func ExampleRead() {
g, err := dot.Read([]byte(`digraph G {Hello->World}`))
if err != nil {
panic(err)
}
s := g.String()
fmt.Println(s)
}
// restructure attempts to recover the control flow primitives of a given
// control flow graph. It does so by repeatedly locating and merging structured
// subgraphs (graph representations of control flow primitives) into single
// nodes until the entire graph is reduced into a single node or no structured
// subgraphs may be located. The list of primitives is ordered in the same
// sequence as they were located.
func restructure(dotPath string, subs []*graphs.SubGraph) (prims []*primitive.Primitive, err error) {
// Parse the unstructured CFG.
var graph *dot.Graph
switch dotPath {
case "-":
// Read from stdin.
buf, err := ioutil.ReadAll(os.Stdin)
if err != nil {
return nil, errutil.Err(err)
}
graph, err = dot.Read(buf)
if err != nil {
return nil, errutil.Err(err)
}
default:
// Read from FILE.
graph, err = dot.ParseFile(dotPath)
if err != nil {
return nil, errutil.Err(err)
}
}
if len(graph.Nodes.Nodes) == 0 {
return nil, errutil.Newf("unable to restructure empty graph %q", dotPath)
}
// Locate control flow primitives.
for step := 1; len(graph.Nodes.Nodes) > 1; step++ {
prim, err := findPrim(graph, subs, step)
if err != nil {
return nil, errutil.Err(err)
}
prims = append(prims, prim)
}
return prims, nil
}