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Diffstat (limited to 'tools/go_stateify/main.go')
-rw-r--r-- | tools/go_stateify/main.go | 428 |
1 files changed, 0 insertions, 428 deletions
diff --git a/tools/go_stateify/main.go b/tools/go_stateify/main.go deleted file mode 100644 index aa9d4543e..000000000 --- a/tools/go_stateify/main.go +++ /dev/null @@ -1,428 +0,0 @@ -// Copyright 2018 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// Stateify provides a simple way to generate Load/Save methods based on -// existing types and struct tags. -package main - -import ( - "flag" - "fmt" - "go/ast" - "go/parser" - "go/token" - "os" - "reflect" - "strings" - "sync" - - "gvisor.dev/gvisor/tools/tags" -) - -var ( - pkg = flag.String("pkg", "", "output package") - imports = flag.String("imports", "", "extra imports for the output file") - output = flag.String("output", "", "output file") - statePkg = flag.String("statepkg", "", "state import package; defaults to empty") -) - -// resolveTypeName returns a qualified type name. -func resolveTypeName(name string, typ ast.Expr) (field string, qualified string) { - for done := false; !done; { - // Resolve star expressions. - switch rs := typ.(type) { - case *ast.StarExpr: - qualified += "*" - typ = rs.X - case *ast.ArrayType: - if rs.Len == nil { - // Slice type declaration. - qualified += "[]" - } else { - // Array type declaration. - qualified += "[" + rs.Len.(*ast.BasicLit).Value + "]" - } - typ = rs.Elt - default: - // No more descent. - done = true - } - } - - // Resolve a package selector. - sel, ok := typ.(*ast.SelectorExpr) - if ok { - qualified = qualified + sel.X.(*ast.Ident).Name + "." - typ = sel.Sel - } - - // Figure out actual type name. - ident, ok := typ.(*ast.Ident) - if !ok { - panic(fmt.Sprintf("type not supported: %s (involves anonymous types?)", name)) - } - field = ident.Name - qualified = qualified + field - return -} - -// extractStateTag pulls the relevant state tag. -func extractStateTag(tag *ast.BasicLit) string { - if tag == nil { - return "" - } - if len(tag.Value) < 2 { - return "" - } - return reflect.StructTag(tag.Value[1 : len(tag.Value)-1]).Get("state") -} - -// scanFunctions is a set of functions passed to scanFields. -type scanFunctions struct { - zerovalue func(name string) - normal func(name string) - wait func(name string) - value func(name, typName string) -} - -// scanFields scans the fields of a struct. -// -// Each provided function will be applied to appropriately tagged fields, or -// skipped if nil. -// -// Fields tagged nosave are skipped. -func scanFields(ss *ast.StructType, fn scanFunctions) { - if ss.Fields.List == nil { - // No fields. - return - } - - // Scan all fields. - for _, field := range ss.Fields.List { - // Calculate the name. - name := "" - if field.Names != nil { - // It's a named field; override. - name = field.Names[0].Name - } else { - // Anonymous types can't be embedded, so we don't need - // to worry about providing a useful name here. - name, _ = resolveTypeName("", field.Type) - } - - // Skip _ fields. - if name == "_" { - continue - } - - switch tag := extractStateTag(field.Tag); tag { - case "zerovalue": - if fn.zerovalue != nil { - fn.zerovalue(name) - } - - case "": - if fn.normal != nil { - fn.normal(name) - } - - case "wait": - if fn.wait != nil { - fn.wait(name) - } - - case "manual", "nosave", "ignore": - // Do nothing. - - default: - if strings.HasPrefix(tag, ".