Add distinct type definition

presto-common/src/main/java/com/facebook/presto/common/type/DistinctType.java

@@ -0,0 +1,382 @@
+/*
+ * Licensed 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 com.facebook.presto.common.type;
+
+import com.facebook.presto.common.QualifiedObjectName;
+import com.facebook.presto.common.block.Block;
+import com.facebook.presto.common.block.BlockBuilder;
+import com.facebook.presto.common.block.BlockBuilderStatus;
+import com.facebook.presto.common.block.UncheckedBlock;
+import com.facebook.presto.common.function.SqlFunctionProperties;
+import io.airlift.slice.Slice;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Queue;
+import java.util.function.Function;
+
+import static java.lang.String.format;
+import static java.util.Objects.requireNonNull;
+
+public class DistinctType
+        implements Type
+{
+    private final QualifiedObjectName name;
+    private final Type baseType;
+    // Distinct type definition specifies whether it is orderable or not, even if baseType is orderable.
+    private final boolean isOrderable;
+
+    private final Optional<QualifiedObjectName> parentTypeName;
+    private Optional<DistinctType> lazilyLoadedParentType;
+    private Function<QualifiedObjectName, DistinctType> distinctTypeLoader;
+
+    public DistinctType(DistinctTypeInfo distinctTypeInfo, Type baseType, Function<QualifiedObjectName, DistinctType> distinctTypeLoader)
+    {
+        this(
+                distinctTypeInfo.getName(),
+                baseType,
+                distinctTypeInfo.isOrderable(),
+                distinctTypeInfo.getTopMostAncestor(),
+                new ArrayDeque<>(distinctTypeInfo.getOtherAncestors()),
+                distinctTypeLoader);
+    }
+
+    private DistinctType(QualifiedObjectName name, Type baseType, boolean isOrderable, Optional<QualifiedObjectName> topMostAncestor, Queue<QualifiedObjectName> otherAncestors, Function<QualifiedObjectName, DistinctType> distinctTypeLoader)
+    {
+        this.name = requireNonNull(name, "name is null");
+        this.baseType = requireNonNull(baseType, "baseType is null");
+        this.isOrderable = isOrderable;
+        boolean rootTypeReached = otherAncestors.isEmpty();
+        this.parentTypeName = rootTypeReached ? topMostAncestor : Optional.of(otherAncestors.poll());
+        this.lazilyLoadedParentType = rootTypeReached ? Optional.empty() : Optional.of(new DistinctType(this.parentTypeName.get(), baseType, isOrderable, topMostAncestor, otherAncestors, distinctTypeLoader));
+        this.distinctTypeLoader = requireNonNull(distinctTypeLoader, "distinctTypeLoader is null");
+    }
+
+    public QualifiedObjectName getName()
+    {
+        return name;
+    }
+
+    public Type getBaseType()
+    {
+        return baseType;
+    }
+
+    public Optional<DistinctType> getParentTypeLoadIfNeeded()
+    {
+        assureLoaded();
+        return lazilyLoadedParentType;
+    }
+
+    public Optional<QualifiedObjectName> getParentTypeName()
+    {
+        return parentTypeName;
+    }
+
+    public static boolean hasAncestorRelationship(DistinctType firstType, DistinctType secondType)
+    {
+        Optional<DistinctType> lowestCommonSuperType = getLowestCommonSuperType(firstType, secondType);
+        return lowestCommonSuperType.isPresent() && (lowestCommonSuperType.get().equals(firstType) || lowestCommonSuperType.get().equals(secondType));
+    }
+
+    // Computes the lowest common ancestor of 2 distinct types in the type tree.
+    // Visits as few types as possible, in order to avoid network calls to fetch the types.
+    public static Optional<DistinctType> getLowestCommonSuperType(DistinctType firstType, DistinctType secondType)
+    {
+        if (firstType.getBaseType() != secondType.getBaseType()) {
+            return Optional.empty();
+        }
+
+        Map<QualifiedObjectName, DistinctType> seenTypes = new HashMap<>();
+        Optional<DistinctType> firstAncestor = Optional.of(firstType);
+        Optional<DistinctType> secondAncestor = Optional.of(secondType);
+
+        // We first check already loaded ancestors of both types, to check if lowest common super type exists in them.
+        // This way, we can avoid loading of parents which are not needed.
