Function getSourceFromFile

internal/report/source.go:884–940

getSourceFromFile collects the sources of a function from a source file and annotates it with the samples in fns. Returns the sources as nodes, using the info.name field to hold the source code.

(file string, reader *sourceReader, fns graph.Nodes, start, end int)

// file and annotates it with the samples in fns. Returns the sources
// as nodes, using the info.name field to hold the source code.
func getSourceFromFile(file string, reader *sourceReader, fns graph.Nodes, start, end int) (graph.Nodes, string, error) {
	lineNodes := make(map[int]graph.Nodes)

	// Collect source coordinates from profile.
	const margin = 5 // Lines before first/after last sample.
	if start == 0 {
		if fns[0].Info.StartLine != 0 {
			start = fns[0].Info.StartLine
		} else {
			start = fns[0].Info.Lineno - margin
		}
	} else {
		start -= margin
	}
	if end == 0 {
		end = fns[0].Info.Lineno
	}
	end += margin
	for _, n := range fns {
		lineno := n.Info.Lineno
		nodeStart := n.Info.StartLine
		if nodeStart == 0 {
			nodeStart = lineno - margin
		}
		nodeEnd := lineno + margin
		if nodeStart < start {
			start = nodeStart
		} else if nodeEnd > end {
			end = nodeEnd
		}
		lineNodes[lineno] = append(lineNodes[lineno], n)
	}
	if start < 1 {
		start = 1
	}

	var src graph.Nodes
	for lineno := start; lineno <= end; lineno++ {
		line, ok := reader.line(file, lineno)
		if !ok {
			break
		}
		flat, cum := lineNodes[lineno].Sum()
		src = append(src, &graph.Node{
			Info: graph.NodeInfo{
				Name:   strings.TrimRight(line, "\n"),
				Lineno: lineno,
			},
			Flat: flat,
			Cum:  cum,
		})
	}
	if err := reader.fileError(file); err != nil {
		return nil, file, err
	}
	return src, file, nil
}