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.JetType;
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, JetType> getCompleteTypeInfo();
039    
040        @NotNull
041        Nullability getNullability(@NotNull DataFlowValue key);
042    
043        /**
044         * IMPORTANT: by default, the original (native) type for this value
045         * are NOT included. So it's quite possible to get an empty set here.
046         */
047        @NotNull
048        Set<JetType> getPossibleTypes(@NotNull DataFlowValue key);
049    
050        /**
051         * Call this function to clear all data flow information about
052         * the given data flow value. Useful when we are not sure how this value can be changed, e.g. in a loop.
053         */
054        @NotNull
055        DataFlowInfo clearValueInfo(@NotNull DataFlowValue value);
056    
057        /**
058         * Call this function when b is assigned to a
059         */
060        @NotNull
061        DataFlowInfo assign(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
062    
063        /**
064         * Call this function when it's known than a == b
065         */
066        @NotNull
067        DataFlowInfo equate(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
068    
069        /**
070         * Call this function when it's known than a != b
071         */
072        @NotNull
073        DataFlowInfo disequate(@NotNull DataFlowValue a, @NotNull DataFlowValue b);
074    
075        @NotNull
076        DataFlowInfo establishSubtyping(@NotNull DataFlowValue value, @NotNull JetType type);
077    
078        /**
079         * Call this function to add data flow information from other to this and return sum as the result
080         */
081        @NotNull
082        DataFlowInfo and(@NotNull DataFlowInfo other);
083    
084        /**
085         * Call this function to choose data flow information common for this and other and return it as the result
086         */
087        @NotNull
088        DataFlowInfo or(@NotNull DataFlowInfo other);
089    }