001    /*
002     * Copyright 2010-2015 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.kotlin.resolve.calls.smartcasts;
018    
019    import com.google.common.collect.ImmutableMap;
020    import com.google.common.collect.SetMultimap;
021    import org.jetbrains.annotations.NotNull;
022    import org.jetbrains.kotlin.types.KotlinType;
023    
024    import java.util.Map;
025    import java.util.Set;
026    
027    /**
028     * This interface is intended to provide and edit information about value nullabilities and possible types.
029     * Data flow info is immutable so functions never change it.
030     */
031    public interface DataFlowInfo {
032        DataFlowInfo EMPTY = new DelegatingDataFlowInfo(null, ImmutableMap.<DataFlowValue, Nullability>of(), DelegatingDataFlowInfo.newTypeInfo());
033    
034        @NotNull
035        Map<DataFlowValue, Nullability> getCompleteNullabilityInfo();
036    
037        @NotNull
038        SetMultimap<DataFlowValue, KotlinType> getCompleteTypeInfo();
039    
040        /**
041         * Returns collected nullability for the given value, NOT taking its predictability into account.
042         */
043        @NotNull
044        Nullability getNullability(@NotNull DataFlowValue key);
045    
046        /**
047         * Returns collected nullability for the given value if it's predictable.
048         * Otherwise basic value nullability is returned
049         */
050        @NotNull
051        Nullability getPredictableNullability(@NotNull DataFlowValue key);
052    
053        /**
054         * IMPORTANT: by default, the original (native) type for this value
055         * are NOT included. So it's quite possible to get an empty set here.
056         */
057        @NotNull
058        Set<KotlinType> getPossibleTypes(@NotNull DataFlowValue key);
059    
060        /**
061         * Call this function to clear all data flow information about
062         * the given data flow value. Useful when we are not sure how this value can be changed, e.g. in a loop.
063         */
064        @NotNull
065        DataFlowInfo clearValueInfo(@NotNull DataFlowValue value);
066    
067        /**
068         * Call this function when b is assigned to a
069         */
070        @NotNull
071        DataFlowInfo assign(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
072    
073        /**
074         * Call this function when it's known than a == b
075         */
076        @NotNull
077        DataFlowInfo equate(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
078    
079        /**
080         * Call this function when it's known than a != b
081         */
082        @NotNull
083        DataFlowInfo disequate(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
084    
085        @NotNull
086        DataFlowInfo establishSubtyping(@NotNull DataFlowValue value, @NotNull KotlinType type);
087    
088        /**
089         * Call this function to add data flow information from other to this and return sum as the result
090         */
091        @NotNull
092        DataFlowInfo and(@NotNull DataFlowInfo other);
093    
094        /**
095         * Call this function to choose data flow information common for this and other and return it as the result
096         */
097        @NotNull
098        DataFlowInfo or(@NotNull DataFlowInfo other);
099    }