HOM_Module.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * COMMENTS:
 *     This class is not directly wrapped by swig.  However, when creating
 *     the swig wrapper modules we wrap each of the methods of this class
 *     in functions in $SHC/HOM/HOM_TopLevel.h.  This way, the methods of this
 *     class appear as the top-level parts of the hou module.
 *     Note that this also means SWIGOUT(%newobject fooMethod;) directives are
 *     not here but in HOM_TopLevel.h instead.
 */

#ifndef __HOM_Module_h__
#define __HOM_Module_h__

#include "HOM_API.h"
#include "HOM_BinaryString.h"
#include "HOM_Defines.h"
#include "HOM_Errors.h"
#include "HOM_ElemPtr.h"
#include "HOM_EnumModules.h"
#include <PY/PY_InterpreterAutoLock.h>
#include <UT/UT_Lock.h>
#include <UT/UT_NonCopyable.h>
#include <UT/UT_Notifier.h>
#include <UT/UT_TaskLock.h>
#include <UT/UT_Thread.h>
#include <UT/UT_UniquePtr.h>
#include <UT/UT_OptionEntry.h>
#include <SYS/SYS_Types.h>
#include <typeinfo>
#include <string>
#include <vector>
#include <map>
#include <hboost/any.hpp>

class OP_Node;
class STORUI_OrboltURLHandler;

class HOM_AdvancedDrawable;
class HOM_AgentClip;
class HOM_AgentDefinition;
class HOM_AgentLayer;
class HOM_AgentMetadata;
class HOM_AgentRig;
class HOM_AgentShape;
class HOM_AgentShapeBinding;
class HOM_AgentShapeDeformer;
class HOM_AgentShapeLibrary;
class HOM_AgentTransformGroup;
class HOM_ApexNode;
class HOM_ApexNodeConnection;
class HOM_ApexStickyNote;
class HOM_AssetGalleryDataSource;
class HOM_AttribDataId;
class HOM_anim;
class HOM_anonstats;
class HOM_audio;
class HOM_ButtonParmTemplate;
class HOM_ChannelPrim;
class HOM_ChopNode;
class HOM_Clip;
class HOM_clone;
class HOM_Color;
class HOM_crowds;
class HOM_DataParmTemplate;
class HOM_SimpleDrawable;
class HOM_dop;
class HOM_DopData;
class HOM_DopSimulation;
class HOM_Edge;
class HOM_EnumValue;
class HOM_FloatParmTemplate;
class HOM_FolderParmTemplate;
class HOM_FolderSetParmTemplate;
class HOM_GadgetContext;
class HOM_GadgetDrawable;
class HOM_galleries;
class HOM_Geometry;
class HOM_GeometryRayCache;
class HOM_GeometrySelection;
class HOM_GUDetailHandle;
class HOM_Handle;
class HOM_hda;
class HOM_HDADefinition;
class HOM_HDAModule;
class HOM_HDAOptions;
class HOM_hipFile;
class HOM_hmath;
class HOM_ik;
class HOM_InterruptableOperation;
class HOM_IntParmTemplate;
class HOM_Keyframe;
class HOM_LabelParmTemplate;
class HOM_logging;
class HOM_logging_FileSink;
class HOM_logging_LogEntry;
class HOM_logging_MemorySink;
class HOM_lop;
class HOM_LopInstanceIdRule;
class HOM_LopSelectionRule;
class HOM_LopViewportLoadMasks;
class HOM_Matrix4;
class HOM_MenuParmTemplate;
class HOM_NetworkBox;
class HOM_NetworkDot;
class HOM_NetworkMovableItem;
class HOM_Node;
class HOM_NodeBundle;
class HOM_NodeConnection;
class HOM_NodeType;
class HOM_NodeTypeCategory;
class HOM_OrboltURLHandler;
class HOM_Parm;
class HOM_ParmTemplate;
class HOM_ParmTemplateGroup;
class HOM_ParmTuple;
class HOM_perfMon;
class HOM_PerfMonRecordOptions;
class HOM_pypanel;
class HOM_playbar;
class HOM_PluginHotkeyDefinitions;
class HOM_Point;
class HOM_Prim;
class HOM_properties;
class HOM_qt;
class HOM_RampParmTemplate;
class HOM_RedrawBlock;
#ifndef SWIG
class HOM_RedrawResumeBlock;
#endif
class HOM_SceneViewer;
class HOM_ScriptEvalContext;
class HOM_Selection;
class HOM_SeparatorParmTemplate;
class HOM_shelves;
class HOM_StickyNote;
class HOM_StringKeyframe;
class HOM_StringParmTemplate;
class HOM_styles;
class HOM_StyleSheet;
class HOM_SubnetIndirectInput;
class HOM_takes;
class HOM_text;
class HOM_TextDrawable;
class HOM_ToggleParmTemplate;
class HOM_ui;
class HOM_hotkeys;
class HOM_UIEvent;
class HOM_UIEventDevice;
class HOM_undos;
class HOM_Vector3;
class HOM_Vertex;
class HOM_VexContext;
class HOM_ViewerEvent;
class HOM_viewportVisualizers;
class HOM_ViewerDragger;
class HOM_ViewerHandleContext;
class HOM_ViewerHandleDragger;
class HOM_ViewerHandleTemplate;
class HOM_ViewerStateContext;
class HOM_ViewerStateDragger;
class HOM_ViewerStateMenu;
class HOM_ViewerStateTemplate;
class HOM_GeometryDrawable;
class HOM_GeometryDrawableGroup;

#define HOM_SESSION_MODULE_NAME         "hou.session"
#define HOM_SESSION_MODULE_CPIO_NAME    "." HOM_SESSION_MODULE_NAME

// Use this function to access the HOM module from C++ in Houdini.  This
// is equivalent to writing "hou" in python.  It will only throw an exception
// if the python module could not be imported, which should not happen.
class HOM_Module;
HOM_API HOM_Module& HOM();

class HOM_API HOM_Module
{
public:
    static void setHOMCreator(void (*homCreator)());

    virtual ~HOM_Module() {}

    virtual std::vector<std::string> _getArgumentAutoComplete(
            const char *method_name, const char *arguments,
            bool meta_info_only = false) = 0;

