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/*
* 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.cassandra.db;
import java.io.IOException;
import java.util.*;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import net.nicoulaj.compilecommand.annotations.DontInline;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.cql3.ColumnIdentifier;
import org.apache.cassandra.db.marshal.SetType;
import org.apache.cassandra.db.marshal.UTF8Type;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.SearchIterator;
import org.apache.cassandra.utils.btree.BTree;
import org.apache.cassandra.utils.btree.BTreeSearchIterator;
import org.apache.cassandra.utils.btree.BTreeRemoval;
import org.apache.cassandra.utils.btree.UpdateFunction;
/**
* An immutable and sorted list of (non-PK) columns for a given table.
*
* Note that in practice, it will either store only static columns, or only regular ones. When
* we need both type of columns, we use a {@link PartitionColumns} object.
*/
public class Columns extends AbstractCollection implements Collection
{
public static final Serializer serializer = new Serializer();
public static final Columns NONE = new Columns(BTree.empty(), 0);
public static final ColumnDefinition FIRST_COMPLEX =
new ColumnDefinition("",
"",
ColumnIdentifier.getInterned(ByteBufferUtil.EMPTY_BYTE_BUFFER, UTF8Type.instance),
SetType.getInstance(UTF8Type.instance, true),
ColumnDefinition.NO_POSITION,
ColumnDefinition.Kind.REGULAR);
private final Object[] columns;
private final int complexIdx; // Index of the first complex column
private Columns(Object[] columns, int complexIdx)
{
assert complexIdx <= BTree.size(columns);
this.columns = columns;
this.complexIdx = complexIdx;
}
private Columns(Object[] columns)
{
this(columns, findFirstComplexIdx(columns));
}
/**
* Creates a {@code Columns} holding only the one column provided.
*
* @param c the column for which to create a {@code Columns} object.
*
* @return the newly created {@code Columns} containing only {@code c}.
*/
public static Columns of(ColumnDefinition c)
{
return new Columns(BTree.singleton(c), c.isComplex() ? 0 : 1);
}
/**
* Returns a new {@code Columns} object holing the same columns than the provided set.
*
* @param s the set from which to create the new {@code Columns}.
* @return the newly created {@code Columns} containing the columns from {@code s}.
*/
public static Columns from(Collection s)
{
Object[] tree = BTree.builder(Comparator.naturalOrder()).addAll(s).build();
return new Columns(tree, findFirstComplexIdx(tree));
}
private static int findFirstComplexIdx(Object[] tree)
{
// have fast path for common no-complex case
int size = BTree.size(tree);
if (!BTree.isEmpty(tree) && BTree.findByIndex(tree, size - 1).isSimple())
return size;
return BTree.ceilIndex(tree, Comparator.naturalOrder(), FIRST_COMPLEX);
}
/**
* Whether this columns is empty.
*
* @return whether this columns is empty.
*/
public boolean isEmpty()
{
return BTree.isEmpty(columns);
}
/**
* The number of simple columns in this object.
*
* @return the number of simple columns in this object.
*/
public int simpleColumnCount()
{
return complexIdx;
}
/**
* The number of complex columns (non-frozen collections, udts, ...) in this object.
*
* @return the number of complex columns in this object.
*/
public int complexColumnCount()
{
return BTree.size(columns) - complexIdx;
}
/**
* The total number of columns in this object.
*
* @return the total number of columns in this object.
*/
public int size()
{
return BTree.size(columns);
}
/**
* Whether this objects contains simple columns.
*
* @return whether this objects contains simple columns.
*/
public boolean hasSimple()
{
return complexIdx > 0;
}
/**
* Whether this objects contains complex columns.
*
* @return whether this objects contains complex columns.
*/
public boolean hasComplex()
{
return complexIdx < BTree.size(columns);
}
/**
* Returns the ith simple column of this object.
*
* @param i the index for the simple column to fectch. This must
* satisfy {@code 0 <= i < simpleColumnCount()}.
*
* @return the {@code i}th simple column in this object.
*/
public ColumnDefinition getSimple(int i)
{
return BTree.findByIndex(columns, i);
}
/**
* Returns the ith complex column of this object.
*
* @param i the index for the complex column to fectch. This must
* satisfy {@code 0 <= i < complexColumnCount()}.
*
* @return the {@code i}th complex column in this object.
