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cbfc4ea0f6df65ebfcce99d49081aff6b94cbbd2
Parabot/parabotv2/src/org/objectweb/asm/util/CheckClassAdapter.java
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Clisprail cbfc4ea0f6 ASM
2014-02-20 01:19:41 +01:00

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/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2011 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.objectweb.asm.util;
import java.io.FileInputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.analysis.Analyzer;
import org.objectweb.asm.tree.analysis.BasicValue;
import org.objectweb.asm.tree.analysis.Frame;
import org.objectweb.asm.tree.analysis.SimpleVerifier;
/**
* A {@link org.objectweb.asm.ClassVisitor} that checks that its methods are properly used. More
* precisely this class adapter checks each method call individually, based
* <i>only</i> on its arguments, but does <i>not</i> check the <i>sequence</i>
* of method calls. For example, the invalid sequence
* <tt>visitField(ACC_PUBLIC, "i", "I", null)</tt> <tt>visitField(ACC_PUBLIC,
* "i", "D", null)</tt> will <i>not</i> be detected by this class adapter.
*
* <p>
* <code>CheckClassAdapter</code> can be also used to verify bytecode
* transformations in order to make sure transformed bytecode is sane. For
* example:
*
* <pre>
* InputStream is = ...; // get bytes for the source class
* ClassReader cr = new ClassReader(is);
* ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS);
* ClassVisitor cv = new <b>MyClassAdapter</b>(new CheckClassAdapter(cw));
* cr.accept(cv, 0);
*
* StringWriter sw = new StringWriter();
* PrintWriter pw = new PrintWriter(sw);
* CheckClassAdapter.verify(new ClassReader(cw.toByteArray()), false, pw);
* assertTrue(sw.toString(), sw.toString().length()==0);
* </pre>
*
* Above code runs transformed bytecode trough the
* <code>CheckClassAdapter</code>. It won't be exactly the same verification as
* JVM does, but it run data flow analysis for the code of each method and
* checks that expectations are met for each method instruction.
*
* <p>
* If method bytecode has errors, assertion text will show the erroneous
* instruction number and dump of the failed method with information about
* locals and stack slot for each instruction. For example (format is -
* insnNumber locals : stack):
*
* <pre>
* org.objectweb.asm.tree.analysis.AnalyzerException: Error at instruction 71: Expected I, but found .
* at org.objectweb.asm.tree.analysis.Analyzer.analyze(Analyzer.java:289)
* at org.objectweb.asm.util.CheckClassAdapter.verify(CheckClassAdapter.java:135)
* ...
* remove()V
* 00000 LinkedBlockingQueue$Itr . . . . . . . . :
* ICONST_0
* 00001 LinkedBlockingQueue$Itr . . . . . . . . : I
* ISTORE 2
* 00001 LinkedBlockingQueue$Itr <b>.</b> I . . . . . . :
* ...
*
* 00071 LinkedBlockingQueue$Itr <b>.</b> I . . . . . . :
* ILOAD 1
* 00072 <b>?</b>
* INVOKESPECIAL java/lang/Integer.<init> (I)V
* ...
* </pre>
*
* In the above output you can see that variable 1 loaded by
* <code>ILOAD 1</code> instruction at position <code>00071</code> is not
* initialized. You can also see that at the beginning of the method (code
* inserted by the transformation) variable 2 is initialized.
*
* <p>
* Note that when used like that, <code>CheckClassAdapter.verify()</code> can
* trigger additional class loading, because it is using
* <code>SimpleVerifier</code>.
*
* @author Eric Bruneton
*/
public class CheckClassAdapter extends ClassVisitor {
/**
* The class version number.
*/
private int version;
/**
* <tt>true</tt> if the visit method has been called.
*/
private boolean start;
/**
* <tt>true</tt> if the visitSource method has been called.
*/
private boolean source;
/**
* <tt>true</tt> if the visitOuterClass method has been called.
*/
private boolean outer;
/**
* <tt>true</tt> if the visitEnd method has been called.
*/
private boolean end;
/**
* The already visited labels. This map associate Integer values to Label
* keys.
*/
private Map<Label, Integer> labels;
/**
* <tt>true</tt> if the method code must be checked with a BasicVerifier.
