Pragya Arya | 324337e | 2020-02-20 14:35:08 +0530 | [diff] [blame] | 1 | // Copyright 2019, The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE.md file. |
| 4 | |
| 5 | package cmp |
| 6 | |
| 7 | import "reflect" |
| 8 | |
| 9 | // valueNode represents a single node within a report, which is a |
| 10 | // structured representation of the value tree, containing information |
| 11 | // regarding which nodes are equal or not. |
| 12 | type valueNode struct { |
| 13 | parent *valueNode |
| 14 | |
| 15 | Type reflect.Type |
| 16 | ValueX reflect.Value |
| 17 | ValueY reflect.Value |
| 18 | |
| 19 | // NumSame is the number of leaf nodes that are equal. |
| 20 | // All descendants are equal only if NumDiff is 0. |
| 21 | NumSame int |
| 22 | // NumDiff is the number of leaf nodes that are not equal. |
| 23 | NumDiff int |
| 24 | // NumIgnored is the number of leaf nodes that are ignored. |
| 25 | NumIgnored int |
| 26 | // NumCompared is the number of leaf nodes that were compared |
| 27 | // using an Equal method or Comparer function. |
| 28 | NumCompared int |
| 29 | // NumTransformed is the number of non-leaf nodes that were transformed. |
| 30 | NumTransformed int |
| 31 | // NumChildren is the number of transitive descendants of this node. |
| 32 | // This counts from zero; thus, leaf nodes have no descendants. |
| 33 | NumChildren int |
| 34 | // MaxDepth is the maximum depth of the tree. This counts from zero; |
| 35 | // thus, leaf nodes have a depth of zero. |
| 36 | MaxDepth int |
| 37 | |
| 38 | // Records is a list of struct fields, slice elements, or map entries. |
| 39 | Records []reportRecord // If populated, implies Value is not populated |
| 40 | |
| 41 | // Value is the result of a transformation, pointer indirect, of |
| 42 | // type assertion. |
| 43 | Value *valueNode // If populated, implies Records is not populated |
| 44 | |
| 45 | // TransformerName is the name of the transformer. |
| 46 | TransformerName string // If non-empty, implies Value is populated |
| 47 | } |
| 48 | type reportRecord struct { |
| 49 | Key reflect.Value // Invalid for slice element |
| 50 | Value *valueNode |
| 51 | } |
| 52 | |
| 53 | func (parent *valueNode) PushStep(ps PathStep) (child *valueNode) { |
| 54 | vx, vy := ps.Values() |
| 55 | child = &valueNode{parent: parent, Type: ps.Type(), ValueX: vx, ValueY: vy} |
| 56 | switch s := ps.(type) { |
| 57 | case StructField: |
| 58 | assert(parent.Value == nil) |
| 59 | parent.Records = append(parent.Records, reportRecord{Key: reflect.ValueOf(s.Name()), Value: child}) |
| 60 | case SliceIndex: |
| 61 | assert(parent.Value == nil) |
| 62 | parent.Records = append(parent.Records, reportRecord{Value: child}) |
| 63 | case MapIndex: |
| 64 | assert(parent.Value == nil) |
| 65 | parent.Records = append(parent.Records, reportRecord{Key: s.Key(), Value: child}) |
| 66 | case Indirect: |
| 67 | assert(parent.Value == nil && parent.Records == nil) |
| 68 | parent.Value = child |
| 69 | case TypeAssertion: |
| 70 | assert(parent.Value == nil && parent.Records == nil) |
| 71 | parent.Value = child |
| 72 | case Transform: |
| 73 | assert(parent.Value == nil && parent.Records == nil) |
| 74 | parent.Value = child |
| 75 | parent.TransformerName = s.Name() |
| 76 | parent.NumTransformed++ |
| 77 | default: |
| 78 | assert(parent == nil) // Must be the root step |
| 79 | } |
| 80 | return child |
| 81 | } |
| 82 | |
| 83 | func (r *valueNode) Report(rs Result) { |
| 84 | assert(r.MaxDepth == 0) // May only be called on leaf nodes |
| 85 | |
| 86 | if rs.ByIgnore() { |
| 87 | r.NumIgnored++ |
| 88 | } else { |
| 89 | if rs.Equal() { |
| 90 | r.NumSame++ |
| 91 | } else { |
| 92 | r.NumDiff++ |
| 93 | } |
| 94 | } |
| 95 | assert(r.NumSame+r.NumDiff+r.NumIgnored == 1) |
| 96 | |
| 97 | if rs.ByMethod() { |
| 98 | r.NumCompared++ |
| 99 | } |
| 100 | if rs.ByFunc() { |
| 101 | r.NumCompared++ |
| 102 | } |
| 103 | assert(r.NumCompared <= 1) |
| 104 | } |
| 105 | |
| 106 | func (child *valueNode) PopStep() (parent *valueNode) { |
| 107 | if child.parent == nil { |
| 108 | return nil |
| 109 | } |
| 110 | parent = child.parent |
| 111 | parent.NumSame += child.NumSame |
| 112 | parent.NumDiff += child.NumDiff |
| 113 | parent.NumIgnored += child.NumIgnored |
| 114 | parent.NumCompared += child.NumCompared |
| 115 | parent.NumTransformed += child.NumTransformed |
| 116 | parent.NumChildren += child.NumChildren + 1 |
| 117 | if parent.MaxDepth < child.MaxDepth+1 { |
| 118 | parent.MaxDepth = child.MaxDepth + 1 |
| 119 | } |
| 120 | return parent |
| 121 | } |