Add support for getting the system wide configuration

These settings are stored in <prefix>/etc/gitconfig. The C Git
binary is installed in <prefix>/bin, so we look for the C Git
executable to find this location, first by looking at the PATH
environment variable and then by attemting to launch bash as
a login shell to find out.

Bug: 333216
Change-Id: I1bbee9fb123a81714a34a9cc242b92beacfbb4a8
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

8 files changed, 171 insertions, 8 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
index 2e7503a133..ce518f73d5 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
@@ -453,6 +453,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String statelessRPCRequiresOptionToBeEnabled;
 	/***/ public String submodulesNotSupported;
 	/***/ public String symlinkCannotBeWrittenAsTheLinkTarget;
+	/***/ public String systemConfigFileInvalid;
 	/***/ public String tagNameInvalid;
 	/***/ public String tagOnRepoWithoutHEADCurrentlyNotSupported;
 	/***/ public String tSizeMustBeGreaterOrEqual1;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileRepository.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileRepository.java
index 417fa4b53e..28b83b0f9e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileRepository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/FileRepository.java
@@ -95,6 +95,8 @@ import org.eclipse.jgit.util.SystemReader;
  *
  */
 public class FileRepository extends Repository {
+	private final FileBasedConfig systemConfig;
+
 	private final FileBasedConfig userConfig;
 
 	private final FileBasedConfig repoConfig;
@@ -152,11 +154,14 @@ public class FileRepository extends Repository {
 	public FileRepository(final BaseRepositoryBuilder options) throws IOException {
 		super(options);
 
-		userConfig = SystemReader.getInstance().openUserConfig(getFS());
+		systemConfig = SystemReader.getInstance().openSystemConfig(null, getFS());
+		userConfig = SystemReader.getInstance().openUserConfig(systemConfig,
+				getFS());
 		repoConfig = new FileBasedConfig(userConfig, //
 				getFS().resolve(getDirectory(), "config"), //
 				getFS());
 
+		loadSystemConfig();
 		loadUserConfig();
 		loadRepoConfig();
 
@@ -184,6 +189,18 @@ public class FileRepository extends Repository {
 		}
 	}
 
+	private void loadSystemConfig() throws IOException {
+		try {
+			systemConfig.load();
+		} catch (ConfigInvalidException e1) {
+			IOException e2 = new IOException(MessageFormat.format(JGitText
+					.get().systemConfigFileInvalid, systemConfig.getFile()
+					.getAbsolutePath(), e1));
+			e2.initCause(e1);
+			throw e2;
+		}
+	}
+
 	private void loadUserConfig() throws IOException {
 		try {
 			userConfig.load();
@@ -285,6 +302,13 @@ public class FileRepository extends Repository {
 	 * @return the configuration of this repository
 	 */
 	public FileBasedConfig getConfig() {
+		if (systemConfig.isOutdated()) {
+			try {
+				loadSystemConfig();
+			} catch (IOException e) {
+				throw new RuntimeException(e);
+			}
+		}
 		if (userConfig.isOutdated()) {
 			try {
 				loadUserConfig();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
index 0a3fad001b..87d5395bf9 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
@@ -252,4 +252,7 @@ public abstract class FS {
 		}
 		return null;
 	}
+
+	/** @return the $prefix directory C Git would use. */
+	public abstract File gitPrefix();
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java
new file mode 100644
index 0000000000..0ebf2e307b
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2010, Robin Rosenberg
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.util;
+
+import java.io.File;
+import java.nio.charset.Charset;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+abstract class FS_POSIX extends FS {
+	@Override
+	public File gitPrefix() {
+		String path = SystemReader.getInstance().getenv("PATH");
+		File gitExe = searchPath(path, "git");
+		if (gitExe != null)
+			return gitExe.getParentFile().getParentFile();
+
+		if (isMacOS()) {
+			// On MacOSX, PATH is shorter when Eclipse is launched from the
+			// Finder than from a terminal. Therefore try to launch bash as a
+			// login shell and search using that.
+			//
+			String w = readPipe(userHome(), //
+					new String[] { "bash", "--login", "-c", "which git" }, //
+					Charset.defaultCharset().name());
+			return new File(w).getParentFile().getParentFile();
+		}
+
+		return null;
+	}
+
+	private static boolean isMacOS() {
+		final String osDotName = AccessController
+				.doPrivileged(new PrivilegedAction<String>() {
+					public String run() {
+						return System.getProperty("os.name");
+					}
+				});
+		return "Mac OS X".equals(osDotName);
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java5.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java5.java
index 950d49189c..ec8175ab5a 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java5.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java5.java
@@ -45,7 +45,7 @@ package org.eclipse.jgit.util;
 
 import java.io.File;
 
