Method formatDiffSlice

cmp/report_slices.go:357–439

(
	vx, vy reflect.Value, chunkSize int, name string,
	makeRec func(reflect.Value, diffMode) textRecord,
)

}

func (opts formatOptions) formatDiffSlice(
	vx, vy reflect.Value, chunkSize int, name string,
	makeRec func(reflect.Value, diffMode) textRecord,
) (list textList) {
	eq := func(ix, iy int) bool {
		return vx.Index(ix).Interface() == vy.Index(iy).Interface()
	}
	es := diff.Difference(vx.Len(), vy.Len(), func(ix, iy int) diff.Result {
		return diff.BoolResult(eq(ix, iy))
	})

	appendChunks := func(v reflect.Value, d diffMode) int {
		n0 := v.Len()
		for v.Len() > 0 {
			n := chunkSize
			if n > v.Len() {
				n = v.Len()
			}
			list = append(list, makeRec(v.Slice(0, n), d))
			v = v.Slice(n, v.Len())
		}
		return n0 - v.Len()
	}

	var numDiffs int
	maxLen := -1
	if opts.LimitVerbosity {
		maxLen = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc...
		opts.VerbosityLevel--
	}

	groups := coalesceAdjacentEdits(name, es)
	groups = coalesceInterveningIdentical(groups, chunkSize/4)
	groups = cleanupSurroundingIdentical(groups, eq)
	maxGroup := diffStats{Name: name}
	for i, ds := range groups {
		if maxLen >= 0 && numDiffs >= maxLen {
			maxGroup = maxGroup.Append(ds)
			continue
		}

		// Print equal.
		if ds.NumDiff() == 0 {
			// Compute the number of leading and trailing equal bytes to print.
			var numLo, numHi int
			numEqual := ds.NumIgnored + ds.NumIdentical
			for numLo < chunkSize*numContextRecords && numLo+numHi < numEqual && i != 0 {
				numLo++
			}
			for numHi < chunkSize*numContextRecords && numLo+numHi < numEqual && i != len(groups)-1 {
				numHi++
			}
			if numEqual-(numLo+numHi) <= chunkSize && ds.NumIgnored == 0 {
				numHi = numEqual - numLo // Avoid pointless coalescing of single equal row
			}

			// Print the equal bytes.
			appendChunks(vx.Slice(0, numLo), diffIdentical)