001/*
002 * Copyright (C) 2012 eXo Platform SAS.
003 *
004 * This is free software; you can redistribute it and/or modify it
005 * under the terms of the GNU Lesser General Public License as
006 * published by the Free Software Foundation; either version 2.1 of
007 * the License, or (at your option) any later version.
008 *
009 * This software is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * You should have received a copy of the GNU Lesser General Public
015 * License along with this software; if not, write to the Free
016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018 */
019package org.crsh.lang;
020
021import org.crsh.lang.impl.script.ScriptCompiler;
022import org.crsh.lang.spi.Compiler;
023import org.crsh.lang.spi.Language;
024import org.crsh.plugin.PluginContext;
025import org.crsh.plugin.ResourceKind;
026import org.crsh.shell.impl.command.spi.Command;
027import org.crsh.shell.impl.command.spi.CommandException;
028import org.crsh.shell.impl.command.spi.CommandResolver;
029import org.crsh.lang.spi.CommandResolution;
030import org.crsh.util.TimestampedObject;
031import org.crsh.vfs.Resource;
032
033import java.util.HashMap;
034import java.util.LinkedHashMap;
035import java.util.Map;
036import java.util.concurrent.ConcurrentHashMap;
037
038/**
039 * A shell command resolver for languages.
040 *
041 * @author Julien Viet
042 */
043public class LanguageCommandResolver implements CommandResolver {
044
045  /** . */
046  private final Map<String, TimestampedObject<CommandResolution>> commandCache = new ConcurrentHashMap<String, TimestampedObject<CommandResolution>>();
047
048  /** . */
049  final HashMap<String, Compiler> activeCompilers = new HashMap<String, Compiler>();
050
051  /** . */
052  final PluginContext context;
053
054  public LanguageCommandResolver(PluginContext context) {
055
056    //
057    activeCompilers.put("script", ScriptCompiler.getInstance());
058
059    //
060    for (Language lang : context.getPlugins(Language.class)) {
061      if (lang.isActive()) {
062        Compiler compiler = lang.getCompiler();
063        if (compiler != null) {
064          for (String ext : compiler.getExtensions()) {
065            activeCompilers.put(ext, compiler);
066          }
067        }
068      }
069    }
070
071    this.context = context;
072  }
073
074  public Compiler getCompiler(String name) {
075    return activeCompilers.get(name);
076  }
077
078  @Override
079  public Iterable<Map.Entry<String, String>> getDescriptions() {
080    LinkedHashMap<String, String> commands = new LinkedHashMap<String, String>();
081    for (String resourceName : context.listResources(ResourceKind.COMMAND)) {
082      int index = resourceName.indexOf('.');
083      String name = resourceName.substring(0, index);
084      String ext = resourceName.substring(index + 1);
085      if (activeCompilers.containsKey(ext)) {
086        try {
087          CommandResolution resolution = resolveCommand2(name);
088          commands.put(name, resolution.getDescription());
089        }
090        catch (CommandException e) {
091          //
092        }
093      }
094    }
095    return commands.entrySet();
096  }
097
098  @Override
099  public Command<?> resolveCommand(String name) throws CommandException, NullPointerException {
100    CommandResolution resolution = resolveCommand2(name);
101    return resolution != null ? resolution.getCommand() : null;
102  }
103
104  private CommandResolution resolveCommand2(String name) throws CommandException, NullPointerException {
105    for (Compiler manager : activeCompilers.values()) {
106      for (String ext : manager.getExtensions()) {
107        Iterable<Resource> resources = context.loadResources(name + "." + ext, ResourceKind.COMMAND);
108        for (Resource resource : resources) {
109          CommandResolution resolution = resolveCommand(manager, name, resource);
110          if (resolution != null) {
111            return resolution;
112          }
113        }
114      }
115    }
116    return null;
117  }
118
119  private CommandResolution resolveCommand(org.crsh.lang.spi.Compiler manager, String name, Resource script) throws CommandException {
120    TimestampedObject<CommandResolution> ref = commandCache.get(name);
121    if (ref != null) {
122      if (script.getTimestamp() != ref.getTimestamp()) {
123        ref = null;
124      }
125    }
126    CommandResolution command;
127    if (ref == null) {
128      command = manager.compileCommand(name, script.getContent());
129      if (command != null) {
130        commandCache.put(name, new TimestampedObject<CommandResolution>(script.getTimestamp(), command));
131      }
132    } else {
133      command = ref.getObject();
134    }
135    return command;
136  }
137
138}