github.com/jd-ly/tools@v0.5.7/internal/imports/mkstdlib.go (about)

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