src

import.go (2840B)

---

 // Copyright 2025 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package stdlib
 
 // This file provides the API for the import graph of the standard library.
 //
 // Be aware that the compiler-generated code for every package
 // implicitly depends on package "runtime" and a handful of others
 // (see runtimePkgs in GOROOT/src/cmd/internal/objabi/pkgspecial.go).
 
 import (
 	"encoding/binary"
 	"iter"
 	"slices"
 	"strings"
 )
 
 // Imports returns the sequence of packages directly imported by the
 // named standard packages, in name order.
 // The imports of an unknown package are the empty set.
 //
 // The graph is built into the application and may differ from the
 // graph in the Go source tree being analyzed by the application.
 func Imports(pkgs ...string) iter.Seq[string] {
 	return func(yield func(string) bool) {
 		for _, pkg := range pkgs {
 			if i, ok := find(pkg); ok {
 				var depIndex uint64
 				for data := []byte(deps[i].deps); len(data) > 0; {
 					delta, n := binary.Uvarint(data)
 					depIndex += delta
 					if !yield(deps[depIndex].name) {
 						return
 					}
 					data = data[n:]
 				}
 			}
 		}
 	}
 }
 
 // Dependencies returns the set of all dependencies of the named
 // standard packages, including the initial package,
 // in a deterministic topological order.
 // The dependencies of an unknown package are the empty set.
 //
 // The graph is built into the application and may differ from the
 // graph in the Go source tree being analyzed by the application.
 func Dependencies(pkgs ...string) iter.Seq[string] {
 	return func(yield func(string) bool) {
 		for _, pkg := range pkgs {
 			if i, ok := find(pkg); ok {
 				var seen [1 + len(deps)/8]byte // bit set of seen packages
 				var visit func(i int) bool
 				visit = func(i int) bool {
 					bit := byte(1) << (i % 8)
 					if seen[i/8]&bit == 0 {
 						seen[i/8] |= bit
 						var depIndex uint64
 						for data := []byte(deps[i].deps); len(data) > 0; {
 							delta, n := binary.Uvarint(data)
 							depIndex += delta
 							if !visit(int(depIndex)) {
 								return false
 							}
 							data = data[n:]
 						}
 						if !yield(deps[i].name) {
 							return false
 						}
 					}
 					return true
 				}
 				if !visit(i) {
 					return
 				}
 			}
 		}
 	}
 }
 
 // find returns the index of pkg in the deps table.
 func find(pkg string) (int, bool) {
 	return slices.BinarySearchFunc(deps[:], pkg, func(p pkginfo, n string) int {
 		return strings.Compare(p.name, n)
 	})
 }
 
 // IsBootstrapPackage reports whether pkg is one of the low-level
 // packages in the Go distribution that must compile with the older
 // language version specified by [BootstrapVersion] during toolchain
 // bootstrapping; see golang.org/s/go15bootstrap.
 func IsBootstrapPackage(pkg string) bool {
 	return bootstrap[pkg]
 }