1 files changed, 166 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandUtils.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandUtils.java
new file mode 100644
index 0000000000..ff738db529
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+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandUtils.java
@@ -0,0 +1,166 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.runtime;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
+import com.google.devtools.build.lib.util.ResourceFileLoader;
+import com.google.devtools.common.options.OptionsBase;
+import com.google.devtools.common.options.OptionsParser;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Utility class for functionality related to Blaze commands.
+ */
+public class BlazeCommandUtils {
+  /**
+   * Options classes used as startup options in Blaze core.
+   */
+  private static final List<Class<? extends OptionsBase>> DEFAULT_STARTUP_OPTIONS =
+      ImmutableList.<Class<? extends OptionsBase>>of(
+          BlazeServerStartupOptions.class,
+          HostJvmStartupOptions.class);
+
+  /**
+   * The set of option-classes that are common to all Blaze commands.
+   */
+  private static final Collection<Class<? extends OptionsBase>> COMMON_COMMAND_OPTIONS =
+      ImmutableList.of(CommonCommandOptions.class, BlazeCommandEventHandler.Options.class);
+
+
+  private BlazeCommandUtils() {}
+
+  public static ImmutableList<Class<? extends OptionsBase>> getStartupOptions(
+      Iterable<BlazeModule> modules) {
+    Set<Class<? extends OptionsBase>> options = new HashSet<>();
+       options.addAll(DEFAULT_STARTUP_OPTIONS);
+    for (BlazeModule blazeModule : modules) {
+      Iterables.addAll(options, blazeModule.getStartupOptions());
+    }
+
+    return ImmutableList.copyOf(options);
+  }
+
+  /**
+   * Returns the set of all options (including those inherited directly and
+   * transitively) for this AbstractCommand's @Command annotation.
+   *
+   * <p>Why does metaprogramming always seem like such a bright idea in the
+   * beginning?
+   */
+  public static ImmutableList<Class<? extends OptionsBase>> getOptions(
+      Class<? extends BlazeCommand> clazz,
+      Iterable<BlazeModule> modules,
+      ConfiguredRuleClassProvider ruleClassProvider) {
+    Command commandAnnotation = clazz.getAnnotation(Command.class);
+    if (commandAnnotation == null) {
+      throw new IllegalStateException("@Command missing for " + clazz.getName());
+    }
+
+    Set<Class<? extends OptionsBase>> options = new HashSet<>();
+    options.addAll(COMMON_COMMAND_OPTIONS);
+    Collections.addAll(options, commandAnnotation.options());
+
+    if (commandAnnotation.usesConfigurationOptions()) {
+      options.addAll(ruleClassProvider.getConfigurationOptions());
+    }
+
+    for (BlazeModule blazeModule : modules) {
+      Iterables.addAll(options, blazeModule.getCommandOptions(commandAnnotation));
+    }
+
+    for (Class<? extends BlazeCommand> base : commandAnnotation.inherits()) {
+      options.addAll(getOptions(base, modules, ruleClassProvider));
+    }
+    return ImmutableList.copyOf(options);
+  }
+
+  /**
+   * Returns the expansion of the specified help topic.
+   *
+   * @param topic the name of the help topic; used in %{command} expansion.
+   * @param help the text template of the help message. Certain %{x} variables
+   *        will be expanded. A prefix of "resource:" means use the .jar
+   *        resource of that name.
+   * @param categoryDescriptions a mapping from option category names to
+   *        descriptions, passed to {@link OptionsParser#describeOptions}.
+   * @param helpVerbosity a tri-state verbosity option selecting between just
+   *        names, names and syntax, and full description.
+   */
+  public static final String expandHelpTopic(String topic, String help,
+                                      Class<? extends BlazeCommand> commandClass,
+                                      Collection<Class<? extends OptionsBase>> options,
+                                      Map<String, String> categoryDescriptions,
+                                      OptionsParser.HelpVerbosity helpVerbosity) {
+    OptionsParser parser = OptionsParser.newOptionsParser(options);
+
+    String template;
+    if (help.startsWith("resource:")) {
+      String resourceName = help.substring("resource:".length());
+      try {
+        template = ResourceFileLoader.loadResource(commandClass, resourceName);
+      } catch (IOException e) {
+        throw new IllegalStateException("failed to load help resource '" + resourceName
+                                        + "' due to I/O error: " + e.getMessage(), e);
+      }
+    } else {
+      template = help;
+    }
+
+    if (!template.contains("%{options}")) {
+      throw new IllegalStateException("Help template for '" + topic + "' omits %{options}!");
+    }
+
+    return template.
+        replace("%{command}", topic).
+        replace("%{options}", parser.describeOptions(categoryDescriptions, helpVerbosity)).
+        trim()
+        + "\n\n"
+        + (helpVerbosity == OptionsParser.HelpVerbosity.MEDIUM
+           ? "(Use 'help --long' for full details or --short to just enumerate options.)\n"
+           : "");
+  }
+
+  /**
+   * The help page for this command.
+   *
+   * @param categoryDescriptions a mapping from option category names to
+   *        descriptions, passed to {@link OptionsParser#describeOptions}.
+   * @param verbosity a tri-state verbosity option selecting between just names,
+   *        names and syntax, and full description.
+   */
+  public static String getUsage(
+      Class<? extends BlazeCommand> commandClass,
+      Map<String, String> categoryDescriptions,
+      OptionsParser.HelpVerbosity verbosity,
+      Iterable<BlazeModule> blazeModules,
+      ConfiguredRuleClassProvider ruleClassProvider) {
+    Command commandAnnotation = commandClass.getAnnotation(Command.class);
+    return BlazeCommandUtils.expandHelpTopic(
+        commandAnnotation.name(),
+        commandAnnotation.help(),
+        commandClass,
+        BlazeCommandUtils.getOptions(commandClass, blazeModules, ruleClassProvider),
+        categoryDescriptions,
+        verbosity);
+  }
+}