/*
* 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.lucene.codecs.blocktreeords;
import java.io.IOException;
import org.apache.lucene.codecs.blocktreeords.FSTOrdsOutputs.Output;
import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.TermState;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.RamUsageEstimator;
import org.apache.lucene.util.StringHelper;
import org.apache.lucene.util.automaton.CompiledAutomaton;
import org.apache.lucene.util.automaton.RunAutomaton;
import org.apache.lucene.util.fst.FST;
// NOTE: cannot seek!
final class OrdsIntersectTermsEnum extends TermsEnum {
final IndexInput in;
private OrdsIntersectTermsEnumFrame[] stack;
@SuppressWarnings({"rawtypes","unchecked"}) private FST.Arc<Output>[] arcs = new FST.Arc[5];
final RunAutomaton runAutomaton;
final CompiledAutomaton compiledAutomaton;
private OrdsIntersectTermsEnumFrame currentFrame;
private final BytesRef term = new BytesRef();
private final FST.BytesReader fstReader;
final OrdsFieldReader fr;
private BytesRef savedStartTerm;
// TODO: in some cases we can filter by length? eg
// regexp foo*bar must be at least length 6 bytes
public OrdsIntersectTermsEnum(OrdsFieldReader fr, CompiledAutomaton compiled, BytesRef startTerm) throws IOException {
// if (DEBUG) {
// System.out.println("\nintEnum.init seg=" + segment + " commonSuffix=" + brToString(compiled.commonSuffixRef));
// }
this.fr = fr;
runAutomaton = compiled.runAutomaton;
compiledAutomaton = compiled;
in = fr.parent.in.clone();
stack = new OrdsIntersectTermsEnumFrame[5];
for(int idx=0;idx<stack.length;idx++) {
stack[idx] = new OrdsIntersectTermsEnumFrame(this, idx);
}
for(int arcIdx=0;arcIdx<arcs.length;arcIdx++) {
arcs[arcIdx] = new FST.Arc<>();
}
if (fr.index == null) {
fstReader = null;
} else {
fstReader = fr.index.getBytesReader();
}
// TODO: if the automaton is "smallish" we really
// should use the terms index to seek at least to
// the initial term and likely to subsequent terms
// (or, maybe just fallback to ATE for such cases).
// Else the seek cost of loading the frames will be
// too costly.
final FST.Arc<Output> arc = fr.index.getFirstArc(arcs[0]);
// Empty string prefix must have an output in the index!
assert arc.isFinal();
// Special pushFrame since it's the first one:
final OrdsIntersectTermsEnumFrame f = stack[0];
f.fp = f.fpOrig = fr.rootBlockFP;
f.prefix = 0;
f.setState(0);
f.arc = arc;
f.outputPrefix = arc.output;
f.load(fr.rootCode);
// for assert:
assert setSavedStartTerm(startTerm);
currentFrame = f;
if (startTerm != null) {
seekToStartTerm(startTerm);
}
}
// only for assert:
private boolean setSavedStartTerm(BytesRef startTerm) {
savedStartTerm = startTerm == null ? null : BytesRef.deepCopyOf(startTerm);
return true;
}
@Override
public TermState termState() throws IOException {
currentFrame.decodeMetaData();
return currentFrame.termState.clone();
}
private OrdsIntersectTermsEnumFrame getFrame(int ord) throws IOException {
if (ord >= stack.length) {
final OrdsIntersectTermsEnumFrame[] next = new OrdsIntersectTermsEnumFrame[ArrayUtil.oversize(1+ord, RamUsageEstimator.NUM_BYTES_OBJECT_REF)];
System.arraycopy(stack, 0, next, 0, stack.length);
for(int stackOrd=stack.length;stackOrd<next.length;stackOrd++) {
next[stackOrd] = new OrdsIntersectTermsEnumFrame(this, stackOrd);
}
stack = next;
}
assert stack[ord].ord == ord;
return stack[ord];
}
private FST.Arc<Output> getArc(int ord) {
if (ord >= arcs.length) {
@SuppressWarnings({"rawtypes","unchecked"}) final FST.Arc<Output>[] next =
new FST.Arc[ArrayUtil.oversize(1+ord, RamUsageEstimator.NUM_BYTES_OBJECT_REF)];
System.arraycopy(arcs, 0, next, 0, arcs.length);
for(int arcOrd=arcs.length;arcOrd<next.length;arcOrd++) {
next[arcOrd] = new FST.Arc<>();
}
arcs = next;
}
return arcs[ord];
}
private OrdsIntersectTermsEnumFrame pushFrame(int state) throws IOException {
final OrdsIntersectTermsEnumFrame f = getFrame(currentFrame == null ? 0 : 1+currentFrame.ord);
f.fp = f.fpOrig = currentFrame.lastSubFP;
f.prefix = currentFrame.prefix + currentFrame.suffix;
// if (DEBUG) System.out.println(" pushFrame state=" + state + " prefix=" + f.prefix);
f.setState(state);
// Walk the arc through the index -- we only
// "bother" with this so we can get the floor data
// from the index and skip floor blocks when
// possible:
FST.Arc<Output> arc = currentFrame.arc;
int idx = currentFrame.prefix;
assert currentFrame.suffix > 0;
Output output = currentFrame.outputPrefix;
while (idx < f.prefix) {
final int target = term.bytes[idx] & 0xff;
// TODO: we could be more efficient for the next()
// case by using current arc as starting point,
// passed to findTargetArc
arc = fr.index.findTargetArc(target, arc, getArc(1+idx), fstReader);
assert arc != null;
output = OrdsBlockTreeTermsWriter.FST_OUTPUTS.add(output, arc.output);
idx++;
}
f.arc = arc;
f.outputPrefix = output;
assert arc.isFinal();
f.load(OrdsBlockTreeTermsWriter.FST_OUTPUTS.add(output, arc.nextFinalOutput));
return f;
}
@Override
public BytesRef term() {
return term;
}
// TODO: do we need ord() here? OrdsIntersectTermsEnumFrame tracks termOrd but it may be buggy!