*/
private boolean checkDataFlow;
/**
* Checks a given class.
* <p>
* Usage: CheckClassAdapter &lt;binary class name or class file name&gt;
*
* @param args
* the command line arguments.
*
* @throws Exception
* if the class cannot be found, or if an IO exception occurs.
*/
public static void main(final String[] args) throws Exception {
if (args.length != 1) {
System.err.println("Verifies the given class.");
System.err.println("Usage: CheckClassAdapter "
+ "<fully qualified class name or class file name>");
return;
}
ClassReader cr;
if (args[0].endsWith(".class")) {
cr = new ClassReader(new FileInputStream(args[0]));
} else {
cr = new ClassReader(args[0]);
}
verify(cr, false, new PrintWriter(System.err));
}
/**
* Checks a given class.
*
* @param cr
* a <code>ClassReader</code> that contains bytecode for the
* analysis.
* @param loader
* a <code>ClassLoader</code> which will be used to load
* referenced classes. This is useful if you are verifiying
* multiple interdependent classes.
* @param dump
* true if bytecode should be printed out not only when errors
* are found.
* @param pw
* write where results going to be printed
*/
public static void verify(final ClassReader cr, final ClassLoader loader,
final boolean dump, final PrintWriter pw) {
ClassNode cn = new ClassNode();
cr.accept(new CheckClassAdapter(cn, false), ClassReader.SKIP_DEBUG);
Type syperType = cn.superName == null ? null : Type
.getObjectType(cn.superName);
List<MethodNode> methods = cn.methods;
List<Type> interfaces = new ArrayList<Type>();
for (Iterator<String> i = cn.interfaces.iterator(); i.hasNext();) {
interfaces.add(Type.getObjectType(i.next().toString()));
}
for (int i = 0; i < methods.size(); ++i) {
MethodNode method = methods.get(i);
SimpleVerifier verifier = new SimpleVerifier(
Type.getObjectType(cn.name), syperType, interfaces,
(cn.access & Opcodes.ACC_INTERFACE) != 0);
Analyzer<BasicValue> a = new Analyzer<BasicValue>(verifier);
if (loader != null) {
verifier.setClassLoader(loader);
}
try {
a.analyze(cn.name, method);
if (!dump) {
continue;
}
} catch (Exception e) {
e.printStackTrace(pw);
}
printAnalyzerResult(method, a, pw);
}
pw.flush();
}
/**
* Checks a given class
*
* @param cr
* a <code>ClassReader</code> that contains bytecode for the
* analysis.
* @param dump
* true if bytecode should be printed out not only when errors
* are found.
* @param pw
* write where results going to be printed
*/
public static void verify(final ClassReader cr, final boolean dump,
final PrintWriter pw) {
verify(cr, null, dump, pw);
}
static void printAnalyzerResult(MethodNode method, Analyzer<BasicValue> a,
final PrintWriter pw) {
Frame<BasicValue>[] frames = a.getFrames();
Textifier t = new Textifier();
TraceMethodVisitor mv = new TraceMethodVisitor(t);
pw.println(method.name + method.desc);
for (int j = 0; j < method.instructions.size(); ++j) {
method.instructions.get(j).accept(mv);
StringBuffer s = new StringBuffer();
Frame<BasicValue> f = frames[j];
if (f == null) {
s.append('?');
} else {
for (int k = 0; k < f.getLocals(); ++k) {
s.append(getShortName(f.getLocal(k).toString()))
.append(' ');
}
s.append(" : ");
for (int k = 0; k < f.getStackSize(); ++k) {
s.append(getShortName(f.getStack(k).toString()))
.append(' ');
}
}
while (s.length() < method.maxStack + method.maxLocals + 1) {
s.append(' ');
}
pw.print(Integer.toString(j + 100000).substring(1));
pw.print(" " + s + " : " + t.text.get(t.text.size() - 1));
}
for (int j = 0; j < method.tryCatchBlocks.size(); ++j) {
method.tryCatchBlocks.get(j).accept(mv);
pw.print(" " + t.text.get(t.text.size() - 1));
}
pw.println();
}
private static String getShortName(final String name) {
int n = name.lastIndexOf('/');
int k = name.length();
if (name.charAt(k - 1) == ';') {
k--;
}
return n == -1 ? name : name.substring(n + 1, k);
}
/**
* Constructs a new {@link org.objectweb.asm.util.CheckClassAdapter}. <i>Subclasses must not use
* this constructor</i>. Instead, they must use the
* {@link #CheckClassAdapter(int, org.objectweb.asm.ClassVisitor, boolean)} version.
