IObject.h

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//-*****************************************************************************
//
// Copyright (c) 2009-2013,
//  Sony Pictures Imageworks, Inc. and
//  Industrial Light & Magic, a division of Lucasfilm Entertainment Company Ltd.
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// *       Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// *       Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// *       Neither the name of Sony Pictures Imageworks, nor
// Industrial Light & Magic nor the names of their contributors may be used
// to endorse or promote products derived from this software without specific
// prior written permission.
//
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//-*****************************************************************************

#ifndef Alembic_Abc_IObject_h
#define Alembic_Abc_IObject_h

#include <Alembic/Util/Export.h>
#include <Alembic/Abc/Foundation.h>
#include <Alembic/Abc/Base.h>
#include <Alembic/Abc/Argument.h>
#include <Alembic/Abc/IArchive.h>

namespace Alembic {
namespace Abc {
namespace ALEMBIC_VERSION_NS {

class ICompoundProperty;

//-*****************************************************************************
class ALEMBIC_EXPORT IObject : public Base
{
public:
    //! By convention, we always define "this_type" in every Abc
    //! class. This convention is relied upon by the unspecified-bool-type
    //! conversion.
    typedef IObject this_type;
    typedef IObject operator_bool_base_type;

    //-*************************************************************************
    // CONSTRUCTION, DESTRUCTION, ASSIGNMENT
    //-*************************************************************************

    //! The default constructor creates an empty IObject function set.
    //! ...
    IObject() {}

    //! This function creates a new object reader.
    //! The first argument is the Abc IObject parent from which the error
    //! handler policy for inheritance is also derived.  The remaining optional
    //! arguments can be used to override the ErrorHandlerPolicy.
    IObject( const IObject & iParent,
             const std::string &iName,
             const Argument &iArg0 = Argument() )
    {
        init( iParent.getPtr(),
              iName,
              GetErrorHandlerPolicy( iParent, iArg0 ) );

        initInstance();
    }

    //! This attaches an IObject wrapper around an existing
    //! ObjectReaderPtr, with an optional error handling policy.
    IObject( AbcA::ObjectReaderPtr iPtr,
             const Argument &iArg0 = Argument() )
        : m_object( GetObjectReaderPtr( iPtr ) )
    {
        // Set the error handling policy
        getErrorHandler().setPolicy(
            GetErrorHandlerPolicy( iPtr, iArg0 ) );

        initInstance();
    }

    // Deprecated in favor of the constructor above
    IObject( AbcA::ObjectReaderPtr iPtr,
             WrapExistingFlag /* iFlag */,
             const Argument &iArg0 = Argument() )
        : m_object( GetObjectReaderPtr( iPtr ) )
    {
        // Set the error handling policy
        getErrorHandler().setPolicy(
            GetErrorHandlerPolicy( iPtr, iArg0 ) );

        initInstance();
    }

    //! This attaches an IObject wrapper around the top
    //! object of an archive.
    IObject( IArchive & iArchive,
             const Argument &iArg0 = Argument() )
    {
        init( iArchive, iArg0 );
    }

    // Deprecated in favor of the constructor above
    IObject( IArchive & iArchive,
             TopFlag iFlag,
             const Argument &iArg0 = Argument() )
    {
        init( iArchive, iArg0 );
    }

    //! Default copy constructor used
    //! Default assignment operator used.

    //! Destructor
    //! ...
    virtual ~IObject();

    //-*************************************************************************
    // OBJECT READER FUNCTIONALITY
    //-*************************************************************************

    //! All objects have a header, which contains all the MetaData that was
    //! specified upon their creation.
    //! This function returns a constant reference to that Header.
    const AbcA::ObjectHeader &getHeader() const;

    //! All objects have a name. This name is unique amongst their siblings
    //! Returned by reference, since it is guaranteed to exist and be
    //! unchanging.
    //! This is a convenience function which returns the header's name.
    const std::string &getName() const;

    //! The full name of an object is the complete path name all the way
    //! to the root object of the archive. It is guaranteed to be fully
    //! unique within the entire archive.
    //! This is a convenience function which returns the header's full name.
    const std::string &getFullName() const;

    //! All objects have metadata. This metadata is identical to the
    //! Metadata of the top level compoundProperty "properties".
    //! Because the metadata must exist and be initialized in order to
    //! bootstrap the object, it is guaranteed to exist and is returned
    //! by reference.
    //! This is a convenience function which returns the header's MetaData.
    const AbcA::MetaData &getMetaData() const
    { return getHeader().getMetaData(); }

    //! This function returns the object's archive, handily
    //! wrapped in an IArchive wrapper.
    IArchive getArchive() const;

    //! This function returns the object's parent, handily
    //! wrapped in an IObject wrapper. If the object is the top
    //! level object, the IObject returned will be NULL.
    IObject getParent() const;