    // This method is called by the expression editor to force autocompletion
    // to be relative to the node containing the expression.  It is not
    // wrapped by swig.
    virtual void setRelativeNodeForAutoComplete(OP_Node *node) = 0;

    virtual HOM_ui& ui() = 0;
    virtual HOM_qt& qt() = 0;
    virtual HOM_hotkeys& hotkeys() = 0;
    virtual HOM_audio& audio() = 0;
    virtual bool isUIAvailable() = 0;
    virtual bool _isExperimentalActive() = 0;
    virtual bool _isCurrentThreadHoldingHOMLock() = 0;

    virtual HOM_galleries& galleries() = 0;
    virtual HOM_hda& hda() = 0;
    virtual HOM_hipFile& hipFile() = 0;
    virtual HOM_perfMon& perfMon() = 0;
    virtual HOM_playbar& playbar() = 0;
    virtual HOM_pypanel& pypanel() = 0;
    virtual HOM_hmath& hmath() = 0;
    virtual HOM_dop& dop() = 0;
    virtual HOM_properties& properties() = 0;
    virtual HOM_shelves& shelves() = 0;
    virtual HOM_styles& styles() = 0;
    virtual HOM_takes& takes() = 0;
    virtual HOM_undos& undos() = 0;
    virtual HOM_viewportVisualizers& viewportVisualizers() = 0;
    virtual HOM_anim& anim() = 0;
    virtual HOM_anonstats& anonstats() = 0;
    virtual HOM_clone& clone() = 0;
    virtual HOM_crowds& crowds() = 0;
    virtual HOM_ik& ik() = 0;
    virtual HOM_logging& logging() = 0;
    virtual HOM_lop& lop() = 0;
    virtual HOM_text& text() = 0;

    virtual bool _assertWrapper(
        const char *file, int linenum, const char *function,
        const char *condition, const char *reason) = 0;

    virtual void exit(int exit_code=0, bool suppress_save_prompt=false) = 0;

    // isExiting() will return true if the program is actually Houdini (not
    // mplay) and the UI queue is closed.  This method is wrapped by swig, but
    // only so houdiniInterpreter can call it.
    virtual bool isExiting() = 0;

    virtual void addPreloadIcon(const char *name, int w, int h) = 0;
    virtual void rasterizePreloadIcons() = 0;

    virtual std::string applicationName() = 0;
    virtual std::vector<int> applicationVersion(bool include_patch=false) = 0;
    virtual std::string applicationVersionString() = 0;
    virtual std::string applicationCompilationDate() = 0;
    virtual std::string applicationPlatformInfo() = 0;
    virtual std::map<std::string, std::string> vdbVersionInfo() = 0;
    virtual int hdkAPIVersion() = 0;
    virtual HOM_EnumValue &licenseCategory() = 0;
    virtual bool isApprentice() = 0;
    virtual void releaseLicense() = 0;

    // Threading controls
    virtual int maxThreads() = 0;
    virtual void setMaxThreads(int max_threads) = 0;

    // These methods return a new HOM_Node object.
    virtual HOM_Node* root() = 0;
    virtual HOM_Node* pwd() = 0;
    virtual HOM_Node* parent() = 0;

    virtual void setPwd(HOM_Node &newpwd) = 0;
    virtual void cd(const char *path) = 0;

    // Calling phm() is a shortcut for calling pwd().hdaModule().
    virtual HOM_HDAModule* phm() = 0;

    // This method returns a new HOM_DopNetNode object or None.
    virtual HOM_Node* currentDopNet() = 0;
    virtual void setCurrentDopNet(HOM_Node &dopnet) = 0;

    // Gets or sets the simulation enabled state.
    virtual bool simulationEnabled() = 0;
    virtual void setSimulationEnabled(bool enabled) = 0;

    // These methods return a new HOM_Node object or null if the node couldn't
    // be found.
    virtual HOM_Node *node(const char *path) = 0;
    virtual HOM_NetworkMovableItem* item(const char *path) = 0;

    virtual std::vector<HOM_ElemPtr<HOM_Node> > nodes(const std::vector<std::string> &paths) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_NetworkMovableItem> > items(const std::vector<std::string> &paths) = 0;

    virtual HOM_Node *nodeBySessionId(int session_id) = 0;
    virtual HOM_NetworkBox *networkBoxBySessionId(int session_id) = 0;
    virtual HOM_StickyNote *stickyNoteBySessionId(int session_id) = 0;
    virtual HOM_SubnetIndirectInput *subnetIndirectInputBySessionId(
            int64 session_id) = 0;
    virtual HOM_NetworkDot *networkDotBySessionId(int session_id) = 0;
    virtual HOM_NetworkMovableItem *itemBySessionId(
            HOM_EnumValue &item_type, int64 session_id) = 0;
    virtual HOM_NodeConnection *nodeConnectionBySessionId(
            int node_session_id, int input_index) = 0;

    // Functions for APEX nodes.
    virtual HOM_ApexNode *createApexRootNode() = 0;
    virtual HOM_ApexNode *apexNodeBySessionId(
            int64 session_id) = 0;
    virtual HOM_ApexNodeConnection *apexNodeConnectionBySessionId(
            int64 session_id) = 0;
    virtual HOM_ApexStickyNote *apexStickyNoteBySessionId(
            int64 session_id) = 0;

    // Functions for configuring default colors on network elements.
    virtual HOM_Color defaultColor(HOM_EnumValue &color_item) = 0;
    virtual void setDefaultColor(HOM_EnumValue &color_item, HOM_Color *color) = 0;

    // Return HOM_Nodes for all selected nodes in the session.
    virtual std::vector<HOM_ElemPtr<HOM_Node> > selectedNodes(
            bool include_hidden = false) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_NetworkMovableItem> > selectedItems(
            bool include_hidden = false) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_NodeConnection> > selectedConnections() = 0;
    virtual void clearAllSelected() = 0;

    // Copy nodes to and paste from clipboard.
    virtual void copyNodesToClipboard(const std::vector<HOM_Node *> &nodes) = 0;
    virtual void pasteNodesFromClipboard(HOM_Node &destination_node) = 0;

    // These methods return new HOM_Parm/HOM_ParmTuple objects or null if the
    // parm couldn't be found.
    virtual HOM_Parm* parm(const char *path) = 0;
    SWIGOUT(%ignore newParm;)
    virtual HOM_Parm* newParm(OP_Node &node, int parm_index, int vector_index) = 0;
    virtual HOM_ParmTuple* parmTuple(const char *path) = 0;
    virtual HOM_Parm *evaluatingParm() = 0;

    // The next methods are not wrapped by swig, and are used
    // by the HOM_ChannelList to manage geometry channel collections.
    // These are necessary as the HOM_ChannelList does not have
    // an implementation at the HOMF level, and cannot directly access
    // Nodes, GU_Details or the MOT_GeometryChannelManager.