(") && strings.HasSuffix(tag, ")") { - if fn.value != nil { - fn.value(name, tag[2:len(tag)-1]) - } - } - } - } -} - -func camelCased(name string) string { - return strings.ToUpper(name[:1]) + name[1:] -} - -func main() { - // Parse flags. - flag.Usage = func() { - fmt.Fprintf(os.Stderr, "Usage: %s [options]\n", os.Args[0]) - flag.PrintDefaults() - } - flag.Parse() - if len(flag.Args()) == 0 { - flag.Usage() - os.Exit(1) - } - if *pkg == "" { - fmt.Fprintf(os.Stderr, "Error: package required.") - os.Exit(1) - } - - // Open the output file. - var ( - outputFile *os.File - err error - ) - if *output == "" || *output == "-" { - outputFile = os.Stdout - } else { - outputFile, err = os.OpenFile(*output, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644) - if err != nil { - fmt.Fprintf(os.Stderr, "Error opening output %q: %v", *output, err) - } - defer outputFile.Close() - } - - // Set the statePrefix for below, depending on the import. - statePrefix := "" - if *statePkg != "" { - parts := strings.Split(*statePkg, "/") - statePrefix = parts[len(parts)-1] + "." - } - - // initCalls is dumped at the end. - var initCalls []string - - // Declare our emission closures. - emitRegister := func(name string) { - initCalls = append(initCalls, fmt.Sprintf("%sRegister(\"%s.%s\", (*%s)(nil), state.Fns{Save: (*%s).save, Load: (*%s).load})", statePrefix, *pkg, name, name, name, name)) - } - emitZeroCheck := func(name string) { - fmt.Fprintf(outputFile, " if !%sIsZeroValue(x.%s) { m.Failf(\"%s is %%v, expected zero\", x.%s) }\n", statePrefix, name, name, name) - } - emitLoadValue := func(name, typName string) { - fmt.Fprintf(outputFile, " m.LoadValue(\"%s\", new(%s), func(y interface{}) { x.load%s(y.(%s)) })\n", name, typName, camelCased(name), typName) - } - emitLoad := func(name string) { - fmt.Fprintf(outputFile, " m.Load(\"%s\", &x.%s)\n", name, name) - } - emitLoadWait := func(name string) { - fmt.Fprintf(outputFile, " m.LoadWait(\"%s\", &x.%s)\n", name, name) - } - emitSaveValue := func(name, typName string) { - fmt.Fprintf(outputFile, " var %s %s = x.save%s()\n", name, typName, camelCased(name)) - fmt.Fprintf(outputFile, " m.SaveValue(\"%s\", %s)\n", name, name) - } - emitSave := func(name string) { - fmt.Fprintf(outputFile, " m.Save(\"%s\", &x.%s)\n", name, name) - } - - // Automated warning. - fmt.Fprint(outputFile, "// automatically generated by stateify.\n\n") - - // Emit build tags. - if t := tags.Aggregate(flag.Args()); len(t) > 0 { - fmt.Fprintf(outputFile, "%s\n\n", strings.Join(t.Lines(), "\n")) - } - - // Emit the package name. - fmt.Fprintf(outputFile, "package %s\n\n", *pkg) - - // Emit the imports lazily. - var once sync.Once - maybeEmitImports := func() { - once.Do(func() { - // Emit the imports. - fmt.Fprint(outputFile, "import (\n") - if *statePkg != "" { - fmt.Fprintf(outputFile, " \"%s\"\n", *statePkg) - } - if *imports != "" { - for _, i := range strings.Split(*imports, ",") { - fmt.Fprintf(outputFile, " \"%s\"\n", i) - } - } - fmt.Fprint(outputFile, ")\n\n") - }) - } - - files := make([]*ast.File, 0, len(flag.Args())) - - // Parse the input files. - for _, filename := range flag.Args() { - // Parse the file. - fset := token.NewFileSet() - f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments) - if err != nil { - // Not a valid input file? - fmt.Fprintf(os.Stderr, "Input %q can't be parsed: %v\n", filename, err) - os.Exit(1) - } - - files = append(files, f) - } - - type method struct { - receiver string - name string - } - - // Search for and add all methods with a pointer receiver and no other - // arguments to a set. We support auto-detecting the existence of - // several different methods with this signature. - simpleMethods := map[method]struct{}{} - for _, f := range files { - - // Go over all functions. - for _, decl := range f.Decls { - d, ok := decl.(*ast.FuncDecl) - if !ok { - continue - } - if d.Name == nil || d.Recv == nil || d.Type == nil { - // Not a named method. - continue - } - if len(d.Recv.List) != 1 { - // Wrong number of receivers? - continue - } - if d.Type.Params != nil && len(d.Type.Params.List) != 0 { - // Has argument(s). - continue - } - if d.Type.Results != nil && len(d.Type.Results.List) != 0 { - // Has return(s). - continue - } - - pt, ok := d.Recv.List[0].Type.