text: //
  // Copyright 2019 Pixar
  //
  // Licensed under the Apache License, Version 2.0 (the "Apache License")
  // with the following modification; you may not use this file except in
  // compliance with the Apache License and the following modification to it:
  // Section 6. Trademarks. is deleted and replaced with:
  //
  // 6. Trademarks. This License does not grant permission to use the trade
  //    names, trademarks, service marks, or product names of the Licensor
  //    and its affiliates, except as required to comply with Section 4(c) of
  //    the License and to reproduce the content of the NOTICE file.
  //
  // You may obtain a copy of the Apache License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the Apache License with the above modification is
  // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied. See the Apache License for the specific
  // language governing permissions and limitations under the Apache License.
  //
  
  #ifndef EXT_RMANPKG_23_0_PLUGIN_RENDERMAN_PLUGIN_RMAN_DISCOVERY_RMAN_DISCOVERY_H
  #define EXT_RMANPKG_23_0_PLUGIN_RENDERMAN_PLUGIN_RMAN_DISCOVERY_RMAN_DISCOVERY_H
  
  /// \file rmanDiscovery/rmanDiscovery.h
  
  #include "pxr/pxr.h"
  #include "pxr/usd/ndr/discoveryPlugin.h"
  #include <functional>
  
  PXR_NAMESPACE_OPEN_SCOPE
  
  /// \class RmanDiscoveryPlugin
  ///
  /// Discovers nodes supported by the HdPrman render delegate.
  ///
  class RmanDiscoveryPlugin final : public NdrDiscoveryPlugin
  {
  public:
      /// A filter for discovered nodes.  If the function returns false
      /// then the discovered node is discarded.  Otherwise the function
      /// can modify the discovery result.
      using Filter = std::function<bool(NdrNodeDiscoveryResult&)>;
  
      /// Constructor.
      RmanDiscoveryPlugin();
  
      /// DiscoverNodes() will pass each result to the given function for
      /// modification.  If the function returns false then the result is
      /// discarded.
      RmanDiscoveryPlugin(Filter filter);
  
      /// Virtual destructor
      ~RmanDiscoveryPlugin();
  
      /// Discover all of the nodes that appear within the the search paths
      /// provided and match the extensions provided.
      NdrNodeDiscoveryResultVec DiscoverNodes(const Context&) override;
  
      /// Gets the paths that this plugin is searching for nodes in.
      const NdrStringVec& GetSearchURIs() const override;
  
  private:
      /// The paths (abs) indicating where the plugin should search for nodes.
      NdrStringVec _searchPaths;
  
      /// The extensions (excluding leading '.') that signify a valid node file.
      /// The extension will be used as the `type` member in the resulting
      /// `NdrNodeDiscoveryResult` instance.
      NdrStringVec _allowedExtensions;
  
      /// Whether or not to follow symlinks while scanning directories for files.
      bool _followSymlinks;
  
      // The filter to run on the results.
      Filter _filter;
  };
  
  void
  RmanDiscoveryPlugin_SetDefaultSearchPaths(const NdrStringVec &paths);
  
  void
  RmanDiscoveryPlugin_SetDefaultFollowSymlinks(bool followSymlinks);
  
  PXR_NAMESPACE_CLOSE_SCOPE
  
  #endif // EXT_RMANPKG_23_0_PLUGIN_RENDERMAN_PLUGIN_RMAN_DISCOVERY_RMAN_DISCOVERY_H
  