1 files changed, 226 insertions, 0 deletions
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/LfsConfig.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/LfsConfig.java
new file mode 100644
index 0000000000..0469337b1f
--- /dev/null
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/internal/LfsConfig.java
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2022, Matthias Fromme <mfromme@dspace.de>
+ *
+ * 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.lfs.internal;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.eclipse.jgit.annotations.Nullable;
+import org.eclipse.jgit.dircache.DirCacheEntry;
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lfs.errors.LfsConfigInvalidException;
+import org.eclipse.jgit.lfs.lib.Constants;
+import org.eclipse.jgit.lib.BlobBasedConfig;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.treewalk.TreeWalk;
+
+import static org.eclipse.jgit.lib.Constants.HEAD;
+
+/**
+ * Encapsulate access to the {@code .lfsconfig}.
+ * <p>
+ * According to the git lfs documentation the order to find the
+ * {@code .lfsconfig} file is:
+ * </p>
+ * <ol>
+ * <li>in the root of the working tree</li>
+ * <li>in the index</li>
+ * <li>in the HEAD; for bare repositories this is the only place that is
+ * searched</li>
+ * </ol>
+ * <p>
+ * Values from the {@code .lfsconfig} are used only if not specified in another
+ * git config file to allow local override without modifiction of a committed
+ * file.
+ * </p>
+ *
+ * @see <a href=
+ *      "https://github.com/git-lfs/git-lfs/blob/main/docs/man/git-lfs-config.5.ronn">Configuration
+ *      options for git-lfs</a>
+ */
+public class LfsConfig {
+	private Repository db;
+	private Config delegate;
+
+	/**
+	 * Create a new instance of the LfsConfig.
+	 *
+	 * @param db
+	 *            the associated repo
+	 */
+	public LfsConfig(Repository db) {
+		this.db = db;
+	}
+
+	/**
+	 * Getter for the delegate to allow lazy initialization.
+	 *
+	 * @return the delegate {@link Config}
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	private Config getDelegate() throws IOException {
+		if (delegate == null) {
+			delegate = this.load();
+		}
+		return delegate;
+	}
+
+	/**
+	 * Read the .lfsconfig file from the repository
+	 *
+	 * An empty config is returned be empty if no lfs config exists.
+	 *
+	 * @return The loaded lfs config
+	 *
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	private Config load() throws IOException {
+		Config result = null;
+
+		if (!db.isBare()) {
+			result = loadFromWorkingTree();
+			if (result == null) {
+				result = loadFromIndex();
+			}
+		}
+
+		if (result == null) {
+			result = loadFromHead();
+		}
+
+		if (result == null) {
+			result = emptyConfig();
+		}
+
+		return result;
+	}
+
+	/**
+	 * Try to read the lfs config from a file called .lfsconfig at the top level
+	 * of the working tree.
+	 *
+	 * @return the config, or <code>null</code>
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	@Nullable
+	private Config loadFromWorkingTree()
+			throws IOException {
+		File lfsConfig = db.getFS().resolve(db.getWorkTree(),
+				Constants.DOT_LFS_CONFIG);
+		if (lfsConfig.isFile()) {
+			FileBasedConfig config = new FileBasedConfig(lfsConfig, db.getFS());
+			try {
+				config.load();
+				return config;
+			} catch (ConfigInvalidException e) {
+				throw new LfsConfigInvalidException(
+						LfsText.get().dotLfsConfigReadFailed, e);
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Try to read the lfs config from an entry called .lfsconfig contained in
+	 * the index.
+	 *
+	 * @return the config, or <code>null</code> if the entry does not exist
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	@Nullable
+	private Config loadFromIndex()
+			throws IOException {
+		try {
+			DirCacheEntry entry = db.readDirCache()
+					.getEntry(Constants.DOT_LFS_CONFIG);
+			if (entry != null) {
+				return new BlobBasedConfig(null, db, entry.getObjectId());
+			}
+		} catch (ConfigInvalidException e) {
+			throw new LfsConfigInvalidException(
+					LfsText.get().dotLfsConfigReadFailed, e);
+		}
+		return null;
+	}
+
+	/**
+	 * Try to read the lfs config from an entry called .lfsconfig contained in
+	 * the head revision.
+	 *
+	 * @return the config, or <code>null</code> if the file does not exist
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	@Nullable
+	private Config loadFromHead() throws IOException {
+		try (RevWalk revWalk = new RevWalk(db)) {
+			ObjectId headCommitId = db.resolve(HEAD);
+			if (headCommitId == null) {
+				return null;
+			}
+			RevCommit commit = revWalk.parseCommit(headCommitId);
+			RevTree tree = commit.getTree();
+			TreeWalk treewalk = TreeWalk.forPath(db, Constants.DOT_LFS_CONFIG,
+					tree);
+			if (treewalk != null) {
+				return new BlobBasedConfig(null, db, treewalk.getObjectId(0));
+			}
+		} catch (ConfigInvalidException e) {
+			throw new LfsConfigInvalidException(
+					LfsText.get().dotLfsConfigReadFailed, e);
+		}
+		return null;
+	}
+
+	/**
+	 * Create an empty config as fallback to avoid null pointer checks.
+	 *
+	 * @return an empty config
+	 */
+	private Config emptyConfig() {
+		return new Config();
+	}
+
+	/**
+	 * Get string value or null if not found.
+	 *
+	 * First tries to find the value in the git config files. If not found tries
+	 * to find data in .lfsconfig.
+	 *
+	 * @param section
+	 *            the section
+	 * @param subsection
+	 *            the subsection for the value
+	 * @param name
+	 *            the key name
+	 * @return a String value from the config, <code>null</code> if not found
+	 * @throws IOException
+	 *             if an IO error occurred
+	 */
+	@Nullable
+	public String getString(final String section, final String subsection,
+			final String name) throws IOException {
+		String result = db.getConfig().getString(section, subsection, name);
+		if (result == null) {
+			result = getDelegate().getString(section, subsection, name);
+		}
+		return result;
+	}
+}