001    /*
002     * Copyright 2010-2013 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.jet.lang.resolve.kotlin;
018    
019    import com.intellij.openapi.vfs.VirtualFile;
020    import com.intellij.util.containers.SLRUCache;
021    import org.jetbrains.annotations.NotNull;
022    import org.jetbrains.annotations.Nullable;
023    import org.jetbrains.jet.lang.resolve.name.FqName;
024    import org.jetbrains.jet.storage.LockBasedStorageManager;
025    
026    public abstract class VirtualFileKotlinClassFinder implements VirtualFileFinder {
027    
028        // This cache must be small: we only query the same file a few times in a row (from different places)
029        private final SLRUCache<VirtualFile, KotlinJvmBinaryClass> cache = new SLRUCache<VirtualFile, KotlinJvmBinaryClass>(2, 2) {
030            @NotNull
031            @Override
032            public KotlinJvmBinaryClass createValue(VirtualFile virtualFile) {
033                // Operations under this lock are not supposed to involve other locks
034                return new VirtualFileKotlinClass(new LockBasedStorageManager(), virtualFile);
035            }
036        };
037    
038        @Nullable
039        @Override
040        public KotlinJvmBinaryClass findKotlinClass(@NotNull FqName fqName) {
041            VirtualFile file = findVirtualFileWithHeader(fqName);
042            return file == null ? null : createKotlinClass(file);
043        }
044    
045        @Override
046        @NotNull
047        public KotlinJvmBinaryClass createKotlinClass(@NotNull VirtualFile file) {
048            synchronized (cache) {
049                return cache.get(file);
050            }
051        }
052    }