# SoPath Class Reference
[General classes]

`#include <Inventor/SoPath.h>`

Inheritance diagram for SoPath:

List of all members.

## Detailed Description

The SoPath class is a container class for traversal path descriptions.

SoPath objects contain a list of SoNode pointers and a list of child indices. Indices are necessary to disambiguate situations where a node uses the same node as a child multiple times.

Paths can be export and imported to/from file, like other SoBase derived objects. Read the documentation on the write() method to see how the file format is.

## Public Member Functions

| SoPath (const int approxlength=4)
| SoPath (SoNode *const head)
| SoPath (const SoPath &rhs)
SoPath & | operator= (const SoPath &rhs)
virtual SoType | getTypeId (void) const
void | setHead (SoNode *const head)
SoNode * | getHead (void) const
void | append (const int childindex)
void | append (SoNode *const node)
void | append (const SoPath *const frompath)
void | push (const int childindex)
void | pop (void)
SoNode * | getTail (void) const
SoNode * | getNode (const int index) const
SoNode * | getNodeFromTail (const int index) const
int | getIndex (const int index) const
int | getIndexFromTail (const int index) const
int | getLength (void) const
void | truncate (const int length)
int | findFork (const SoPath *const path) const
int | findNode (const SoNode *const node) const
SbBool | containsNode (const SoNode *const node) const
SbBool | containsPath (const SoPath *const path) const
SoPath * | copy (const int startfromnodeindex=0, int numnodes=0) const
void | insertIndex (SoNode *const parent, const int newindex)
void | removeIndex (SoNode *const parent, const int oldindex)
void | replaceIndex (SoNode *const parent, const int index, SoNode *const newchild)
SbBool | isRelevantNotification (SoNotList *const l) const
virtual void | write (SoWriteAction *action)

## Static Public Member Functions

void | initClass (void)
SoType | getClassTypeId (void)
SoPath * | getByName (const SbName name)
int | getByName (const SbName name, SoPathList &l)

## Protected Member Functions

virtual | ~SoPath ()
void | auditPath (const SbBool flag)

## Friends

class | SoFullPath
class | SoNodeKitPath
class | SoAction
class | SoTempPath
SbBool | operator== (const SoPath &lhs, const SoPath &rhs)
SbBool | operator!= (const SoPath &lhs, const SoPath &rhs)

## Constructor & Destructor Documentation

SoPath::SoPath | ( | const int | approxlength = 4 | ) |

| The default constructor. approxlength is used to indicate in advance the length of the path to minimize the number of reallocations.

SoPath::SoPath | ( | SoNode *const | head | ) |

| A constructor. The argument is set as the head (and only) node of the path.

SoPath::SoPath | ( | const SoPath & | rhs | ) |

| Copy constructor. Not part of the original Open Inventor API.

SoPath::~SoPath | ( | void |  | ) | `[protected, virtual]`

| The destructor is protected as destruction of SoPath instances happens through unref() (as for all objects derived from classes inheriting SoBase).

## Member Function Documentation

void SoPath::initClass | ( | void |  | ) | `[static]`

| Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system. Reimplemented from SoBase.

SoPath & SoPath::operator= | ( | const SoPath & | rhs | ) |

| Assignment operator, copies the rhs path into this. Not part of the original Open Inventor API.

SoType SoPath::getClassTypeId | ( | void |  | ) | `[static]`

| This static method returns the SoType object associated with objects of this class. Reimplemented from SoBase.

SoType SoPath::getTypeId | ( | void |  | ) | const`[virtual]`

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting.

Usage example:

      void foo(SoNode * node)
      {
        if (node->getTypeId() == SoFile::getClassTypeId()) {
          SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
        }
        else if (node->getTypeId().isOfType(SoGroup::getClassTypeId())) {
          SoGroup * group = (SoGroup *)node;  // safe downward cast, knows the type
        }
      }

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Implements SoBase.

void SoPath::setHead | ( | SoNode *const | node | ) |

| This method sets the head of the path to node. If the object already has a path set, it will be truncated.

SoNode * SoPath::getHead | ( | void |  | ) | const

| This method returns the head of the path, or `NULL` if the path is empty.

void SoPath::append | ( | const int | childindex | ) |

| This function appends the childindex child of the path's tail to the end of the path. It can only be used after the head is set.

void SoPath::append | ( | SoNode *const | node | ) |

| This function adds node to the end if it is a child of the current tail. If path is empty, this is equivalent to calling setHead().

void SoPath::append | ( | const SoPath *const | frompath | ) |

| This method appends the path to the end of the path if the head of frompath is either the tail of the path or a child of the path's tail. If the head of frompath is used multiple times as a child of the path tail, the lowest child index is used.

void SoPath::push | ( | const int | childindex | ) | `[inline]`

| This method pushes the child at childindex on the tail on the path.

void SoPath::pop | ( | void |  | ) | `[inline]`

| This method pops the tail off the path. Reimplemented in SoFullPath, and SoNodeKitPath.

SoNode * SoPath::getTail | ( | void |  | ) | const

| This method returns the tail node of the path. Reimplemented in SoFullPath, and SoNodeKitPath.

SoNode * SoPath::getNode | ( | const int | index | ) | const

| This method returns the node at index in the path, counted from 0 at the head. Reimplemented in SoNodeKitPath.