*
* @param cv
* the class visitor to which this adapter must delegate calls.
*/
public CheckClassAdapter(final ClassVisitor cv) {
this(cv, true);
}
/**
* Constructs a new {@link org.objectweb.asm.util.CheckClassAdapter}. <i>Subclasses must not use
* this constructor</i>. Instead, they must use the
* {@link #CheckClassAdapter(int, org.objectweb.asm.ClassVisitor, boolean)} version.
*
* @param cv
* the class visitor to which this adapter must delegate calls.
* @param checkDataFlow
* <tt>true</tt> to perform basic data flow checks, or
* <tt>false</tt> to not perform any data flow check (see
* {@link CheckMethodAdapter}). This option requires valid
* maxLocals and maxStack values.
*/
public CheckClassAdapter(final ClassVisitor cv, final boolean checkDataFlow) {
this(Opcodes.ASM4, cv, checkDataFlow);
}
/**
* Constructs a new {@link org.objectweb.asm.util.CheckClassAdapter}.
*
* @param api
* the ASM API version implemented by this visitor. Must be one
* of {@link org.objectweb.asm.Opcodes#ASM4}.
* @param cv
* the class visitor to which this adapter must delegate calls.
* @param checkDataFlow
* <tt>true</tt> to perform basic data flow checks, or
* <tt>false</tt> to not perform any data flow check (see
* {@link CheckMethodAdapter}). This option requires valid
* maxLocals and maxStack values.
*/
protected CheckClassAdapter(final int api, final ClassVisitor cv,
final boolean checkDataFlow) {
super(api, cv);
this.labels = new HashMap<Label, Integer>();
this.checkDataFlow = checkDataFlow;
}
// ------------------------------------------------------------------------
// Implementation of the ClassVisitor interface
// ------------------------------------------------------------------------
@Override
public void visit(final int version, final int access, final String name,
final String signature, final String superName,
final String[] interfaces) {
if (start) {
throw new IllegalStateException("visit must be called only once");
}
start = true;
checkState();
checkAccess(access, Opcodes.ACC_PUBLIC + Opcodes.ACC_FINAL
+ Opcodes.ACC_SUPER + Opcodes.ACC_INTERFACE
+ Opcodes.ACC_ABSTRACT + Opcodes.ACC_SYNTHETIC
+ Opcodes.ACC_ANNOTATION + Opcodes.ACC_ENUM
+ Opcodes.ACC_DEPRECATED + 0x40000); // ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
if (name == null || !name.endsWith("package-info")) {
CheckMethodAdapter.checkInternalName(name, "class name");
}
if ("java/lang/Object".equals(name)) {
if (superName != null) {
throw new IllegalArgumentException(
"The super class name of the Object class must be 'null'");
}
} else {
CheckMethodAdapter.checkInternalName(superName, "super class name");
}
if (signature != null) {
checkClassSignature(signature);
}
if ((access & Opcodes.ACC_INTERFACE) != 0) {
if (!"java/lang/Object".equals(superName)) {
throw new IllegalArgumentException(
"The super class name of interfaces must be 'java/lang/Object'");
}
}
if (interfaces != null) {
for (int i = 0; i < interfaces.length; ++i) {
CheckMethodAdapter.checkInternalName(interfaces[i],
"interface name at index " + i);
}
}
this.version = version;
super.visit(version, access, name, signature, superName, interfaces);
}
@Override
public void visitSource(final String file, final String debug) {
checkState();
if (source) {
throw new IllegalStateException(
"visitSource can be called only once.");
}
source = true;
super.visitSource(file, debug);
}
@Override
public void visitOuterClass(final String owner, final String name,
final String desc) {
checkState();
if (outer) {
throw new IllegalStateException(
"visitOuterClass can be called only once.");
}
outer = true;
if (owner == null) {
throw new IllegalArgumentException("Illegal outer class owner");
