HUSD_DataHandle.h

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/*
 * Copyright 2019 Side Effects Software Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef __HUSD_DataHandle_h__
#define __HUSD_DataHandle_h__

#include "HUSD_API.h"
#include <UT/UT_Assert.h>
#include <UT/UT_Function.h>
#include <UT/UT_IntrusivePtr.h>
#include <UT/UT_NonCopyable.h>
#include <UT/UT_Set.h>
#include <UT/UT_SharedPtr.h>
#include <UT/UT_StringArray.h>
#include <UT/UT_StringHolder.h>
#include <UT/UT_StringMap.h>
#include <UT/UT_StringSet.h>
#include <UT/UT_WeakPtr.h>
#include <pxr/pxr.h>

class UT_Color;
class UT_StringArray;
class HUSD_FindPrims;
class HUSD_MirrorRootLayer;

class HUSD_Overrides;
typedef UT_IntrusivePtr<HUSD_Overrides>          HUSD_OverridesPtr;
typedef UT_IntrusivePtr<const HUSD_Overrides>    HUSD_ConstOverridesPtr;
class HUSD_PostLayers;
typedef UT_IntrusivePtr<HUSD_PostLayers>         HUSD_PostLayersPtr;
typedef UT_IntrusivePtr<const HUSD_PostLayers>   HUSD_ConstPostLayersPtr;

class HUSD_LockedStage;
typedef UT_SharedPtr<HUSD_LockedStage> HUSD_LockedStagePtr;
typedef UT_Set<HUSD_LockedStagePtr> HUSD_LockedStageSet;
typedef UT_WeakPtr<HUSD_LockedStage> HUSD_LockedStageWeakPtr;

// Use a SharedPtr instead of an IntrusivePtr for HUSD_LoadMasks because we
// want to be able to copy these objects.
class HUSD_LoadMasks;
typedef UT_SharedPtr<HUSD_LoadMasks>             HUSD_LoadMasksPtr;

PXR_NAMESPACE_OPEN_SCOPE

class XUSD_Data;
typedef UT_IntrusivePtr<XUSD_Data>               XUSD_DataPtr;
typedef UT_IntrusivePtr<const XUSD_Data>         XUSD_ConstDataPtr;
class XUSD_Layer;
typedef UT_IntrusivePtr<XUSD_Layer>              XUSD_LayerPtr;
typedef UT_IntrusivePtr<const XUSD_Layer>        XUSD_ConstLayerPtr;
class XUSD_DataLock;
typedef UT_IntrusivePtr<XUSD_DataLock>           XUSD_DataLockPtr;
class XUSD_LockedGeo;
typedef UT_IntrusivePtr<XUSD_LockedGeo>          XUSD_LockedGeoPtr;
typedef UT_Set<XUSD_LockedGeoPtr>                XUSD_LockedGeoSet;
template <class T> class TfRefPtr;
class SdfLayer;
typedef TfRefPtr<SdfLayer> SdfLayerRefPtr;
typedef UT_Array<SdfLayerRefPtr> XUSD_LayerArray;
typedef UT_Set<SdfLayerRefPtr> XUSD_LayerSet;

PXR_NAMESPACE_CLOSE_SCOPE

enum HUSD_MirroringType {
    HUSD_NOT_FOR_MIRRORING,
    HUSD_FOR_MIRRORING,
    HUSD_EXTERNAL_STAGE,
};

typedef UT_Function<UT_StringHolder(const UT_StringRef &oldpath)>
    HUSD_MakeNewPathFunc;

class HUSD_API HUSD_DataHandle
{
public:
                                 HUSD_DataHandle(HUSD_MirroringType
                                        mirroring = HUSD_NOT_FOR_MIRRORING);
                                 HUSD_DataHandle(const HUSD_DataHandle &src);
    explicit                     HUSD_DataHandle(void *stage_ptr);
    explicit                     HUSD_DataHandle(const UT_StringRef &filepath);
                                ~HUSD_DataHandle();

