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8150488: Scanner.findAll() can return infinite stream if regex matches zero chars

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Reviewed-by: sherman
This commit is contained in:
Stuart Marks 2017-04-28 12:16:30 -07:00
parent b0ddb372f0
commit cb05e8ea85
2 changed files with 109 additions and 10 deletions
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31
jdk/src/java.base/share/classes/java/util/Scanner.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -2846,6 +2846,7 @@ public final class Scanner implements Iterator<String>, Closeable {
class FindSpliterator extends Spliterators.AbstractSpliterator<MatchResult> {
final Pattern pattern;
int expectedCount = -1;
private boolean advance = false; // true if we need to auto-advance
FindSpliterator(Pattern pattern) {
super(Long.MAX_VALUE,
@ -2861,12 +2862,15 @@ public final class Scanner implements Iterator<String>, Closeable {
throw new ConcurrentModificationException();
}
} else {
// init
matchValid = false;
matcher.usePattern(pattern);
expectedCount = modCount;
}
while (true) {
// assert expectedCount == modCount
if (findPatternInBuffer(pattern, 0)) { // doesn't increment modCount
if (nextInBuffer()) { // doesn't increment modCount
cons.accept(matcher.toMatchResult());
if (expectedCount != modCount) {
throw new ConcurrentModificationException();
@ -2879,6 +2883,29 @@ public final class Scanner implements Iterator<String>, Closeable {
return false; // reached end of input
}
}
// reimplementation of findPatternInBuffer with auto-advance on zero-length matches
private boolean nextInBuffer() {
if (advance) {
if (position + 1 > buf.limit()) {
if (!sourceClosed)
needInput = true;
return false;
}
position++;
advance = false;
}
matcher.region(position, buf.limit());
if (matcher.find() && (!matcher.hitEnd() || sourceClosed)) {
// Did not hit end, or hit real end
position = matcher.end();
advance = matcher.start() == position;
return true;
}
if (!sourceClosed)
needInput = true;
return false;
}
}
/** Small LRU cache of Patterns. */