*/
public ColumnDefinition getComplex(int i)
{
return BTree.findByIndex(columns, complexIdx + i);
}
/**
* The index of the provided simple column in this object (if it contains
* the provided column).
*
* @param c the simple column for which to return the index of.
*
* @return the index for simple column {@code c} if it is contains in this
* object
*/
public int simpleIdx(ColumnDefinition c)
{
return BTree.findIndex(columns, Comparator.naturalOrder(), c);
}
/**
* The index of the provided complex column in this object (if it contains
* the provided column).
*
* @param c the complex column for which to return the index of.
*
* @return the index for complex column {@code c} if it is contains in this
* object
*/
public int complexIdx(ColumnDefinition c)
{
return BTree.findIndex(columns, Comparator.naturalOrder(), c) - complexIdx;
}
/**
* Whether the provided column is contained by this object.
*
* @param c the column to check presence of.
*
* @return whether {@code c} is contained by this object.
*/
public boolean contains(ColumnDefinition c)
{
return BTree.findIndex(columns, Comparator.naturalOrder(), c) >= 0;
}
/**
* Returns the result of merging this {@code Columns} object with the
* provided one.
*
* @param other the other {@code Columns} to merge this object with.
*
* @return the result of merging/taking the union of {@code this} and
* {@code other}. The returned object may be one of the operand and that
* operand is a subset of the other operand.
*/
public Columns mergeTo(Columns other)
{
if (this == other || other == NONE)
return this;
if (this == NONE)
return other;
Object[] tree = BTree.merge(this.columns, other.columns, Comparator.naturalOrder(),
UpdateFunction.noOp());
if (tree == this.columns)
return this;
if (tree == other.columns)
return other;
return new Columns(tree, findFirstComplexIdx(tree));
}
/**
* Whether this object is a superset of the provided other {@code Columns object}.
*
* @param other the other object to test for inclusion in this object.
*
* @return whether all the columns of {@code other} are contained by this object.
*/
public boolean containsAll(Collection other)
{
if (other == this)
return true;
if (other.size() > this.size())
return false;
BTreeSearchIterator iter = BTree.slice(columns, Comparator.naturalOrder(), BTree.Dir.ASC);
for (Object def : other)
if (iter.next((ColumnDefinition) def) == null)
return false;
return true;
}
/**
* Iterator over the simple columns of this object.
*
* @return an iterator over the simple columns of this object.
*/
public Iterator simpleColumns()
{
return BTree.iterator(columns, 0, complexIdx - 1, BTree.Dir.ASC);
}
/**
* Iterator over the complex columns of this object.
*
* @return an iterator over the complex columns of this object.
*/
public Iterator complexColumns()
{
return BTree.iterator(columns, complexIdx, BTree.size(columns) - 1, BTree.Dir.ASC);
}
/**
* Iterator over all the columns of this object.
*
* @return an iterator over all the columns of this object.
*/
public BTreeSearchIterator iterator()
{
return BTree.slice(columns, Comparator.naturalOrder(), BTree.Dir.ASC);
}
/**
* An iterator that returns the columns of this object in "select" order (that
* is in global alphabetical order, where the "normal" iterator returns simple
* columns first and the complex second).
*
* @return an iterator returning columns in alphabetical order.
*/
public Iterator selectOrderIterator()
{
// In wildcard selection, we want to return all columns in alphabetical order,
// irregarding of whether they are complex or not
return Iterators.
mergeSorted(ImmutableList.of(simpleColumns(), complexColumns()),
(s, c) ->
{
assert !s.kind.isPrimaryKeyKind();
return s.name.bytes.compareTo(c.name.bytes);
});
}
/**
* Returns the equivalent of those columns but with the provided column removed.
*
* @param column the column to remove.
*
* @return newly allocated columns containing all the columns of {@code this} expect
* for {@code column}.
*/
public Columns without(ColumnDefinition column)
{
if (!contains(column))
return this;
Object[] newColumns = BTreeRemoval.remove(columns, Comparator.naturalOrder(), column);
return new Columns(newColumns);
}
/**
* Returns a predicate to test whether columns are included in this {@code Columns} object,
* assuming that tes tested columns are passed to the predicate in sorted order.
*
* @return a predicate to test the inclusion of sorted columns in this object.