    // This method asks the MOT_GeometryChannelManager for a new
    // geometry channel collection name, ensuring uniqueness.
    SWIGOUT(%ignore reserveNewGeometryCollectionName;)
    virtual UT_StringHolder reserveNewGeometryCollectionName() = 0;
    // This method accesses the GU_Detail to get the names of geometry channels,
    // so they can be stored in the HOM_ChannelList.
    SWIGOUT(%ignore geometryChannelNames;)
    virtual UT_StringArray geometryChannelNames(
            HOM_GUDetailHandle *gdh, UT_StringHolder pattern) = 0;

    // Returns the path of a node from its unique id.
    // Used by the HOM_ChannelList.
    SWIGOUT(%ignore getNodePathFromNodeId;)
    virtual UT_StringHolder getNodePathFromNodeId(int id) = 0;

    // Fetch the list of channel primitives in a geometry. Used
    // by HOM_ChannelList to display channel primitives added to the
    // channel list
    SWIGOUT(%ignore getChannelPrims;)
    virtual std::vector<HOM_ElemPtr<HOM_ChannelPrim>> getChannelPrims(
            HOM_GUDetailHandle *gdh,
            const UT_StringHolder &pattern) = 0;

    virtual HOM_ScriptEvalContext * newScriptEvalContext(HOM_Node &node) = 0;
    virtual HOM_ScriptEvalContext * newScriptEvalContext(HOM_Parm &parm) = 0;

    // Access to the contents of the parm clipboard
    virtual std::vector< std::map<std::string, std::string> >
        parmClipboardContents() = 0;

    // These methods return a new HOM_NodeType object or null if it couldn't
    // be found.
    virtual HOM_NodeType *nodeType(
            HOM_NodeTypeCategory &category, const char *name) = 0;
    virtual HOM_NodeType *nodeType(const char *name) = 0;

    virtual HOM_NodeType *preferredNodeType(
            const char *name, HOM_Node *parentNode = NULL) = 0;

    virtual HOM_NodeTypeCategory &objNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &sopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &dopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &cop2NodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &copNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &shopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &vopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &ropNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &chopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &topNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &lopNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &cop2NetNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &vopNetNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &chopNetNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &topNetNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &managerNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &rootNodeTypeCategory() = 0;
    virtual HOM_NodeTypeCategory &dataNodeTypeCategory() = 0;
    virtual std::map<std::string, HOM_NodeTypeCategory *>
            nodeTypeCategories() = 0;
    virtual HOM_NodeTypeCategory &apexNodeTypeCategory() = 0;

    virtual std::vector<HOM_ElemPtr<HOM_Node> > copyNodesTo(
            const std::vector<HOM_Node *> &nodes, 
            HOM_Node &destination_node) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_Node> > moveNodesTo(
            const std::vector<HOM_Node *> &nodes, 
            HOM_Node &destination_node) = 0;

    virtual HOM_NodeBundle *addNodeBundle(const char *name = NULL) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_NodeBundle> > nodeBundles() = 0;
    virtual std::vector<HOM_ElemPtr<HOM_NodeBundle> > selectedNodeBundles() = 0;
    virtual HOM_NodeBundle *nodeBundle(const char *name) = 0;

    virtual HOM_HDADefinition *hdaDefinition(
            HOM_NodeTypeCategory &category, const char *name,
            const char *file_path) = 0;

    // Note that getTimeWithoutAddingDependency is not wrapped by swig.
    virtual fpreal getTimeWithoutAddingDependency() = 0;
    virtual double time() = 0;
    virtual void setTime(double time) = 0;
    virtual double frame(bool full_precision=false) = 0;
    virtual int intFrame() = 0;
    virtual void setFrame(double frame) = 0;
    virtual double fps() = 0;
    virtual void setFps(
            double fps,
            bool modify_frame_count = true,
            bool preserve_keyframes = false,
            bool preserve_frame_start = false)
            = 0;
    virtual double timeToFrame(double time, bool full_precision=false) = 0;
    virtual double frameToTime(double frame) = 0;

    /// Private methods for ensuring that the current eval context
    /// (including global time) is in-sync with the main thread's eval
    /// context.
    virtual void _syncFromMainContext() = 0;
    virtual void _syncToMainContext() = 0;

    // Computes a scale factor given units
    virtual fpreal scaleFromMKS(const char *units) = 0;
    virtual fpreal scaleToMKS(const char *units) = 0;

    virtual double bezier() = 0;
    virtual double constant() = 0;
    virtual double cubic() = 0;
    virtual double cycle(double start_frame, double end_frame) = 0;
    virtual double cyclet(double start_time, double end_time) = 0;
    virtual double cycleoffset(double start_frame, double end_frame) = 0;
    virtual double cycleoffsett(double start_time, double end_time) = 0;
    virtual double ease() = 0;
    virtual double easein() = 0;
    virtual double easeinp(double ease_speed) = 0;
    virtual double easeout() = 0;
    virtual double easeoutp(double ease_speed) = 0;
    virtual double easep(double ease_bias) = 0;
    virtual double linear() = 0;
    virtual double match() = 0;
    virtual double matchin() = 0;
    virtual double matchout() = 0;
    virtual double qlinear() = 0;
    virtual double quintic() = 0;
    virtual double repeat(double start_frame, double end_frame) = 0;
    virtual double repeatt(double start_time, double end_time) = 0;
    virtual double spline() = 0;
    virtual double vmatch() = 0;
    virtual double vmatchin() = 0;
    virtual double vmatchout() = 0;

    virtual std::string chopExportConflictResolutionPattern() = 0;
    virtual void setChopExportConflictResolutionPattern( const char *pattern) = 0;

    virtual std::vector<HOM_ElemPtr<HOM_VexContext> >
        vexContexts() = 0;

    virtual HOM_VexContext* vexContextForShaderType(HOM_EnumValue &shader_type) = 0;

    virtual HOM_VexContext* vexContextForNodeTypeCategory(
            HOM_NodeTypeCategory &node_type_category) = 0;

    virtual std::string helpServerUrl() = 0;

    virtual std::string hscriptCommandHelp(const char *command_name) = 0;

    // This method returns a pair of strings: one for stdout and one for
    // stderr.
    virtual std::vector<std::string> hscript(const char *command) = 0;

