Merge pull request #4 from campoy/refactor
moving the parser to a reusable package
This commit is contained in:
Francesc Campoy
commit
0ab873adbf
151
jsonenums.go
151
jsonenums.go
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@ -67,22 +67,14 @@ package main
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import (
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"bytes"
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"flag"
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"fmt"
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"go/ast"
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"go/build"
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"go/format"
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"go/parser"
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"go/token"
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"io/ioutil"
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"log"
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"os"
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"path/filepath"
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"strings"
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"golang.org/x/tools/go/exact"
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"golang.org/x/tools/go/types"
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_ "golang.org/x/tools/go/gcimporter"
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"github.com/campoy/jsonenums/parser"
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)
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var (
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@ -105,7 +97,7 @@ func main() {
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log.Fatalf("only one directory at a time")
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}
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pkg, err := parsePackage(dir, *outputSuffix+".go")
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pkg, err := parser.ParsePackage(dir, *outputSuffix+".go")
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if err != nil {
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log.Fatalf("parsing package: %v", err)
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}
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@ -116,13 +108,13 @@ func main() {
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TypesAndValues map[string][]string
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}{
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Command: strings.Join(os.Args[1:], " "),
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PackageName: pkg.name,
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PackageName: pkg.Name,
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TypesAndValues: make(map[string][]string),
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}
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// Run generate for each type.
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for _, typeName := range types {
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values, err := pkg.valuesOfType(typeName)
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values, err := pkg.ValuesOfType(typeName)
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if err != nil {
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log.Fatalf("finding values for type %v: %v", typeName, err)
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}
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@ -149,138 +141,3 @@ func main() {
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}
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}
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}
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type Package struct {
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name string
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files []*ast.File
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defs map[*ast.Ident]types.Object
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}
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// parsePackage parses the package in the given directory and returns it.
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func parsePackage(directory string, skipSuffix string) (*Package, error) {
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pkgDir, err := build.Default.ImportDir(directory, 0)
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if err != nil {
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return nil, fmt.Errorf("cannot process directory %s: %s", directory, err)
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}
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var files []*ast.File
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fs := token.NewFileSet()
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for _, name := range pkgDir.GoFiles {
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if !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, skipSuffix) {
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continue
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}
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if directory != "." {
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name = filepath.Join(directory, name)
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}
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f, err := parser.ParseFile(fs, name, nil, 0)
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if err != nil {
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return nil, fmt.Errorf("parsing file %v: %v", name, err)
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}
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files = append(files, f)
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}
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if len(files) == 0 {
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return nil, fmt.Errorf("%s: no buildable Go files", directory)
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}
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// type-check the package
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defs := make(map[*ast.Ident]types.Object)
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config := types.Config{FakeImportC: true}
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info := &types.Info{Defs: defs}
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if _, err := config.Check(directory, fs, files, info); err != nil {
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return nil, fmt.Errorf("type-checking package: %v", err)
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}
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return &Package{
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name: files[0].Name.Name,
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files: files,
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defs: defs,
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}, nil
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}
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// generate produces the String method for the named type.
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func (pkg *Package) valuesOfType(typeName string) ([]string, error) {
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var values, inspectErrs []string
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for _, file := range pkg.files {
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ast.Inspect(file, func(node ast.Node) bool {
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decl, ok := node.(*ast.GenDecl)
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if !ok || decl.Tok != token.CONST {
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// We only care about const declarations.
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return true
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}
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if vs, err := pkg.valuesOfTypeIn(typeName, decl); err != nil {
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inspectErrs = append(inspectErrs, err.Error())
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} else {
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values = append(values, vs...)
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}
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return false
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})
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}
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if len(inspectErrs) > 0 {
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return nil, fmt.Errorf("inspecting code:\n\t%v", strings.Join(inspectErrs, "\n\t"))
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}
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if len(values) == 0 {
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return nil, fmt.Errorf("no values defined for type %s", typeName)
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}
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return values, nil
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}
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func (pkg *Package) valuesOfTypeIn(typeName string, decl *ast.GenDecl) ([]string, error) {
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var values []string
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// The name of the type of the constants we are declaring.
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// Can change if this is a multi-element declaration.
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typ := ""
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// Loop over the elements of the declaration. Each element is a ValueSpec:
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// a list of names possibly followed by a type, possibly followed by values.