    // Test if myData has been set.
    bool                         hasData() const;
    // Compare the resolver context on this data handle with another.
    bool                         matchesResolverContext(
                                        const HUSD_DataHandle &other) const;

    void                         reset(int nodeid);
    const HUSD_DataHandle       &operator=(const HUSD_DataHandle &src);
    // Create a new, empty stage in our XUSD_Data.
    void                         createNewData(
                                        const HUSD_LoadMasksPtr &
                                            load_masks = HUSD_LoadMasksPtr(),
                                        const HUSD_DataHandle *
                                            resolver_context_data = nullptr);
    // Share the stage from the src XUSD_Data object, unless the load_masks
    // is supplied, in which case we may need to create a new stage with the
    // specified load masks.
    bool                         createSoftCopy(const HUSD_DataHandle &src,
                                        const HUSD_LoadMasksPtr &load_masks,
                                        bool make_new_implicit_layer);
    // Create a new stage that is a copy of the src stage, but replacing any
    // composition of the "frompath" with the "topath". This check works
    // recursively, which may require performing other layer replacements
    // as we make modified versions of referencing layers (and layers that
    // reference those layers, and so on).
    bool                         createCopyWithReplacement(
                                        const HUSD_DataHandle &src,
                                        const UT_StringRef &frompath,
                                        const UT_StringRef &topath,
                                        HUSD_MakeNewPathFunc make_new_path,
                                        UT_StringSet &replaced_layers);
    // Make a new stage by flattening the layer stack of our current stage.
    bool                         flattenLayers();
    // Make a new stage by flattening our current stage.
    bool                         flattenStage();

    // For an HUSD_FOR_MIRRORING data handle, create a duplicate of the src
    // data handle's stage and layer stack.
    bool                         mirror(const HUSD_DataHandle &src,
                                        const HUSD_LoadMasks &load_masks);
    void                         clearMirror();

    // For an HUSD_FOR_MIRRORING data handle, update our stage's root layer
    // with the information in the HUSD_MirrorRootLayer. This is currently
    // just a description of the viewport camera.
    bool                         mirrorUpdateRootLayer(
                                        const HUSD_MirrorRootLayer &rootlayer);

    bool                         hasLayerColorIndex(int &clridx) const;
    int                          layerCount() const;
    int                          nodeId() const
                                 { return myNodeId; }
    HUSD_LoadMasksPtr            loadMasks() const;
    const std::string           &rootLayerIdentifier() const;

    bool                         isLocked() const;
    PXR_NS::XUSD_ConstDataPtr    readLock(
                                        const HUSD_ConstOverridesPtr
                                            &overrides,
                                        const HUSD_ConstPostLayersPtr
                                            &postlayers,
                                        bool remove_layer_break) const;
    PXR_NS::XUSD_DataPtr         writeOverridesLock(
                                        const HUSD_OverridesPtr
                                            &overrides) const;
    PXR_NS::XUSD_DataPtr         writeLock() const;
    PXR_NS::XUSD_LayerPtr        layerLock(PXR_NS::XUSD_DataPtr &data,
                                        bool create_change_block) const;
    void                         release() const;

    // Return true if this data handle's node was the most recent node to
    // create a lock on the stage we may be sharing with many other nodes.
    bool                         isMostRecentStageLock() const;

    // Clear out all mirrored stages completely. They must be rebuilt from
    // scratch the next time they are asked to mirror a stage.
    static void                  clearAllMirroredData();

private:
    HUSD_ConstOverridesPtr       currentOverrides() const;
    HUSD_ConstPostLayersPtr      currentPostLayers() const;

    friend class HUSD_AutoReadLock;

    PXR_NS::XUSD_DataPtr         myData;
    PXR_NS::XUSD_DataLockPtr     myDataLock;
    HUSD_MirroringType           myMirroring;
    int                          myNodeId;
};

// Parent class for read and write locks that permits reading.
class HUSD_API HUSD_AutoAnyLock : UT_NonCopyable
{
public:
    explicit                             HUSD_AutoAnyLock(
                                                const HUSD_DataHandle &handle)
                                            : myHandle(handle)
                                         { }
    virtual                             ~HUSD_AutoAnyLock()
                                         { }

    bool                                 isStageValid() const;
    const HUSD_DataHandle               &dataHandle() const
                                         { return myHandle; }
    virtual PXR_NS::XUSD_ConstDataPtr    constData() const = 0;

private:
    const HUSD_DataHandle               &myHandle;
};

