expressionVariables.h

//
// Copyright 2023 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_PCP_EXPRESSION_VARIABLES_H
#define PXR_USD_PCP_EXPRESSION_VARIABLES_H
 
#include "pxr/pxr.h"
#include "pxr/usd/pcp/api.h"
#include "pxr/usd/pcp/layerStackIdentifier.h"
#include "pxr/usd/pcp/expressionVariablesSource.h"
 
#include "pxr/base/vt/dictionary.h"
 
#include <utility>
#include <unordered_map>
 
PXR_NAMESPACE_OPEN_SCOPE
 
class PcpExpressionVariables
{
public:
    PCP_API
    static PcpExpressionVariables
    Compute(
        const PcpLayerStackIdentifier& sourceLayerStackId,
        const PcpLayerStackIdentifier& rootLayerStackId,
        const PcpExpressionVariables* overrideExpressionVars = nullptr);
 
    PcpExpressionVariables() = default;
 
    PcpExpressionVariables(
        const PcpExpressionVariablesSource& source,
        const VtDictionary& expressionVariables)
        : PcpExpressionVariables(
            PcpExpressionVariablesSource(source),
            VtDictionary(expressionVariables))
    { }
 
    PcpExpressionVariables(
        PcpExpressionVariablesSource&& source,
        VtDictionary&& expressionVariables)
        : _source(std::move(source))
        , _expressionVariables(std::move(expressionVariables))
    { }
 
    bool operator==(const PcpExpressionVariables& rhs) const
    { 
        return (this == &rhs) || 
        (std::tie(_source, _expressionVariables) == 
         std::tie(rhs._source, rhs._expressionVariables));
    }
 
    bool operator!=(const PcpExpressionVariables& rhs) const
    { 
        return !(*this == rhs);
    }
 
    const PcpExpressionVariablesSource& GetSource() const
    { return _source; }
 
    const VtDictionary& GetVariables() const
    { return _expressionVariables; }
 
    void SetVariables(const VtDictionary& variables)
    { _expressionVariables = variables; }
 
private:
    PcpExpressionVariablesSource _source;
    VtDictionary _expressionVariables;
};
 
// ------------------------------------------------------------
 
class PcpExpressionVariableCachingComposer
{
public:
    PCP_API
    explicit PcpExpressionVariableCachingComposer(
        const PcpLayerStackIdentifier& rootLayerStackIdentifier);
 
    PCP_API
    const PcpExpressionVariables&
    ComputeExpressionVariables(const PcpLayerStackIdentifier& id);
 
private:
    PcpLayerStackIdentifier _rootLayerStackId;
 
    using _IdentifierToExpressionVarsMap = std::unordered_map<
        PcpLayerStackIdentifier, PcpExpressionVariables, TfHash>;
    _IdentifierToExpressionVarsMap _identifierToExpressionVars;
};
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif