LONG = 4;
public static final int CP_DOUBLE = 5;
public static final int CP_STRING = 6;
public static final int CP_CLASS = 7;
public static final int SIGNATURE = 8; // TODO and more to come --
public static final int CP_DESCR = 9;
public static final int CP_FIELD = 10;
public static final int CP_METHOD = 11;
public static final int CP_IMETHOD = 12;
protected static final String REGEX_MATCH_ALL = ".*";
protected static final String INITSTRING = "";
protected static final String REGEX_MATCH_INIT = "^" + INITSTRING + ".*";
public ClassFileEntry getValue(final int cp, final long value) throws Pack200Exception {
final int index = (int) value;
if (index == -1) {
return null;
}
if (index < 0) {
throw new Pack200Exception("Cannot have a negative range");
}
if (cp == UTF_8) {
return bands.cpUTF8Value(index);
}
if (cp == CP_INT) {
return bands.cpIntegerValue(index);
}
if (cp == CP_FLOAT) {
return bands.cpFloatValue(index);
}
if (cp == CP_LONG) {
return bands.cpLongValue(index);
}
if (cp == CP_DOUBLE) {
return bands.cpDoubleValue(index);
}
if (cp == CP_STRING) {
return bands.cpStringValue(index);
}
if (cp == CP_CLASS) {
return bands.cpClassValue(index);
}
if (cp == SIGNATURE) {
return bands.cpSignatureValue(index);
}
if (cp == CP_DESCR) {
return bands.cpNameAndTypeValue(index);
}
throw new Error("Tried to get a value I don't know about: " + cp);
}
/**
* Subset the constant pool of the specified type to be just that which has the specified class name. Answer the
* ConstantPoolEntry at the desiredIndex of the subsetted pool.
*
* @param cp type of constant pool array to search
* @param desiredIndex index of the constant pool
* @param desiredClassName class to use to generate a subset of the pool
* @return ConstantPoolEntry
* @throws Pack200Exception TODO
*/
public ConstantPoolEntry getClassSpecificPoolEntry(final int cp, final long desiredIndex,
final String desiredClassName) throws Pack200Exception {
final int index = (int) desiredIndex;
int realIndex = -1;
String array[] = null;
if (cp == CP_FIELD) {
array = bands.getCpFieldClass();
} else if (cp == CP_METHOD) {
array = bands.getCpMethodClass();
} else if (cp == CP_IMETHOD) {
array = bands.getCpIMethodClass();
} else {
throw new Error("Don't know how to handle " + cp);
}
realIndex = matchSpecificPoolEntryIndex(array, desiredClassName, index);
return getConstantPoolEntry(cp, realIndex);
}
/**
* Given the name of a class, answer the CPClass associated with that class. Answer null if the class doesn't exist.
*
* @param name Class name to look for (form: java/lang/Object)
* @return CPClass for that class name, or null if not found.
*/
public ConstantPoolEntry getClassPoolEntry(final String name) {
final String classes[] = bands.getCpClass();
final int index = matchSpecificPoolEntryIndex(classes, name, 0);
if (index == -1) {
return null;
}
try {
return getConstantPoolEntry(CP_CLASS, index);
} catch (final Pack200Exception ex) {
throw new Error("Error getting class pool entry");
}
}
/**
* Answer the init method for the specified class.
*
* @param cp constant pool to search (must be CP_METHOD)
* @param value index of init method
* @param desiredClassName String class name of the init method
* @return CPMethod init method
* @throws Pack200Exception TODO
*/
public ConstantPoolEntry getInitMethodPoolEntry(final int cp, final long value, final String desiredClassName)
throws Pack200Exception {
int realIndex = -1;
final String desiredRegex = REGEX_MATCH_INIT;
if (cp != CP_METHOD) {
// TODO really an error?
throw new Error("Nothing but CP_METHOD can be an ");
}
realIndex = matchSpecificPoolEntryIndex(bands.getCpMethodClass(), bands.getCpMethodDescriptor(),
desiredClassName, desiredRegex, (int) value);
return getConstantPoolEntry(cp, realIndex);
}
/**
* A number of things make use of subsets of structures. In one particular example, _super bytecodes will use a
* subset of method or field classes which have just those methods / fields defined in the superclass. Similarly,
* _this bytecodes use just those methods/fields defined in this class, and _init bytecodes use just those methods
* that start with {@code }.
*
* This method takes an array of names, a String to match for, an index and a boolean as parameters, and answers the
* array position in the array of the indexth element which matches (or equals) the String (depending on the state
* of the boolean)
*
* In other words, if the class array consists of: Object [position 0, 0th instance of Object] String [position 1,
* 0th instance of String] String [position 2, 1st instance of String] Object [position 3, 1st instance of Object]
* Object [position 4, 2nd instance of Object] then matchSpecificPoolEntryIndex(..., "Object", 2, false) will answer
* 4. matchSpecificPoolEntryIndex(..., "String", 0, false) will answer 1.