}
if (desc != null) {
CheckMethodAdapter.checkMethodDesc(desc);
}
super.visitOuterClass(owner, name, desc);
}
@Override
public void visitInnerClass(final String name, final String outerName,
final String innerName, final int access) {
checkState();
CheckMethodAdapter.checkInternalName(name, "class name");
if (outerName != null) {
CheckMethodAdapter.checkInternalName(outerName, "outer class name");
}
if (innerName != null) {
CheckMethodAdapter.checkIdentifier(innerName, "inner class name");
}
checkAccess(access, Opcodes.ACC_PUBLIC + Opcodes.ACC_PRIVATE
+ Opcodes.ACC_PROTECTED + Opcodes.ACC_STATIC
+ Opcodes.ACC_FINAL + Opcodes.ACC_INTERFACE
+ Opcodes.ACC_ABSTRACT + Opcodes.ACC_SYNTHETIC
+ Opcodes.ACC_ANNOTATION + Opcodes.ACC_ENUM);
super.visitInnerClass(name, outerName, innerName, access);
}
@Override
public FieldVisitor visitField(final int access, final String name,
final String desc, final String signature, final Object value) {
checkState();
checkAccess(access, Opcodes.ACC_PUBLIC + Opcodes.ACC_PRIVATE
+ Opcodes.ACC_PROTECTED + Opcodes.ACC_STATIC
+ Opcodes.ACC_FINAL + Opcodes.ACC_VOLATILE
+ Opcodes.ACC_TRANSIENT + Opcodes.ACC_SYNTHETIC
+ Opcodes.ACC_ENUM + Opcodes.ACC_DEPRECATED + 0x40000); // ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
CheckMethodAdapter.checkUnqualifiedName(version, name, "field name");
CheckMethodAdapter.checkDesc(desc, false);
if (signature != null) {
checkFieldSignature(signature);
}
if (value != null) {
CheckMethodAdapter.checkConstant(value);
}
FieldVisitor av = super
.visitField(access, name, desc, signature, value);
return new CheckFieldAdapter(av);
}
@Override
public MethodVisitor visitMethod(final int access, final String name,
final String desc, final String signature, final String[] exceptions) {
checkState();
checkAccess(access, Opcodes.ACC_PUBLIC + Opcodes.ACC_PRIVATE
+ Opcodes.ACC_PROTECTED + Opcodes.ACC_STATIC
+ Opcodes.ACC_FINAL + Opcodes.ACC_SYNCHRONIZED
+ Opcodes.ACC_BRIDGE + Opcodes.ACC_VARARGS + Opcodes.ACC_NATIVE
+ Opcodes.ACC_ABSTRACT + Opcodes.ACC_STRICT
+ Opcodes.ACC_SYNTHETIC + Opcodes.ACC_DEPRECATED + 0x40000); // ClassWriter.ACC_SYNTHETIC_ATTRIBUTE
if (!"<init>".equals(name) && !"<clinit>".equals(name)) {
CheckMethodAdapter.checkMethodIdentifier(version, name,
"method name");
}
CheckMethodAdapter.checkMethodDesc(desc);
if (signature != null) {
checkMethodSignature(signature);
}
if (exceptions != null) {
for (int i = 0; i < exceptions.length; ++i) {
CheckMethodAdapter.checkInternalName(exceptions[i],
"exception name at index " + i);
}
}
CheckMethodAdapter cma;
if (checkDataFlow) {
cma = new CheckMethodAdapter(access, name, desc, super.visitMethod(
access, name, desc, signature, exceptions), labels);
} else {
cma = new CheckMethodAdapter(super.visitMethod(access, name, desc,
signature, exceptions), labels);
}
cma.version = version;
return cma;
}
@Override
public AnnotationVisitor visitAnnotation(final String desc,
final boolean visible) {
checkState();
CheckMethodAdapter.checkDesc(desc, false);
return new CheckAnnotationAdapter(super.visitAnnotation(desc, visible));
}
@Override
public void visitAttribute(final Attribute attr) {
checkState();
if (attr == null) {
throw new IllegalArgumentException(
"Invalid attribute (must not be null)");
}
super.visitAttribute(attr);
}
@Override
public void visitEnd() {
checkState();
end = true;
super.visitEnd();
}
// ------------------------------------------------------------------------
// Utility methods
// ------------------------------------------------------------------------
/**
* Checks that the visit method has been called and that visitEnd has not
* been called.
