| // Copyright 2019 CUE 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. |
| |
| package gocode |
| |
| import ( |
| "bytes" |
| "fmt" |
| "go/ast" |
| "go/format" |
| "go/types" |
| "text/template" |
| |
| "golang.org/x/tools/go/packages" |
| |
| "cuelang.org/go/cue" |
| "cuelang.org/go/cue/errors" |
| "cuelang.org/go/internal" |
| ) |
| |
| // Config defines options for generation Go code. |
| type Config struct { |
| // Prefix is used as a prefix to all generated variables. It defaults to |
| // cuegen. |
| Prefix string |
| |
| // ValidateName defines the default name for validation methods or prefix |
| // for validation functions. The default is "Validate". Set to "-" to |
| // disable generating validators. |
| ValidateName string |
| |
| // CompleteName defines the default name for complete methods or prefix |
| // for complete functions. The default is "-" (disabled). |
| CompleteName string |
| |
| // The cue.Runtime variable name to use for initializing Codecs. |
| // A new Runtime is created by default. |
| RuntimeVar string |
| } |
| |
| const defaultPrefix = "cuegen" |
| |
| // Generate generates Go code for the given instance in the directory of the |
| // given package. |
| // |
| // Generate converts top-level declarations to corresponding Go code. By default, |
| // it will only generate validation functions of methods for exported top-level |
| // declarations. The behavior can be altered with the @go attribute. |
| // |
| // The go attribute has the following form @go(<name>{,<option>}), where option |
| // is either a key-value pair or a flag. The name maps the CUE name to an |
| // alternative Go name. The special value '-' is used to indicate the field |
| // should be ignored for any Go generation. |
| // |
| // The following options are supported: |
| // |
| // type=<gotype> The Go type as which this value should be interpreted. |
| // This defaults to the type with the (possibly overridden) |
| // name of the field. |
| // validate=<name> Alternative name for the validation function or method |
| // Setting this to the empty string disables generation. |
| // complete=<name> Alternative name for the validation function or method. |
| // Setting this to the empty string disables generation. |
| // func Generate as a function instead of a method. |
| // |
| // |
| // Selection and Naming |
| // |
| // Generate will not generate any code for fields that have no go attribute |
| // and that are not exported or for which there is no namesake Go type. |
| // If the go attribute has the special value '-' as its name it wil be dropped |
| // as well. In all other cases Generate will generate Go code, even if the |
| // resulting code will not compile. For instance, Generate will generate Go |
| // code even if the user defines a Go type in the attribute that does not |
| // exist. |
| // |
| // If a field selected for generation and the go name matches that the name of |
| // the Go type, the corresponding validate and complete code are generated as |
| // methods by default. If not, it will be generated as a function. The default |
| // function name is the default operation name with the Go name as a suffix. |
| // |
| // |
| // Caveats |
| // Currently not supported: |
| // - option to generate Go structs (or automatically generate if undefined) |
| // - for type option to refer to types outside the package. |
| // |
| func Generate(pkgPath string, inst *cue.Instance, c *Config) (b []byte, err error) { |
| // TODO: if inst is nil, the instance is loaded from CUE files in the same |
| // package directory with the same package name. |
| if err = inst.Value().Validate(); err != nil { |
| return nil, err |
| } |
| if c == nil { |
| c = &Config{} |
| } |
| g := &generator{ |
| Config: *c, |
| |
| typeMap: map[string]types.Type{}, |
| } |
| |
| pkgName := inst.PkgName |
| |
| if pkgPath != "" { |
| loadCfg := &packages.Config{ |
| Mode: packages.LoadAllSyntax, |
| } |
