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.
11package main
12
13import (
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
30func 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
38func api(base string) string {
39	return filepath.Join(runtime.GOROOT(), "api", base)
40}
41
42var sym = regexp.MustCompile(`^pkg (\S+).*?, (?:var|func|type|const) ([A-Z]\w*)`)
43
44var unsafeSyms = map[string]bool{"Alignof": true, "ArbitraryType": true, "Offsetof": true, "Pointer": true, "Sizeof": true}
45
46func 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
73		// The API of the syscall/js package needs to be computed explicitly,
74		// because it's not included in the GOROOT/api/go1.*.txt files at this time.
75		syscallJSAPI(),
76	)
77	sc := bufio.NewScanner(f)
78
79	pkgs := map[string]map[string]bool{
80		"unsafe": unsafeSyms,
81	}
82	paths := []string{"unsafe"}
83
84	for sc.Scan() {
85		l := sc.Text()
86		if m := sym.FindStringSubmatch(l); m != nil {
87			path, sym := m[1], m[2]
88
89			if _, ok := pkgs[path]; !ok {
90				pkgs[path] = map[string]bool{}
91				paths = append(paths, path)
92			}
93			pkgs[path][sym] = true
94		}
95	}
96	if err := sc.Err(); err != nil {
97		log.Fatal(err)
98	}
99	sort.Strings(paths)
100	for _, path := range paths {
101		outf("\t%q: []string{\n", path)
102		pkg := pkgs[path]
103		var syms []string
104		for sym := range pkg {
105			syms = append(syms, sym)
106		}
107		sort.Strings(syms)
108		for _, sym := range syms {
109			outf("\t\t%q,\n", sym)
110		}
111		outf("},\n")
112	}
113	outf("}\n")
114	fmtbuf, err := format.Source(buf.Bytes())
115	if err != nil {
116		log.Fatal(err)
117	}
118	err = ioutil.WriteFile("zstdlib.go", fmtbuf, 0666)
119	if err != nil {
120		log.Fatal(err)
121	}
122}
123
124// syscallJSAPI returns the API of the syscall/js package.
125// It's computed from the contents of $(go env GOROOT)/src/syscall/js.
126func syscallJSAPI() io.Reader {
127	var exeSuffix string
128	if runtime.GOOS == "windows" {
129		exeSuffix = ".exe"
130	}
131	cmd := exec.Command("go"+exeSuffix, "run", "cmd/api", "-contexts", "js-wasm", "syscall/js")
132	out, err := cmd.Output()
133	if err != nil {
134		log.Fatalln(err)
135	}
136	return bytes.NewReader(out)
137}
138