report_value.go

Documentation: github.com/google/go-cmp/cmp

     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 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  }
   122
View as plain text