1 files changed, 120 insertions, 0 deletions
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/UrlConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UrlConfig.java
new file mode 100644
index 0000000000..574fcf806d
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UrlConfig.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2022 Thomas Wolf <thomas.wolf@paranor.ch> and others
+ *
+ * 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.transport;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * Support for URL translations via git configs {@code url.<base>.insteadOf} and
+ * {@code url.<base>.pushInsteadOf}.
+ *
+ * @since 6.2
+ */
+public class UrlConfig {
+
+	private static final String KEY_INSTEADOF = "insteadof"; //$NON-NLS-1$
+
+	private static final String KEY_PUSHINSTEADOF = "pushinsteadof"; //$NON-NLS-1$
+
+	private static final String SECTION_URL = "url"; //$NON-NLS-1$
+
+	private final Config config;
+
+	private Map<String, String> insteadOf;
+
+	private Map<String, String> pushInsteadOf;
+
+	/**
+	 * Creates a new {@link UrlConfig} instance.
+	 *
+	 * @param config
+	 *            {@link Config} to read values from
+	 */
+	public UrlConfig(Config config) {
+		this.config = config;
+	}
+
+	/**
+	 * Performs replacements as defined by git config
+	 * {@code url.<base>.insteadOf}. If there is no match, the input is returned
+	 * unchanged.
+	 *
+	 * @param url
+	 *            to substitute
+	 * @return the {@code url} with substitution applied
+	 */
+	public String replace(String url) {
+		if (insteadOf == null) {
+			insteadOf = load(KEY_INSTEADOF);
+		}
+		return replace(url, insteadOf);
+	}
+
+	/**
+	 * Tells whether there are push replacements.
+	 *
+	 * @return {@code true} if there are push replacements, {@code false}
+	 *         otherwise
+	 */
+	public boolean hasPushReplacements() {
+		if (pushInsteadOf == null) {
+			pushInsteadOf = load(KEY_PUSHINSTEADOF);
+		}
+		return !pushInsteadOf.isEmpty();
+	}
+
+	/**
+	 * Performs replacements as defined by git config
+	 * {@code url.<base>.pushInsteadOf}. If there is no match, the input is
+	 * returned unchanged.
+	 *
+	 * @param url
+	 *            to substitute
+	 * @return the {@code url} with substitution applied
+	 */
+	public String replacePush(String url) {
+		if (pushInsteadOf == null) {
+			pushInsteadOf = load(KEY_PUSHINSTEADOF);
+		}
+		return replace(url, pushInsteadOf);
+	}
+
+	private Map<String, String> load(String key) {
+		Map<String, String> replacements = new HashMap<>();
+		for (String url : config.getSubsections(SECTION_URL)) {
+			for (String prefix : config.getStringList(SECTION_URL, url, key)) {
+				replacements.put(prefix, url);
+			}
+		}
+		return replacements;
+	}
+
+	private String replace(String uri, Map<String, String> replacements) {
+		Entry<String, String> match = null;
+		for (Entry<String, String> replacement : replacements.entrySet()) {
+			// Ignore current entry if not longer than previous match
+			if (match != null && match.getKey().length() > replacement.getKey()
+					.length()) {
+				continue;
+			}
+			if (uri.startsWith(replacement.getKey())) {
+				match = replacement;
+			}
+		}
+		if (match != null) {
+			return match.getValue() + uri.substring(match.getKey().length());
+		}
+		return uri;
+	}
+}