defaultResolverContext.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 PXR_USD_AR_DEFAULT_RESOLVER_CONTEXT_H
#define PXR_USD_AR_DEFAULT_RESOLVER_CONTEXT_H

/// \file ar/defaultResolverContext.h

#include "pxr/pxr.h"
#include "pxr/usd/ar/api.h"
#include "pxr/usd/ar/defineResolverContext.h"

#include <string>
#include <vector>

PXR_NAMESPACE_OPEN_SCOPE

/// \class ArDefaultResolverContext
///
/// Resolver context object that specifies a search path to use during
/// asset resolution. This object is intended for use with the default
/// ArDefaultResolver asset resolution implementation; see documentation for
/// that class for more details on the search path resolution algorithm.
///
/// Example usage:
/// \code
/// ArDefaultResolverContext ctx({"/Local/Models", "/Installed/Models"});
/// {
///     // Bind the context object:
///     ArResolverContextBinder binder(ctx);
///
///    // While the context is bound, all calls to ArResolver::Resolve
///    // (assuming ArDefaultResolver is the underlying implementation being
///    // used) will include the specified paths during resolution.
///    std::string resolvedPath = resolver.Resolve("ModelName/File.txt")
/// }
///
/// // Once the context is no longer bound (due to the ArResolverContextBinder
/// // going out of scope), its search path no longer factors into asset
/// // resolution.
/// \endcode
///
class ArDefaultResolverContext
{
public:
    /// Default construct a context with no search path.
    ArDefaultResolverContext() = default;        

    /// Construct a context with the given \p searchPath.
    /// Elements in \p searchPath should be absolute paths. If they are not,
    /// they will be anchored to the current working directory.
    AR_API ArDefaultResolverContext(const std::vector<std::string>& searchPath);

    AR_API bool operator<(const ArDefaultResolverContext& rhs) const;
    AR_API bool operator==(const ArDefaultResolverContext& rhs) const;
    AR_API bool operator!=(const ArDefaultResolverContext& rhs) const;

    /// Return this context's search path.
    const std::vector<std::string>& GetSearchPath() const
    {
        return _searchPath;
    }

    /// Return a string representation of this context for debugging.
    AR_API std::string GetAsString() const;

private:
    std::vector<std::string> _searchPath;
};

AR_API size_t 
hash_value(const ArDefaultResolverContext& context);

inline std::string 
ArGetDebugString(const ArDefaultResolverContext& context)
{
    return context.GetAsString();
}

AR_DECLARE_RESOLVER_CONTEXT(ArDefaultResolverContext);

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_USD_AR_DEFAULT_RESOLVER_CONTEXT_H