com.facebook.buck.features.project.intellij.StringTemplateFile.java Source code

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Here is the source code for com.facebook.buck.features.project.intellij.StringTemplateFile.java

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/*
 * Copyright 2015-present Facebook, Inc.
 *
 * 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.buck.features.project.intellij;

import com.facebook.buck.io.filesystem.ProjectFilesystem;
import com.facebook.buck.util.sha1.Sha1HashCode;
import com.google.common.hash.Hashing;
import com.google.common.io.Resources;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import org.stringtemplate.v4.ST;

enum StringTemplateFile {
    ANDROID_MANIFEST("AndroidManifest.st"), MODULE_TEMPLATE("ij-module.st"), MODULE_INDEX_TEMPLATE(
            "ij-module-index.st"), MISC_TEMPLATE("ij-misc.st"), LIBRARY_TEMPLATE(
                    "ij-library.st"), GENERATED_BY_IDEA_CLASS("GeneratedByIdeaClass.st");

    private static final char DELIMITER = '%';

    private final String fileName;

    StringTemplateFile(String fileName) {
        this.fileName = fileName;
    }

    public String getFileName() {
        return fileName;
    }

    /**
     * Not thread safe, see discussion in: https://github.com/antlr/stringtemplate4/issues/61 could be
     * made faster by sharing STGroup across threads using a supplier, see {@link
     * com.facebook.buck.parser.function.BuckPyFunction}. May be fixed in ST4.1
     */
    public synchronized ST getST() throws IOException {
        URL templateUrl = Resources.getResource(StringTemplateFile.class, "templates/" + fileName);
        String template = Resources.toString(templateUrl, StandardCharsets.UTF_8);
        return new ST(template, DELIMITER, DELIMITER);
    }

    public static boolean writeToFile(ProjectFilesystem projectFilesystem, ST contents, Path path,
            Path ideaConfigDir) throws IOException {

        byte[] renderedContentsBytes = contents.render().getBytes();
        projectFilesystem.createParentDirs(path);
        if (projectFilesystem.exists(path)) {
            Sha1HashCode fileSha1 = projectFilesystem.computeSha1(path);
            Sha1HashCode contentsSha1 = Sha1HashCode.fromHashCode(Hashing.sha1().hashBytes(renderedContentsBytes));
            if (fileSha1.equals(contentsSha1)) {
                return false;
            }

            boolean danglingTempFile = false;
            Path tempFile = projectFilesystem.createTempFile(ideaConfigDir, path.getFileName().toString(), ".tmp");
            try {
                danglingTempFile = true;
                try (OutputStream outputStream = projectFilesystem.newFileOutputStream(tempFile)) {
                    outputStream.write(renderedContentsBytes);
                }
                projectFilesystem.move(tempFile, path, StandardCopyOption.REPLACE_EXISTING);
                danglingTempFile = false;
            } finally {
                if (danglingTempFile) {
                    projectFilesystem.deleteFileAtPath(tempFile);
                }
            }
        } else {
            try (OutputStream outputStream = projectFilesystem.newFileOutputStream(path)) {
                outputStream.write(renderedContentsBytes);
            }
        }
        return true;
    }
}