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package edu.umd.cs.findbugs.util;
import java.util.*;
import java.util.stream.Stream;
import org.apache.bcel.Repository;
import org.apache.bcel.classfile.AnnotationEntry;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import edu.umd.cs.findbugs.ba.AnalysisContext;
public class MutableClasses {
private static final Set KNOWN_IMMUTABLE_CLASSES = new HashSet<>(Arrays.asList(
"java.lang.String", "java.lang.Integer", "java.lang.Byte", "java.lang.Character",
"java.lang.Short", "java.lang.Boolean", "java.lang.Long", "java.lang.Double",
"java.lang.Float", "java.lang.StackTraceElement", "java.lang.Class", "java.math.BigInteger",
"java.math.Decimal", "java.io.File", "java.awt.Font", "java.awt.BasicStroke",
"java.awt.Color", "java.awt.GradientPaint", "java.awt.LinearGradientPaint",
"java.awt.RadialGradientPaint", "java.awt.Cursor", "java.util.Locale", "java.util.UUID", "java.net.URL",
"java.util.regex.Pattern",
"java.net.URI", "java.net.Inet4Address", "java.net.Inet6Address", "java.net.InetSocketAddress",
"java.security.Permission", "com.google.common.collect.ImmutableBiMap",
"com.google.common.collect.ImmutableClassToInstanceMap",
"com.google.common.collect.ImmutableCollection",
"com.google.common.collect.ImmutableList",
"com.google.common.collect.ImmutableListMultimap",
"com.google.common.collect.ImmutableMap",
"com.google.common.collect.ImmutableMultimap",
"com.google.common.collect.ImmutableMultiset",
"com.google.common.collect.ImmutableRangeMap",
"com.google.common.collect.ImmutableRangeSet",
"com.google.common.collect.ImmutableSet",
"com.google.common.collect.ImmutableSetMultimap",
"com.google.common.collect.ImmutableSortedMap",
"com.google.common.collect.ImmutableSortedMultiset",
"com.google.common.collect.ImmutableSortedSet",
"com.google.common.collect.ImmutableTable",
"java.util.Collections$EmptyList",
"java.util.Collections$EmptyMap",
"java.util.Collections$EmptyNavigableMap",
"java.util.Collections$EmptySet",
"java.util.Collections$EmptyNavigableSet",
"java.util.Collections$SingletonList",
"java.util.Collections$SingletonMap",
"java.util.Collections$SingletonSet",
"java.util.Collections$UnmodifiableList",
"java.util.Collections$UnmodifiableMap",
"java.util.Collections$UnmodifiableNavigableMap",
"java.util.Collections$UnmodifiableSortedMap",
"java.util.Collections$UnmodifiableSet",
"java.util.Collections$UnmodifiableNavigableSet",
"java.util.Collections$UnmodifiableSortedSet",
"java.util.ImmutableCollections$AbstractImmutableList",
"java.util.ImmutableCollections$AbstractImmutableMap",
"java.util.ImmutableCollections$AbstractImmutableSet"));
private static final Set KNOWN_IMMUTABLE_PACKAGES = new HashSet<>(Arrays.asList(
"java.math", "java.time"));
private static final List SETTER_LIKE_PREFIXES = Arrays.asList(
"set", "put", "add", "insert", "delete", "remove", "erase", "clear", "push", "pop",
"enqueue", "dequeue", "write", "append", "replace");
public static boolean mutableSignature(String sig) {
if (sig.charAt(0) == '[') {
return true;
}
if (sig.charAt(0) != 'L') {
return false;
}
String dottedClassName = ClassName.fromFieldSignatureToDottedClassName(sig);
int lastDot = dottedClassName.lastIndexOf('.');
if (lastDot >= 0) {
String dottedPackageName = dottedClassName.substring(0, lastDot);
if (KNOWN_IMMUTABLE_PACKAGES.contains(dottedPackageName)) {
return false;
}
}
if (KNOWN_IMMUTABLE_CLASSES.contains(dottedClassName)) {
return false;
}
try {
JavaClass cls = Repository.lookupClass(dottedClassName);
if (Stream.of(cls.getAnnotationEntries()).map(AnnotationEntry::getAnnotationType)
.anyMatch(type -> type.endsWith("/Immutable;") || type.equals("Ljdk/internal/ValueBased;"))) {
return false;
}
return ClassAnalysis.load(cls, sig).isMutable();
} catch (ClassNotFoundException e) {
AnalysisContext.reportMissingClass(e);
return false;
}
}
public static boolean looksLikeASetter(String methodName, String classSig, String retSig) {
if (Objects.equals(classSig, retSig)) {
return false;
}
return SETTER_LIKE_PREFIXES.stream().anyMatch(name -> methodName.startsWith(name));
}
/**
* Analytic information about a {@link JavaClass} relevant to determining its mutability properties.
