registry.h

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//
// Copyright 2018 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 NDR_REGISTRY_H
#define NDR_REGISTRY_H


#include "pxr/pxr.h"
#include "pxr/usd/ndr/api.h"
#include "pxr/base/tf/singleton.h"
#include "pxr/base/tf/weakBase.h"
#include "pxr/usd/ndr/declare.h"
#include "pxr/usd/ndr/discoveryPlugin.h"
#include "pxr/usd/ndr/node.h"
#include "pxr/usd/ndr/nodeDiscoveryResult.h"
#include "pxr/usd/ndr/parserPlugin.h"
#include "pxr/usd/sdf/assetPath.h"

PXR_NAMESPACE_OPEN_SCOPE

class NdrRegistry : public TfWeakBase
{
public:
    using DiscoveryPluginRefPtrVec = NdrDiscoveryPluginRefPtrVector;

    NDR_API
    static NdrRegistry& GetInstance();

    NDR_API
    void SetExtraDiscoveryPlugins(DiscoveryPluginRefPtrVec plugins);

    NDR_API
    void SetExtraDiscoveryPlugins(const std::vector<TfType>& pluginTypes);

    NDR_API
    NdrNodeConstPtr GetNodeFromAsset(const SdfAssetPath &asset,
                                     const NdrTokenMap &metadata);

    NDR_API
    NdrNodeConstPtr GetNodeFromSourceCode(const std::string &sourceCode,
                                          const TfToken &sourceType,
                                          const NdrTokenMap &metadata);

    NDR_API
    NdrStringVec GetSearchURIs() const;

    NDR_API
    NdrIdentifierVec
    GetNodeIdentifiers(const TfToken& family = TfToken(),
                       NdrVersionFilter filter =
                           NdrVersionFilterDefaultOnly) const;

    NDR_API
    NdrStringVec GetNodeNames(const TfToken& family = TfToken()) const;

    NDR_API
    NdrNodeConstPtr GetNodeByIdentifier(const NdrIdentifier& identifier,
                            const NdrTokenVec& typePriority = NdrTokenVec());

    NDR_API
    NdrNodeConstPtr GetNodeByIdentifierAndType(const NdrIdentifier& identifier,
                                               const TfToken& nodeType);

    NDR_API
    NdrNodeConstPtr GetNodeByName(const std::string& name,
                            const NdrTokenVec& typePriority = NdrTokenVec(),
                            NdrVersionFilter filter =
                                NdrVersionFilterDefaultOnly);

    NDR_API
    NdrNodeConstPtr GetNodeByNameAndType(const std::string& name,
                                         const TfToken& nodeType,
                                         NdrVersionFilter filter =
                                             NdrVersionFilterDefaultOnly);

    NDR_API
    NdrNodeConstPtr GetNodeByURI(const std::string& uri);

    NDR_API
    NdrNodeConstPtrVec GetNodesByIdentifier(const NdrIdentifier& identifier);

    NDR_API
    NdrNodeConstPtrVec GetNodesByName(const std::string& name,
                                      NdrVersionFilter filter =
                                          NdrVersionFilterDefaultOnly);

    NDR_API
    NdrNodeConstPtrVec GetNodesByFamily(const TfToken& family = TfToken(),
                                        NdrVersionFilter filter =
                                            NdrVersionFilterDefaultOnly);

    NDR_API
    NdrTokenVec GetAllNodeSourceTypes() const;

protected:
    NdrRegistry(const NdrRegistry&) = delete;
    NdrRegistry& operator=(const NdrRegistry&) = delete;

    // Allow TF to construct the class
    friend class TfSingleton<NdrRegistry>;

    NDR_API
    NdrRegistry();

    NDR_API
    virtual ~NdrRegistry();

private:
    class _DiscoveryContext;
    friend class _DiscoveryContext;

    typedef std::unordered_map<TfToken, NdrParserPlugin*,
        TfToken::HashFunctor> TypeToParserPluginMap;
    typedef std::pair<NdrIdentifier, TfToken> NodeMapKey;
    struct NodeMapKeyHashFunctor {
        size_t operator()(const NodeMapKey& x) const {
            return NdrIdentifierHashFunctor()(x.first) ^
                   TfToken::HashFunctor()(x.second);
        }
    };
    typedef std::unordered_multimap<NodeMapKey, NdrNodeUniquePtr,
                                    NodeMapKeyHashFunctor> NodeMap;

    // The discovery result vec is not a concurrent data structure, thus it
    // needs some locking infrastructure.
    mutable std::mutex _discoveryResultMutex;

    // The node map is not a concurrent data structure, thus it needs some
    // locking infrastructure.
    mutable std::mutex _nodeMapMutex;

    // Runs each discovery plugin provided and appends the results to the
    // internal discovery results vector
    void _RunDiscoveryPlugins(const DiscoveryPluginRefPtrVec& discoveryPlugins);

    // Finds and instantiates the discovery plugins via Tf
    void _FindAndInstantiateDiscoveryPlugins();

    // Finds and instantiates the parser plugins via Tf
    void _FindAndInstantiateParserPlugins();

    // Parses all nodes that match the specified predicate, optionally only
    // parsing the first node that matches (good to use when the predicate will
    // only ever match one node). This is a lightweight, single-threaded version
    // of the parsing routine found in `GetNodes()`. Note that if a node matches
    // the predicate and it has already been parsed, the already-parsed version
    // will be returned, and a new node will not be inserted into the map.
    NdrNodeConstPtrVec _ParseNodesMatchingPredicate(
        std::function<bool(const NdrNodeDiscoveryResult&)> shouldParsePredicate,
        bool onlyParseFirstMatch);

    // Inserts a new node into the node cache. If a node with the
    // same name and type already exists in the cache, the pointer to the
    // existing node will be returned. If there was an error inserting the node,
    // `nullptr` will be returned.
    NdrNodeConstPtr _InsertNodeIntoCache(const NdrNodeDiscoveryResult& dr);

    // Get a vector of all of the node unique_ptrs in the node map as raw ptrs
    NdrNodeConstPtrVec _GetNodeMapAsNodePtrVec(const TfToken& family,
                                               NdrVersionFilter filter) const;

    // Return the source type for a discovery type or the empty token if
    // no parser plugin has that discovery type.
    NdrParserPlugin*
    _GetParserForDiscoveryType(const TfToken& discoveryType) const;

    // Return the first node matching the strongest possible source type.
    // That is, for each source type from beginning to end, check every
    // node in nodes beginning-to-end and return the first node that
    // has the source type.
    static NdrNodeConstPtr
    _GetNodeByTypePriority(const NdrNodeConstPtrVec& nodes,
                           const NdrTokenVec& typePriority);

    // The discovery plugins that were found through libplug and/or provided by
    // the client
    DiscoveryPluginRefPtrVec _discoveryPlugins;

    // The parser plugins that have been discovered via the plugin system. Maps
    // a discovery result's "discovery type" to a specific parser.
    TypeToParserPluginMap _parserPluginMap;

    // The parser plugins.  This has ownership of the plugin objects.
    std::vector<std::unique_ptr<NdrParserPlugin>> _parserPlugins;

    // The preliminary discovery results prior to parsing. If accessing or
    // mutating, _discoveryResultMutex should be used.
    NdrNodeDiscoveryResultVec _discoveryResults;

    // Maps a node's name to a node instance. If accessing or mutating,
    // _nodeMapMutex should be used.
    NodeMap _nodeMap;

    // The source types that have been made available via parser plugins
    NdrTokenVec _availableSourceTypes;
};

PXR_NAMESPACE_CLOSE_SCOPE

#endif // NDR_REGISTRY_H