| pkgs, err := packages.Load(loadCfg, pkgPath) |
| if err != nil { |
| return nil, fmt.Errorf("generating failed: %v", err) |
| } |
| |
| if len(pkgs) != 1 { |
| return nil, fmt.Errorf( |
| "generate only allowed for one package at a time, found %d", |
| len(pkgs)) |
| } |
| |
| g.pkg = pkgs[0] |
| if len(g.pkg.Errors) > 0 { |
| for _, err := range g.pkg.Errors { |
| g.addErr(err) |
| } |
| return nil, g.err |
| } |
| |
| pkgName = g.pkg.Name |
| |
| for _, obj := range g.pkg.TypesInfo.Defs { |
| if obj == nil || obj.Pkg() != g.pkg.Types || obj.Parent() == nil { |
| continue |
| } |
| g.typeMap[obj.Name()] = obj.Type() |
| } |
| } |
| |
| // TODO: add package doc if there is no existing Go package or if it doesn't |
| // have package documentation already. |
| g.exec(headerCode, map[string]string{ |
| "pkgName": pkgName, |
| }) |
| |
| iter, err := inst.Value().Fields(cue.Definitions(true)) |
| g.addErr(err) |
| |
| for iter.Next() { |
| g.decl(iter.Label(), iter.Value()) |
| } |
| |
| r := internal.GetRuntimeNew(inst).(*cue.Runtime) |
| b, err = r.Marshal(inst) |
| g.addErr(err) |
| |
| g.exec(loadCode, map[string]string{ |
| "runtime": g.RuntimeVar, |
| "prefix": strValue(g.Prefix, defaultPrefix), |
| "data": string(b), |
| }) |
| |
| if g.err != nil { |
| return nil, g.err |
| } |
| |
| b, err = format.Source(g.w.Bytes()) |
| if err != nil { |
| // Return bytes as well to allow analysis of the failed Go code. |
| return g.w.Bytes(), err |
| } |
| |
| return b, err |
| } |
| |
| type generator struct { |
| Config |
| pkg *packages.Package |
| typeMap map[string]types.Type |
| |
| w bytes.Buffer |
| err errors.Error |
| } |
| |
| func (g *generator) addErr(err error) { |
| if err != nil { |
| g.err = errors.Append(g.err, errors.Promote(err, "generate failed")) |
| } |
| } |
| |
| func (g *generator) exec(t *template.Template, data interface{}) { |
| g.addErr(t.Execute(&g.w, data)) |
| } |
| |
| func (g *generator) decl(name string, v cue.Value) { |
| attr := v.Attribute("go") |
| |
| if !ast.IsExported(name) && attr.Err() != nil { |
| return |
| } |
| |
| goName := name |
| switch s, _ := attr.String(0); s { |
| case "": |
| case "-": |
| return |
| default: |
| goName = s |
| } |
| |
| goTypeName := goName |
| goType := "" |
| if str, ok, _ := attr.Lookup(1, "type"); ok { |
| goType = str |
| goTypeName = str |
| } |
| |
| isFunc, _ := attr.Flag(1, "func") |
| if goTypeName != goName { |
| isFunc = true |
| } |
| |
| zero := "nil" |
| |
| typ, ok := g.typeMap[goTypeName] |
| if !ok && !mappedGoTypes(goTypeName) { |
| return |
| } |
| if goType == "" { |
| goType = goTypeName |
| if typ != nil { |
| switch typ.Underlying().(type) { |
| case *types.Struct, *types.Array: |
| goType = "*" + goTypeName |
| zero = fmt.Sprintf("&%s{}", goTypeName) |
| case *types.Pointer: |
| zero = fmt.Sprintf("%s(nil)", goTypeName) |
| isFunc = true |
| } |
| } |
| } |
| |
| g.exec(stubCode, map[string]interface{}{ |
| "prefix": strValue(g.Prefix, defaultPrefix), |
| "cueName": name, // the field name of the CUE type |
| "goType": goType, // the receiver or argument type |
| "zero": zero, // the zero value of the underlying type |
| |
| // @go attribute options |
| "func": isFunc, |
| "validate": lookupName(attr, "validate", strValue(g.ValidateName, "Validate")), |
| "complete": lookupName(attr, "complete", g.CompleteName), |
| }) |
| } |
| |
| func lookupName(attr cue.Attribute, option, config string) string { |
| name, ok, _ := attr.Lookup(1, option) |
| if !ok { |
| name = config |
| } |
| if name == "-" { |
| return "" |
| } |
| return name |
| } |
| |
| func strValue(have, fallback string) string { |
| if have == "" { |
| return fallback |
| } |
| return have |
| } |
| |
| func mappedGoTypes(s string) bool { |
| switch s { |
| case "bool", "float32", "float64", |
| "int", "int8", "int16", "int32", "int64", "string", |
| "uint", "uint8", "uint16", "uint32", "uint64": |
| return true |
| } |
| return false |
| } |