@Override
public int docFreq() throws IOException {
//if (DEBUG) System.out.println("BTIR.docFreq");
currentFrame.decodeMetaData();
//if (DEBUG) System.out.println(" return " + currentFrame.termState.docFreq);
return currentFrame.termState.docFreq;
}
@Override
public long totalTermFreq() throws IOException {
currentFrame.decodeMetaData();
return currentFrame.termState.totalTermFreq;
}
@Override
public PostingsEnum postings(PostingsEnum reuse, int flags) throws IOException {
currentFrame.decodeMetaData();
return fr.parent.postingsReader.postings(fr.fieldInfo, currentFrame.termState, reuse, flags);
}
private int getState() {
int state = currentFrame.state;
for(int idx=0;idx<currentFrame.suffix;idx++) {
state = runAutomaton.step(state, currentFrame.suffixBytes[currentFrame.startBytePos+idx] & 0xff);
assert state != -1;
}
return state;
}
// NOTE: specialized to only doing the first-time
// seek, but we could generalize it to allow
// arbitrary seekExact/Ceil. Note that this is a
// seekFloor!
private void seekToStartTerm(BytesRef target) throws IOException {
//if (DEBUG) System.out.println("seek to startTerm=" + target.utf8ToString());
assert currentFrame.ord == 0;
if (term.length < target.length) {
term.bytes = ArrayUtil.grow(term.bytes, target.length);
}
FST.Arc<Output> arc = arcs[0];
assert arc == currentFrame.arc;
for(int idx=0;idx<=target.length;idx++) {
while (true) {
final int savePos = currentFrame.suffixesReader.getPosition();
final int saveStartBytePos = currentFrame.startBytePos;
final int saveSuffix = currentFrame.suffix;
final long saveLastSubFP = currentFrame.lastSubFP;
final int saveTermBlockOrd = currentFrame.termState.termBlockOrd;
final boolean isSubBlock = currentFrame.next();
//if (DEBUG) System.out.println(" cycle ent=" + currentFrame.nextEnt + " (of " + currentFrame.entCount + ") prefix=" + currentFrame.prefix + " suffix=" + currentFrame.suffix + " isBlock=" + isSubBlock + " firstLabel=" + (currentFrame.suffix == 0 ? "" : (currentFrame.suffixBytes[currentFrame.startBytePos])&0xff));
term.length = currentFrame.prefix + currentFrame.suffix;
if (term.bytes.length < term.length) {
term.bytes = ArrayUtil.grow(term.bytes, term.length);
}
System.arraycopy(currentFrame.suffixBytes, currentFrame.startBytePos, term.bytes, currentFrame.prefix, currentFrame.suffix);
if (isSubBlock && StringHelper.startsWith(target, term)) {
// Recurse
//if (DEBUG) System.out.println(" recurse!");
currentFrame = pushFrame(getState());
break;
} else {
final int cmp = term.compareTo(target);
if (cmp < 0) {
if (currentFrame.nextEnt == currentFrame.entCount) {
if (!currentFrame.isLastInFloor) {
//if (DEBUG) System.out.println(" load floorBlock");
currentFrame.loadNextFloorBlock();
continue;
} else {
//if (DEBUG) System.out.println(" return term=" + brToString(term));
return;
}
}
continue;
} else if (cmp == 0) {
//if (DEBUG) System.out.println(" return term=" + brToString(term));
return;
} else {
// Fallback to prior entry: the semantics of
// this method is that the first call to
// next() will return the term after the
// requested term
currentFrame.nextEnt--;
currentFrame.lastSubFP = saveLastSubFP;
currentFrame.startBytePos = saveStartBytePos;
currentFrame.suffix = saveSuffix;
currentFrame.suffixesReader.setPosition(savePos);
currentFrame.termState.termBlockOrd = saveTermBlockOrd;
System.arraycopy(currentFrame.suffixBytes, currentFrame.startBytePos, term.bytes, currentFrame.prefix, currentFrame.suffix);
term.length = currentFrame.prefix + currentFrame.suffix;
// If the last entry was a block we don't
// need to bother recursing and pushing to
// the last term under it because the first
// next() will simply skip the frame anyway
return;
}
