com.google.idea.blaze.base.sync.filediff.FileDiffService.java Source code

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Here is the source code for com.google.idea.blaze.base.sync.filediff.FileDiffService.java

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/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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.google.idea.blaze.base.sync.filediff;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.idea.blaze.base.async.executor.BlazeExecutor;
import com.google.idea.blaze.base.io.FileAttributeProvider;
import com.intellij.openapi.diagnostic.Logger;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.io.File;
import java.io.Serializable;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;

/**
 * Provides a diffing service for a collection of files.
 */
public class FileDiffService {
    private static Logger LOG = Logger.getInstance(FileDiffService.class);

    public static class State implements Serializable {
        private static final long serialVersionUID = 2L;
        Map<File, FileEntry> fileEntryMap;
    }

    static class FileEntry implements Serializable {
        private static final long serialVersionUID = 2L;

        public File file;
        public long timestamp;

        @Override
        public boolean equals(Object o) {
            if (this == o)
                return true;
            if (o == null || getClass() != o.getClass())
                return false;
            FileEntry fileEntry = (FileEntry) o;
            return Objects.equal(timestamp, fileEntry.timestamp) && Objects.equal(file, fileEntry.file);
        }

        @Override
        public int hashCode() {
            return Objects.hashCode(file, timestamp);
        }
    }

    @Nullable
    public State updateFiles(@Nullable State oldState, @NotNull Iterable<File> files,
            @NotNull List<File> updatedFiles, @NotNull List<File> removedFiles) {
        Map<File, FileEntry> oldFiles = oldState != null ? oldState.fileEntryMap : ImmutableMap.of();

        List<FileEntry> fileEntryList = null;
        try {
            fileEntryList = updateTimeStamps(files);
        } catch (Exception e) {
            LOG.error(e);
            return null;
        }

        // Find changed/new
        for (FileEntry newFile : fileEntryList) {
            FileEntry oldFile = oldFiles.get(newFile.file);
            final boolean isNew = oldFile == null || newFile.timestamp != oldFile.timestamp;
            if (isNew) {
                updatedFiles.add(newFile.file);
            }
        }

        // Find removed
        Set<File> newFiles = Sets.newHashSet();
        for (File file : files) {
            newFiles.add(file);
        }
        for (File file : oldFiles.keySet()) {
            if (!newFiles.contains(file)) {
                removedFiles.add(file);
            }
        }
        ImmutableMap.Builder<File, FileEntry> fileMap = ImmutableMap.builder();
        for (FileEntry fileEntry : fileEntryList) {
            fileMap.put(fileEntry.file, fileEntry);
        }
        State newState = new State();
        newState.fileEntryMap = fileMap.build();
        return newState;
    }

    private static List<FileEntry> updateTimeStamps(@NotNull Iterable<File> fileList) throws Exception {
        final FileAttributeProvider fileAttributeProvider = FileAttributeProvider.getInstance();
        List<ListenableFuture<FileEntry>> futures = Lists.newArrayList();
        for (File file : fileList) {
            futures.add(submit(() -> {
                FileEntry fileEntry = new FileEntry();
                fileEntry.file = file;
                fileEntry.timestamp = fileAttributeProvider.getFileModifiedTime(fileEntry.file);
                return fileEntry;
            }));
        }
        return Futures.allAsList(futures).get();
    }

    private static <T> ListenableFuture<T> submit(Callable<T> callable) {
        return BlazeExecutor.getInstance().submit(callable);
    }
}