    // Compare if two numbers are almost equal.
    virtual bool almostEqual(double x, double y) = 0;

    virtual std::vector<std::pair<HOM_ElemPtr<HOM_Parm>, std::string> >
        fileReferences(
        const char *project_dir_variable="HIP", bool include_all_refs=true) = 0;

    // Find files in $HOUDINI_PATH.
    virtual std::string findFile(const char *file_name) = 0;
    virtual std::vector<std::string> findFiles(
        const char *file_name) = 0;
    virtual std::vector<std::string> findFilesWithExtension(
        const char *file_extension, const char *subdirectory = NULL) = 0;

    // Find directories in $HOUDINI_PATH.
    virtual std::string findDirectory(const char *directory_name) = 0;
    virtual std::vector<std::string> findDirectories(
        const char *directory_name) = 0;

    virtual std::vector<std::string> houdiniPath(const char *pathvar = nullptr) = 0;

    virtual std::string homeHoudiniDirectory() = 0;

    virtual std::string readFile(const char *file_path) = 0;
    virtual HOM_BinaryString readBinaryFile(const char *file_path) = 0;

    virtual std::map<std::string, HOM_BinaryString> loadIndexDataFromString(
            const char *data, int length) = 0;

    virtual std::map<std::string, HOM_BinaryString> loadIndexDataFromFile(
            const char *file_path) = 0;

    virtual HOM_BinaryString saveIndexDataToString(
            const std::map<std::string, HOM_BinaryString> &index_data) = 0;

    virtual void saveIndexDataToFile(
            const char *file_path,
            const std::map<std::string, HOM_BinaryString> &index_data) = 0;

    // Note that, when wrapped by swig, this function takes a single string
    // parameter.
    virtual std::vector<std::pair<std::string, HOM_BinaryString> >
            loadCPIODataFromString(const char *data, int length) = 0;

    virtual HOM_BinaryString saveCPIODataToString(
            const std::vector<std::pair<std::string, HOM_BinaryString> > 
                &data) = 0;

    // These 3 methods are not wrapped by swig.  They are used to notify
    // interested parties that a change to the module source code was made and
    // that they should forcefully update to match the change.  The third
    // is used to load the session module source from a hip file, even though
    // that source might generate an exception.
    virtual UT_NotifierImpl<int> &getSessionModuleSourceForceUpdateNotifier()=0;
    virtual void forceUpdateFromSessionModuleSource() = 0;
    virtual void forceSetSessionModuleSource(const char *source) = 0;

    virtual void setSessionModuleSource(const char *source) = 0;
    virtual void appendSessionModuleSource(const char *source) = 0;
    virtual std::string sessionModuleSource() = 0;
    // This method is not wrapped by swig:
    virtual int sessionModuleSourceChangeCount() = 0;

    // This static method lets you know if the HOM implementation is set,
    // so you can check if it's safe to call the HOM() function.  This method
    // should only be called in rare cases.
    static bool isImplementationSet()
    { return theImplementation != NULL; }

    // Evaluates a parameter as if it was an OPpath parameter
    virtual std::string chsop(const char *path) = 0;

    // Evaluates a parameter as if it was an OPlist parameter
    virtual std::string chsoplist(const char *path) = 0;

    // Sorts a list of node paths using topological order from the graph.
    virtual std::vector<std::string>
        sortedNodePaths(const std::vector<std::string> &paths) = 0;

    // Sorts a list of HOM_Node using topological order from the graph.
    virtual std::vector<HOM_ElemPtr<HOM_Node> >
        sortedNodes(const std::vector<HOM_Node*> &nodes) = 0;

    // deprecated in favour of hou.text.patternMatch
    virtual int patternMatch(
            const char *pattern, const char *str,
            bool ignore_case = false,
            bool path_match = false) = 0;

    // hscriptExpression() will return different types, according to
    // the return value of the expression.
    virtual hboost::any hscriptExpression(const char *expression) = 0;
    virtual double hscriptFloatExpression(const char *expression) = 0;
    virtual std::string hscriptStringExpression(const char *expression) = 0;
    virtual std::vector<double>hscriptVectorExpression(
            const char *expression) = 0;
    virtual std::vector<std::vector<double> > hscriptMatrixExpression(
            const char *expression) = 0;

    virtual hboost::any lvar(const char *name) = 0;

    virtual char *getEnvConfigValue(
            const char *name, const char *default_value=NULL) = 0;

    virtual char *getenv(const char *name, const char *default_value=NULL) = 0;

    virtual void putenv(const char *name, const char *value) = 0;

    virtual void unsetenv(const char *name) = 0;

    virtual void allowEnvironmentToOverwriteVariable(
            const char *name, bool onoff) = 0;

    virtual void *expressionGlobals() = 0;

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

    // This method is used to interact with the global interrupt object.
    virtual bool updateProgressAndCheckForInterrupt(int percentage=-1) = 0;

    virtual std::map<std::string, hboost::any> runVex(
            const char *vex_file,
            const std::map<std::string, hboost::any> &inputs,
            const char *precision = "32") = 0;

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

    virtual void saveImageDataToFile(
            const std::vector<float> &color_and_alpha_data,
            int width, int height,
            const char *file_name) = 0;

    virtual void saveImageDataToFile(
            const std::string &color_and_alpha_data,
            int width, int height,
            const char *file_name) = 0;

    virtual HOM_BinaryString loadImageDataFromFile(
            const char *image_file_name,
            HOM_EnumValue &image_depth = HOM_imageDepth::Int8) = 0;

    virtual std::vector<int> imageResolution(const char *image_file_name) = 0;

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

    virtual HOM_EnumValue &updateModeSetting() = 0;
    virtual void setUpdateMode(HOM_EnumValue &mode) = 0;

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

    virtual HOM_OrboltURLHandler *orboltURLHandler() = 0;

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

    virtual void *opaqueRunCallbackAndCatchCrashes(void *opaque_callback) = 0;

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

    // These methods are used to grant functions defined in an asset's
    // PythonModule enhanced privileges.  They are not wrapped by swig.
    virtual void pushAccessPrivilege(const char *key) = 0;
    virtual void popAccessPrivilege(const char *key) = 0;

    virtual std::string currentPythonModuleKey() = 0;

    virtual void registerAccessPrivilegePyClient(void *opaque_python_object) = 0;