*/
public Predicate inOrderInclusionTester()
{
SearchIterator iter = BTree.slice(columns, Comparator.naturalOrder(), BTree.Dir.ASC);
return column -> iter.next(column) != null;
}
public void digest(MessageDigest digest)
{
for (ColumnDefinition c : this)
digest.update(c.name.bytes.duplicate());
}
/**
* Apply a function to each column definition in forwards or reversed order.
* @param function
* @param reversed
*/
public void apply(Consumer function, boolean reversed)
{
BTree.apply(columns, function, reversed);
}
@Override
public boolean equals(Object other)
{
if (other == this)
return true;
if (!(other instanceof Columns))
return false;
Columns that = (Columns)other;
return this.complexIdx == that.complexIdx && BTree.equals(this.columns, that.columns);
}
@Override
public int hashCode()
{
return Objects.hash(complexIdx, BTree.hashCode(columns));
}
@Override
public String toString()
{
StringBuilder sb = new StringBuilder("[");
boolean first = true;
for (ColumnDefinition def : this)
{
if (first) first = false; else sb.append(" ");
sb.append(def.name);
}
return sb.append("]").toString();
}
public static class Serializer
{
public void serialize(Columns columns, DataOutputPlus out) throws IOException
{
out.writeUnsignedVInt(columns.size());
for (ColumnDefinition column : columns)
ByteBufferUtil.writeWithVIntLength(column.name.bytes, out);
}
public long serializedSize(Columns columns)
{
long size = TypeSizes.sizeofUnsignedVInt(columns.size());
for (ColumnDefinition column : columns)
size += ByteBufferUtil.serializedSizeWithVIntLength(column.name.bytes);
return size;
}
public Columns deserialize(DataInputPlus in, CFMetaData metadata) throws IOException
{
int length = (int)in.readUnsignedVInt();
BTree.Builder builder = BTree.builder(Comparator.naturalOrder());
builder.auto(false);
for (int i = 0; i < length; i++)
{
ByteBuffer name = ByteBufferUtil.readWithVIntLength(in);
ColumnDefinition column = metadata.getColumnDefinition(name);
if (column == null)
{
// If we don't find the definition, it could be we have data for a dropped column, and we shouldn't
// fail deserialization because of that. So we grab a "fake" ColumnDefinition that ensure proper
// deserialization. The column will be ignore later on anyway.
column = metadata.getDroppedColumnDefinition(name);
if (column == null)
throw new RuntimeException("Unknown column " + UTF8Type.instance.getString(name) + " during deserialization");
}
builder.add(column);
}
return new Columns(builder.build());
}
/**
* If both ends have a pre-shared superset of the columns we are serializing, we can send them much
* more efficiently. Both ends must provide the identically same set of columns.
*/
public void serializeSubset(Collection columns, Columns superset, DataOutputPlus out) throws IOException
{
/**
* We weight this towards small sets, and sets where the majority of items are present, since
* we expect this to mostly be used for serializing result sets.
*
* For supersets with fewer than 64 columns, we encode a bitmap of *missing* columns,
* which equates to a zero (single byte) when all columns are present, and otherwise
* a positive integer that can typically be vint encoded efficiently.
*
* If we have 64 or more columns, we cannot neatly perform a bitmap encoding, so we just switch
* to a vint encoded set of deltas, either adding or subtracting (whichever is most efficient).
