1 files changed, 261 insertions, 0 deletions
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/FileElement.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/FileElement.java
new file mode 100644
index 0000000000..5902c1e1b8
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/FileElement.java
@@ -0,0 +1,261 @@
+/*
+ * Copyright (C) 2018-2021, Andre Bossert <andre.bossert@siemens.com>
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * https://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+package org.eclipse.jgit.internal.diffmergetool;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Map;
+
+import org.eclipse.jgit.diff.DiffEntry;
+
+/**
+ * The element used as left or right file for compare.
+ *
+ */
+public class FileElement {
+
+	/**
+	 * The file element type.
+	 *
+	 */
+	public enum Type {
+		/**
+		 * The local file element (ours).
+		 */
+		LOCAL,
+		/**
+		 * The remote file element (theirs).
+		 */
+		REMOTE,
+		/**
+		 * The merged file element (path in worktree).
+		 */
+		MERGED,
+		/**
+		 * The base file element (of ours and theirs).
+		 */
+		BASE,
+		/**
+		 * The backup file element (copy of merged / conflicted).
+		 */
+		BACKUP
+	}
+
+	private final String path;
+
+	private final Type type;
+
+	private InputStream stream;
+
+	private File tempFile;
+
+	/**
+	 * Creates file element for path.
+	 *
+	 * @param path
+	 *            the file path
+	 * @param type
+	 *            the element type
+	 */
+	public FileElement(String path, Type type) {
+		this(path, type, null, null);
+	}
+
+	/**
+	 * Creates file element for path.
+	 *
+	 * @param path
+	 *            the file path
+	 * @param type
+	 *            the element type
+	 * @param tempFile
+	 *            the temporary file to be used (can be null and will be created
+	 *            then)
+	 * @param stream
+	 *            the object stream to load instead of file
+	 */
+	public FileElement(String path, Type type, File tempFile,
+			InputStream stream) {
+		this.path = path;
+		this.type = type;
+		this.tempFile = tempFile;
+		this.stream = stream;
+	}
+
+	/**
+	 * @return the file path
+	 */
+	public String getPath() {
+		return path;
+	}
+
+	/**
+	 * @return the element type
+	 */
+	public Type getType() {
+		return type;
+	}
+
+	/**
+	 * Return a temporary file within passed directory and fills it with stream
+	 * if valid.
+	 *
+	 * @param directory
+	 *            the directory where the temporary file is created
+	 * @param midName
+	 *            name added in the middle of generated temporary file name
+	 * @return the object stream
+	 * @throws IOException
+	 */
+	public File getFile(File directory, String midName) throws IOException {
+		if ((tempFile != null) && (stream == null)) {
+			return tempFile;
+		}
+		tempFile = getTempFile(path, directory, midName);
+		return copyFromStream(tempFile, stream);
+	}
+
+	/**
+	 * Return a real file from work tree or a temporary file with content if
+	 * stream is valid or if path is "/dev/null"
+	 *
+	 * @return the object stream
+	 * @throws IOException
+	 */
+	public File getFile() throws IOException {
+		if ((tempFile != null) && (stream == null)) {
+			return tempFile;
+		}
+		File file = new File(path);
+		// if we have a stream or file is missing ("/dev/null") then create
+		// temporary file
+		if ((stream != null) || isNullPath()) {
+			tempFile = getTempFile(file);
+			return copyFromStream(tempFile, stream);
+		}
+		return file;
+	}
+
+	/**
+	 * Check if path id "/dev/null"
+	 *
+	 * @return true if path is "/dev/null"
+	 */
+	public boolean isNullPath() {
+		return path.equals(DiffEntry.DEV_NULL);
+	}
+
+	/**
+	 * Create temporary file in given or system temporary directory
+	 *
+	 * @param directory
+	 *            the directory for the file (can be null); if null system
+	 *            temporary directory is used
+	 * @return temporary file in directory or in the system temporary directory
+	 * @throws IOException
+	 */
+	public File createTempFile(File directory) throws IOException {
+		if (tempFile == null) {
+			File file = new File(path);
+			if (directory != null) {
+				tempFile = getTempFile(file, directory, type.name());
+			} else {
+				tempFile = getTempFile(file);
+			}
+		}
+		return tempFile;
+	}
+
+	private static File getTempFile(File file) throws IOException {
+		return File.createTempFile(".__", "__" + file.getName()); //$NON-NLS-1$ //$NON-NLS-2$
+	}
+
+	private static File getTempFile(File file, File directory, String midName)
+			throws IOException {
+		String[] fileNameAndExtension = splitBaseFileNameAndExtension(file);
+		return File.createTempFile(
+				fileNameAndExtension[0] + "_" + midName + "_", //$NON-NLS-1$ //$NON-NLS-2$
+				fileNameAndExtension[1], directory);
+	}
+
+	private static File getTempFile(String path, File directory, String midName)
+			throws IOException {
+		return getTempFile(new File(path), directory, midName);
+	}
+
+	/**
+	 * Delete and invalidate temporary file if necessary.
+	 */
+	public void cleanTemporaries() {
+		if (tempFile != null && tempFile.exists())
+		tempFile.delete();
+		tempFile = null;
+	}
+
+	private static File copyFromStream(File file, final InputStream stream)
+			throws IOException, FileNotFoundException {
+		if (stream != null) {
+			try (OutputStream outStream = new FileOutputStream(file)) {
+				int read = 0;
+				byte[] bytes = new byte[8 * 1024];
+				while ((read = stream.read(bytes)) != -1) {
+					outStream.write(bytes, 0, read);
+				}
+			} finally {
+				// stream can only be consumed once --> close it
+				stream.close();
+			}
+		}
+		return file;
+	}
+
+	private static String[] splitBaseFileNameAndExtension(File file) {
+		String[] result = new String[2];
+		result[0] = file.getName();
+		result[1] = ""; //$NON-NLS-1$
+		int idx = result[0].lastIndexOf("."); //$NON-NLS-1$
+		// if "." was found (>-1) and last-index is not first char (>0), then
+		// split (same behavior like cgit)
+		if (idx > 0) {
+			result[1] = result[0].substring(idx, result[0].length());
+			result[0] = result[0].substring(0, idx);
+		}
+		return result;
+	}
+
+	/**
+	 * Replace variable in input
+	 *
+	 * @param input
+	 *            the input string
+	 * @return the replaced input string
+	 * @throws IOException
+	 */
+	public String replaceVariable(String input) throws IOException {
+		return input.replace("$" + type.name(), getFile().getPath()); //$NON-NLS-1$
+	}
+
+	/**
+	 * Add variable to environment map.
+	 *
+	 * @param env
+	 *            the environment where this element should be added
+	 * @throws IOException
+	 */
+	public void addToEnv(Map<String, String> env) throws IOException {
+		env.put(type.name(), getFile().getPath());
+	}
+
+}