SoNode * SoPath::getNodeFromTail | ( | const int | index | ) | const

| This method returns the node at index in the path, counting from the tail. Reimplemented in SoFullPath, and SoNodeKitPath.

int SoPath::getIndex | ( | const int | index | ) | const

| This method returns the child index of the node at index in the path.

int SoPath::getIndexFromTail | ( | const int | index | ) | const

| This method returns the child index of the node at index in the path, counting from the tail. Reimplemented in SoFullPath.

int SoPath::getLength | ( | void |  | ) | const

| This method returns the number of nodes in the path. Only the "visible" nodes are counted, i.e. hidden nodes of e.g. nodekits are not included. Reimplemented in SoFullPath, and SoNodeKitPath.

void SoPath::truncate | ( | const int | length | ) |

| This method truncates the path to the given length (i.e. all nodes in the path list from index length and onwards will be removed from the path list). Reimplemented in SoNodeKitPath.

int SoPath::findFork | ( | const SoPath *const | path | ) | const

| This method returns the index of the last node that is the same for both paths, or `-1` if the paths don't even start on the same node.

int SoPath::findNode | ( | const SoNode *const | node | ) | const

| Returns the index of node if found in path, `-1` otherwise. Note that this method is not part of the original Open Inventor API.

SbBool SoPath::containsNode | ( | const SoNode *const | node | ) | const

| This method returns `TRUE` is node is contained in path, and `FALSE` otherwise.

SbBool SoPath::containsPath | ( | const SoPath *const | path | ) | const

| This method returns `TRUE` if path is contained in the path, and `FALSE` otherwise.

SoPath * SoPath::copy | ( | const int | startfromnodeindex = 0,
|  | int | numnodes = 0
| ) | const

| This method returns a copy of the path starting at startfromnodeindex with length numnodes. If numnodes is 0 (default) the path will be copied to the end. The returned SoPath instance will have an initial reference count of 0. It is the caller's responsibility to ref() and unref() it according to use.

SoPath * SoPath::getByName | ( | const SbName | name | ) | `[static]`

| This static method is for retrieving an SoPath by it's name. The last registered SoPath with the given name is returned, or `NULL` if no SoPath by name exists.

int SoPath::getByName | ( | const SbName | name,
|  | SoPathList & | l
| ) | `[static]`

| This static method is for finding all the paths with a given name and append them to the l list. The number of SoPath instances with name found is returned.

void SoPath::insertIndex | ( | SoNode *const | parent,
|  | const int | newindex
| ) |

| This method is called when a node in the path chain has a child added, to update the index of it's child. newindex is the index of the child which was inserted. If newindex is lower than the index value of the child node stored in the path, the path is updated accordingly.

void SoPath::removeIndex | ( | SoNode *const | parent,
|  | const int | oldindex
| ) |

| This method is called when a node in the path chain has a child removed, to update the index of it's child. oldindex was the index of the removed child. If oldindex is lower than or equal to the index value of the child node stored in the path, the path is updated accordingly.

void SoPath::replaceIndex | ( | SoNode *const | parent,
|  | const int | index,
|  | SoNode *const | newchild
| ) |

| This method is called when a node newchild replaces a node in the path. index is the position of the child which has been replaced.

SbBool SoPath::isRelevantNotification | ( | SoNotList *const | l | ) | const

| Return TRUE if the notification chain l will affect the path. l will affect the path either if the notification is in the path (the notification started on a field in a node in the path), or off the path (the notification started in a non-separator node that is left of the path's node).

void SoPath::write | ( | SoWriteAction * | action | ) | `[virtual]`

This method is used to write the contents of an SoPath.

A path is written as:

        Path {
          HEAD-NODE-OF-SUBGRAPH
          NUMBER-OF-INDICES
          INDEX0
          INDEX1
          ...
        }

[The rest of the documentation for this method only explains the reason behind a mismatch in behavior between the original Open Inventor and Coin. Don't read it if you're not taking a particular interest. (Short version: we do SoPath export in a somewhat more inefficient way to avoid the potential for bugs).]

Note that unlike Open Inventor, we write the complete subgraph below the head node. Only writing the parts of the subgraph affecting the state for nodes within the path is error prone if a subgraph is written out as part of path before it is written out "properly". Consider writing a scene graph which looks like this (in memory):

        DEF top_sep Separator {
          Cone { }
          DEF a_sphere Sphere { }
          Cube { }
        }

        DEF path_switch PathSwitch {
          path Path {
            ...path from "top_sep" to "a_sphere"...
          }
        }

..if we now do:

        SoSeparator * root = new SoSeparator;
        root->addChild([ptr to path_switch]);
        root->addChild([ptr to top_sep]);
        SoWriteAction wa;
        wa.apply(root);

..we would get the scene graph exported like this:

        Separator {
          DEF path_switch PathSwitch {
            path Path {
              DEF top_sep Separator {
                DEF a_sphere Sphere {
                }
              }
              1
              0
            }
          }
          USE top_sep
        }

..and as you can see, both the Cone and the Cube nodes has vanished, as they was not important for the part per se, and not written as part of it.

This is why we do full subgraph export for head nodes in paths.

void SoPath::auditPath | ( | const SbBool | flag | ) | `[protected]`

| Set whether or not to audit the nodes in the path to detect changes.

## Friends And Related Function Documentation

SbBool operator== | ( | const SoPath & | lhs,
|  | const SoPath & | rhs
| ) | `[friend]`

| Compares contents of path lhs and path rhs, and returns `TRUE` if they are equal.

SbBool operator!= | ( | const SoPath & | lhs,
|  | const SoPath & | rhs
| ) | `[friend]`

| Returns `TRUE` if paths lhs and rhs does not contain the same nodes in the same order.

The documentation for this class was generated from the following files:

- SoPath.h
- SoPath.cpp