*
* @param nameArray Array of Strings against which the compareString is tested
* @param compareString String for which to search
* @param desiredIndex nth element with that match (counting from 0)
* @return int index into nameArray, or -1 if not found.
*/
protected int matchSpecificPoolEntryIndex(final String[] nameArray, final String compareString,
final int desiredIndex) {
return matchSpecificPoolEntryIndex(nameArray, nameArray, compareString, REGEX_MATCH_ALL, desiredIndex);
}
/**
* This method's function is to look through pairs of arrays. It keeps track of the number of hits it finds using
* the following basis of comparison for a hit: - the primaryArray[index] must be .equals() to the
* primaryCompareString - the secondaryArray[index] .matches() the secondaryCompareString. When the desiredIndex
* number of hits has been reached, the index into the original two arrays of the element hit is returned.
*
* @param primaryArray The first array to search
* @param secondaryArray The second array (must be same .length as primaryArray)
* @param primaryCompareString The String to compare against primaryArray using .equals()
* @param secondaryCompareRegex The String to compare against secondaryArray using .matches()
* @param desiredIndex The nth hit whose position we're seeking
* @return int index that represents the position of the nth hit in primaryArray and secondaryArray
*/
protected int matchSpecificPoolEntryIndex(final String[] primaryArray, final String[] secondaryArray,
final String primaryCompareString, final String secondaryCompareRegex, final int desiredIndex) {
int instanceCount = -1;
final List indexList = arrayCache.indexesForArrayKey(primaryArray, primaryCompareString);
if (indexList.isEmpty()) {
// Primary key not found, no chance of finding secondary
return -1;
}
for (int index = 0; index < indexList.size(); index++) {
final int arrayIndex = ((Integer) indexList.get(index)).intValue();
if (regexMatches(secondaryCompareRegex, secondaryArray[arrayIndex])) {
instanceCount++;
if (instanceCount == desiredIndex) {
return arrayIndex;
}
}
}
// We didn't return in the for loop, so the desiredMatch
// with desiredIndex must not exist in the arrays.
return -1;
}
/**
* We don't want a dependency on regex in Pack200. The only place one exists is in matchSpecificPoolEntryIndex(). To
* eliminate this dependency, we've implemented the world's stupidest regexMatch. It knows about the two forms we
* care about: .* (aka REGEX_MATCH_ALL) {@code ^;.*} (aka REGEX_MATCH_INIT) and will answer correctly if those
* are passed as the regexString.
*
* @param regexString String against which the compareString will be matched
* @param compareString String to match against the regexString
* @return boolean true if the compareString matches the regexString; otherwise false.
*/
protected static boolean regexMatches(final String regexString, final String compareString) {
if (REGEX_MATCH_ALL.equals(regexString)) {
return true;
}
if (REGEX_MATCH_INIT.equals(regexString)) {
if (compareString.length() < (INITSTRING.length())) {
return false;
}
return (INITSTRING.equals(compareString.substring(0, INITSTRING.length())));
}
throw new Error("regex trying to match a pattern I don't know: " + regexString);
}
public ConstantPoolEntry getConstantPoolEntry(final int cp, final long value) throws Pack200Exception {
final int index = (int) value;
if (index == -1) {
return null;
}
if (index < 0) {
throw new Pack200Exception("Cannot have a negative range");
}
if (cp == UTF_8) {
return bands.cpUTF8Value(index);
}
if (cp == CP_INT) {
return bands.cpIntegerValue(index);
}
if (cp == CP_FLOAT) {
return bands.cpFloatValue(index);
}
if (cp == CP_LONG) {
return bands.cpLongValue(index);
}
if (cp == CP_DOUBLE) {
return bands.cpDoubleValue(index);
}
if (cp == CP_STRING) {
return bands.cpStringValue(index);
}
if (cp == CP_CLASS) {
return bands.cpClassValue(index);
}
if (cp == SIGNATURE) {
throw new Error("I don't know what to do with signatures yet");
// return null /* new CPSignature(bands.getCpSignature()[index]) */;
}
if (cp == CP_DESCR) {
throw new Error("I don't know what to do with descriptors yet");
// return null /* new CPDescriptor(bands.getCpDescriptor()[index])
// */;
}
if (cp == CP_FIELD) {
return bands.cpFieldValue(index);
}
if (cp == CP_METHOD) {
return bands.cpMethodValue(index);
}
if (cp == CP_IMETHOD) {
return bands.cpIMethodValue(index);
}
// etc
throw new Error("Get value incomplete");
}
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