*/
private void checkState() {
if (!start) {
throw new IllegalStateException(
"Cannot visit member before visit has been called.");
}
if (end) {
throw new IllegalStateException(
"Cannot visit member after visitEnd has been called.");
}
}
/**
* Checks that the given access flags do not contain invalid flags. This
* method also checks that mutually incompatible flags are not set
* simultaneously.
*
* @param access
* the access flags to be checked
* @param possibleAccess
* the valid access flags.
*/
static void checkAccess(final int access, final int possibleAccess) {
if ((access & ~possibleAccess) != 0) {
throw new IllegalArgumentException("Invalid access flags: "
+ access);
}
int pub = (access & Opcodes.ACC_PUBLIC) == 0 ? 0 : 1;
int pri = (access & Opcodes.ACC_PRIVATE) == 0 ? 0 : 1;
int pro = (access & Opcodes.ACC_PROTECTED) == 0 ? 0 : 1;
if (pub + pri + pro > 1) {
throw new IllegalArgumentException(
"public private and protected are mutually exclusive: "
+ access);
}
int fin = (access & Opcodes.ACC_FINAL) == 0 ? 0 : 1;
int abs = (access & Opcodes.ACC_ABSTRACT) == 0 ? 0 : 1;
if (fin + abs > 1) {
throw new IllegalArgumentException(
"final and abstract are mutually exclusive: " + access);
}
}
/**
* Checks a class signature.
*
* @param signature
* a string containing the signature that must be checked.
*/
public static void checkClassSignature(final String signature) {
// ClassSignature:
// FormalTypeParameters? ClassTypeSignature ClassTypeSignature*
int pos = 0;
if (getChar(signature, 0) == '<') {
pos = checkFormalTypeParameters(signature, pos);
}
pos = checkClassTypeSignature(signature, pos);
while (getChar(signature, pos) == 'L') {
pos = checkClassTypeSignature(signature, pos);
}
if (pos != signature.length()) {
throw new IllegalArgumentException(signature + ": error at index "
+ pos);
}
}
/**
* Checks a method signature.
*
* @param signature
* a string containing the signature that must be checked.
*/
public static void checkMethodSignature(final String signature) {
// MethodTypeSignature:
// FormalTypeParameters? ( TypeSignature* ) ( TypeSignature | V ) (
// ^ClassTypeSignature | ^TypeVariableSignature )*
int pos = 0;
if (getChar(signature, 0) == '<') {
pos = checkFormalTypeParameters(signature, pos);
}
pos = checkChar('(', signature, pos);
while ("ZCBSIFJDL[T".indexOf(getChar(signature, pos)) != -1) {
pos = checkTypeSignature(signature, pos);
}
pos = checkChar(')', signature, pos);
if (getChar(signature, pos) == 'V') {
++pos;
} else {
pos = checkTypeSignature(signature, pos);
}
while (getChar(signature, pos) == '^') {
++pos;
if (getChar(signature, pos) == 'L') {
pos = checkClassTypeSignature(signature, pos);
} else {
pos = checkTypeVariableSignature(signature, pos);
}
}
if (pos != signature.length()) {
throw new IllegalArgumentException(signature + ": error at index "
+ pos);
}
}
/**
* Checks a field signature.
*
* @param signature
* a string containing the signature that must be checked.