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

    // These methods are used to instantiate HOMF objects from the HOM
    // library level.  They are not wrapped by swig.
    virtual HOM_FloatParmTemplate *newFloatParmTemplate(
            const char *name,
            const char *label,
            int num_components,
            const std::vector<double> &default_value,
            double min, double max,
            bool min_is_strict, bool max_is_strict,
            HOM_EnumValue &look,
            HOM_EnumValue &naming_scheme,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::vector<std::string> &default_expression,
            const std::vector<HOM_EnumValue *> &default_expression_language) = 0;

    virtual HOM_IntParmTemplate *newIntParmTemplate(
            const char *name,
            const char *label,
            int num_components,
            const std::vector<int64> &default_value,
            int64 min, int64 max,
            bool min_is_strict, bool max_is_strict,
            HOM_EnumValue &look,
            HOM_EnumValue &naming_scheme,
            const std::vector<std::string> &menu_items,
            const std::vector<std::string> &menu_labels,
            const std::vector<std::string> &icon_names,
            const std::string &item_generator_script,
            HOM_EnumValue *item_generator_script_language,
            HOM_EnumValue &menu_type,
            bool menu_use_token,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::vector<std::string> &default_expression,
            const std::vector<HOM_EnumValue *> &default_expression_language) = 0;

    virtual HOM_StringParmTemplate *newStringParmTemplate(
            const char *name,
            const char *label,
            int num_components,
            const std::vector<std::string> &default_value,
            HOM_EnumValue &naming_scheme,
            HOM_EnumValue &string_type,
            HOM_EnumValue &file_type,
            const std::vector<std::string> &menu_items,
            const std::vector<std::string> &menu_labels,
            const std::vector<std::string> &icon_names,
            const std::string &item_generator_script,
            HOM_EnumValue *item_generator_script_language,
            HOM_EnumValue &menu_type,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::vector<std::string> &default_expression,
            const std::vector<HOM_EnumValue *> &default_expression_language) = 0;

    virtual HOM_DataParmTemplate *newDataParmTemplate(
            const char *name,
            const char *label,
            int num_components,
            HOM_EnumValue &look,
            HOM_EnumValue &naming_scheme,
            HOM_EnumValue &data_parm_type,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::vector<std::string> &default_expression,
            const std::vector<HOM_EnumValue *> &default_expression_language) = 0;

    virtual HOM_ToggleParmTemplate *newToggleParmTemplate(
            const char *name,
            const char *label,
            bool default_value,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::string &default_expression,
            const HOM_EnumValue &default_expression_language) = 0;

    virtual HOM_MenuParmTemplate *newMenuParmTemplate(
            const char *name,
            const char *label,
            const std::vector<std::string> &menu_items,
            const std::vector<std::string> &menu_labels,
            int64 default_value,
            const std::vector<std::string> &icon_names,
            const std::string &item_generator_script,
            HOM_EnumValue *item_generator_script_language,
            HOM_EnumValue &menu_type,
            bool menu_use_token,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::string &default_expression,
            const HOM_EnumValue &default_expression_language,
            bool store_default_value_as_string,
            bool is_button_strip,
            bool strip_uses_icons
            ) = 0;

    virtual HOM_ButtonParmTemplate *newButtonParmTemplate(
            const char *name,
            const char *label,
            const char *disable_when,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals ) = 0;

    virtual HOM_LabelParmTemplate *newLabelParmTemplate(
            const char *name,
            const char *label,
            const std::vector<std::string> &column_labels,
            HOM_EnumValue &label_parm_type,
            bool is_hidden,
            bool is_label_hidden,
            bool join_with_next,
            const char *help,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals) = 0;

    virtual HOM_SeparatorParmTemplate *newSeparatorParmTemplate(
            const char *name,
            bool is_hidden,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals) = 0;

    virtual HOM_FolderSetParmTemplate *newFolderSetParmTemplate(
            const char *name,
            const std::vector<std::string> &folder_names,
            HOM_EnumValue &folder_type,
            const std::map<std::string, std::string> &tags) = 0;

    virtual HOM_FolderParmTemplate *newFolderParmTemplate(
            const char *name,
            const char *label,
            const std::vector<HOM_ParmTemplate *> &parm_templates,
            HOM_EnumValue &folder_type,
            int default_value,
            bool is_hidden,
            bool ends_tab_group,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::map<HOM_EnumValue *, std::string> &tab_conditionals) = 0;

    virtual HOM_RampParmTemplate *newRampParmTemplate(
            const char *name,
            const char *label,
            HOM_EnumValue &ramp_parm_type,
            int default_value,
            HOM_EnumValue *default_basis,
            bool show_controls,
            HOM_EnumValue *color_type,
            const char *disable_when,
            bool is_hidden,
            const char *help,
            const char *script_callback,
            HOM_EnumValue &script_callback_language,
            const std::map<std::string, std::string> &tags,
            const std::map<HOM_EnumValue *, std::string> &conditionals,
            const std::string &default_expression,
            const HOM_EnumValue &default_expression_language) = 0;

    virtual HOM_ParmTemplateGroup *newParmTemplateGroup(
            const std::vector<HOM_ParmTemplate *> &parm_templates) = 0;

    virtual HOM_PerfMonRecordOptions *newPerfMonRecordOptions(
            bool cook_stats, bool pdg_cook_stats, bool solve_stats,
            bool draw_stats, bool gpu_draw_stats, bool viewport_stats,
            bool script_stats, bool render_stats, bool thread_stats,
            bool frame_stats, bool memory_stats, bool errors,
            bool pane_stats) = 0;

    virtual HOM_Keyframe *newKeyframe() = 0;
    virtual HOM_Keyframe *newKeyframe(double value) = 0;
    virtual HOM_Keyframe *newKeyframe(double value, double time) = 0;
    virtual HOM_Keyframe *newKeyframe(const HOM_Keyframe &keyframe) = 0;

    virtual HOM_StringKeyframe *newStringKeyframe() = 0;
    virtual HOM_StringKeyframe *newStringKeyframe(
        const std::string &value, HOM_EnumValue &language) = 0;
    virtual HOM_StringKeyframe *newStringKeyframe(
        const std::string &value, double time, HOM_EnumValue &language) = 0;
    virtual HOM_StringKeyframe *newStringKeyframe(
        const HOM_StringKeyframe &string_keyframe) = 0;

    virtual HOM_HDAOptions *newHDAOptions() = 0;
    virtual HOM_LopViewportLoadMasks *newLopViewportLoadMasks() = 0;
    virtual HOM_LopInstanceIdRule *newLopInstanceIdRule() = 0;
    virtual HOM_LopSelectionRule *newLopSelectionRule(
        const char *pattern = nullptr) = 0;