(*ast.StarExpr) - if !ok { - // Not a pointer receiver. - continue - } - - t, ok := pt.X.(*ast.Ident) - if !ok { - // This shouldn't happen with valid Go. - continue - } - - simpleMethods[method{t.Name, d.Name.Name}] = struct{}{} - } - } - - for _, f := range files { - // Go over all named types. - for _, decl := range f.Decls { - d, ok := decl.(*ast.GenDecl) - if !ok || d.Tok != token.TYPE { - continue - } - - // Only generate code for types marked - // "// +stateify savable" in one of the proceeding - // comment lines. - if d.Doc == nil { - continue - } - savable := false - for _, l := range d.Doc.List { - if l.Text == "// +stateify savable" { - savable = true - break - } - } - if !savable { - continue - } - - for _, gs := range d.Specs { - ts := gs.(*ast.TypeSpec) - switch ts.Type.(type) { - case *ast.InterfaceType, *ast.ChanType, *ast.FuncType, *ast.ParenExpr, *ast.StarExpr: - // Don't register. - break - case *ast.StructType: - maybeEmitImports() - - ss := ts.Type.(*ast.StructType) - - // Define beforeSave if a definition was not found. This - // prevents the code from compiling if a custom beforeSave - // was defined in a file not provided to this binary and - // prevents inherited methods from being called multiple times - // by overriding them. - if _, ok := simpleMethods[method{ts.Name.Name, "beforeSave"}]; !ok { - fmt.Fprintf(outputFile, "func (x *%s) beforeSave() {}\n", ts.Name.Name) - } - - // Generate the save method. - fmt.Fprintf(outputFile, "func (x *%s) save(m %sMap) {\n", ts.Name.Name, statePrefix) - fmt.Fprintf(outputFile, " x.beforeSave()\n") - scanFields(ss, scanFunctions{zerovalue: emitZeroCheck}) - scanFields(ss, scanFunctions{value: emitSaveValue}) - scanFields(ss, scanFunctions{normal: emitSave, wait: emitSave}) - fmt.Fprintf(outputFile, "}\n\n") - - // Define afterLoad if a definition was not found. We do this - // for the same reason that we do it for beforeSave. - _, hasAfterLoad := simpleMethods[method{ts.Name.Name, "afterLoad"}] - if !hasAfterLoad { - fmt.Fprintf(outputFile, "func (x *%s) afterLoad() {}\n", ts.Name.Name) - } - - // Generate the load method. - // - // Note that the manual loads always follow the - // automated loads. - fmt.Fprintf(outputFile, "func (x *%s) load(m %sMap) {\n", ts.Name.Name, statePrefix) - scanFields(ss, scanFunctions{normal: emitLoad, wait: emitLoadWait}) - scanFields(ss, scanFunctions{value: emitLoadValue}) - if hasAfterLoad { - // The call to afterLoad is made conditionally, because when - // AfterLoad is called, the object encodes a dependency on - // referred objects (i.e. fields). This means that afterLoad - // will not be called until the other afterLoads are called. - fmt.Fprintf(outputFile, " m.AfterLoad(x.afterLoad)\n") - } - fmt.Fprintf(outputFile, "}\n\n") - - // Add to our registration. - emitRegister(ts.Name.Name) - case *ast.Ident, *ast.SelectorExpr, *ast.ArrayType: - maybeEmitImports() - - _, val := resolveTypeName(ts.Name.Name, ts.Type) - - // Dispatch directly. - fmt.Fprintf(outputFile, "func (x *%s) save(m %sMap) {\n", ts.Name.Name, statePrefix) - fmt.Fprintf(outputFile, " m.SaveValue(\"\", (%s)(*x))\n", val) - fmt.Fprintf(outputFile, "}\n\n") - fmt.Fprintf(outputFile, "func (x *%s) load(m %sMap) {\n", ts.Name.Name, statePrefix) - fmt.Fprintf(outputFile, " m.LoadValue(\"\", new(%s), func(y interface{}) { *x = (%s)(y.(%s)) })\n", val, ts.Name.Name, val) - fmt.Fprintf(outputFile, "}\n\n") - - // See above. - emitRegister(ts.Name.Name) - } - } - } - } - - if len(initCalls) > 0 { - // Emit the init() function. - fmt.Fprintf(outputFile, "func init() {\n") - for _, ic := range initCalls { - fmt.Fprintf(outputFile, " %s\n", ic) - } - fmt.Fprintf(outputFile, "}\n") - } -} |