visit.go

Documentation: golang.org/x/tools/go/packages

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package packages
     6  
     7  import (
     8  	"fmt"
     9  	"os"
    10  	"sort"
    11  )
    12  
    13  // Visit visits all the packages in the import graph whose roots are
    14  // pkgs, calling the optional pre function the first time each package
    15  // is encountered (preorder), and the optional post function after a
    16  // package's dependencies have been visited (postorder).
    17  // The boolean result of pre(pkg) determines whether
    18  // the imports of package pkg are visited.
    19  func Visit(pkgs []*Package, pre func(*Package) bool, post func(*Package)) {
    20  	seen := make(map[*Package]bool)
    21  	var visit func(*Package)
    22  	visit = func(pkg *Package) {
    23  		if !seen[pkg] {
    24  			seen[pkg] = true
    25  
    26  			if pre == nil || pre(pkg) {
    27  				paths := make([]string, 0, len(pkg.Imports))
    28  				for path := range pkg.Imports {
    29  					paths = append(paths, path)
    30  				}
    31  				sort.Strings(paths) // Imports is a map, this makes visit stable
    32  				for _, path := range paths {
    33  					visit(pkg.Imports[path])
    34  				}
    35  			}
    36  
    37  			if post != nil {
    38  				post(pkg)
    39  			}
    40  		}
    41  	}
    42  	for _, pkg := range pkgs {
    43  		visit(pkg)
    44  	}
    45  }
    46  
    47  // PrintErrors prints to os.Stderr the accumulated errors of all
    48  // packages in the import graph rooted at pkgs, dependencies first.
    49  // PrintErrors returns the number of errors printed.
    50  func PrintErrors(pkgs []*Package) int {
    51  	var n int
    52  	Visit(pkgs, nil, func(pkg *Package) {
    53  		for _, err := range pkg.Errors {
    54  			fmt.Fprintln(os.Stderr, err)
    55  			n++
    56  		}
    57  	})
    58  	return n
    59  }
    60
View as plain text