+        seenTypes.put(firstAncestor.get().getName(), firstAncestor.get());
+        while (firstAncestor.get().lazilyLoadedParentType.isPresent()) {
+            firstAncestor = firstAncestor.get().lazilyLoadedParentType;
+            seenTypes.put(firstAncestor.get().getName(), firstAncestor.get());
+        }
+
+        if (seenTypes.containsKey(secondAncestor.get().getName())) {
+            return secondAncestor;
+        }
+        seenTypes.put(secondAncestor.get().getName(), secondAncestor.get());
+
+        while (secondAncestor.get().lazilyLoadedParentType.isPresent()) {
+            secondAncestor = secondAncestor.get().lazilyLoadedParentType;
+            if (seenTypes.containsKey(secondAncestor.get().getName())) {
+                return secondAncestor;
+            }
+            seenTypes.put(secondAncestor.get().getName(), secondAncestor.get());
+        }
+
+        // If we don't get any common ancestor among already loaded ancestors, we can load more ancestors.
+        while (firstAncestor.get().getParentTypeName().isPresent() || secondAncestor.get().getParentTypeName().isPresent()) {
+            if (firstAncestor.get().getParentTypeName().isPresent()) {
+                if (seenTypes.containsKey(firstAncestor.get().getParentTypeName().get())) {
+                    return Optional.of(seenTypes.get(firstAncestor.get().getParentTypeName().get()));
+                }
+                firstAncestor = firstAncestor.get().getParentTypeLoadIfNeeded();
+                checkState(firstAncestor.isPresent(), "firstAncestor is empty");
+                seenTypes.put(firstAncestor.get().getName(), firstAncestor.get());
+            }
+
+            if (secondAncestor.get().getParentTypeName().isPresent()) {
+                if (seenTypes.containsKey(secondAncestor.get().getParentTypeName().get())) {
+                    return Optional.of(seenTypes.get(secondAncestor.get().getParentTypeName().get()));
+                }
+                secondAncestor = secondAncestor.get().getParentTypeLoadIfNeeded();
+                checkState(secondAncestor.isPresent(), "secondAncestor is empty");
+                seenTypes.put(secondAncestor.get().getName(), secondAncestor.get());
+            }
+        }
+        return Optional.empty();
+    }
+
+    @Override
+    public boolean equals(Object obj)
+    {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+
+        DistinctType other = (DistinctType) obj;
+
+        return Objects.equals(this.name, other.name);
+    }
+
+    @Override
+    public int hashCode()
+    {
+        return Objects.hash(name);
+    }
+
+    @Override
+    public TypeSignature getTypeSignature()
+    {
+        List<QualifiedObjectName> ancestors = new ArrayList<>();
+        Optional<QualifiedObjectName> lastAncestor;
+        DistinctType type = this;
+        while (true) {
+            Optional<QualifiedObjectName> parentTypeName = type.getParentTypeName();
+            // We only populate type signature with already loaded parent types, this helps avoid
+            // loading information about all ancestors.
+            if (!type.lazilyLoadedParentType.isPresent()) {
+                lastAncestor = parentTypeName;
+                break;
+            }
+            else {
+                type = type.lazilyLoadedParentType.get();
+                checkState(parentTypeName.isPresent(), "parentTypeName is empty");
+                ancestors.add(parentTypeName.get());
+            }
+        }
+        return new TypeSignature(new DistinctTypeInfo(name, baseType.getTypeSignature(), lastAncestor, ancestors, isOrderable));
+    }
+
+    @Override
+    public String getDisplayName()
+    {
+        return format("%s(%s)", name.toString(), baseType.getDisplayName());
+    }
+
+    @Override
+    public boolean isComparable()
+    {
+        return baseType.isComparable();
+    }
+
+    @Override
+    public boolean isOrderable()
+    {
+        return isOrderable;
+    }
+
+    @Override
+    public Class<?> getJavaType()
+    {
+        return baseType.getJavaType();
+    }
+
+    @Override
+    public List<Type> getTypeParameters()
+    {
+        return baseType.getTypeParameters();
+    }
+
+    @Override
+    public BlockBuilder createBlockBuilder(BlockBuilderStatus blockBuilderStatus, int expectedEntries, int expectedBytesPerEntry)
+    {
