56 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			56 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			Go
		
	
	
	
| package packages
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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