1 files changed, 251 insertions, 0 deletions
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/ExternalToolUtils.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/ExternalToolUtils.java
new file mode 100644
index 0000000000..e5947102eb
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/diffmergetool/ExternalToolUtils.java
@@ -0,0 +1,251 @@
+/*
+ * 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.util.TreeMap;
+import java.io.File;
+import java.io.IOException;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+import org.eclipse.jgit.attributes.Attributes;
+import org.eclipse.jgit.errors.RevisionSyntaxException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.treewalk.FileTreeIterator;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.eclipse.jgit.treewalk.WorkingTreeIterator;
+import org.eclipse.jgit.treewalk.filter.NotIgnoredFilter;
+import org.eclipse.jgit.util.FS;
+
+/**
+ * Utilities for diff- and merge-tools.
+ */
+public class ExternalToolUtils {
+
+	/**
+	 * Key for merge tool git configuration section
+	 */
+	public static final String KEY_MERGE_TOOL = "mergetool"; //$NON-NLS-1$
+
+	/**
+	 * Key for diff tool git configuration section
+	 */
+	public static final String KEY_DIFF_TOOL = "difftool"; //$NON-NLS-1$
+
+	/**
+	 * Prepare command for execution.
+	 *
+	 * @param command
+	 *            the input "command" string
+	 * @param localFile
+	 *            the local file (ours)
+	 * @param remoteFile
+	 *            the remote file (theirs)
+	 * @param mergedFile
+	 *            the merged file (worktree)
+	 * @param baseFile
+	 *            the base file (can be null)
+	 * @return the prepared (with replaced variables) command string
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	public static String prepareCommand(String command, FileElement localFile,
+			FileElement remoteFile, FileElement mergedFile,
+			FileElement baseFile) throws IOException {
+		if (localFile != null) {
+			command = localFile.replaceVariable(command);
+		}
+		if (remoteFile != null) {
+			command = remoteFile.replaceVariable(command);
+		}
+		if (mergedFile != null) {
+			command = mergedFile.replaceVariable(command);
+		}
+		if (baseFile != null) {
+			command = baseFile.replaceVariable(command);
+		}
+		return command;
+	}
+
+	/**
+	 * Prepare environment needed for execution.
+	 *
+	 * @param gitDir
+	 *            the .git directory
+	 * @param localFile
+	 *            the local file (ours)
+	 * @param remoteFile
+	 *            the remote file (theirs)
+	 * @param mergedFile
+	 *            the merged file (worktree)
+	 * @param baseFile
+	 *            the base file (can be null)
+	 * @return the environment map with variables and values (file paths)
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	public static Map<String, String> prepareEnvironment(File gitDir,
+			FileElement localFile, FileElement remoteFile,
+			FileElement mergedFile, FileElement baseFile) throws IOException {
+		Map<String, String> env = new TreeMap<>();
+		if (gitDir != null) {
+			env.put(Constants.GIT_DIR_KEY, gitDir.getAbsolutePath());
+		}
+		if (localFile != null) {
+			localFile.addToEnv(env);
+		}
+		if (remoteFile != null) {
+			remoteFile.addToEnv(env);
+		}
+		if (mergedFile != null) {
+			mergedFile.addToEnv(env);
+		}
+		if (baseFile != null) {
+			baseFile.addToEnv(env);
+		}
+		return env;
+	}
+
+	/**
+	 * Quote path
+	 *
+	 * @param path
+	 *            the path to be quoted
+	 * @return quoted path if it contains spaces
+	 */
+	@SuppressWarnings("nls")
+	public static String quotePath(String path) {
+		// handling of spaces in path
+		if (path.contains(" ")) {
+			// add quotes before if needed
+			if (!path.startsWith("\"")) {
+				path = "\"" + path;
+			}
+			// add quotes after if needed
+			if (!path.endsWith("\"")) {
+				path = path + "\"";
+			}
+		}
+		return path;
+	}
+
+	/**
+	 * Whether tool is available
+	 *
+	 * @param fs
+	 *            the file system abstraction
+	 * @param gitDir
+	 *            the .git directory
+	 * @param directory
+	 *            the working directory
+	 * @param path
+	 *            the tool path
+	 * @return true if tool available and false otherwise
+	 */
+	public static boolean isToolAvailable(FS fs, File gitDir, File directory,
+			String path) {
+		boolean available = true;
+		try {
+			CommandExecutor cmdExec = new CommandExecutor(fs, false);
+			available = cmdExec.checkExecutable(path, directory,
+					prepareEnvironment(gitDir, null, null, null, null));
+		} catch (Exception e) {
+			available = false;
+		}
+		return available;
+	}
+
+	/**
+	 * Create sorted tool set
+	 *
+	 * @param defaultName
+	 *            the default tool name
+	 * @param userDefinedNames
+	 *            the user defined tool names
+	 * @param preDefinedNames
+	 *            the pre defined tool names
+	 * @return the sorted tool names set: first element is default tool name if
+	 *         valid, then user defined tool names and then pre defined tool
+	 *         names
+	 */
+	public static Set<String> createSortedToolSet(String defaultName,
+			Set<String> userDefinedNames, Set<String> preDefinedNames) {
+		Set<String> names = new LinkedHashSet<>();
+		if (defaultName != null) {
+			// remove defaultName from both sets
+			Set<String> namesPredef = new LinkedHashSet<>();
+			Set<String> namesUser = new LinkedHashSet<>();
+			namesUser.addAll(userDefinedNames);
+			namesUser.remove(defaultName);
+			namesPredef.addAll(preDefinedNames);
+			namesPredef.remove(defaultName);
+			// add defaultName as first in set
+			names.add(defaultName);
+			names.addAll(namesUser);
+			names.addAll(namesPredef);
+		} else {
+			names.addAll(userDefinedNames);
+			names.addAll(preDefinedNames);
+		}
+		return names;
+	}
+
+	/**
+	 * Provides {@link Optional} with the name of an external tool if specified
+	 * in git configuration for a path.
+	 *
+	 * The formed git configuration results from global rules as well as merged
+	 * rules from info and worktree attributes.
+	 *
+	 * Triggers {@link TreeWalk} until specified path found in the tree.
+	 *
+	 * @param repository
+	 *            target repository to traverse into
+	 * @param path
+	 *            path to the node in repository to parse git attributes for
+	 * @param toolKey
+	 *            config key name for the tool
+	 * @return attribute value for the given tool key if set
+	 * @throws ToolException
+	 *             if the tool failed
+	 */
+	public static Optional<String> getExternalToolFromAttributes(
+			final Repository repository, final String path,
+			final String toolKey) throws ToolException {
+		try {
+			WorkingTreeIterator treeIterator = new FileTreeIterator(repository);
+			try (TreeWalk walk = new TreeWalk(repository)) {
+				walk.addTree(treeIterator);
+				walk.setFilter(new NotIgnoredFilter(0));
+				while (walk.next()) {
+					String treePath = walk.getPathString();
+					if (treePath.equals(path)) {
+						Attributes attrs = walk.getAttributes();
+						if (attrs.containsKey(toolKey)) {
+							return Optional.of(attrs.getValue(toolKey));
+						}
+					}
+					if (walk.isSubtree()) {
+						walk.enterSubtree();
+					}
+				}
+				// no external tool specified
+				return Optional.empty();
+			}
+
+		} catch (RevisionSyntaxException | IOException e) {
+			throw new ToolException(e);
+		}
+	}
+
+}