-class FS_POSIX_Java5 extends FS {
+class FS_POSIX_Java5 extends FS_POSIX {
 	public boolean supportsExecute() {
 		return false;
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java6.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java6.java
index 192d9bbbbf..dfc03c4510 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java6.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX_Java6.java
@@ -49,7 +49,7 @@ import java.io.File;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 
-class FS_POSIX_Java6 extends FS {
+class FS_POSIX_Java6 extends FS_POSIX {
 	private static final Method canExecute;
 
 	private static final Method setExecute;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java
index 4e35e6ee4b..2cf8bf9554 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS_Win32.java
@@ -45,6 +45,7 @@
 package org.eclipse.jgit.util;
 
 import java.io.File;
+import java.nio.charset.Charset;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 
@@ -76,4 +77,23 @@ class FS_Win32 extends FS {
 	public boolean retryFailedLockFileCommit() {
 		return true;
 	}
+
+	@Override
+	public File gitPrefix() {
+		String path = SystemReader.getInstance().getenv("PATH");
+		File gitExe = searchPath(path, "git.exe", "git.cmd");
+		if (gitExe != null)
+			return gitExe.getParentFile().getParentFile();
+
+		// This isn't likely to work, if bash is in $PATH, git should
+		// also be in $PATH. But its worth trying.
+		//
+		String w = readPipe(userHome(), //
+				new String[] { "bash", "--login", "-c", "which git" }, //
+				Charset.defaultCharset().name());
+		if (w != null)
+			return new File(w).getParentFile().getParentFile();
+
+		return null;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/SystemReader.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/SystemReader.java
index 475c871c3c..ced1d90b8e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/SystemReader.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/SystemReader.java
@@ -50,6 +50,7 @@ import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.TimeZone;
 
+import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 
 /**
@@ -72,9 +73,28 @@ public abstract class SystemReader {
 			return System.getProperty(key);
 		}
 
-		public FileBasedConfig openUserConfig(FS fs) {
+		public FileBasedConfig openSystemConfig(Config parent, FS fs) {
+			File prefix = fs.gitPrefix();
+			if (prefix == null) {
+				return new FileBasedConfig(null, fs) {
+					public void load() {
+						// empty, do not load
+					}
+
+					public boolean isOutdated() {
+						// regular class would bomb here
+						return false;
+					}
+				};
+			}
+			File etc = fs.resolve(prefix, "etc");
+			File config = fs.resolve(etc, "gitconfig");
+			return new FileBasedConfig(parent, config, fs);
+		}
+
+		public FileBasedConfig openUserConfig(Config parent, FS fs) {
 			final File home = fs.userHome();
-			return new FileBasedConfig(new File(home, ".gitconfig"), fs);
+			return new FileBasedConfig(parent, new File(home, ".gitconfig"), fs);
 		}
 
 		public String getHostname() {
@@ -136,12 +156,26 @@ public abstract class SystemReader {
 	public abstract String getProperty(String key);
 
 	/**
+	 * @param parent
+	 *            a config with values not found directly in the returned config
 	 * @param fs
-	 *            the file system abstraction which will be necessary to
-	 *            perform certain file system operations.
+	 *            the file system abstraction which will be necessary to perform
+	 *            certain file system operations.
 	 * @return the git configuration found in the user home
 	 */
-	public abstract FileBasedConfig openUserConfig(FS fs);
+	public abstract FileBasedConfig openUserConfig(Config parent, FS fs);
+
+	/**
+	 * @param parent
+	 *            a config with values not found directly in the returned
+	 *            config. Null is a reasonable value here.
+	 * @param fs
+	 *            the file system abstraction which will be necessary to perform
+	 *            certain file system operations.
+	 * @return the gitonfig configuration found in the system-wide "etc"
+	 *         directory
+	 */
+	public abstract FileBasedConfig openSystemConfig(Config parent, FS fs);
 
 	/**
 	 * @return the current system time