*/
public static void checkFieldSignature(final String signature) {
int pos = checkFieldTypeSignature(signature, 0);
if (pos != signature.length()) {
throw new IllegalArgumentException(signature + ": error at index "
+ pos);
}
}
/**
* Checks the formal type parameters of a class or method signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkFormalTypeParameters(final String signature, int pos) {
// FormalTypeParameters:
// < FormalTypeParameter+ >
pos = checkChar('<', signature, pos);
pos = checkFormalTypeParameter(signature, pos);
while (getChar(signature, pos) != '>') {
pos = checkFormalTypeParameter(signature, pos);
}
return pos + 1;
}
/**
* Checks a formal type parameter of a class or method signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkFormalTypeParameter(final String signature, int pos) {
// FormalTypeParameter:
// Identifier : FieldTypeSignature? (: FieldTypeSignature)*
pos = checkIdentifier(signature, pos);
pos = checkChar(':', signature, pos);
if ("L[T".indexOf(getChar(signature, pos)) != -1) {
pos = checkFieldTypeSignature(signature, pos);
}
while (getChar(signature, pos) == ':') {
pos = checkFieldTypeSignature(signature, pos + 1);
}
return pos;
}
/**
* Checks a field type signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkFieldTypeSignature(final String signature, int pos) {
// FieldTypeSignature:
// ClassTypeSignature | ArrayTypeSignature | TypeVariableSignature
//
// ArrayTypeSignature:
// [ TypeSignature
switch (getChar(signature, pos)) {
case 'L':
return checkClassTypeSignature(signature, pos);
case '[':
return checkTypeSignature(signature, pos + 1);
default:
return checkTypeVariableSignature(signature, pos);
}
}
/**
* Checks a class type signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkClassTypeSignature(final String signature, int pos) {
// ClassTypeSignature:
// L Identifier ( / Identifier )* TypeArguments? ( . Identifier
// TypeArguments? )* ;
pos = checkChar('L', signature, pos);
pos = checkIdentifier(signature, pos);
while (getChar(signature, pos) == '/') {
pos = checkIdentifier(signature, pos + 1);
}
if (getChar(signature, pos) == '<') {
pos = checkTypeArguments(signature, pos);
}
while (getChar(signature, pos) == '.') {
pos = checkIdentifier(signature, pos + 1);
if (getChar(signature, pos) == '<') {
pos = checkTypeArguments(signature, pos);
}
}
return checkChar(';', signature, pos);
}
/**
* Checks the type arguments in a class type signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkTypeArguments(final String signature, int pos) {
// TypeArguments:
// < TypeArgument+ >
pos = checkChar('<', signature, pos);
pos = checkTypeArgument(signature, pos);
while (getChar(signature, pos) != '>') {
pos = checkTypeArgument(signature, pos);
}
return pos + 1;
}
/**
* Checks a type argument in a class type signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkTypeArgument(final String signature, int pos) {
// TypeArgument:
// * | ( ( + | - )? FieldTypeSignature )
char c = getChar(signature, pos);
if (c == '*') {
return pos + 1;
} else if (c == '+' || c == '-') {
pos++;
}
return checkFieldTypeSignature(signature, pos);
}
/**
* Checks a type variable signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkTypeVariableSignature(final String signature,
int pos) {
// TypeVariableSignature:
// T Identifier ;
pos = checkChar('T', signature, pos);
pos = checkIdentifier(signature, pos);
return checkChar(';', signature, pos);
}
/**
* Checks a type signature.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkTypeSignature(final String signature, int pos) {
// TypeSignature:
// Z | C | B | S | I | F | J | D | FieldTypeSignature
switch (getChar(signature, pos)) {
case 'Z':
case 'C':
case 'B':
case 'S':
case 'I':
case 'F':
case 'J':
case 'D':
return pos + 1;
default:
return checkFieldTypeSignature(signature, pos);
}
}
/**
* Checks an identifier.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkIdentifier(final String signature, int pos) {
if (!Character.isJavaIdentifierStart(getChar(signature, pos))) {
throw new IllegalArgumentException(signature
+ ": identifier expected at index " + pos);
}
++pos;
while (Character.isJavaIdentifierPart(getChar(signature, pos))) {
++pos;
}
return pos;
}
/**
* Checks a single character.
*
* @param signature
* a string containing the signature that must be checked.
* @param pos
* index of first character to be checked.
* @return the index of the first character after the checked part.
*/
private static int checkChar(final char c, final String signature, int pos) {
if (getChar(signature, pos) == c) {
return pos + 1;
}
throw new IllegalArgumentException(signature + ": '" + c
+ "' expected at index " + pos);
}
/**
* Returns the signature car at the given index.
*
* @param signature
* a signature.
* @param pos
* an index in signature.
* @return the character at the given index, or 0 if there is no such
* character.
*/
private static char getChar(final String signature, int pos) {
return pos < signature.length() ? signature.charAt(pos) : (char) 0;
}
}
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