// 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.cmdline;

/**
 * A callback interface that is used during the process of converting target patterns (such as
 * <code>//foo:all</code>) into one or more lists of targets (such as <code>//foo:foo,
 * //foo:bar</code>). During a call to {@link TargetPattern#eval}, the {@link TargetPattern} makes
 * calls to this interface to implement the target pattern semantics. The generic type {@code T} is
 * only for compile-time type safety; there are no requirements to the actual type.
 */
public interface TargetPatternResolver<T> {

  /**
   * Reports the given warning.
   */
  void warn(String msg);

  /**
   * Returns a single target corresponding to the given name, or null. This method may only throw an
   * exception if the current thread was interrupted.
   */
  T getTargetOrNull(String targetName) throws InterruptedException;

  /**
   * Returns a single target corresponding to the given name, or an empty or failed result.
   */
  ResolvedTargets<T> getExplicitTarget(String targetName)
      throws TargetParsingException, InterruptedException;

  /**
   * Returns the set containing the targets found in the given package. The specified directory is
   * not necessarily a valid package name. If {@code rulesOnly} is true, then this method should
   * only return rules in the given package.
   *
   * @param originalPattern the original target pattern for error reporting purposes
   * @param packageName the name of the package
   * @param rulesOnly whether to return rules only
   */
  ResolvedTargets<T> getTargetsInPackage(String originalPattern, String packageName,
      boolean rulesOnly) throws TargetParsingException, InterruptedException;

  /**
   * Returns the set containing the targets found below the given {@code pathPrefix}. Conceptually,
   * this method should look for all packages that start with the {@code pathPrefix} (as a proper
   * prefix directory, i.e., "foo/ba" is not a proper prefix of "foo/bar/"), and then collect all
   * targets in each such package (subject to {@code rulesOnly}) as if calling {@link
   * #getTargetsInPackage}. The specified directory is not necessarily a valid package name.
   *
   * <p>Note that the {@code pathPrefix} can be empty, which corresponds to the "//..." pattern.
   * Implementations may choose not to support this case and throw an exception instead, or may
   * restrict the set of directories that are considered by default.
   *
   * <p>If the {@code pathPrefix} points to a package, then that package should also be part of the
   * result.
   *
   * @param originalPattern the original target pattern for error reporting purposes
   * @param pathPrefix the directory in which to look for packages
   * @param rulesOnly whether to return rules only
   */
  ResolvedTargets<T> findTargetsBeneathDirectory(String originalPattern, String pathPrefix,
      boolean rulesOnly) throws TargetParsingException, InterruptedException;

  /**
   * Returns true, if and only if the given name corresponds to a package, i.e., a file with the
   * name {@code packageName/BUILD} exists.
   */
  boolean isPackage(String packageName);

  /**
   * Returns the target kind of the given target, for example {@code cc_library rule}.
   */
  String getTargetKind(T target);


}