[JGIT PATCH 16/28] Convert jgit's Main to use args4j for basic parsing services

From

Shawn O. Pearce <spearce@spearce.org>

Date

Jul 18, 2008, 01:44 UTC

Message-ID

<1216345461-59382-17-git-send-email-spearce@spearce.org>

In-Reply-To

<1216345461-59382-16-git-send-email-spearce@spearce.org>

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 .../src/org/spearce/jgit/pgm/Main.java             |  111 ++++++---------
 .../src/org/spearce/jgit/pgm/TextBuiltin.java      |   19 +++
 .../spearce/jgit/pgm/opt/SubcommandHandler.java    |  149 ++++++++++++++++++++
 3 files changed, 214 insertions(+), 65 deletions(-)
 create mode 100644 org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/opt/SubcommandHandler.java

diff --git a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Main.java b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Main.java
index 68748bf..c069989 100644
--- a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Main.java
+++ b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/Main.java
@@ -39,8 +39,13 @@
 package org.spearce.jgit.pgm;
 
 import java.io.File;
-import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.List;
 
+import org.kohsuke.args4j.Argument;
+import org.kohsuke.args4j.CmdLineException;
+import org.kohsuke.args4j.ExampleMode;
+import org.kohsuke.args4j.Option;
 import org.spearce.jgit.awtui.AwtAuthenticator;
 import org.spearce.jgit.errors.TransportException;
 import org.spearce.jgit.lib.Repository;
@@ -50,7 +55,20 @@ import org.spearce.jgit.util.HttpSupport;
 
 /** Command line entry point. */
 public class Main {
-	private static boolean showStackTrace;
+	@Option(name = "--help", usage = "display this help text", aliases = { "-h" })
+	private boolean help;
+
+	@Option(name = "--show-stack-trace", usage = "display the Java stack trace on exceptions")
+	private boolean showStackTrace;
+
+	@Option(name = "--git-dir", metaVar = "GIT_DIR", usage = "set the git repository to operate on")
+	private File gitdir;
+
+	@Argument(index = 0, metaVar = "command", required = true, handler = SubcommandHandler.class)
+	private TextBuiltin subcommand;
+
+	@Argument(index = 1, metaVar = "ARG")
+	private List<String> arguments = new ArrayList<String>();
 
 	/**
 	 * Execute the command line.
@@ -59,23 +77,24 @@ public class Main {
 	 *            arguments.
 	 */
 	public static void main(final String[] argv) {
+		final Main me = new Main();
 		try {
 			AwtAuthenticator.install();
 			HttpSupport.configureHttpProxy();
-			execute(argv);
+			me.execute(argv);
 		} catch (Die err) {
 			System.err.println("fatal: " + err.getMessage());
-			if (showStackTrace)
+			if (me.showStackTrace)
 				err.printStackTrace();
 			System.exit(128);
 		} catch (Exception err) {
-			if (!showStackTrace && err.getCause() != null
+			if (!me.showStackTrace && err.getCause() != null
 					&& err instanceof TransportException)
 				System.err.println("fatal: " + err.getCause().getMessage());
 
 			if (err.getClass().getName().startsWith("org.spearce.jgit.errors.")) {
 				System.err.println("fatal: " + err.getMessage());
-				if (showStackTrace)
+				if (me.showStackTrace)
 					err.printStackTrace();
 				System.exit(128);
 			}
@@ -84,24 +103,28 @@ public class Main {
 		}
 	}
 
-	private static void execute(final String[] argv) throws Exception {
-		int argi = 0;
+	private void execute(final String[] argv) throws Exception {
+		final CmdLineParser clp = new CmdLineParser(this);
+		try {
+			clp.parseArgument(argv);
+		} catch (CmdLineException err) {
+			if (argv.length > 0 && !help) {
+				System.err.println("fatal: " + err.getMessage());
+				System.exit(1);
+			}
+		}
 