}
}
}
assert false;
}
@Override
public BytesRef next() throws IOException {
// if (DEBUG) {
// System.out.println("\nintEnum.next seg=" + segment);
// System.out.println(" frame ord=" + currentFrame.ord + " prefix=" + brToString(new BytesRef(term.bytes, term.offset, currentFrame.prefix)) + " state=" + currentFrame.state + " lastInFloor?=" + currentFrame.isLastInFloor + " fp=" + currentFrame.fp + " trans=" + (currentFrame.transitions.length == 0 ? "n/a" : currentFrame.transitions[currentFrame.transitionIndex]) + " outputPrefix=" + currentFrame.outputPrefix);
// }
nextTerm:
while(true) {
// Pop finished frames
while (currentFrame.nextEnt == currentFrame.entCount) {
if (!currentFrame.isLastInFloor) {
//if (DEBUG) System.out.println(" next-floor-block");
currentFrame.loadNextFloorBlock();
//if (DEBUG) System.out.println("\n frame ord=" + currentFrame.ord + " prefix=" + brToString(new BytesRef(term.bytes, term.offset, currentFrame.prefix)) + " state=" + currentFrame.state + " lastInFloor?=" + currentFrame.isLastInFloor + " fp=" + currentFrame.fp + " trans=" + (currentFrame.transitions.length == 0 ? "n/a" : currentFrame.transitions[currentFrame.transitionIndex]) + " outputPrefix=" + currentFrame.outputPrefix);
} else {
//if (DEBUG) System.out.println(" pop frame");
if (currentFrame.ord == 0) {
return null;
}
final long lastFP = currentFrame.fpOrig;
currentFrame = stack[currentFrame.ord-1];
assert currentFrame.lastSubFP == lastFP;
//if (DEBUG) System.out.println("\n frame ord=" + currentFrame.ord + " prefix=" + brToString(new BytesRef(term.bytes, term.offset, currentFrame.prefix)) + " state=" + currentFrame.state + " lastInFloor?=" + currentFrame.isLastInFloor + " fp=" + currentFrame.fp + " trans=" + (currentFrame.transitions.length == 0 ? "n/a" : currentFrame.transitions[currentFrame.transitionIndex]) + " outputPrefix=" + currentFrame.outputPrefix);
}
}
final boolean isSubBlock = currentFrame.next();
// if (DEBUG) {
// final BytesRef suffixRef = new BytesRef();
// suffixRef.bytes = currentFrame.suffixBytes;
// suffixRef.offset = currentFrame.startBytePos;
// suffixRef.length = currentFrame.suffix;
// System.out.println(" " + (isSubBlock ? "sub-block" : "term") + " " + currentFrame.nextEnt + " (of " + currentFrame.entCount + ") suffix=" + brToString(suffixRef));
// }
if (currentFrame.suffix != 0) {
final int label = currentFrame.suffixBytes[currentFrame.startBytePos] & 0xff;
while (label > currentFrame.curTransitionMax) {
if (currentFrame.transitionIndex >= currentFrame.transitionCount-1) {
// Stop processing this frame -- no further
// matches are possible because we've moved
// beyond what the max transition will allow
//if (DEBUG) System.out.println(" break: trans=" + (currentFrame.transitions.length == 0 ? "n/a" : currentFrame.transitions[currentFrame.transitionIndex]));
// sneaky! forces a pop above
currentFrame.isLastInFloor = true;
currentFrame.nextEnt = currentFrame.entCount;
continue nextTerm;
}
currentFrame.transitionIndex++;
compiledAutomaton.automaton.getNextTransition(currentFrame.transition);
currentFrame.curTransitionMax = currentFrame.transition.max;
//if (DEBUG) System.out.println(" next trans=" + currentFrame.transitions[currentFrame.transitionIndex]);
}
}
// First test the common suffix, if set:
if (compiledAutomaton.commonSuffixRef != null && !isSubBlock) {
final int termLen = currentFrame.prefix + currentFrame.suffix;
if (termLen < compiledAutomaton.commonSuffixRef.length) {
// No match
// if (DEBUG) {
// System.out.println(" skip: common suffix length");
// }
continue nextTerm;
}
final byte[] suffixBytes = currentFrame.suffixBytes;
final byte[] commonSuffixBytes = compiledAutomaton.commonSuffixRef.bytes;
