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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cql3.selection;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import com.google.common.base.Objects;
import com.google.common.collect.Iterables;
import org.apache.commons.lang3.text.StrBuilder;
import org.apache.cassandra.cql3.functions.Arguments;
import org.apache.cassandra.cql3.functions.FunctionResolver;
import org.apache.cassandra.schema.ColumnMetadata;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.transport.ProtocolVersion;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.cql3.ColumnSpecification;
import org.apache.cassandra.cql3.QueryOptions;
import org.apache.cassandra.cql3.functions.Function;
import org.apache.cassandra.cql3.functions.FunctionName;
import org.apache.cassandra.cql3.functions.PartialScalarFunction;
import org.apache.cassandra.cql3.functions.ScalarFunction;
import org.apache.cassandra.cql3.statements.RequestValidations;
import org.apache.cassandra.db.TypeSizes;
import org.apache.cassandra.db.filter.ColumnFilter;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import static java.util.stream.Collectors.joining;
abstract class AbstractFunctionSelector extends Selector
{
protected static abstract class AbstractFunctionSelectorDeserializer extends SelectorDeserializer
{
protected Selector deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
{
// The selector will only be deserialized on the replicas for GROUP BY queries. Due to that we
// can safely use the current protocol version.
final ProtocolVersion protocolVersion = ProtocolVersion.CURRENT;
FunctionName name = new FunctionName(in.readUTF(), in.readUTF());
int numberOfArguments = in.readUnsignedVInt32();
List> argTypes = new ArrayList<>(numberOfArguments);
for (int i = 0; i < numberOfArguments; i++)
{
argTypes.add(readType(metadata, in));
}
Function function = FunctionResolver.get(metadata.keyspace, name, argTypes, metadata.keyspace, metadata.name, null);
if (function == null)
throw new IOException(String.format("Unknown serialized function %s(%s)",
name,
argTypes.stream()
.map(p -> p.asCQL3Type().toString())
.collect(joining(", "))));
boolean isPartial = in.readBoolean();
// if the function is partial we need to retrieve the resolved arguments.
// The resolved arguments are encoded as follow: [vint]([vint][bytes])*
// The first vint contains the bitset used to determine which arguments were resolved.
// A bit equals to one meaning a resolved argument.
// The arguments are encoded as [vint][bytes] where the vint contains the size in bytes of the
// argument.
if (isPartial)
{
// We use a bitset to track the position of the unresolved arguments
int bitset = in.readUnsignedVInt32();
List partialArguments = new ArrayList<>(numberOfArguments);
for (int i = 0; i < numberOfArguments; i++)
{
boolean isArgumentResolved = getRightMostBit(bitset) == 1;
ByteBuffer argument = isArgumentResolved ? ByteBufferUtil.readWithVIntLength(in)
: Function.UNRESOLVED;
partialArguments.add(argument);
bitset >>= 1;
}
function = ((ScalarFunction) function).partialApplication(protocolVersion, partialArguments);
}
int numberOfRemainingArguments = in.readUnsignedVInt32();
List argSelectors = new ArrayList<>(numberOfRemainingArguments);
for (int i = 0; i < numberOfRemainingArguments; i++)
{
argSelectors.add(Selector.serializer.deserialize(in, version, metadata));
}
return newFunctionSelector(protocolVersion, function, argSelectors);
}
/**
* Returns the value of the right most bit.
* @param bitset the bitset
* @return the value of the right most bit
*/
private int getRightMostBit(int bitset)
{
return bitset & 1;
}
protected abstract Selector newFunctionSelector(ProtocolVersion version,
Function function,
List argSelectors);
}
protected final T fun;
/**
* The list used to pass the function arguments is recycled to avoid the cost of instantiating a new list
* with each function call.