*/
private static final class ClassAnalysis {
/**
* Class under analysis.
*/
private final JavaClass cls;
/**
* Superclass {@link ClassAnalysis}, lazily instantiated if present, otherwise {@code null}.
*/
private ClassAnalysis superAnalysis;
// Various lazily-determined properties of this class. null indicates the property has not been determined yet.
private String sig;
private Boolean mutable;
private Boolean immutableByContract;
private ClassAnalysis(JavaClass cls, String sig) {
this.cls = cls;
this.sig = sig;
}
static ClassAnalysis load(JavaClass cls, String sig) {
// TODO: is there a place where we can maintain a cache of these for the duration of analysis?
return new ClassAnalysis(cls, sig);
}
boolean isMutable() {
Boolean local = mutable;
if (local == null) {
mutable = local = computeMutable();
}
return local;
}
private boolean computeMutable() {
if (isImmutableByContract()) {
return false;
}
for (Method method : cls.getMethods()) {
if (!method.isStatic() && looksLikeASetter(method)) {
return true;
}
}
final ClassAnalysis maybeSuper = getSuperAnalysis();
return maybeSuper != null && maybeSuper.isMutable();
}
private boolean looksLikeASetter(Method method) {
return MutableClasses.looksLikeASetter(method.getName(), getSig(), method.getReturnType().getSignature());
}
private String getSig() {
String local = sig;
if (local == null) {
sig = local = "L" + ClassName.toSlashedClassName(cls.getClassName()) + ";";
}
return local;
}
private boolean isImmutableByContract() {
Boolean local = immutableByContract;
if (local == null) {
immutableByContract = local = computeByImmutableContract();
}
return local;
}
private boolean computeByImmutableContract() {
if ("java.lang.Enum".equals(cls.getClassName())) {
return true;
}
if ("java.lang.Record".equals(cls.getClassName())) {
return true;
}
for (AnnotationEntry entry : cls.getAnnotationEntries()) {
// Error-Prone's @Immutable annotation is @Inherited, hence it applies to subclasses as well
if (entry.getAnnotationType().equals("Lcom/google/errorprone/annotations/Immutable;")) {
return true;
}
}
final ClassAnalysis maybeSuper = getSuperAnalysis();
return maybeSuper != null && maybeSuper.isImmutableByContract();
}
private ClassAnalysis getSuperAnalysis() {
ClassAnalysis local = superAnalysis;
if (local == null) {
superAnalysis = local = loadSuperAnalysis();
}
return local;
}
private ClassAnalysis loadSuperAnalysis() {
// Quick check if there is a superclass of importance
final String superName = cls.getSuperclassName();
if (superName == null || superName.equals("java.lang.Object")) {
return null;
}
final JavaClass superClass;
try {
superClass = cls.getSuperClass();
} catch (ClassNotFoundException e) {
AnalysisContext.reportMissingClass(e);
return null;
}
if (superClass == null) {
return null;
}
return load(superClass, null);
}
}
}