    virtual HOM_InterruptableOperation *newInterruptableOperation(
        const char *operation_name, const char *long_operation_name,
        bool open_interrupt_dialog) = 0;

    virtual HOM_RedrawBlock *newRedrawBlock() = 0;
#ifndef SWIG
    virtual HOM_RedrawResumeBlock *newRedrawResumeBlock() = 0;
#endif

    virtual HOM_StyleSheet *newStyleSheet() = 0;
    virtual HOM_StyleSheet *newStyleSheet(const char *json_text) = 0;

    virtual HOM_Selection *newSelection(HOM_EnumValue &selection_type,
        HOM_Geometry *geo, const char *selection_string) = 0;
    virtual HOM_Selection *newSelection(
        const std::vector<HOM_EnumValue *> &selection_types,
        HOM_Geometry *geo, const char *selection_string) = 0;
    virtual HOM_Selection *newSelection(
        const std::vector<HOM_Prim *> &prims) = 0;
    virtual HOM_Selection *newSelection(
        const std::vector<HOM_Point *> &points) = 0;
    virtual HOM_Selection *newSelection(
        const std::vector<HOM_Vertex *> &vertices) = 0;
    virtual HOM_Selection *newSelection(
        const std::vector<HOM_Edge *> &edges) = 0;

    // This method returns a new HOM_Geometry object.
    virtual HOM_Geometry *newGeometry(HOM_Geometry *geo = nullptr,
                                      bool clone_data_ids = false) = 0;

    virtual HOM_GeometryRayCache *newGeometryRayCache() = 0;

    virtual HOM_DopSimulation *newDopSimulation() = 0;

    virtual HOM_Clip *newClip() = 0;

    virtual HOM_AgentDefinition *newAgentDefinition(
        const HOM_AgentRig *rig, const HOM_AgentShapeLibrary *shapelib) = 0;

    virtual HOM_AgentClip *newAgentClip(
        const char *name, const char *path, const HOM_AgentRig &rig,
        bool keep_external_ref, bool delay_load) = 0;

    virtual HOM_AgentClip *newAgentClip(
        const char *name, HOM_ChopNode &chop, const HOM_AgentRig &rig,
        double frame) = 0;

    virtual HOM_AgentClip *newAgentClip(
        const char *name, const HOM_AgentRig &rig, int sample_count) = 0;

    virtual HOM_AgentClip *newAgentClip(
        const HOM_AgentClip &clip, const HOM_AgentRig &rig,
        const char *name) = 0;

    virtual HOM_AgentClip *newAgentClip(
            const char *name,
            void *stage,
            const char *prim_path,
            const HOM_AgentRig &rig) = 0;

    virtual HOM_AgentRig *newAgentRig(const char *path, bool keep_external_ref) = 0;

    virtual HOM_AgentRig *newAgentRig(
        const char *name, const std::vector<std::string> &transform_names,
        const std::vector<std::vector<int>> &hierarchy) = 0;

    virtual HOM_AgentTransformGroup *newAgentTransformGroup(
        const char *path, const HOM_AgentRig &rig,
        bool keep_external_ref = true) = 0;

    virtual HOM_AgentTransformGroup *newAgentTransformGroup(
        const char *name, const std::vector<int> &transforms,
        const HOM_AgentRig &rig, const std::vector<double> &weights,
        const std::vector<int> &channels) = 0;

    virtual HOM_AgentShapeLibrary *newAgentShapeLibrary() = 0;
    virtual HOM_AgentShapeLibrary *newAgentShapeLibrary(
        HOM_Geometry &geometry, const char *name) = 0;
    virtual HOM_AgentShapeLibrary *newAgentShapeLibrary(
        const char *path, bool keep_external_ref) = 0;

    virtual HOM_AgentShapeBinding *
    newAgentShapeBinding(int transform, const HOM_AgentShape &shape,
                         bool deforming, double bounds_scale) = 0;

    virtual HOM_AgentShapeBinding *
    newAgentShapeBinding(int transform, const HOM_AgentShape &shape,
                         const HOM_AgentShapeDeformer *deformer,
                         const HOM_Vector3 &bounds_scale) = 0;

    virtual HOM_AgentShapeDeformer *
    newAgentShapeDeformer(const char *name) = 0;

    virtual HOM_AgentShapeDeformer *
    newAgentShapeDeformer(const HOM_EnumValue &deformer_type) = 0;

    virtual HOM_AgentLayer *newAgentLayer(
        const char *name, const HOM_AgentRig &rig,
        const HOM_AgentShapeLibrary &shapelib,
        const std::vector<HOM_AgentShapeBinding *> &shape_bindings,
        const HOM_AgentLayer *source_layer = 0) = 0;

    virtual HOM_AgentLayer *
    newAgentLayer(const char *path, const HOM_AgentRig &rig,
                  const HOM_AgentShapeLibrary &shapelib,
                  bool keep_external_ref = true) = 0;

    virtual HOM_AgentMetadata *newAgentMetadata(
            const char *path,
            bool keep_external_ref = true) = 0;
    virtual HOM_AgentMetadata *newAgentMetadata(
            const std::map<std::string, hboost::any> &data) = 0;

    virtual bool compareNode(const char *path, const char *dest = NULL) = 0;
    virtual bool compareNodeBackup(const char *path, int index,
        const char *dest = NULL) = 0;
    virtual bool compareHDA(const char *path_left, const char *path_right,
        const char *dest = NULL) = 0;
    virtual bool compareHDABackup(const char *path, int index,
        const char *dest = NULL) = 0;
    virtual bool compareHip(const char *dest = NULL) = 0;
    virtual bool compareHipBackup(int index, const char *dest = NULL) = 0;

    virtual bool hasContextOption(const char *opt) = 0;
    virtual UT_OptionEntryPtr contextOption(const char *opt) = 0;
    virtual std::vector<std::string> contextOptionNames() = 0;
    virtual void setContextOption(const char *opt, const char *value) =0;
    virtual void setContextOption(const char *opt, double value) = 0;
    virtual void removeContextOption(const char *opt) = 0;
    virtual std::string contextOptionConfig(const char *opt) = 0;
    virtual void setContextOptionConfig(const char *opt,
        const char *config) = 0;
    virtual bool isAutoContextOption(const char *opt) = 0;
    virtual bool isAutoContextOptionOverridden(const char *opt) = 0;