*/
private final Arguments args;
protected final List argSelectors;
public static Factory newFactory(final Function fun, final SelectorFactories factories) throws InvalidRequestException
{
if (fun.isAggregate())
{
if (factories.doesAggregation())
throw new InvalidRequestException("aggregate functions cannot be used as arguments of aggregate functions");
}
return new Factory()
{
protected String getColumnName()
{
return fun.columnName(factories.getColumnNames());
}
protected AbstractType getReturnType()
{
return fun.returnType();
}
protected void addColumnMapping(SelectionColumnMapping mapping, ColumnSpecification resultsColumn)
{
SelectionColumnMapping tmpMapping = SelectionColumnMapping.newMapping();
for (Factory factory : factories)
factory.addColumnMapping(tmpMapping, resultsColumn);
if (tmpMapping.getMappings().get(resultsColumn).isEmpty())
// add a null mapping for cases where there are no
// further selectors, such as no-arg functions and count
mapping.addMapping(resultsColumn, (ColumnMetadata)null);
else
// collate the mapped columns from the child factories & add those
mapping.addMapping(resultsColumn, tmpMapping.getMappings().values());
}
public void addFunctionsTo(List functions)
{
fun.addFunctionsTo(functions);
factories.addFunctionsTo(functions);
}
public Selector newInstance(QueryOptions options) throws InvalidRequestException
{
return fun.isAggregate() ? new AggregateFunctionSelector(options.getProtocolVersion(), fun, factories.newInstances(options))
: createScalarSelector(options, (ScalarFunction) fun, factories.newInstances(options));
}
private Selector createScalarSelector(QueryOptions options, ScalarFunction function, List argSelectors)
{
ProtocolVersion version = options.getProtocolVersion();
int terminalCount = 0;
List terminalArgs = new ArrayList<>(argSelectors.size());
for (Selector selector : argSelectors)
{
if (selector.isTerminal())
{
++terminalCount;
ByteBuffer output = selector.getOutput(version);
RequestValidations.checkBindValueSet(output, "Invalid unset value for argument in call to function %s", fun.name().name);
terminalArgs.add(output);
}
else
{
terminalArgs.add(Function.UNRESOLVED);
}
}
if (terminalCount == 0)
return new ScalarFunctionSelector(version, fun, argSelectors);
// We have some terminal arguments, do a partial application
ScalarFunction partialFunction = function.partialApplication(version, terminalArgs);
// If all the arguments are terminal and the function is pure we can reduce to a simple value.
if (terminalCount == argSelectors.size() && fun.isPure())
{
Arguments arguments = partialFunction.newArguments(version);
return new TermSelector(partialFunction.execute(arguments), partialFunction.returnType());
}
List remainingSelectors = new ArrayList<>(argSelectors.size() - terminalCount);
for (Selector selector : argSelectors)
{
if (!selector.isTerminal())
remainingSelectors.add(selector);
}
return new ScalarFunctionSelector(version, partialFunction, remainingSelectors);
}
public boolean isWritetimeSelectorFactory()
{
return factories.containsWritetimeSelectorFactory();
}
public boolean isTTLSelectorFactory()
{
return factories.containsTTLSelectorFactory();
}
public boolean isAggregateSelectorFactory()
{
return fun.isAggregate() || factories.doesAggregation();
}
@Override
public boolean areAllFetchedColumnsKnown()
{
return Iterables.all(factories, f -> f.areAllFetchedColumnsKnown());
}
@Override
public void addFetchedColumns(ColumnFilter.Builder builder)
{
for (Selector.Factory factory : factories)
factory.addFetchedColumns(builder);
}
};
}
protected AbstractFunctionSelector(Kind kind, ProtocolVersion version, T fun, List argSelectors)
{
super(kind);
this.fun = fun;
this.argSelectors = argSelectors;
this.args = fun.newArguments(version);
}
@Override
public void addFetchedColumns(ColumnFilter.Builder builder)
{
for (Selector selector : argSelectors)
selector.addFetchedColumns(builder);
}
// Sets a given arg value. We should use that instead of directly setting the args list for the
// sake of validation.
