fieldpath

package
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 Go to latest Published: Feb 9, 2021 License: Apache-2.0 Imports: 10 Imported by: 0

Documentation

Overview

Package fieldpath defines a way for referencing path elements (e.g., an index in an array, or a key in a map). It provides types for arranging these into paths for referencing nested fields, and for grouping those into sets, for referencing multiple nested fields.

Index

Constants

This section is empty.

Variables

View Source 
var AssociativeListCandidateFieldNames = []string{
	"key",
	"id",
	"name",
}

AssociativeListCandidateFieldNames lists the field names which are considered keys if found in a list element.

View Source 
var ErrUnknownPathElementType = errors.New("unknown path element type")

Functions

func KeyByFields 

func KeyByFields(nameValues ...interface{}) []value.Field

KeyByFields is a helper function which constructs a key for an associative list type. `nameValues` must have an even number of entries, alternating names (type must be string) with values (type must be value.Value). If these conditions are not met, KeyByFields will panic--it's intended for static construction and shouldn't have user-produced values passed to it.

func SerializePathElement 

func SerializePathElement(pe PathElement) (string, error)

SerializePathElement serializes a path element

Types

type APIVersion 

type APIVersion string

APIVersion describes the version of an object or of a fieldset.

type ManagedFields 

type ManagedFields map[string]VersionedSet

ManagedFields is a map from manager to VersionedSet (what they own in what version).

func (ManagedFields) Difference 

func (lhs ManagedFields) Difference(rhs ManagedFields) ManagedFields

Difference returns a symmetric difference between two Managers. If a given user's entry has version X in lhs and version Y in rhs, then the return value for that user will be from rhs. If the difference for a user is an empty set, that user will not be inserted in the map.

type Path 

type Path []PathElement

Path describes how to select a potentially deeply-nested child field given a containing object.

func MakePath 

func MakePath(parts ...interface{}) (Path, error)

MakePath constructs a Path. The parts may be PathElements, ints, strings.

func MakePathOrDie 

func MakePathOrDie(parts ...interface{}) Path

MakePathOrDie panics if parts can't be turned into a path. Good for things that are known at complie time.

func (Path) Copy 

func (fp Path) Copy() Path

func (Path) Equals 

func (fp Path) Equals(fp2 Path) bool

Equals returns true if the two paths are equivalent.

func (Path) Less 

func (fp Path) Less(rhs Path) bool

Less provides a lexical order for Paths.

func (Path) String 

func (fp Path) String() string

type PathElement 

type PathElement struct {

	// FieldName selects a single field from a map (reminder: this is also
	// how structs are represented). The containing object must be a map.
	FieldName *string

	// Key selects the list element which has fields matching those given.
	// The containing object must be an associative list with map typed
	// elements.
	Key *value.Map

	// Value selects the list element with the given value. The containing
	// object must be an associative list with a primitive typed element
	// (i.e., a set).
	Value *value.Value

	// Index selects a list element by its index number. The containing
	// object must be an atomic list.
	Index *int
}

PathElement describes how to select a child field given a containing object.

func DeserializePathElement 

func DeserializePathElement(s string) (PathElement, error)

DeserializePathElement parses a serialized path element

func GuessBestListPathElement 

func GuessBestListPathElement(index int, item value.Value) PathElement

GuessBestListPathElement guesses whether item is an associative list element, which should be referenced by key(s), or if it is not and therefore referencing by index is acceptable. Currently this is done by checking whether item has any of the fields listed in AssociativeListCandidateFieldNames which have scalar values.

func (PathElement) Equals 

func (e PathElement) Equals(rhs PathElement) bool

Equals returns true if both path elements are equal.

func (PathElement) Less 

func (e PathElement) Less(rhs PathElement) bool

Less provides an order for path elements.

func (PathElement) String 

func (e PathElement) String() string

String presents the path element as a human-readable string.

type PathElementSet 

type PathElementSet struct {
	// contains filtered or unexported fields
}

PathElementSet is a set of path elements. TODO: serialize as a list.

func (*PathElementSet) Difference 

func (s *PathElementSet) Difference(s2 *PathElementSet) *PathElementSet

Difference returns a set containing elements which appear in s but not in s2.

func (*PathElementSet) Equals 

func (s *PathElementSet) Equals(s2 *PathElementSet) bool

Equals returns true if s and s2 have exactly the same members.

func (*PathElementSet) Has 

func (s *PathElementSet) Has(pe PathElement) bool

Has returns true if pe is a member of the set.

func (*PathElementSet) Insert 

func (s *PathElementSet) Insert(pe PathElement)

Insert adds pe to the set.

func (*PathElementSet) Intersection 

func (s *PathElementSet) Intersection(s2 *PathElementSet) *PathElementSet

Intersection returns a set containing elements which appear in both s and s2.

func (*PathElementSet) Iterate 

func (s *PathElementSet) Iterate(f func(PathElement))

Iterate calls f for each PathElement in the set. The order is deterministic.

func (*PathElementSet) Size 

func (s *PathElementSet) Size() int

Size retuns the number of elements in the set.

