resolver.h

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//
// Copyright 2020 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_RESOLVER_H
#define PXR_USD_AR_RESOLVER_H


#include "pxr/pxr.h"
#include "pxr/usd/ar/api.h"
#include "pxr/usd/ar/ar.h"
#include "pxr/usd/ar/resolvedPath.h"
#include "pxr/usd/ar/resolverContext.h"
#include "pxr/usd/ar/timestamp.h"

#include <memory>
#include <string>
#include <vector>

PXR_NAMESPACE_OPEN_SCOPE

class ArAsset;
class ArAssetInfo;
class ArResolverContext;
class ArWritableAsset;
class TfType;
class VtValue;

class ArResolver 
{
public:
    AR_API
    virtual ~ArResolver();

    // Disallow copies
    ArResolver(const ArResolver&) = delete;
    ArResolver& operator=(const ArResolver&) = delete;

    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    std::string CreateIdentifier(
        const std::string& assetPath,
        const ArResolvedPath& anchorAssetPath = ArResolvedPath()) const;

    AR_API
    std::string CreateIdentifierForNewAsset(
        const std::string& assetPath,
        const ArResolvedPath& anchorAssetPath = ArResolvedPath()) const;


    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    ArResolvedPath Resolve(
        const std::string& assetPath) const;

    AR_API
    ArResolvedPath ResolveForNewAsset(
        const std::string& assetPath) const;


    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    void BindContext(
        const ArResolverContext& context,
        VtValue* bindingData);

    AR_API
    void UnbindContext(
        const ArResolverContext& context,
        VtValue* bindingData);

    AR_API
    ArResolverContext CreateDefaultContext() const;

    AR_API
    ArResolverContext CreateDefaultContextForAsset(
        const std::string& assetPath) const;

    AR_API
    ArResolverContext CreateContextFromString(
        const std::string& contextStr) const;

    AR_API
    ArResolverContext CreateContextFromString(
        const std::string& uriScheme, const std::string& contextStr) const;

    AR_API
    ArResolverContext CreateContextFromStrings(
        const std::vector<
            std::pair<std::string, std::string>>& contextStrs) const;

    AR_API
    void RefreshContext(
        const ArResolverContext& context);

    AR_API
    ArResolverContext GetCurrentContext() const;

    AR_API
    bool IsContextDependentPath(
        const std::string& assetPath) const;


    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    std::string GetExtension(
        const std::string& assetPath) const;

    AR_API
    ArAssetInfo GetAssetInfo(
        const std::string& assetPath,
        const ArResolvedPath& resolvedPath) const;

    AR_API
    ArTimestamp GetModificationTimestamp(
        const std::string& assetPath,
        const ArResolvedPath& resolvedPath) const;

    AR_API
    std::shared_ptr<ArAsset> OpenAsset(
        const ArResolvedPath& resolvedPath) const;

    enum class WriteMode
    {
        Update = 0, 

        Replace
    };

    AR_API
    std::shared_ptr<ArWritableAsset> OpenAssetForWrite(
        const ArResolvedPath& resolvedPath,
        WriteMode writeMode) const;

    AR_API
    bool CanWriteAssetToPath(
        const ArResolvedPath& resolvedPath,
        std::string* whyNot = nullptr) const;


    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    void BeginCacheScope(
        VtValue* cacheScopeData);

    AR_API
    void EndCacheScope(
        VtValue* cacheScopeData);


    // --------------------------------------------------------------------- //
    // --------------------------------------------------------------------- //

    AR_API
    bool IsRepositoryPath(const std::string& path) const;


protected:
    AR_API
    ArResolver();

    // --------------------------------------------------------------------- //

    virtual std::string _CreateIdentifier(
        const std::string& assetPath,
        const ArResolvedPath& anchorAssetPath) const = 0;

    virtual std::string _CreateIdentifierForNewAsset(
        const std::string& assetPath,
        const ArResolvedPath& anchorAssetPath) const = 0;

    virtual ArResolvedPath _Resolve(
        const std::string& assetPath) const = 0;

    virtual ArResolvedPath _ResolveForNewAsset(
        const std::string& assetPath) const = 0;


    // --------------------------------------------------------------------- //

    AR_API
    virtual void _BindContext(
        const ArResolverContext& context,
        VtValue* bindingData);

    AR_API
    virtual void _UnbindContext(
        const ArResolverContext& context,
        VtValue* bindingData);

    AR_API
    virtual ArResolverContext _CreateDefaultContext() const;

    AR_API
    virtual ArResolverContext _CreateDefaultContextForAsset(
        const std::string& assetPath) const;

    AR_API
    virtual ArResolverContext _CreateContextFromString(
        const std::string& contextStr) const;

    AR_API
    virtual void _RefreshContext(
        const ArResolverContext& context);

    AR_API
    virtual ArResolverContext _GetCurrentContext() const;

    AR_API
    virtual bool _IsContextDependentPath(
        const std::string& assetPath) const;


    // --------------------------------------------------------------------- //

    AR_API
    virtual std::string _GetExtension(
        const std::string& assetPath) const;

    AR_API
    virtual ArAssetInfo _GetAssetInfo(
        const std::string& assetPath,
        const ArResolvedPath& resolvedPath) const;

    AR_API
    virtual ArTimestamp _GetModificationTimestamp(
        const std::string& assetPath,
        const ArResolvedPath& resolvedPath) const;

    AR_API
    virtual std::shared_ptr<ArAsset> _OpenAsset(
        const ArResolvedPath& resolvedPath) const = 0;

    AR_API
    virtual bool _CanWriteAssetToPath(
        const ArResolvedPath& resolvedPath,
        std::string* whyNot) const;

    AR_API
    virtual std::shared_ptr<ArWritableAsset>
    _OpenAssetForWrite(
        const ArResolvedPath& resolvedPath,
        WriteMode writeMode) const = 0;


    // --------------------------------------------------------------------- //

    AR_API
    virtual void _BeginCacheScope(
        VtValue* cacheScopeData);

    AR_API
    virtual void _EndCacheScope(
        VtValue* cacheScopeData);


    AR_API
    virtual bool _IsRepositoryPath(
        const std::string& path) const;

    // --------------------------------------------------------------------- //

    template <class ContextObj>
    const ContextObj* _GetCurrentContextObject() const
    {
        const ArResolverContext* ctx = _GetInternallyManagedCurrentContext();
        return ctx ? ctx->Get<ContextObj>() : nullptr;
    }


private:
    // Returns pointer to ArResolverContext that was most recently bound
    // via BindContext. This is *not* the same as GetCurrentContext,
    // since subclasses may return an ArResolverContext that hasn't
    // been bound via BindContext in their implementations.
    AR_API
    const ArResolverContext* _GetInternallyManagedCurrentContext() const;

};

AR_API
ArResolver& ArGetResolver();

AR_API
void ArSetPreferredResolver(const std::string& resolverTypeName);


AR_API
ArResolver& ArGetUnderlyingResolver();

AR_API
std::vector<TfType> ArGetAvailableResolvers();

AR_API
std::unique_ptr<ArResolver> ArCreateResolver(const TfType& resolverType);


PXR_NAMESPACE_CLOSE_SCOPE

#endif