final int lenInPrefix = compiledAutomaton.commonSuffixRef.length - currentFrame.suffix;
assert compiledAutomaton.commonSuffixRef.offset == 0;
int suffixBytesPos;
int commonSuffixBytesPos = 0;
if (lenInPrefix > 0) {
// A prefix of the common suffix overlaps with
// the suffix of the block prefix so we first
// test whether the prefix part matches:
final byte[] termBytes = term.bytes;
int termBytesPos = currentFrame.prefix - lenInPrefix;
assert termBytesPos >= 0;
final int termBytesPosEnd = currentFrame.prefix;
while (termBytesPos < termBytesPosEnd) {
if (termBytes[termBytesPos++] != commonSuffixBytes[commonSuffixBytesPos++]) {
// if (DEBUG) {
// System.out.println(" skip: common suffix mismatch (in prefix)");
// }
continue nextTerm;
}
}
suffixBytesPos = currentFrame.startBytePos;
} else {
suffixBytesPos = currentFrame.startBytePos + currentFrame.suffix - compiledAutomaton.commonSuffixRef.length;
}
// Test overlapping suffix part:
final int commonSuffixBytesPosEnd = compiledAutomaton.commonSuffixRef.length;
while (commonSuffixBytesPos < commonSuffixBytesPosEnd) {
if (suffixBytes[suffixBytesPos++] != commonSuffixBytes[commonSuffixBytesPos++]) {
// if (DEBUG) {
// System.out.println(" skip: common suffix mismatch");
// }
continue nextTerm;
}
}
}
// TODO: maybe we should do the same linear test
// that AutomatonTermsEnum does, so that if we
// reach a part of the automaton where .* is
// "temporarily" accepted, we just blindly .next()
// until the limit
// See if the term prefix matches the automaton:
int state = currentFrame.state;
for (int idx=0;idx<currentFrame.suffix;idx++) {
state = runAutomaton.step(state, currentFrame.suffixBytes[currentFrame.startBytePos+idx] & 0xff);
if (state == -1) {
// No match
//System.out.println(" no s=" + state);
continue nextTerm;
} else {
//System.out.println(" c s=" + state);
}
}
if (isSubBlock) {
// Match! Recurse:
//if (DEBUG) System.out.println(" sub-block match to state=" + state + "; recurse fp=" + currentFrame.lastSubFP);
copyTerm();
currentFrame = pushFrame(state);
//if (DEBUG) System.out.println("\n frame ord=" + currentFrame.ord + " prefix=" + brToString(new BytesRef(term.bytes, term.offset, currentFrame.prefix)) + " state=" + currentFrame.state + " lastInFloor?=" + currentFrame.isLastInFloor + " fp=" + currentFrame.fp + " trans=" + (currentFrame.transitions.length == 0 ? "n/a" : currentFrame.transitions[currentFrame.transitionIndex]) + " outputPrefix=" + currentFrame.outputPrefix);
} else if (runAutomaton.isAccept(state)) {
copyTerm();
//if (DEBUG) System.out.println(" term match to state=" + state + "; return term=" + brToString(term));
assert savedStartTerm == null || term.compareTo(savedStartTerm) > 0: "saveStartTerm=" + savedStartTerm.utf8ToString() + " term=" + term.utf8ToString();
return term;
} else {
//System.out.println(" no s=" + state);
}
}
}
private void copyTerm() {
//System.out.println(" copyTerm cur.prefix=" + currentFrame.prefix + " cur.suffix=" + currentFrame.suffix + " first=" + (char) currentFrame.suffixBytes[currentFrame.startBytePos]);
final int len = currentFrame.prefix + currentFrame.suffix;
if (term.bytes.length < len) {
term.bytes = ArrayUtil.grow(term.bytes, len);
}
System.arraycopy(currentFrame.suffixBytes, currentFrame.startBytePos, term.bytes, currentFrame.prefix, currentFrame.suffix);
term.length = len;
}
@Override
public boolean seekExact(BytesRef text) {
throw new UnsupportedOperationException();
}
@Override
public void seekExact(long ord) {
throw new UnsupportedOperationException();
}
@Override
public long ord() {
throw new UnsupportedOperationException();
}
@Override
public SeekStatus seekCeil(BytesRef text) {
throw new UnsupportedOperationException();
}
}