| /* |
| * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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.pgm; |
| |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| |
| import java.io.BufferedReader; |
| import java.io.IOException; |
| import java.io.InputStreamReader; |
| import java.net.URL; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Enumeration; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Vector; |
| |
| /** |
| * List of all commands known by jgit's command line tools. |
| * <p> |
| * Commands are implementations of {@link org.eclipse.jgit.pgm.TextBuiltin}, |
| * with an optional {@link org.eclipse.jgit.pgm.Command} class annotation to |
| * insert additional documentation or override the default command name (which |
| * is guessed from the class name). |
| * <p> |
| * Commands may be registered by adding them to a services file in the same JAR |
| * (or classes directory) as the command implementation. The service file name |
| * is <code>META-INF/services/org.eclipse.jgit.pgm.TextBuiltin</code> and it |
| * contains one concrete implementation class name per line. |
| * <p> |
| * Command registration is identical to Java 6's services, however the catalog |
| * uses a lightweight wrapper to delay creating a command instance as much as |
| * possible. This avoids initializing the AWT or SWT GUI toolkits even if the |
| * command's constructor might require them. |
| */ |
| public class CommandCatalog { |
| private static final CommandCatalog INSTANCE = new CommandCatalog(); |
| |
| /** |
| * Locate a single command by its user friendly name. |
| * |
| * @param name |
| * name of the command. Typically in dash-lower-case-form, which |
| * was derived from the DashLowerCaseForm class name. |
| * @return the command instance; null if no command exists by that name. |
| */ |
| public static CommandRef get(String name) { |
| return INSTANCE.commands.get(name); |
| } |
| |
| /** |
| * Get all commands sorted by their name |
| * |
| * @return all known commands, sorted by command name. |
| */ |
| public static CommandRef[] all() { |
| return toSortedArray(INSTANCE.commands.values()); |
| } |
| |
| /** |
| * Get all common commands sorted by their name |
| * |
| * @return all common commands, sorted by command name. |
| */ |
| public static CommandRef[] common() { |
| final ArrayList<CommandRef> common = new ArrayList<>(); |
| for (CommandRef c : INSTANCE.commands.values()) |
| if (c.isCommon()) |
| common.add(c); |
| return toSortedArray(common); |
| } |
| |
| private static CommandRef[] toSortedArray(Collection<CommandRef> c) { |
| final CommandRef[] r = c.toArray(new CommandRef[0]); |
| Arrays.sort(r, (CommandRef o1, CommandRef o2) -> o1.getName() |
| .compareTo(o2.getName())); |
| return r; |
| } |
| |
| private final ClassLoader ldr; |
| |
| private final Map<String, CommandRef> commands; |
| |
| private CommandCatalog() { |
| ldr = Thread.currentThread().getContextClassLoader(); |
| commands = new HashMap<>(); |
| |
| final Enumeration<URL> catalogs = catalogs(); |
| while (catalogs.hasMoreElements()) |
| scan(catalogs.nextElement()); |
| } |
| |
| private Enumeration<URL> catalogs() { |
| try { |
| final String pfx = "META-INF/services/"; //$NON-NLS-1$ |
| return ldr.getResources(pfx + TextBuiltin.class.getName()); |
| } catch (IOException err) { |
| return new Vector<URL>().elements(); |
| } |
| } |
| |
| private void scan(URL cUrl) { |
| try (BufferedReader cIn = new BufferedReader( |
| new InputStreamReader(cUrl.openStream(), UTF_8))) { |
| String line; |
| while ((line = cIn.readLine()) != null) { |
| if (line.length() > 0 && !line.startsWith("#")) //$NON-NLS-1$ |
| load(line); |
| } |
| } catch (IOException e) { |
| // Ignore errors |
| } |
| } |
| |
| private void load(String cn) { |
| final Class<? extends TextBuiltin> clazz; |
| try { |
| clazz = Class.forName(cn, false, ldr).asSubclass(TextBuiltin.class); |
| } catch (ClassNotFoundException | ClassCastException notBuiltin) { |
| // Doesn't exist, even though the service entry is present. |
| // Isn't really a builtin, even though its listed as such. |
| return; |
| } |
| |
| final CommandRef cr; |
| final Command a = clazz.getAnnotation(Command.class); |
| if (a != null) |
| cr = new CommandRef(clazz, a); |
| else |
| cr = new CommandRef(clazz); |
| |
| commands.put(cr.getName(), cr); |
| } |
| } |