matthiasblaesing commented on code in PR #5299:
URL: https://github.com/apache/netbeans/pull/5299#discussion_r1097864205
##########
java/debugger.jpda/src/org/netbeans/modules/debugger/jpda/models/ShortenedStrings.java:
##########
@@ -130,7 +213,14 @@ static String getStringWithLengthControl(StringReference
sr) throws InternalExce
try {
ReferenceType st = ObjectReferenceWrapper.referenceType(sr);
ArrayReference sa = null;
+ //only applicable if the string implementation uses a byte[]
instead
+ //of a char[]
+ boolean isUTF16 = false;
+ boolean isCompactImpl = false;
Review Comment:
Please add a comment like:
> JEP 254: Compact Strings after the boolean
that might help people to later understand the intention
##########
java/debugger.jpda/src/org/netbeans/modules/debugger/jpda/models/ShortenedStrings.java:
##########
@@ -130,7 +213,14 @@ static String getStringWithLengthControl(StringReference
sr) throws InternalExce
try {
ReferenceType st = ObjectReferenceWrapper.referenceType(sr);
ArrayReference sa = null;
+ //only applicable if the string implementation uses a byte[]
instead
+ //of a char[]
+ boolean isUTF16 = false;
+ boolean isCompactImpl = false;
+ int hiByteShift = 0;
+ int lowByteShift = 0;
Review Comment:
Please move these down to the use-site (directly before the if in 318) and
remove the initializer. The if will initialize them.
##########
java/debugger.jpda/src/org/netbeans/modules/debugger/jpda/models/ShortenedStrings.java:
##########
@@ -92,6 +108,73 @@ public static StringInfo getShortenedInfo(String s) {
}
}
+ private static boolean isLittleEndian(VirtualMachine virtualMachine) {
+ synchronized(isLittleEndianCache){
+ Boolean cached = isLittleEndianCache.get(virtualMachine);
+ if (cached != null){
+ return cached;
+ }
+ List<ReferenceType> possibleClasses = virtualMachine.classesByName(
+ "java.lang.StringUTF16");
+ //If we don't know, we are going to assume little endian encoding.
+ //This should work for most architectures (x86, arm, riscv), but
+ //will result in bogus data on big endian architectures
+ final boolean defaultValue = true;
+ if (possibleClasses.isEmpty()){
+ ClassType ct = (ClassType) virtualMachine.classesByName(
+ "java.lang.Class").iterator().next();
+ Method m = ct.concreteMethodByName("forName",
+ "(Ljava/lang/String;)Ljava/lang/Class;");
+ StringReference referenceString = virtualMachine.mirrorOf(
+ "java.lang.StringUTF16");
+ try {
+ ThreadReference threadReference = virtualMachine.
+ allThreads().get(0);
+ ct.invokeMethod(threadReference, m, Collections.
+ singletonList(referenceString), 0);
+ possibleClasses = virtualMachine.classesByName(
+ "java.lang.StringUTF16");
+ } catch (InvalidTypeException | ClassNotLoadedException |
+ IncompatibleThreadStateException | InvocationException
ex) {
+ Exceptions.printStackTrace(ex);
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ }
+ ReferenceType utf16;
+ if (possibleClasses.size() == 1){
+ utf16 = possibleClasses.get(0);
+ }
+ else {
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ Field hiByteShift;
+ try{
+ hiByteShift = ReferenceTypeWrapper.fieldByName(utf16,
+ "HI_BYTE_SHIFT");
+ }
+ catch (ClassNotPreparedExceptionWrapper | InternalExceptionWrapper
|
+ ObjectCollectedExceptionWrapper |
VMDisconnectedExceptionWrapper e){
+ Exceptions.printStackTrace(e);
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ if (hiByteShift == null){
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ Value val = utf16.getValue(hiByteShift);
Review Comment:
I suggest to switch variable to `hiByteShiftValue`.