-		File gitdir = null;
-		for (; argi < argv.length; argi++) {
-			final String arg = argv[argi];
-			if (arg.startsWith("--git-dir="))
-				gitdir = new File(arg.substring("--git-dir=".length()));
-			else if (arg.equals("--show-stack-trace"))
-				showStackTrace = true;
-			else if (arg.startsWith("--"))
-				usage();
-			else
-				break;
+		if (argv.length == 0 || help) {
+			final String ex = clp.printExample(ExampleMode.ALL);
+			System.err.println("jgit" + ex + " command [ARG ...]");
+			if (help) {
+				System.err.println();
+				clp.printUsage(System.err);
+				System.err.println();
+			}
+			System.exit(1);
 		}
 
-		if (argi == argv.length)
-			usage();
 		if (gitdir == null)
 			gitdir = findGitDir();
 		if (gitdir == null || !gitdir.isDirectory()) {
@@ -109,10 +132,10 @@ public class Main {
 			System.exit(1);
 		}
 
-		final TextBuiltin cmd = createCommand(argv[argi++]);
+		final TextBuiltin cmd = subcommand;
 		cmd.init(new Repository(gitdir));
 		try {
-			cmd.execute(subarray(argv, argi));
+			cmd.execute(arguments.toArray(new String[arguments.size()]));
 		} finally {
 			if (cmd.out != null)
 				cmd.out.flush();
@@ -129,46 +152,4 @@ public class Main {
 		}
 		return null;
 	}
-
-	private static String[] subarray(final String[] argv, final int i) {
-		return Arrays.asList(argv).subList(i, argv.length).toArray(
-				new String[0]);
-	}
-
-	private static TextBuiltin createCommand(final String name) {
-		final StringBuilder s = new StringBuilder();
-		s.append(mypackage());
-		s.append('.');
-		boolean upnext = true;
-		for (int i = 0; i < name.length(); i++) {
-			final char c = name.charAt(i);
-			if (c == '-') {
-				upnext = true;
-				continue;
-			}
-			if (upnext)
-				s.append(Character.toUpperCase(c));
-			else
-				s.append(c);
-			upnext = false;
-		}
-		try {
-			return (TextBuiltin) Class.forName(s.toString()).newInstance();
-		} catch (Exception e) {
-			System.err.println("error: " + name + " is not a jgit command.");
-			System.exit(1);
-			return null;
-		}
-	}
-
-	private static String mypackage() {
-		final String p = Main.class.getName();
-		final int dot = p.lastIndexOf('.');
-		return p.substring(0, dot);
-	}
-
-	private static void usage() {
-		System.err.println("jgit [--git-dir=path] cmd ...");
-		System.exit(1);
-	}
 }
diff --git a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/TextBuiltin.java b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/TextBuiltin.java
index 05ad211..0f39f11 100644
--- a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/TextBuiltin.java
+++ b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/TextBuiltin.java
@@ -65,12 +65,24 @@ public abstract class TextBuiltin {
 
 	protected static final String REFS_TAGS = Constants.TAGS_PREFIX + "/";
 
+	private String commandName;
+
 	/** Stream to output to, typically this is standard output. */
 	protected PrintWriter out;
 
 	/** Git repository the command was invoked within. */
 	protected Repository db;
 
+	/**
+	 * Set the name this command can be invoked as on the command line.
+	 * 
+	 * @param name
+	 *            the name of the command.
+	 */
+	public void setCommandName(final String name) {
+		commandName = name;
+	}
+
 	void init(final Repository repo) {
 		try {
 			out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
@@ -93,6 +105,13 @@ public abstract class TextBuiltin {
 	 */
 	public abstract void execute(String[] args) throws Exception;
 