protected void setArg(int i, ByteBuffer value) throws InvalidRequestException
{
RequestValidations.checkBindValueSet(value, "Invalid unset value for argument in call to function %s", fun.name().name);
args.set(i, value);
}
protected Arguments args()
{
return args;
}
public AbstractType getType()
{
return fun.returnType();
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (!(o instanceof AbstractFunctionSelector))
return false;
AbstractFunctionSelector s = (AbstractFunctionSelector) o;
return Objects.equal(fun.name(), s.fun.name())
&& Objects.equal(fun.argTypes(), s.fun.argTypes())
&& Objects.equal(argSelectors, s.argSelectors);
}
@Override
public int hashCode()
{
return Objects.hashCode(fun.name(), fun.argTypes(), argSelectors);
}
@Override
public String toString()
{
return new StrBuilder().append(fun.name())
.append("(")
.appendWithSeparators(argSelectors, ", ")
.append(")")
.toString();
}
@Override
protected int serializedSize(int version)
{
boolean isPartial = fun instanceof PartialScalarFunction;
Function function = isPartial ? ((PartialScalarFunction) fun).getFunction() : fun;
FunctionName name = function.name();
int size = TypeSizes.sizeof(name.keyspace) + TypeSizes.sizeof(name.name);
List> argTypes = function.argTypes();
size += TypeSizes.sizeofUnsignedVInt(argTypes.size());
for (int i = 0, m = argTypes.size(); i < m; i++)
{
size += sizeOf(argTypes.get(i));
}
size += TypeSizes.sizeof(isPartial);
if (isPartial)
{
List partialArguments = ((PartialScalarFunction) fun).getPartialArguments();
// We use a bitset to track the position of the unresolved arguments
size += TypeSizes.sizeofUnsignedVInt(computeBitSet(partialArguments));
for (int i = 0, m = partialArguments.size(); i < m; i++)
{
ByteBuffer buffer = partialArguments.get(i);
if (buffer != Function.UNRESOLVED)
size += ByteBufferUtil.serializedSizeWithVIntLength(buffer);
}
}
int numberOfRemainingArguments = argSelectors.size();
size += TypeSizes.sizeofUnsignedVInt(numberOfRemainingArguments);
for (int i = 0; i < numberOfRemainingArguments; i++)
size += serializer.serializedSize(argSelectors.get(i), version);
return size;
}
@Override
protected void serialize(DataOutputPlus out, int version) throws IOException
{
boolean isPartial = fun instanceof PartialScalarFunction;
Function function = isPartial ? ((PartialScalarFunction) fun).getFunction() : fun;
FunctionName name = function.name();
out.writeUTF(name.keyspace);
out.writeUTF(name.name);
List> argTypes = function.argTypes();
int numberOfArguments = argTypes.size();
out.writeUnsignedVInt32(numberOfArguments);
for (int i = 0; i < numberOfArguments; i++)
writeType(out, argTypes.get(i));
out.writeBoolean(isPartial);
if (isPartial)
{
List partialArguments = ((PartialScalarFunction) fun).getPartialArguments();
// We use a bitset to track the position of the unresolved arguments
out.writeUnsignedVInt32(computeBitSet(partialArguments));
for (int i = 0, m = partialArguments.size(); i < m; i++)
{
ByteBuffer buffer = partialArguments.get(i);
if (buffer != Function.UNRESOLVED)
ByteBufferUtil.writeWithVIntLength(buffer, out);
}
}
int numberOfRemainingArguments = argSelectors.size();
out.writeUnsignedVInt32(numberOfRemainingArguments);
for (int i = 0; i < numberOfRemainingArguments; i++)
serializer.serialize(argSelectors.get(i), out, version);
}
private int computeBitSet(List partialArguments)
{
assert partialArguments.size() <= 32 : "cannot serialize partial function with more than 32 arguments";
int bitset = 0;
for (int i = 0, m = partialArguments.size(); i < m; i++)
{
if (partialArguments.get(i) != Function.UNRESOLVED)
bitset |= 1 << i;
}
return bitset;
}
}