+        return baseType.createBlockBuilder(blockBuilderStatus, expectedEntries, expectedBytesPerEntry);
+    }
+
+    @Override
+    public BlockBuilder createBlockBuilder(BlockBuilderStatus blockBuilderStatus, int expectedEntries)
+    {
+        return baseType.createBlockBuilder(blockBuilderStatus, expectedEntries);
+    }
+
+    @Override
+    public Object getObjectValue(SqlFunctionProperties properties, Block block, int position)
+    {
+        return baseType.getObjectValue(properties, block, position);
+    }
+
+    @Override
+    public boolean getBoolean(Block block, int position)
+    {
+        return baseType.getBoolean(block, position);
+    }
+
+    @Override
+    public boolean getBooleanUnchecked(UncheckedBlock block, int internalPosition)
+    {
+        return baseType.getBooleanUnchecked(block, internalPosition);
+    }
+
+    @Override
+    public long getLong(Block block, int position)
+    {
+        return baseType.getLong(block, position);
+    }
+
+    @Override
+    public long getLongUnchecked(UncheckedBlock block, int internalPosition)
+    {
+        return baseType.getLongUnchecked(block, internalPosition);
+    }
+
+    @Override
+    public double getDouble(Block block, int position)
+    {
+        return baseType.getDouble(block, position);
+    }
+
+    @Override
+    public double getDoubleUnchecked(UncheckedBlock block, int internalPosition)
+    {
+        return baseType.getDoubleUnchecked(block, internalPosition);
+    }
+
+    @Override
+    public Slice getSlice(Block block, int position)
+    {
+        return baseType.getSlice(block, position);
+    }
+
+    @Override
+    public Slice getSliceUnchecked(Block block, int internalPosition)
+    {
+        return baseType.getSliceUnchecked(block, internalPosition);
+    }
+
+    @Override
+    public Object getObject(Block block, int position)
+    {
+        return baseType.getObject(block, position);
+    }
+
+    @Override
+    public Block getBlockUnchecked(Block block, int internalPosition)
+    {
+        return baseType.getBlockUnchecked(block, internalPosition);
+    }
+
+    @Override
+    public void writeBoolean(BlockBuilder blockBuilder, boolean value)
+    {
+        baseType.writeBoolean(blockBuilder, value);
+    }
+
+    @Override
+    public void writeLong(BlockBuilder blockBuilder, long value)
+    {
+        baseType.writeLong(blockBuilder, value);
+    }
+
+    @Override
+    public void writeDouble(BlockBuilder blockBuilder, double value)
+    {
+        baseType.writeDouble(blockBuilder, value);
+    }
+
+    @Override
+    public void writeSlice(BlockBuilder blockBuilder, Slice value)
+    {
+        baseType.writeSlice(blockBuilder, value);
+    }
+
+    @Override
+    public void writeSlice(BlockBuilder blockBuilder, Slice value, int offset, int length)
+    {
+        baseType.writeSlice(blockBuilder, value, offset, length);
+    }
+
+    @Override
+    public void writeObject(BlockBuilder blockBuilder, Object value)
+    {
+        baseType.writeObject(blockBuilder, value);
+    }
+
+    @Override
+    public void appendTo(Block block, int position, BlockBuilder blockBuilder)
+    {
+        baseType.appendTo(block, position, blockBuilder);
+    }
+
+    @Override
+    public boolean equalTo(Block leftBlock, int leftPosition, Block rightBlock, int rightPosition)
+    {
+        return baseType.equalTo(leftBlock, leftPosition, rightBlock, rightPosition);
+    }
+
+    @Override
+    public long hash(Block block, int position)
+    {
+        return baseType.hash(block, position);
+    }
+
+    @Override
+    public int compareTo(Block leftBlock, int leftPosition, Block rightBlock, int rightPosition)
+    {
+        return baseType.compareTo(leftBlock, leftPosition, rightBlock, rightPosition);
+    }
+
+    private void assureLoaded()
+    {
+        // If type has no parent, or the parent type is already loaded, we don't need to do anything.
+        if (!parentTypeName.isPresent() || lazilyLoadedParentType.isPresent()) {
+            return;
+        }
+        lazilyLoadedParentType = Optional.of(distinctTypeLoader.apply(parentTypeName.get()));
+        distinctTypeLoader = null;
+    }
+
+    private static void checkState(boolean condition, String message)
+    {
+        if (!condition) {
+            throw new IllegalStateException(message);
+        }
+    }
+}