145 lines
3.3 KiB
Go
145 lines
3.3 KiB
Go
//+build ignore
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// types_generate.go is meant to run with go generate. It will use
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// go/{importer,types} to track down all the RR struct types. Then for each type
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// it will generate conversion tables (TypeToRR and TypeToString) and banal
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// methods (len, Header, copy) based on the struct tags. The generated source is
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// written to ztypes.go, and is meant to be checked into git.
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package main
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import (
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"bytes"
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"fmt"
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"go/format"
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"go/importer"
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"go/types"
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"log"
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"os"
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)
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var packageHdr = `
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// Code generated by "go run duplicate_generate.go"; DO NOT EDIT.
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package dns
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`
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func getTypeStruct(t types.Type, scope *types.Scope) (*types.Struct, bool) {
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st, ok := t.Underlying().(*types.Struct)
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if !ok {
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return nil, false
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}
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if st.Field(0).Type() == scope.Lookup("RR_Header").Type() {
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return st, false
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}
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if st.Field(0).Anonymous() {
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st, _ := getTypeStruct(st.Field(0).Type(), scope)
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return st, true
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}
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return nil, false
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}
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func main() {
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// Import and type-check the package
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pkg, err := importer.Default().Import("github.com/miekg/dns")
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fatalIfErr(err)
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scope := pkg.Scope()
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// Collect actual types (*X)
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var namedTypes []string
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for _, name := range scope.Names() {
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o := scope.Lookup(name)
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if o == nil || !o.Exported() {
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continue
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}
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if st, _ := getTypeStruct(o.Type(), scope); st == nil {
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continue
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}
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if name == "PrivateRR" || name == "OPT" {
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continue
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}
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namedTypes = append(namedTypes, o.Name())
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}
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b := &bytes.Buffer{}
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b.WriteString(packageHdr)
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// Generate the duplicate check for each type.
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fmt.Fprint(b, "// isDuplicate() functions\n\n")
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for _, name := range namedTypes {
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o := scope.Lookup(name)
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st, isEmbedded := getTypeStruct(o.Type(), scope)
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if isEmbedded {
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continue
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}
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fmt.Fprintf(b, "func (r1 *%s) isDuplicate(_r2 RR) bool {\n", name)
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fmt.Fprintf(b, "r2, ok := _r2.(*%s)\n", name)
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fmt.Fprint(b, "if !ok { return false }\n")
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fmt.Fprint(b, "_ = r2\n")
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for i := 1; i < st.NumFields(); i++ {
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field := st.Field(i).Name()
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o2 := func(s string) { fmt.Fprintf(b, s+"\n", field, field) }
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o3 := func(s string) { fmt.Fprintf(b, s+"\n", field, field, field) }
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// For some reason, a and aaaa don't pop up as *types.Slice here (mostly like because the are
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// *indirectly* defined as a slice in the net package).
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if _, ok := st.Field(i).Type().(*types.Slice); ok {
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o2("if len(r1.%s) != len(r2.%s) {\nreturn false\n}")
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if st.Tag(i) == `dns:"cdomain-name"` || st.Tag(i) == `dns:"domain-name"` {
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o3(`for i := 0; i < len(r1.%s); i++ {
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if !isDuplicateName(r1.%s[i], r2.%s[i]) {
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return false
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}
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}`)
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continue
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}
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o3(`for i := 0; i < len(r1.%s); i++ {
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if r1.%s[i] != r2.%s[i] {
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return false
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}
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}`)
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continue
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}
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switch st.Tag(i) {
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case `dns:"-"`:
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// ignored
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case `dns:"a"`, `dns:"aaaa"`:
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o2("if !r1.%s.Equal(r2.%s) {\nreturn false\n}")
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case `dns:"cdomain-name"`, `dns:"domain-name"`:
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o2("if !isDuplicateName(r1.%s, r2.%s) {\nreturn false\n}")
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default:
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o2("if r1.%s != r2.%s {\nreturn false\n}")
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}
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}
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fmt.Fprintf(b, "return true\n}\n\n")
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}
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// gofmt
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res, err := format.Source(b.Bytes())
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if err != nil {
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b.WriteTo(os.Stderr)
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log.Fatal(err)
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}
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// write result
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f, err := os.Create("zduplicate.go")
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fatalIfErr(err)
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defer f.Close()
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f.Write(res)
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}
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func fatalIfErr(err error) {
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if err != nil {
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log.Fatal(err)
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}
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}
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