func (*PathElementSet) Union 

func (s *PathElementSet) Union(s2 *PathElementSet) *PathElementSet

Union returns a set containing elements that appear in either s or s2.

type Set 

type Set struct {
	// Members lists fields that are part of the set.
	// TODO: will be serialized as a list of path elements.
	Members PathElementSet

	// Children lists child fields which themselves have children that are
	// members of the set. Appearance in this list does not imply membership.
	// Note: this is a tree, not an arbitrary graph.
	Children SetNodeMap
}

Set identifies a set of fields.

func NewSet 

func NewSet(paths ...Path) *Set

NewSet makes a set from a list of paths.

func SetFromValue 

func SetFromValue(v value.Value) *Set

SetFromValue creates a set containing every leaf field mentioned in v.

func (*Set) Difference 

func (s *Set) Difference(s2 *Set) *Set

Difference returns a Set containing elements which: * appear in s * do not appear in s2

In other words, for leaf fields, this acts like a regular set difference operation. When non leaf fields are compared with leaf fields ("parents" which contain "children"), the effect is: * parent - child = parent * child - parent = {empty set}

func (*Set) Empty 

func (s *Set) Empty() bool

Empty returns true if there are no members of the set. It is a separate function from Size since it's common to check whether size > 0, and potentially much faster to return as soon as a single element is found.

func (*Set) Equals 

func (s *Set) Equals(s2 *Set) bool

Equals returns true if s and s2 have exactly the same members.

func (*Set) FromJSON 

func (s *Set) FromJSON(r io.Reader) error

FromJSON clears s and reads a JSON formatted set structure.

func (*Set) Has 

func (s *Set) Has(p Path) bool

Has returns true if the field referenced by `p` is a member of the set.

func (*Set) Insert 

func (s *Set) Insert(p Path)

Insert adds the field identified by `p` to the set. Important: parent fields are NOT added to the set; if that is desired, they must be added separately.

func (*Set) Intersection 

func (s *Set) Intersection(s2 *Set) *Set

Intersection returns a Set containing leaf elements which appear in both s and s2. Intersection can be constructed from Union and Difference operations (example in the tests) but it's much faster to do it in one pass.

func (*Set) Iterate 

func (s *Set) Iterate(f func(Path))

Iterate calls f once for each field that is a member of the set (preorder DFS). The path passed to f will be reused so make a copy if you wish to keep it.

func (*Set) Size 

func (s *Set) Size() int

Size returns the number of members of the set.

func (*Set) String 

func (s *Set) String() string

String returns the set one element per line.

func (*Set) ToJSON 

func (s *Set) ToJSON() ([]byte, error)

func (*Set) ToJSONStream 

func (s *Set) ToJSONStream(w io.Writer) error

func (*Set) Union 

func (s *Set) Union(s2 *Set) *Set

Union returns a Set containing elements which appear in either s or s2.

func (*Set) WithPrefix 

func (s *Set) WithPrefix(pe PathElement) *Set

WithPrefix returns the subset of paths which begin with the given prefix, with the prefix not included.

type SetNodeMap 

type SetNodeMap struct {
	// contains filtered or unexported fields
}

SetNodeMap is a map of PathElement to subset.

func (*SetNodeMap) Descend 

func (s *SetNodeMap) Descend(pe PathElement) *Set

Descend adds pe to the set if necessary, returning the associated subset.

func (*SetNodeMap) Difference 

func (s *SetNodeMap) Difference(s2 *Set) *SetNodeMap

Difference returns a SetNodeMap with members that appear in s but not in s2.

func (*SetNodeMap) Empty 

func (s *SetNodeMap) Empty() bool

Empty returns false if there's at least one member in some child set.

func (*SetNodeMap) Equals 

func (s *SetNodeMap) Equals(s2 *SetNodeMap) bool

Equals returns true if s and s2 have the same structure (same nested child sets).

func (*SetNodeMap) Get 

func (s *SetNodeMap) Get(pe PathElement) (*Set, bool)

Get returns (the associated set, true) or (nil, false) if there is none.

func (*SetNodeMap) Intersection 

func (s *SetNodeMap) Intersection(s2 *SetNodeMap) *SetNodeMap

Intersection returns a SetNodeMap with members that appear in both s and s2.

func (*SetNodeMap) Iterate 

func (s *SetNodeMap) Iterate(f func(PathElement))

Iterate calls f for each PathElement in the set.

func (*SetNodeMap) Size 

func (s *SetNodeMap) Size() int

Size returns the sum of the number of members of all subsets.

func (*SetNodeMap) Union 

func (s *SetNodeMap) Union(s2 *SetNodeMap) *SetNodeMap

Union returns a SetNodeMap with members that appear in either s or s2.

type VersionedSet 

type VersionedSet interface {
	Set() *Set
	APIVersion() APIVersion
	Applied() bool
}

func NewVersionedSet 

func NewVersionedSet(set *Set, apiVersion APIVersion, applied bool) VersionedSet

Source Files

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