78 lines
1.9 KiB
Go
78 lines
1.9 KiB
Go
// Copyright 2013 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 callgraph
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// This file provides various utilities over call graphs, such as
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// visitation and path search.
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// CalleesOf returns a new set containing all direct callees of the
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// caller node.
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//
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func CalleesOf(caller *Node) map[*Node]bool {
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callees := make(map[*Node]bool)
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for _, e := range caller.Out {
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callees[e.Callee] = true
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}
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return callees
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}
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// GraphVisitEdges visits all the edges in graph g in depth-first order.
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// The edge function is called for each edge in postorder. If it
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// returns non-nil, visitation stops and GraphVisitEdges returns that
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// value.
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//
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func GraphVisitEdges(g *Graph, edge func(*Edge) error) error {
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seen := make(map[*Node]bool)
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var visit func(n *Node) error
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visit = func(n *Node) error {
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if !seen[n] {
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seen[n] = true
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for _, e := range n.Out {
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if err := visit(e.Callee); err != nil {
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return err
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}
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if err := edge(e); err != nil {
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return err
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}
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}
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}
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return nil
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}
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for _, n := range g.Nodes {
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if err := visit(n); err != nil {
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return err
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}
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}
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return nil
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}
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// PathSearch finds an arbitrary path starting at node start and
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// ending at some node for which isEnd() returns true. On success,
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// PathSearch returns the path as an ordered list of edges; on
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// failure, it returns nil.
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//
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func PathSearch(start *Node, isEnd func(*Node) bool) []*Edge {
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stack := make([]*Edge, 0, 32)
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seen := make(map[*Node]bool)
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var search func(n *Node) []*Edge
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search = func(n *Node) []*Edge {
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if !seen[n] {
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seen[n] = true
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if isEnd(n) {
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return stack
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}
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for _, e := range n.Out {
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stack = append(stack, e) // push
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if found := search(e.Callee); found != nil {
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return found
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}
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stack = stack[:len(stack)-1] // pop
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}
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}
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return nil
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}
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return search(start)
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}
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