diff options
Diffstat (limited to 'vendor/github.com/google/go-cmp/cmp/path.go')
-rw-r--r-- | vendor/github.com/google/go-cmp/cmp/path.go | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/vendor/github.com/google/go-cmp/cmp/path.go b/vendor/github.com/google/go-cmp/cmp/path.go new file mode 100644 index 00000000..c08a3cf8 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/path.go @@ -0,0 +1,309 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +package cmp + +import ( + "fmt" + "reflect" + "strings" + "unicode" + "unicode/utf8" +) + +type ( + // Path is a list of PathSteps describing the sequence of operations to get + // from some root type to the current position in the value tree. + // The first Path element is always an operation-less PathStep that exists + // simply to identify the initial type. + // + // When traversing structs with embedded structs, the embedded struct will + // always be accessed as a field before traversing the fields of the + // embedded struct themselves. That is, an exported field from the + // embedded struct will never be accessed directly from the parent struct. + Path []PathStep + + // PathStep is a union-type for specific operations to traverse + // a value's tree structure. Users of this package never need to implement + // these types as values of this type will be returned by this package. + PathStep interface { + String() string + Type() reflect.Type // Resulting type after performing the path step + isPathStep() + } + + // SliceIndex is an index operation on a slice or array at some index Key. + SliceIndex interface { + PathStep + Key() int // May return -1 if in a split state + + // SplitKeys returns the indexes for indexing into slices in the + // x and y values, respectively. These indexes may differ due to the + // insertion or removal of an element in one of the slices, causing + // all of the indexes to be shifted. If an index is -1, then that + // indicates that the element does not exist in the associated slice. + // + // Key is guaranteed to return -1 if and only if the indexes returned + // by SplitKeys are not the same. SplitKeys will never return -1 for + // both indexes. + SplitKeys() (x int, y int) + + isSliceIndex() + } + // MapIndex is an index operation on a map at some index Key. + MapIndex interface { + PathStep + Key() reflect.Value + isMapIndex() + } + // TypeAssertion represents a type assertion on an interface. + TypeAssertion interface { + PathStep + isTypeAssertion() + } + // StructField represents a struct field access on a field called Name. + StructField interface { + PathStep + Name() string + Index() int + isStructField() + } + // Indirect represents pointer indirection on the parent type. + Indirect interface { + PathStep + isIndirect() + } + // Transform is a transformation from the parent type to the current type. + Transform interface { + PathStep + Name() string + Func() reflect.Value + + // Option returns the originally constructed Transformer option. + // The == operator can be used to detect the exact option used. + Option() Option + + isTransform() + } +) + +func (pa *Path) push(s PathStep) { + *pa = append(*pa, s) +} + +func (pa *Path) pop() { + *pa = (*pa)[:len(*pa)-1] +} + +// Last returns the last PathStep in the Path. +// If the path is empty, this returns a non-nil PathStep that reports a nil Type. +func (pa Path) Last() PathStep { + return pa.Index(-1) +} + +// Index returns the ith step in the Path and supports negative indexing. +// A negative index starts counting from the tail of the Path such that -1 +// refers to the last step, -2 refers to the second-to-last step, and so on. +// If index is invalid, this returns a non-nil PathStep that reports a nil Type. +func (pa Path) Index(i int) PathStep { + if i < 0 { + i = len(pa) + i + } + if i < 0 || i >= len(pa) { + return pathStep{} + } + return pa[i] +} + +// String returns the simplified path to a node. +// The simplified path only contains struct field accesses. +// +// For example: +// MyMap.MySlices.MyField +func (pa Path) String() string { + var ss []string + for _, s := range pa { + if _, ok := s.(*structField); ok { + ss = append(ss, s.String()) + } + } + return strings.TrimPrefix(strings.Join(ss, ""), ".") +} + +// GoString returns the path to a specific node using Go syntax. +// +// For example: +// (*root.MyMap["key"].(*mypkg.MyStruct).MySlices)[2][3].MyField +func (pa Path) GoString() string { + var ssPre, ssPost []string + var numIndirect int + for i, s := range pa { + var nextStep PathStep + if i+1 < len(pa) { + nextStep = pa[i+1] + } + switch s := s.