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// Copyright 2017, The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package cmp
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// defaultReporter implements the reporter interface.
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//
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// As Equal serially calls the PushStep, Report, and PopStep methods, the
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// defaultReporter constructs a tree-based representation of the compared value
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// and the result of each comparison (see valueNode).
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//
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// When the String method is called, the FormatDiff method transforms the
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// valueNode tree into a textNode tree, which is a tree-based representation
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// of the textual output (see textNode).
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//
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// Lastly, the textNode.String method produces the final report as a string.
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type defaultReporter struct {
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	root *valueNode
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	curr *valueNode
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}
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func (r *defaultReporter) PushStep(ps PathStep) {
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	r.curr = r.curr.PushStep(ps)
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	if r.root == nil {
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		r.root = r.curr
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	}
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}
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func (r *defaultReporter) Report(rs Result) {
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	r.curr.Report(rs)
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}
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func (r *defaultReporter) PopStep() {
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	r.curr = r.curr.PopStep()
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}
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// String provides a full report of the differences detected as a structured
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// literal in pseudo-Go syntax. String may only be called after the entire tree
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// has been traversed.
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func (r *defaultReporter) String() string {
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	assert(r.root != nil && r.curr == nil)
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	if r.root.NumDiff == 0 {
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		return ""
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	}
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	ptrs := new(pointerReferences)
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	text := formatOptions{}.FormatDiff(r.root, ptrs)
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	resolveReferences(text)
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	return text.String()
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}
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func assert(ok bool) {
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	if !ok {
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		panic("assertion failure")
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	}
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}
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