collectionMembershipQuery.h

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//
// 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 PXR_USD_USD_COLLECTION_MEMBERSHIP_QUERY_H
#define PXR_USD_USD_COLLECTION_MEMBERSHIP_QUERY_H
 
 
#include "pxr/base/tf/declarePtrs.h"
#include "pxr/pxr.h"
#include "pxr/usd/sdf/path.h"
#include "pxr/usd/sdf/pathExpression.h"
#include "pxr/usd/sdf/pathExpressionEval.h"
#include "pxr/usd/usd/common.h"
#include "pxr/usd/usd/primFlags.h"
#include "pxr/usd/usd/collectionPredicateLibrary.h"
 
#include <unordered_map>
 
PXR_NAMESPACE_OPEN_SCOPE
 
// -------------------------------------------------------------------------- //
// UsdCollectionMembershipQuery                                               //
// -------------------------------------------------------------------------- //
class UsdCollectionMembershipQuery
{
public:
 
    class ExpressionEvaluator {
        struct ObjToPath {
            SdfPath operator()(UsdObject const &obj) const {
                return obj.GetPath();
            }
        };
        
        struct PathToObj {
            UsdObject operator()(SdfPath const &path) const {
                return stage->GetObjectAtPath(path);
            }
            UsdStageWeakPtr stage;
        };
        
    public:
        using PathExprEval = SdfPathExpressionEval<UsdObject>;
        using IncrementalSearcher =
            typename PathExprEval::IncrementalSearcher<ObjToPath, PathToObj>;
 
        ExpressionEvaluator() = default;
 
        SDF_API
        ExpressionEvaluator(UsdStageWeakPtr const &stage,
                            SdfPathExpression const &expr);
 
        bool IsEmpty() const {
            return !_stage || _evaluator.IsEmpty();
        }
 
        UsdStageWeakPtr const &GetStage() const { return _stage; }
 
        SDF_API
        SdfPredicateFunctionResult
        Match(UsdObject const &object) const;
 
        SDF_API
        IncrementalSearcher MakeIncrementalSearcher() const;
        
    private:
        UsdStageWeakPtr _stage;
        PathExprEval _evaluator;
    };
    
    using PathExpansionRuleMap = std::unordered_map<SdfPath,
          TfToken, SdfPath::Hash>;
 
    UsdCollectionMembershipQuery() = default;
 
    UsdCollectionMembershipQuery(
        const PathExpansionRuleMap& pathExpansionRuleMap,
        const SdfPathSet& includedCollections);
 
    UsdCollectionMembershipQuery(
        PathExpansionRuleMap&& pathExpansionRuleMap,
        SdfPathSet&& includedCollections);
 
    UsdCollectionMembershipQuery(
        const PathExpansionRuleMap& pathExpansionRuleMap,
        const SdfPathSet& includedCollections,
        const ExpressionEvaluator &exprEval,
        const TfToken &topExpansionRule);
 
    UsdCollectionMembershipQuery(
        PathExpansionRuleMap&& pathExpansionRuleMap,
        SdfPathSet&& includedCollections,
        ExpressionEvaluator &&exprEval,
        TfToken const &topExpansionRule);
    
    USD_API
    bool IsPathIncluded(const SdfPath &path,
                        TfToken *expansionRule=nullptr) const;
 
    USD_API
    bool IsPathIncluded(const SdfPath &path,
                        const TfToken &parentExpansionRule,
                        TfToken *expansionRule=nullptr) const;
 
    bool HasExcludes() const {
        return _hasExcludes;
    }
    
    bool operator==(UsdCollectionMembershipQuery const& rhs) const {
        // Note that MembershipQuery objects that have non-empty _exprEval never
        // compare equal to each other.  This is because the evaluator objects
        // run code, and there's no good way to determine equivalence.
        return _topExpansionRule == rhs._topExpansionRule &&
        _hasExcludes == rhs._hasExcludes &&
        _pathExpansionRuleMap == rhs._pathExpansionRuleMap &&
        _includedCollections == rhs._includedCollections &&
        _exprEval.IsEmpty() == rhs._exprEval.IsEmpty();
        ;
    }
 
    bool operator!=(UsdCollectionMembershipQuery const& rhs) const {
        return !(*this == rhs);
    }
 
    struct Hash {
        USD_API
        size_t operator()(UsdCollectionMembershipQuery const& query) const;
    };
 
    inline size_t GetHash() const {
        return Hash()(*this);
    }
 
    const PathExpansionRuleMap& GetAsPathExpansionRuleMap() const {
        return _pathExpansionRuleMap;
    }
 
    const SdfPathSet& GetIncludedCollections() const {
        return _includedCollections;
    }
 
    ExpressionEvaluator const &
    GetExpressionEvaluator() const {
        return _exprEval;
    }
 
    bool HasExpression() const {
        return !_exprEval.IsEmpty();
    }
 
    TfToken GetTopExpansionRule() const {
        return _topExpansionRule;
    }
 
private:
    TfToken _topExpansionRule;
    
    PathExpansionRuleMap _pathExpansionRuleMap;
 
    SdfPathSet _includedCollections;
 
    ExpressionEvaluator _exprEval;
 
    // A cached flag indicating whether _pathExpansionRuleMap contains
    // any exclude rules.
    bool _hasExcludes=false;
};
 
USD_API
std::set<UsdObject> UsdComputeIncludedObjectsFromCollection(
    const UsdCollectionMembershipQuery &query,
    const UsdStageWeakPtr &stage,
    const Usd_PrimFlagsPredicate &pred=UsdPrimDefaultPredicate);
 
USD_API
SdfPathSet UsdComputeIncludedPathsFromCollection(
    const UsdCollectionMembershipQuery &query,
    const UsdStageWeakPtr &stage,
    const Usd_PrimFlagsPredicate &pred=UsdPrimDefaultPredicate);
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif