github.com/powerman/golang-tools@v0.1.11-0.20220410185822-5ad214d8d803/internal/imports/mkstdlib.go (about)

     1  // Copyright 2019 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  //go:build ignore
     6  // +build ignore
     7  
     8  // mkstdlib generates the zstdlib.go file, containing the Go standard
     9  // library API symbols. It's baked into the binary to avoid scanning
    10  // GOPATH in the common case.
    11  package main
    12  
    13  import (
    14  	"bufio"
    15  	"bytes"
    16  	"fmt"
    17  	"go/format"
    18  	"io"
    19  	"io/ioutil"
    20  	"log"
    21  	"os"
    22  	"path/filepath"
    23  	"regexp"
    24  	"runtime"
    25  	"sort"
    26  
    27  	exec "golang.org/x/sys/execabs"
    28  )
    29  
    30  func mustOpen(name string) io.Reader {
    31  	f, err := os.Open(name)
    32  	if err != nil {
    33  		log.Fatal(err)
    34  	}
    35  	return f
    36  }
    37  
    38  func api(base string) string {
    39  	return filepath.Join(runtime.GOROOT(), "api", base)
    40  }
    41  
    42  var sym = regexp.MustCompile(`^pkg (\S+).*?, (?:var|func|type|const) ([A-Z]\w*)`)
    43  
    44  var unsafeSyms = map[string]bool{"Alignof": true, "ArbitraryType": true, "Offsetof": true, "Pointer": true, "Sizeof": true}
    45  
    46  func main() {
    47  	var buf bytes.Buffer
    48  	outf := func(format string, args ...interface{}) {
    49  		fmt.Fprintf(&buf, format, args...)
    50  	}
    51  	outf("// Code generated by mkstdlib.go. DO NOT EDIT.\n\n")
    52  	outf("package imports\n")
    53  	outf("var stdlib = map[string][]string{\n")
    54  	f := io.MultiReader(
    55  		mustOpen(api("go1.txt")),
    56  		mustOpen(api("go1.1.txt")),
    57  		mustOpen(api("go1.2.txt")),
    58  		mustOpen(api("go1.3.txt")),
    59  		mustOpen(api("go1.4.txt")),
    60  		mustOpen(api("go1.5.txt")),
    61  		mustOpen(api("go1.6.txt")),
    62  		mustOpen(api("go1.7.txt")),
    63  		mustOpen(api("go1.8.txt")),
    64  		mustOpen(api("go1.9.txt")),
    65  		mustOpen(api("go1.10.txt")),
    66  		mustOpen(api("go1.11.txt")),
    67  		mustOpen(api("go1.12.txt")),
    68  		mustOpen(api("go1.13.txt")),
    69  		mustOpen(api("go1.14.txt")),
    70  		mustOpen(api("go1.15.txt")),
    71  		mustOpen(api("go1.16.txt")),
    72  		mustOpen(api("go1.17.txt")),
    73  		mustOpen(api("go1.18.txt")),
    74  
    75  		// The API of the syscall/js package needs to be computed explicitly,
    76  		// because it's not included in the GOROOT/api/go1.*.txt files at this time.
    77  		syscallJSAPI(),
    78  	)
    79  	sc := bufio.NewScanner(f)
    80  
    81  	pkgs := map[string]map[string]bool{
    82  		"unsafe": unsafeSyms,
    83  	}
    84  	paths := []string{"unsafe"}
    85  
    86  	for sc.Scan() {
    87  		l := sc.Text()
    88  		if m := sym.FindStringSubmatch(l); m != nil {
    89  			path, sym := m[1], m[2]
    90  
    91  			if _, ok := pkgs[path]; !ok {
    92  				pkgs[path] = map[string]bool{}
    93  				paths = append(paths, path)
    94  			}
    95  			pkgs[path][sym] = true
    96  		}
    97  	}
    98  	if err := sc.Err(); err != nil {
    99  		log.Fatal(err)
   100  	}
   101  	sort.Strings(paths)
   102  	for _, path := range paths {
   103  		outf("\t%q: []string{\n", path)
   104  		pkg := pkgs[path]
   105  		var syms []string
   106  		for sym := range pkg {
   107  			syms = append(syms, sym)
   108  		}
   109  		sort.Strings(syms)
   110  		for _, sym := range syms {
   111  			outf("\t\t%q,\n", sym)
   112  		}
   113  		outf("},\n")
   114  	}
   115  	outf("}\n")
   116  	fmtbuf, err := format.Source(buf.Bytes())
   117  	if err != nil {
   118  		log.Fatal(err)
   119  	}
   120  	err = ioutil.WriteFile("zstdlib.go", fmtbuf, 0666)
   121  	if err != nil {
   122  		log.Fatal(err)
   123  	}
   124  }
   125  
   126  // syscallJSAPI returns the API of the syscall/js package.
   127  // It's computed from the contents of $(go env GOROOT)/src/syscall/js.
   128  func syscallJSAPI() io.Reader {
   129  	var exeSuffix string
   130  	if runtime.GOOS == "windows" {
   131  		exeSuffix = ".exe"
   132  	}
   133  	cmd := exec.Command("go"+exeSuffix, "run", "cmd/api", "-contexts", "js-wasm", "syscall/js")
   134  	out, err := cmd.Output()
   135  	if err != nil {
   136  		log.Fatalln(err)
   137  	}
   138  	return bytes.NewReader(out)
   139  }