    SWIGOUT(%ignore addOpaqueContextOptionChangeCallback;)
    virtual void addOpaqueContextOptionChangeCallback(void *callback) = 0;
    SWIGOUT(%ignore removeOpaqueContextOptionChangeCallback;)
    virtual void removeOpaqueContextOptionChangeCallback(void *callback) = 0;
    virtual void removeAllContextOptionChangeCallbacks() = 0;
    SWIGOUT(%ignore opaqueContextOptionChangeCallbacks;)
    virtual std::vector<void *> opaqueContextOptionChangeCallbacks() = 0;

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

    // This method is called when orbolt_url runs.  It is not wrapped by swig.
    virtual void setOrboltURLHandler(
        STORUI_OrboltURLHandler &orbolt_url_handler) = 0;

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

    // These methods are used to help debug HOM to make sure no objects
    // get allocated that don't get deallocated.
    virtual void constructObject(void *pointer, const std::type_info &type) = 0;
    virtual void destructObject(void *pointer, const std::type_info &type) = 0;
    virtual std::map<std::string, int> objectCounts() = 0;

    // Preferences
    virtual std::vector<std::string> getPreferenceNames() = 0;
    virtual std::string getPreference(const char *name) = 0;
    virtual bool setPreference(const char *name, const char* value) = 0;
    virtual bool addPreference(const char *name, const char* value) = 0;
    virtual bool removePreference(const char *name) = 0;
    virtual void refreshPreferences() = 0;

    virtual HOM_ViewerStateTemplate * newViewerStateTemplate(
        std::string const &                         type_name, 
        std::string const &                         label,
        HOM_NodeTypeCategory const &                category,
        std::vector<HOM_NodeTypeCategory*> const &  contexts) = 0;

    virtual HOM_ViewerHandleTemplate * newViewerHandleTemplate(
        std::string const &                         type_name, 
        std::string const &                         label,
        std::vector<HOM_NodeTypeCategory*> const &  categories) = 0;

    virtual HOM_ViewerStateMenu * newViewerStateMenu(std::string const & handle, std::string const & label) = 0;

    virtual HOM_PluginHotkeyDefinitions * newPluginHotkeyDefinitions() = 0;

    virtual HOM_SimpleDrawable * newSimpleDrawable( HOM_SceneViewer& scene_viewer, HOM_EnumValue const &prim_type, std::string const &name) = 0;
    virtual HOM_SimpleDrawable * newSimpleDrawable( HOM_SceneViewer& scene_viewer, HOM_Geometry const &geometry, std::string const &name) = 0;

    virtual HOM_ViewerHandleDragger * newViewerHandleDragger(std::string const & name) = 0;
    virtual HOM_ViewerStateDragger * newViewerStateDragger(std::string const & name, HOM_Matrix4 const & xform, HOM_Matrix4 const & inv_xform) = 0;

    virtual HOM_UIEvent * newUIEvent( int64 val, int64 val2 ) = 0;
    virtual HOM_ViewerEvent * newViewerEvent( HOM_SceneViewer& sceneViewer, int64 val, int64 val2 ) = 0;
    virtual HOM_UIEventDevice * newUIEventDevice(int64 val, int64 val2, int64 val3) = 0;

    virtual HOM_Handle * newHandle(HOM_SceneViewer& scene_viewer, std::string const &name ) = 0;
    virtual HOM_ViewerHandleContext * newViewerHandleContext(int64 val) = 0;

    virtual HOM_ViewerStateContext * newViewerStateContext(int64 val) = 0;

    virtual HOM_TextDrawable * newTextDrawable(
        HOM_SceneViewer&                            scene_viewer,
        std::string const &                         name,
        std::map<std::string, hboost::any> const &  params,
        std::string const &                         label) = 0;

    virtual HOM_GeometryDrawable * newGeometryDrawable(
        HOM_SceneViewer&                            scene_viewer,
        HOM_EnumValue const &                       geo_type,
        std::string const &                         name,
        HOM_Geometry *                              geometry,
        std::map<std::string, hboost::any> const &  params,
        std::string const &                         label) = 0;

    virtual HOM_GeometryDrawableGroup* newGeometryDrawableGroup(std::string const & name, std::string const & label) = 0;

    virtual HOM_GadgetDrawable * newGadgetDrawable(int64 widget, int64 gadget_context) = 0;

    virtual void startHoudiniEngineDebugger(unsigned short port) = 0;
    virtual void startHoudiniEngineDebugger(const char *pipe_name) = 0;

    virtual HOM_GeometrySelection * newGeometrySelection() = 0;
    virtual HOM_GeometrySelection * newGeometrySelection(int64 val) = 0;

    virtual HOM_logging_MemorySink * newMemorySink() = 0;
    virtual HOM_logging_FileSink * newFileSink(const char *filepath) = 0;

    virtual HOM_BinaryString convertClipData(HOM_BinaryString data,
                                             bool from_binary,
                                             bool from_blosc_compression,
                                             bool to_binary,
                                             bool to_blosc_compression) = 0;

    virtual HOM_BinaryString convertKeyframesToClipData(
        const std::map<std::string, std::vector<HOM_Keyframe *>> &keyframe_map,
        bool binary = true, bool use_blosc_compression = true) = 0;

    virtual std::string _clipInfo(HOM_BinaryString data, bool binary = true,
                                  bool blosc_compressed = true) = 0;

    virtual std::vector<HOM_ElemPtr<HOM_Node> > _nodesFromOPNodeList(int64 val) = 0;
    virtual std::vector<HOM_ElemPtr<HOM_DopData> >
    _dopDataList(int64 val) = 0;
    virtual std::vector<std::pair<HOM_ElemPtr<HOM_DopData>, HOM_ElemPtr<HOM_GeometrySelection> > > 
    _dopDataPointList(int64 val) = 0;
    virtual std::vector<std::pair<HOM_ElemPtr<HOM_DopData>, HOM_ElemPtr<HOM_GeometrySelection> > >
    _dopDataPolyList(int64 val) = 0;

    virtual HOM_AttribDataId * newAttribDataId() = 0;

    virtual std::string userName(bool alpha=true) = 0;

    virtual std::string machineName(bool alpha=true) = 0;

    virtual HOM_GeometryDrawable * _newGeometryDrawable(int64 val) = 0;

    virtual HOM_Node * createAnimationLayers(const std::string &path) = 0;
    virtual HOM_Node * addAnimationLayer(HOM_Node &layermixer, const std::string &layername) = 0;
    virtual bool removeAnimationLayer(HOM_Node &layermixer, const std::string &layername, bool merge=false) = 0;
    virtual HOM_Node* createAnimationClip(const std::string &path, bool set_export) = 0;

    virtual void* _sceneViewerWindow(int64 val) = 0;

    virtual void registerOpdefPath(
            const std::string &path,
            const std::string &server_name,
            const std::string &port_name)
            = 0;

    virtual std::vector<std::string> videoEncoders(
        HOM_EnumValue const &driver, const bool available=false) = 0;

private:
    // HOMF_Module::createHOMModule() uses this to create the HOM_Module.
    static void (*theHOMCreator)();

