vendor/github.com/google/go-cmp/cmp/report.go

   1 // Copyright 2017, 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 // defaultReporter implements the reporter interface.
   8 //
   9 // As Equal serially calls the PushStep, Report, and PopStep methods, the
  10 // defaultReporter constructs a tree-based representation of the compared value
  11 // and the result of each comparison (see valueNode).
  12 //
  13 // When the String method is called, the FormatDiff method transforms the
  14 // valueNode tree into a textNode tree, which is a tree-based representation
  15 // of the textual output (see textNode).
  16 //
  17 // Lastly, the textNode.String method produces the final report as a string.
  18 type defaultReporter struct {
  19         root *valueNode
  20         curr *valueNode
  21 }
  22
  23 func (r *defaultReporter) PushStep(ps PathStep) {
  24         r.curr = r.curr.PushStep(ps)
  25         if r.root == nil {
  26                 r.root = r.curr
  27         }
  28 }
  29 func (r *defaultReporter) Report(rs Result) {
  30         r.curr.Report(rs)
  31 }
  32 func (r *defaultReporter) PopStep() {
  33         r.curr = r.curr.PopStep()
  34 }
  35
  36 // String provides a full report of the differences detected as a structured
  37 // literal in pseudo-Go syntax. String may only be called after the entire tree
  38 // has been traversed.
  39 func (r *defaultReporter) String() string {
  40         assert(r.root != nil && r.curr == nil)
  41         if r.root.NumDiff == 0 {
  42                 return ""
  43         }
  44         return formatOptions{}.FormatDiff(r.root).String()
  45 }
  46
  47 func assert(ok bool) {
  48         if !ok {
  49                 panic("assertion failure")
  50         }
  51 }