91 lines
2.1 KiB
Go
91 lines
2.1 KiB
Go
package codegen
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import (
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"errors"
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"go/ast"
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"go/token"
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"strconv"
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)
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// FileGen is a utility for generating/patching golang file ASTs.
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type FileGen struct {
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File *ast.File
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idents map[string]bool
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codegenPkgPath string
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pkgImportMap map[string]*importInfo
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}
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// NewFileGen creates a new FileGen instance from a file AST with the provided package path.
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func NewFileGen(file *ast.File, codegenPkgPath string) (*FileGen, error) {
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g := &FileGen{
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File: file,
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idents: map[string]bool{},
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codegenPkgPath: codegenPkgPath,
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pkgImportMap: map[string]*importInfo{},
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}
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// add all go keywords to reserved idents
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for i := token.Token(0); i <= token.TILDE; i++ {
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name := i.String()
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if token.IsKeyword(name) {
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g.idents[name] = true
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}
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}
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// add all top-level decl idents
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for _, decl := range file.Decls {
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switch decl := decl.(type) {
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case *ast.FuncDecl:
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g.idents[decl.Name.Name] = true
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case *ast.GenDecl:
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for _, spec := range decl.Specs {
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switch spec := spec.(type) {
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case *ast.TypeSpec:
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g.idents[spec.Name.Name] = true
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case *ast.ValueSpec:
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for _, name := range spec.Names {
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g.idents[name.Name] = true
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}
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}
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}
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}
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}
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for _, spec := range file.Imports {
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pkgPath, err := strconv.Unquote(spec.Path.Value)
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if err != nil {
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return nil, err
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}
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var info *importInfo
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if spec.Name != nil {
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name := spec.Name.Name
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if name == "." {
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return nil, errors.New(". package imports are not allowed")
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}
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info = &importInfo{importPrefix: name, ImportSpec: spec}
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} else {
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prefix := defaultPkgPrefix(pkgPath)
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info = &importInfo{importPrefix: prefix, ImportSpec: spec}
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}
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g.pkgImportMap[pkgPath] = info
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g.idents[info.importPrefix] = true
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}
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return g, nil
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}
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// PatchFuncDecl returns a FuncGen instance for the function declaration with the given name or returns nil.
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func (g *FileGen) PatchFuncDecl(name string) *FuncGen {
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for _, decl := range g.File.Decls {
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funcDecl, ok := decl.(*ast.FuncDecl)
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if ok {
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if funcDecl.Name.Name == name {
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return newFuncGen(g, funcDecl)
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}
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}
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}
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return nil
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}
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