60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
// Copyright 2018 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 packages
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import (
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"fmt"
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"os"
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"sort"
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)
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// Visit visits all the packages in the import graph whose roots are
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// pkgs, calling the optional pre function the first time each package
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// is encountered (preorder), and the optional post function after a
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// package's dependencies have been visited (postorder).
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// The boolean result of pre(pkg) determines whether
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// the imports of package pkg are visited.
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func Visit(pkgs []*Package, pre func(*Package) bool, post func(*Package)) {
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seen := make(map[*Package]bool)
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var visit func(*Package)
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visit = func(pkg *Package) {
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if !seen[pkg] {
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seen[pkg] = true
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if pre == nil || pre(pkg) {
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paths := make([]string, 0, len(pkg.Imports))
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for path := range pkg.Imports {
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paths = append(paths, path)
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}
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sort.Strings(paths) // Imports is a map, this makes visit stable
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for _, path := range paths {
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visit(pkg.Imports[path])
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}
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}
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if post != nil {
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post(pkg)
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}
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}
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}
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for _, pkg := range pkgs {
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visit(pkg)
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}
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}
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// PrintErrors prints to os.Stderr the accumulated errors of all
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// packages in the import graph rooted at pkgs, dependencies first.
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// PrintErrors returns the number of errors printed.
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func PrintErrors(pkgs []*Package) int {
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var n int
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Visit(pkgs, nil, func(pkg *Package) {
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for _, err := range pkg.Errors {
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fmt.Fprintln(os.Stderr, err)
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n++
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}
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})
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return n
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}
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