// Locks an HUSD_DataHandle for read-only operations.
class HUSD_API HUSD_AutoReadLock : public HUSD_AutoAnyLock
{
public:
    enum HUSD_OverridesUnchangedType { OVERRIDES_UNCHANGED };
    enum HUSD_RemoveLayerBreaksType { REMOVE_LAYER_BREAKS, KEEP_LAYER_BREAKS };

    explicit                             HUSD_AutoReadLock(
                                                const HUSD_DataHandle &handle);
    explicit                             HUSD_AutoReadLock(
                                                const HUSD_DataHandle &handle,
                                                HUSD_OverridesUnchangedType);
    explicit                             HUSD_AutoReadLock(
                                                const HUSD_DataHandle &handle,
                                                const HUSD_ConstOverridesPtr
                                                    &overrides,
                                                const HUSD_ConstPostLayersPtr
                                                    &postlayers,
                                                HUSD_RemoveLayerBreaksType
                                                    lbtype = KEEP_LAYER_BREAKS);
                                        ~HUSD_AutoReadLock() override;

    const PXR_NS::XUSD_ConstDataPtr     &data() const
                                         { return myData; }
    PXR_NS::XUSD_ConstDataPtr            constData() const override;

private:
    PXR_NS::XUSD_ConstDataPtr            myData;
};

// Locks an HUSD_DataHandle in a way that allows read-only operations on the
// data, but write access to the supplied overrides layer.
class HUSD_API HUSD_AutoWriteOverridesLock : public HUSD_AutoAnyLock
{
public:
    explicit                             HUSD_AutoWriteOverridesLock(
                                                const HUSD_DataHandle &handle,
                                                const HUSD_OverridesPtr
                                                    &overrides);
                                        ~HUSD_AutoWriteOverridesLock() override;

    const PXR_NS::XUSD_DataPtr          &data() const
                                         { return myData; }
    const HUSD_OverridesPtr             &overrides() const
                                         { return myOverrides; }
    PXR_NS::XUSD_ConstDataPtr            constData() const override;

private:
    PXR_NS::XUSD_DataPtr                 myData;
    HUSD_OverridesPtr                    myOverrides;
};

// Locks an HUSD_DataHandle for writing to the active layer in the context
// of the current stage.
class HUSD_API HUSD_AutoWriteLock : public HUSD_AutoAnyLock
{
public:
    explicit                             HUSD_AutoWriteLock(
                                                const HUSD_DataHandle &handle);
                                        ~HUSD_AutoWriteLock() override;

    const PXR_NS::XUSD_DataPtr          &data() const
                                         { return myData; }
    void                                 addLockedStages(const
                                            HUSD_LockedStageSet &stages);
    PXR_NS::XUSD_ConstDataPtr            constData() const override;

private:
    PXR_NS::XUSD_DataPtr                 myData;
};

// Locks an HUSD_DataHandle for writing to the active layer outside the
// context of the current stage (which is accessible read-only while editing
// this off-stage layer).
//
// A layer lock can be constructed from an HUSD_AutoWriteLock as well. This
// doesn't re-lock the data handle, but instead grabs from the write lock all
// the data it needs to implement the interface of this class. If the
// ScopedLock flag is passed as a second argument, an SdfChangeBlock is
// created for the lifetime of this object. This is only safe if this
// object will be destroyed before the next time the WriteLock is used
// to edit the stage.
class HUSD_API HUSD_AutoLayerLock : public HUSD_AutoAnyLock
{
public:
    enum ChangeBlockTag {
        ChangeBlock,
        NoChangeBlock
    };

    explicit                             HUSD_AutoLayerLock(
                                                const HUSD_DataHandle &handle,
                                                ChangeBlockTag change_block =
                                                    ChangeBlock);
    explicit                             HUSD_AutoLayerLock(
                                                const HUSD_AutoWriteLock &lock,
                                                ChangeBlockTag change_block =
                                                    NoChangeBlock);
                                        ~HUSD_AutoLayerLock() override;

    const PXR_NS::XUSD_LayerPtr         &layer() const
                                         { return myLayer; }
    void                                 addLockedGeos(const PXR_NS::
                                            XUSD_LockedGeoSet &lockedgeos);
    void                                 addHeldLayers(const PXR_NS::
                                            XUSD_LayerSet &layers);
    void                                 addReplacements(const PXR_NS::
                                            XUSD_LayerSet &replacements);
    void                                 addLockedStages(const
                                            HUSD_LockedStageSet &stages);
    PXR_NS::XUSD_ConstDataPtr            constData() const override;

private:
    PXR_NS::XUSD_DataPtr                 myData;
    PXR_NS::XUSD_LayerPtr                myLayer;
    bool                                 myOwnsHandleLock;
};

#endif