(type) { + case *indirect: + numIndirect++ + pPre, pPost := "(", ")" + switch nextStep.(type) { + case *indirect: + continue // Next step is indirection, so let them batch up + case *structField: + numIndirect-- // Automatic indirection on struct fields + case nil: + pPre, pPost = "", "" // Last step; no need for parenthesis + } + if numIndirect > 0 { + ssPre = append(ssPre, pPre+strings.Repeat("*", numIndirect)) + ssPost = append(ssPost, pPost) + } + numIndirect = 0 + continue + case *transform: + ssPre = append(ssPre, s.trans.name+"(") + ssPost = append(ssPost, ")") + continue + case *typeAssertion: + // As a special-case, elide type assertions on anonymous types + // since they are typically generated dynamically and can be very + // verbose. For example, some transforms return interface{} because + // of Go's lack of generics, but typically take in and return the + // exact same concrete type. + if s.Type().PkgPath() == "" { + continue + } + } + ssPost = append(ssPost, s.String()) + } + for i, j := 0, len(ssPre)-1; i < j; i, j = i+1, j-1 { + ssPre[i], ssPre[j] = ssPre[j], ssPre[i] + } + return strings.Join(ssPre, "") + strings.Join(ssPost, "") +} + +type ( + pathStep struct { + typ reflect.Type + } + + sliceIndex struct { + pathStep + xkey, ykey int + } + mapIndex struct { + pathStep + key reflect.Value + } + typeAssertion struct { + pathStep + } + structField struct { + pathStep + name string + idx int + + // These fields are used for forcibly accessing an unexported field. + // pvx, pvy, and field are only valid if unexported is true. + unexported bool + force bool // Forcibly allow visibility + pvx, pvy reflect.Value // Parent values + field reflect.StructField // Field information + } + indirect struct { + pathStep + } + transform struct { + pathStep + trans *transformer + } +) + +func (ps pathStep) Type() reflect.Type { return ps.typ } +func (ps pathStep) String() string { + if ps.typ == nil { + return "<nil>" + } + s := ps.typ.String() + if s == "" || strings.ContainsAny(s, "{}\n") { + return "root" // Type too simple or complex to print + } + return fmt.Sprintf("{%s}", s) +} + +func (si sliceIndex) String() string { + switch { + case si.xkey == si.ykey: + return fmt.Sprintf("[%d]", si.xkey) + case si.ykey == -1: + // [5->?] means "I don't know where X[5] went" + return fmt.Sprintf("[%d->?]", si.xkey) + case si.xkey == -1: + // [?->3] means "I don't know where Y[3] came from" + return fmt.Sprintf("[?->%d]", si.ykey) + default: + // [5->3] means "X[5] moved to Y[3]" + return fmt.Sprintf("[%d->%d]", si.xkey, si.ykey) + } +} +func (mi mapIndex) String() string { return fmt.Sprintf("[%#v]", mi.key) } +func (ta typeAssertion) String() string { return fmt.Sprintf(".(%v)", ta.typ) } +func (sf structField) String() string { return fmt.Sprintf(".%s", sf.name) } +func (in indirect) String() string { return "*" } +func (tf transform) String() string { return fmt.Sprintf("%s()", tf.trans.name) } + +func (si sliceIndex) Key() int { + if si.xkey != si.ykey { + return -1 + } + return si.xkey +} +func (si sliceIndex) SplitKeys() (x, y int) { return si.xkey, si.ykey } +func (mi mapIndex) Key() reflect.Value { return mi.key } +func (sf structField) Name() string { return sf.name } +func (sf structField) Index() int { return sf.idx } +func (tf transform) Name() string { return tf.trans.name } +func (tf transform) Func() reflect.Value { return tf.trans.fnc } +func (tf transform) Option() Option { return tf.trans } + +func (pathStep) isPathStep() {} +func (sliceIndex) isSliceIndex() {} +func (mapIndex) isMapIndex() {} +func (typeAssertion) isTypeAssertion() {} +func (structField) isStructField() {} +func (indirect) isIndirect() {} +func (transform) isTransform() {} + +var ( + _ SliceIndex = sliceIndex{} + _ MapIndex = mapIndex{} + _ TypeAssertion = typeAssertion{} + _ StructField = structField{} + _ Indirect = indirect{} + _ Transform = transform{} + + _ PathStep = sliceIndex{} + _ PathStep = mapIndex{} + _ PathStep = typeAssertion{} + _ PathStep = structField{} + _ PathStep = indirect{} + _ PathStep = transform{} +) + +// isExported reports whether the identifier is exported. +func isExported(id string) bool { + r, _ := utf8.DecodeRuneInString(id) + return unicode.IsUpper(r) +} + +// isValid reports whether the identifier is valid. +// Empty and underscore-only strings are not valid. +func isValid(id string) bool { + ok := id != "" && id != "_" + for j, c := range id { + ok = ok && (j > 0 || !unicode.IsDigit(c)) + ok = ok && (c == '_' || unicode.IsLetter(c) || unicode.IsDigit(c)) + } + return ok +} |