    // A subclass of HOM_Module in the HOMF library will define the
    // implementation of HOM.  Importing the python module will set the
    // implementation, so this function should only be called by HOMF_Module::
    // createHOMModule().
    friend class HOMF_Module;
    static void setImplementation(HOM_Module* implementation);

    // We could add a static method to access the implementation, but we
    // want to make it easy to access the HOM module from C++.  So, the
    // global function HOM() needs access to the implementation.
    friend HOM_API HOM_Module& HOM();
    static HOM_Module *theImplementation;
};


// Use this function to automatically delete objects for functions that
// return new objects.  This lets you, for example, write code like
//     HOMdel(HOM().findNode("/obj/geo1"))->setName("geo2")
template <typename T>
UT_UniquePtr<T> HOMdel(T *hom_object)
{ return UT_UniquePtr<T>(hom_object); }


// This lock is used to synchronize HOM scripts running in a separate
// thread and Houdini.  Houdini's UI queue will give up the lock when it's
// waiting for events and reacquire it when it handles an event.
//
// Note that this lock allows multiple threads in the same thread group to hold
// it at the same time.  By default, a thread started from Houdini is added to
// the group containing the main thread.  This way, since Houdini started the
// thread, we can be confident that it will use other locks to synchronize
// access to Houdini.  This approach allows, for example, a volume SOP to
// cook using multiple threads, evaluating Python in each thread while the
// main thread holds the HOM lock, without deadlocking and without allowing
// non-Houdini threads to acquire the HOM lock.  (Note that the GIL will
// synchronize access to Python's internals.)
HOM_API extern UT_TaskRootLock *HOM_theHOMLock;
inline UT_TaskRootLock &HOMgetLock()
{
    // This is not thread-safe but should be ok because HOMgetLock() is called
    // pretty early on during startup when there is only one thread executing.
    if (!HOM_theHOMLock)
        HOM_theHOMLock = new UT_TaskRootLock();

    UT_ASSERT(HOM_theHOMLock);
    return *HOM_theHOMLock;
}

// The HOM implementation uses the HOM_AutoLock to make sure Houdini isn't busy
// when they make calls into the Houdini libraries.  Note that constructing
// a HOM_AutoLock will release the python global interpreter lock (GIL) if
// it was held before acquiring the HOM lock.  This way, other python threads
// can run if it needs to block waiting for the HOM lock.
class HOM_API HOM_AutoLock : UT_NonCopyable
{
public:
    HOM_AutoLock()
    {
        if (!HOMgetLock().hasLock())
        {
            HOMgetLock().lock();
            myLocked = true;
        }
        else
            myLocked = false;
    }

    ~HOM_AutoLock()
    {
        if (myLocked)
            HOMgetLock().unlock();
    }

private:

    // It is important that we release the python global interpreter lock
    // (GIL) for the duration of waiting for, acquiring and holding onto
    // the HOM lock.  This gives other threads that are either blocked
    // on the GIL or that will try to acquire the GIL a chance to continue
    // execution.
    //
    // If the current thread needs to access the Python API, 
    // then it should explicitly acquire the GIL by creating a
    // PY_InterpreterAutoLock object.  The PY_InterpreterAutoLock must be
    // constructed *after* the HOM_AutoLock or it will have no effect.
    //
    // This prevents deadlocks that occur when the current thread
    // spawns other threads which access the Python API and try to
    // acquire the GIL.
    //
    // Note that we will reacquire the GIL when the HOM auto lock is destructed.
    PY_InterpreterAutoUnlock    myPyInterpAutoUnlock;

    // Boolean to determine if the auto lock actually locked the HOM lock.
    bool myLocked;
};

// The HOM implementation uses HOM_AutoUnlock to allow the main thread to
// run while waiting for something to happen.  Constructing a HOM_AutoUnlock
// instance will release the HOM lock but not the Python GIL.  When it's
// destructed it will reacquire the HOM lock.  Since it releases the HOM lock,
// it's important that a HOM_AutoLock was already created in a containing
// scope.
//
// Use HOM_AutoUnlock in conjunction with PY_InterpreterAutoUnlock to
// also release the Python GIL.  Be sure to create the HOM_AutoUnlock *after*
// the PY_InterpreterAutoUnlock, so that when the auto locks are destructed
// the HOM lock is reacquired before the Python GIL.  Otherwise, it will grab
// the GIL and then try to grab the HOM lock, and if another thread with the
// HOM lock tries to run Python we'll end up with deadlock.
class HOM_API HOM_AutoUnlock : UT_NonCopyable
{
public:
    HOM_AutoUnlock()
    { 
        if (HOMgetLock().hasLock())
        {
            HOMgetLock().unlock();
            myUnlocked = true;
        }
        else
        {
            myUnlocked = false;
        }
    }

    ~HOM_AutoUnlock()
    { 
        if (myUnlocked)
            HOMgetLock().lock(); 
    }

private:
    bool myUnlocked;
};


// These macros are used to help detect memory leaks when debugging is enabled.
#ifdef HOM_DEBUG
#define HOM_CONSTRUCT_OBJECT(pointer) \
    HOM().constructObject(pointer, typeid(*pointer));
#define HOM_DESTRUCT_OBJECT(pointer) \
    HOM().destructObject(pointer, typeid(*pointer));
#else
#define HOM_CONSTRUCT_OBJECT(pointer)
#define HOM_DESTRUCT_OBJECT(pointer)
#endif

// NOTE: These typedefs cannot actually be used in any method declaration
//       that SWIG needs to generate code for because it doesn't understand
//       them.
// gcc gets a parse error if we try to give a default map value in the
// signature, and the typedef avoids the error.
typedef std::map<std::string, std::string> HOM_StdMapStringString;
typedef std::map<HOM_EnumValue *, std::string> HOM_StdMapEnumString;


// Houdini will call HOMextendLibrary() in HDK dso's so the user can install
// C++ HOM extensions.
extern "C" {
   SYS_VISIBILITY_EXPORT extern void HOMextendLibrary();
}

#endif //__HOM_Module_h__