##########
java/debugger.jpda/src/org/netbeans/modules/debugger/jpda/models/ShortenedStrings.java:
##########
@@ -92,6 +108,73 @@ public static StringInfo getShortenedInfo(String s) {
}
}
+ private static boolean isLittleEndian(VirtualMachine virtualMachine) {
+ synchronized(isLittleEndianCache){
+ Boolean cached = isLittleEndianCache.get(virtualMachine);
+ if (cached != null){
+ return cached;
+ }
+ List<ReferenceType> possibleClasses = virtualMachine.classesByName(
+ "java.lang.StringUTF16");
+ //If we don't know, we are going to assume little endian encoding.
+ //This should work for most architectures (x86, arm, riscv), but
+ //will result in bogus data on big endian architectures
+ final boolean defaultValue = true;
+ if (possibleClasses.isEmpty()){
+ ClassType ct = (ClassType) virtualMachine.classesByName(
+ "java.lang.Class").iterator().next();
+ Method m = ct.concreteMethodByName("forName",
+ "(Ljava/lang/String;)Ljava/lang/Class;");
+ StringReference referenceString = virtualMachine.mirrorOf(
+ "java.lang.StringUTF16");
+ try {
+ ThreadReference threadReference = virtualMachine.
+ allThreads().get(0);
+ ct.invokeMethod(threadReference, m, Collections.
+ singletonList(referenceString), 0);
+ possibleClasses = virtualMachine.classesByName(
+ "java.lang.StringUTF16");
+ } catch (InvalidTypeException | ClassNotLoadedException |
+ IncompatibleThreadStateException | InvocationException
ex) {
+ Exceptions.printStackTrace(ex);
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ }
+ ReferenceType utf16;
+ if (possibleClasses.size() == 1){
+ utf16 = possibleClasses.get(0);
+ }
+ else {
+ isLittleEndianCache.put(virtualMachine, defaultValue);
+ return defaultValue;
+ }
+ Field hiByteShift;
Review Comment:
Please follow the naming convention you also used in the other method and
make this `hiByteShiftField`
##########
java/debugger.jpda/src/org/netbeans/modules/debugger/jpda/models/ShortenedStrings.java:
##########
@@ -171,21 +295,73 @@ static String getStringWithLengthControl(StringReference
sr) throws InternalExce
} else {
assert sa != null;
int l = AbstractObjectVariable.MAX_STRING_LENGTH;
- List<Value> values = ArrayReferenceWrapper.getValues(sa, 0, l);
+ List<Value> values = ArrayReferenceWrapper.getValues(sa, 0,
+ isUTF16 ? (l * 2) : l);
char[] characters = new char[l + 3];
- for (int i = 0; i < l; i++) {
- Value v = values.get(i);
- if (!(v instanceof CharValue)) {
- return "<Unreadable>";
+ if (isCompactImpl) {
+ //java compact string
+ if (!isUTF16) {
+ //we can just cast to char
+ for (int i = 0; i < l; i++) {
+ Value v = values.get(i);
+ if (!(v instanceof ByteValue)) {
+ return ERROR_RESULT;
+ }
+ char c = (char)((ByteValue) v).byteValue();
+ //remove the extended sign
+ c &= 0xFF;
+ characters[i] = c;
+ }
+ }
+ else {
+ //is it little or big endian?
+ if (isLittleEndian(sr.virtualMachine())){
+ hiByteShift = 0;
+ lowByteShift = 8;
+ }
+ else{
+ hiByteShift = 8;
+ lowByteShift = 0;
+ }
+ for (int i = 0; i < l; i++) {
+ int index = i * 2;
+ Value v = values.get(index);
+ if (!(v instanceof ByteValue)) {
+ return ERROR_RESULT;
+ }
+ Value v2 = values.get(index + 1);
+ if (!(v instanceof ByteValue)) {
+ return ERROR_RESULT;
+ }
+ char c1 = (char) ((ByteValue) v).byteValue();
+ char c2 = (char) ((ByteValue) v2).byteValue();
+ //remove the extended sign
+ c1 = (char) (0xFF & c1);
+ c2 = (char) (0xFF & c2);
+ char c = (char)(c1 << hiByteShift |
+ c2 << lowByteShift);
+ // char bigEndianChar = (char) ((c1 << 8) | c2);
+ //char litteEndianChar = (char) ((c2 << 8) | c1);
Review Comment:
Please remove the comment ed code
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