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// 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
// defaultReporter implements the reporter interface.
//
// As Equal serially calls the PushStep, Report, and PopStep methods, the
// defaultReporter constructs a tree-based representation of the compared value
// and the result of each comparison (see valueNode).
//
// When the String method is called, the FormatDiff method transforms the
// valueNode tree into a textNode tree, which is a tree-based representation
// of the textual output (see textNode).
//
// Lastly, the textNode.String method produces the final report as a string.
type defaultReporter struct {
root *valueNode
curr *valueNode
}
func (r *defaultReporter) PushStep(ps PathStep) {
r.curr = r.curr.PushStep(ps)
if r.root == nil {
r.root = r.curr
}
}
func (r *defaultReporter) Report(rs Result) {
r.curr.Report(rs)
}
func (r *defaultReporter) PopStep() {
r.curr = r.curr.PopStep()
}
// String provides a full report of the differences detected as a structured
// literal in pseudo-Go syntax. String may only be called after the entire tree
// has been traversed.
func (r *defaultReporter) String() string {
assert(r.root != nil && r.curr == nil)
if r.root.NumDiff == 0 {
return ""
}
return formatOptions{}.FormatDiff(r.root).String()
}
func assert(ok bool) {
if !ok {
panic("assertion failure")
}
}