+	/**
+	 * @return the repository this command accesses.
+	 */
+	public Repository getRepository() {
+		return db;
+	}
+
 	protected ObjectId resolve(final String s) throws IOException {
 		final ObjectId r = db.resolve(s);
 		if (r == null)
diff --git a/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/opt/SubcommandHandler.java b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/opt/SubcommandHandler.java
new file mode 100644
index 0000000..2318a03
--- /dev/null
+++ b/org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/opt/SubcommandHandler.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
+ *
+ * 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 Git Development Community 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.spearce.jgit.pgm.opt;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.text.MessageFormat;
+
+import org.kohsuke.args4j.CmdLineException;
+import org.kohsuke.args4j.CmdLineParser;
+import org.kohsuke.args4j.OptionDef;
+import org.kohsuke.args4j.spi.OptionHandler;
+import org.kohsuke.args4j.spi.Parameters;
+import org.kohsuke.args4j.spi.Setter;
+import org.spearce.jgit.pgm.Main;
+import org.spearce.jgit.pgm.TextBuiltin;
+
+/**
+ * Custom Argument handler for jgit command selection.
+ * <p>
+ * Translates a single argument string to a {@link TextBuiltin} instance which
+ * we can execute at runtime with the remaining arguments of the parser.
+ */
+public class SubcommandHandler extends OptionHandler<TextBuiltin> {
+	private static String mypackage() {
+		final String p = Main.class.getName();
+		final int dot = p.lastIndexOf('.');
+		return p.substring(0, dot);
+	}
+
+	/**
+	 * Create a new handler for the command name.
+	 * <p>
+	 * This constructor is used only by args4j.
+	 * 
+	 * @param parser
+	 * @param option
+	 * @param setter
+	 */
+	public SubcommandHandler(final CmdLineParser parser,
+			final OptionDef option, final Setter<? super TextBuiltin> setter) {
+		super(parser, option, setter);
+	}
+
+	@Override
+	public int parseArguments(final Parameters params) throws CmdLineException {
+		final String name = params.getParameter(0);
+		final StringBuilder s = new StringBuilder();
+		s.append(mypackage());
+		s.append('.');
+		boolean upnext = true;
+		for (int i = 0; i < name.length(); i++) {
+			final char c = name.charAt(i);
+			if (c == '-') {
+				upnext = true;
+				continue;
+			}
+			if (upnext)
+				s.append(Character.toUpperCase(c));
+			else
+				s.append(c);
+			upnext = false;
+		}
+
+		final Class<?> clazz;
+		try {
+			clazz = Class.forName(s.toString());
+		} catch (ClassNotFoundException e) {
+			throw new CmdLineException(MessageFormat.format(
+					"{0} is not a jgit command", name));
+		}
+
+		if (!TextBuiltin.class.isAssignableFrom(clazz))
+			throw new CmdLineException(MessageFormat.format(
+					"{0} is not a jgit command", name));
+
+		final Constructor<?> cons;
+		try {
+			cons = clazz.getDeclaredConstructor();
+		} catch (SecurityException e) {
+			throw new CmdLineException("Cannot create " + name, e);
+		} catch (NoSuchMethodException e) {
+			throw new CmdLineException("Cannot create " + name, e);
+		}
+		cons.setAccessible(true);
+
+		final TextBuiltin cmd;
+		try {
+			cmd = (TextBuiltin) cons.newInstance();
+		} catch (InstantiationException e) {
+			throw new CmdLineException("Cannot create " + name, e);
+		} catch (IllegalAccessException e) {
+			throw new CmdLineException("Cannot create " + name, e);
+		} catch (InvocationTargetException e) {
+			throw new CmdLineException("Cannot create " + name, e);
+		}
+
+		cmd.setCommandName(name);
+		setter.addValue(cmd);
+
+		// Force option parsing to stop. Everything after us should
+		// be arguments known only to this command and must not be
+		// recognized by the current parser.
+		//
+		owner.stopOptionParsing();
+
+		return 1;
+	}
+
+	@Override
+	public String getDefaultMetaVariable() {
+		return "command";
+	}
+}

-- 
1.5.6.3.569.ga9185