* We indicate this switch by sending our bitmap with every bit set, i.e. -1L
*/
int columnCount = columns.size();
int supersetCount = superset.size();
if (columnCount == supersetCount)
{
out.writeUnsignedVInt(0);
}
else if (supersetCount < 64)
{
out.writeUnsignedVInt(encodeBitmap(columns, superset, supersetCount));
}
else
{
serializeLargeSubset(columns, columnCount, superset, supersetCount, out);
}
}
public long serializedSubsetSize(Collection columns, Columns superset)
{
int columnCount = columns.size();
int supersetCount = superset.size();
if (columnCount == supersetCount)
{
return TypeSizes.sizeofUnsignedVInt(0);
}
else if (supersetCount < 64)
{
return TypeSizes.sizeofUnsignedVInt(encodeBitmap(columns, superset, supersetCount));
}
else
{
return serializeLargeSubsetSize(columns, columnCount, superset, supersetCount);
}
}
public Columns deserializeSubset(Columns superset, DataInputPlus in) throws IOException
{
long encoded = in.readUnsignedVInt();
if (encoded == 0L)
{
return superset;
}
else if (superset.size() >= 64)
{
return deserializeLargeSubset(in, superset, (int) encoded);
}
else
{
BTree.Builder builder = BTree.builder(Comparator.naturalOrder());
int firstComplexIdx = 0;
for (ColumnDefinition column : superset)
{
if ((encoded & 1) == 0)
{
builder.add(column);
if (column.isSimple())
++firstComplexIdx;
}
encoded >>>= 1;
}
return new Columns(builder.build(), firstComplexIdx);
}
}
// encodes a 1 bit for every *missing* column, on the assumption presence is more common,
// and because this is consistent with encoding 0 to represent all present
private static long encodeBitmap(Collection columns, Columns superset, int supersetCount)
{
long bitmap = 0L;
BTreeSearchIterator iter = superset.iterator();
// the index we would encounter next if all columns are present
int expectIndex = 0;
for (ColumnDefinition column : columns)
{
if (iter.next(column) == null)
throw new IllegalStateException(columns + " is not a subset of " + superset);
int currentIndex = iter.indexOfCurrent();
int count = currentIndex - expectIndex;
// (1L << count) - 1 gives us count bits set at the bottom of the register
// so << expectIndex moves these bits to start at expectIndex, which is where our missing portion
// begins (assuming count > 0; if not, we're adding 0 bits, so it's a no-op)
bitmap |= ((1L << count) - 1) << expectIndex;
expectIndex = currentIndex + 1;
}
int count = supersetCount - expectIndex;
bitmap |= ((1L << count) - 1) << expectIndex;
return bitmap;
}
@DontInline
private void serializeLargeSubset(Collection columns, int columnCount, Columns superset, int supersetCount, DataOutputPlus out) throws IOException
{
// write flag indicating we're in lengthy mode
out.writeUnsignedVInt(supersetCount - columnCount);
BTreeSearchIterator iter = superset.iterator();
if (columnCount < supersetCount / 2)
{
// write present columns
for (ColumnDefinition column : columns)
{
if (iter.next(column) == null)
throw new IllegalStateException();
out.writeUnsignedVInt(iter.indexOfCurrent());
}
}
else
{
// write missing columns
int prev = -1;
for (ColumnDefinition column : columns)
{
if (iter.next(column) == null)
throw new IllegalStateException();
int cur = iter.indexOfCurrent();
while (++prev != cur)
out.writeUnsignedVInt(prev);
}
while (++prev != supersetCount)
out.writeUnsignedVInt(prev);
}
}
@DontInline
private Columns deserializeLargeSubset(DataInputPlus in, Columns superset, int delta) throws IOException
{
int supersetCount = superset.size();
int columnCount = supersetCount - delta;
BTree.Builder builder = BTree.builder(Comparator.naturalOrder());
if (columnCount < supersetCount / 2)
{
for (int i = 0 ; i < columnCount ; i++)
{
int idx = (int) in.readUnsignedVInt();
builder.add(BTree.findByIndex(superset.columns, idx));
}
}
else
{
Iterator iter = superset.iterator();
int idx = 0;
int skipped = 0;
while (true)
{
int nextMissingIndex = skipped < delta ? (int)in.readUnsignedVInt() : supersetCount;
while (idx < nextMissingIndex)
{
ColumnDefinition def = iter.next();
builder.add(def);
idx++;
}
if (idx == supersetCount)
break;
iter.next();
idx++;
skipped++;
}
}
return new Columns(builder.build());
}
@DontInline
private int serializeLargeSubsetSize(Collection columns, int columnCount, Columns superset, int supersetCount)
{
// write flag indicating we're in lengthy mode
int size = TypeSizes.sizeofUnsignedVInt(supersetCount - columnCount);
BTreeSearchIterator iter = superset.iterator();
if (columnCount < supersetCount / 2)
{
// write present columns
for (ColumnDefinition column : columns)
{
if (iter.next(column) == null)
throw new IllegalStateException();
size += TypeSizes.sizeofUnsignedVInt(iter.indexOfCurrent());
}
}
else
{
// write missing columns
int prev = -1;
for (ColumnDefinition column : columns)
{
if (iter.next(column) == null)
throw new IllegalStateException();
int cur = iter.indexOfCurrent();
while (++prev != cur)
size += TypeSizes.sizeofUnsignedVInt(prev);
}
while (++prev != supersetCount)
size += TypeSizes.sizeofUnsignedVInt(prev);
}
return size;
}
}
}