    //! This function returns the number of child objects that
    //! this object has.
    size_t getNumChildren() const;

    //! This function returns the headers of each of the child
    //! objects that were written as children of this object.
    const AbcA::ObjectHeader & getChildHeader( size_t i ) const;

    //! Return the header of an object by name.
    //! This will return a NULL pointer if no header by that name is found.
    const AbcA::ObjectHeader *
    getChildHeader( const std::string &iName ) const;

    //! This returns the single top-level CompoundPropertyReader that exists
    //! automatically as part of the object.
    ICompoundProperty getProperties() const;

    //-*************************************************************************
    // ADVANCED TOOLS
    // Unless you really know why you need to be using these next few
    // functions, they're probably best left alone. The right way to create
    // an IObject is to actually call its constructor.
    //-*************************************************************************

    //! This function returns an IObject constructed from the indexed
    //! object.
    IObject getChild( size_t iChildIndex ) const;

    //! This function returns an IObject wrapped constructed from the
    //! header referenced by the name. If the child of the given name
    //! does not exist, this will fail in the same way as if the
    //! equivalent constructor was called.
    IObject getChild( const std::string &iChildName ) const;

    //!-************************************************************************
    // INSTANCE METHODS
    // An IObject can refer to another IObject in the same cache and stand in
    // as an instance for that target hierarchy. On disk only the instance
    // object is required. When read in however, a normal hierarchy is
    // returned. Optionally, client code could use the isInstanceRoot() and
    // instanceSourcePath() methods to discover that the hierarchies are
    // duplicate and instance them appropriately in memory.
    //!-************************************************************************

    //! Returns whether this object directly instances another object.
    bool isInstanceRoot() const;

    //! Returns whether this object has been arrived at via an instance, or if
    //! this object is an instance itself.
    bool isInstanceDescendant() const;

    //! If this object is an instance (isInstanceRoot), returns the source path
    //! that the instance points at.  Otherwise and empty string is returned.
    std::string instanceSourcePath() const;

    bool isChildInstance(size_t iChildIndex) const;
    bool isChildInstance(const std::string &iChildName) const;

    //! Returns the original ObjectReaderPtr, if this object is an instance
    AbcA::ObjectReaderPtr getInstancePtr() const { return m_instanceObject; }

    //-*************************************************************************
    // ABC BASE MECHANISMS
    // These functions are used by Abc to deal with errors, rewrapping,
    // and so on.
    //-*************************************************************************

    //! getPtr, as usual, returns a shared ptr to the
    //! underlying AbcCoreAbstract object, in this case the
    //! ObjectReaderPtr.  If this object happens to be an instance, it points
    //! to the instance source ObjectReaderPtr
    AbcA::ObjectReaderPtr getPtr() const { return m_object; }

    //! Reset returns this function set to an empty, default state.
    void reset();

    //! Valid returns whether this function set is
    //! valid.
    bool valid() const
    {
        return ( Base::valid() && m_object );
    }

    //! If an aggregated properties hash exists fill oDigest with it and
    //! return true, if it doesn't exist return false
    bool getPropertiesHash( Util::Digest & oDigest );

    //! If an aggregated child objects hash exists fill oDigest with it and
    //! return true, if it doesn't exist return false
    bool getChildrenHash( Util::Digest & oDigest );

    //! The unspecified-bool-type operator casts the object to "true"
    //! if it is valid, and "false" otherwise.
    ALEMBIC_OPERATOR_BOOL( valid() );

public:
    AbcA::ObjectReaderPtr m_object;

private:

    void init( IArchive & iArchive, const Argument &iArg0 );

    void init( AbcA::ObjectReaderPtr iParentObject,
               const std::string &iName,
               ErrorHandler::Policy iPolicy );

    void initInstance();

    void setInstancedFullName(const std::string& parentPath) const;

    // This is the "original" object when it is an instance (not the source)
    AbcA::ObjectReaderPtr m_instanceObject;

    // All IObject ancestors of an instance object have these set.
    mutable std::string m_instancedFullName;
};

typedef Alembic::Util::shared_ptr< IObject > IObjectPtr;

//-*****************************************************************************
inline AbcA::ObjectReaderPtr
GetObjectReaderPtr( IObject& iPrp ) { return iPrp.getPtr(); }

//-*****************************************************************************
// TEMPLATE AND INLINE FUNCTIONS
//-*****************************************************************************

template <class OBJ>
inline ErrorHandler::Policy GetErrorHandlerPolicy( OBJ iObj,
                                                   ErrorHandler::Policy iPcy )
{
    Argument arg( iPcy );
    return GetErrorHandlerPolicy( iObj, arg );
}

} // End namespace ALEMBIC_VERSION_NS

using namespace ALEMBIC_VERSION_NS;

} // End namespace Abc
} // End namespace Alembic

#endif