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// If the type and value are both missing, we carry down the type (and value,
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// but the "go/types" package takes care of that).
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for _, spec := range decl.Specs {
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vspec := spec.(*ast.ValueSpec) // Guaranteed to succeed as this is CONST.
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if vspec.Type == nil && len(vspec.Values) > 0 {
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// "X = 1". With no type but a value, the constant is untyped.
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// Skip this vspec and reset the remembered type.
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typ = ""
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continue
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}
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if vspec.Type != nil {
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// "X T". We have a type. Remember it.
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ident, ok := vspec.Type.(*ast.Ident)
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if !ok {
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continue
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}
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typ = ident.Name
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}
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if typ != typeName {
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// This is not the type we're looking for.
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continue
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}
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// We now have a list of names (from one line of source code) all being
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// declared with the desired type.
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// Grab their names and actual values and store them in f.values.
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for _, name := range vspec.Names {
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if name.Name == "_" {
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continue
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}
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// This dance lets the type checker find the values for us. It's a
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// bit tricky: look up the object declared by the name, find its
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// types.Const, and extract its value.
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obj, ok := pkg.defs[name]
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if !ok {
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return nil, fmt.Errorf("no value for constant %s", name)
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}
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info := obj.Type().Underlying().(*types.Basic).Info()
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if info&types.IsInteger == 0 {
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return nil, fmt.Errorf("can't handle non-integer constant type %s", typ)
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}
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value := obj.(*types.Const).Val() // Guaranteed to succeed as this is CONST.
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if value.Kind() != exact.Int {
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log.Fatalf("can't happen: constant is not an integer %s", name)
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}
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values = append(values, name.Name)
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}
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}
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return values, nil
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}
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@ -0,0 +1,159 @@
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package parser parses Go code and keeps track of all the types defined
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// and provides access to all the constants defined for an int type.
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package parser
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import (
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"fmt"
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"go/ast"
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"go/build"
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"go/parser"
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"go/token"
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"log"
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"path/filepath"
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"strings"
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"golang.org/x/tools/go/exact"
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_ "golang.org/x/tools/go/gcimporter"
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"golang.org/x/tools/go/types"
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)
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// A Package contains all the information related to a parsed package.
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type Package struct {
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Name string
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files []*ast.File
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defs map[*ast.Ident]types.Object
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}
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// ParsePackage parses the package in the given directory and returns it.
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func ParsePackage(directory string, skipSuffix string) (*Package, error) {
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pkgDir, err := build.Default.ImportDir(directory, 0)
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if err != nil {
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return nil, fmt.Errorf("cannot process directory %s: %s", directory, err)
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}
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var files []*ast.File
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fs := token.NewFileSet()
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for _, name := range pkgDir.GoFiles {
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if !strings.HasSuffix(name, ".go") ||
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(skipSuffix != "" && strings.HasSuffix(name, skipSuffix)) {
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continue
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}
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if directory != "." {
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name = filepath.Join(directory, name)
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}
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f, err := parser.ParseFile(fs, name, nil, 0)
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if err != nil {
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return nil, fmt.Errorf("parsing file %v: %v", name, err)
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}
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files = append(files, f)
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}
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if len(files) == 0 {
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return nil, fmt.Errorf("%s: no buildable Go files", directory)
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}
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// type-check the package
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defs := make(map[*ast.Ident]types.Object)
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config := types.Config{FakeImportC: true}
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info := &types.Info{Defs: defs}
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if _, err := config.Check(directory, fs, files, info); err != nil {
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return nil, fmt.Errorf("type-checking package: %v", err)
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}
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return &Package{
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Name: files[0].Name.Name,
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files: files,
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defs: defs,
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}, nil
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}
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// generate produces the String method for the named type.
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func (pkg *Package) ValuesOfType(typeName string) ([]string, error) {
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var values, inspectErrs []string
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for _, file := range pkg.files {
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ast.Inspect(file, func(node ast.Node) bool {
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decl, ok := node.(*ast.GenDecl)
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if !ok || decl.Tok != token.CONST {
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// We only care about const declarations.
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return true
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}
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if vs, err := pkg.valuesOfTypeIn(typeName, decl); err != nil {
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inspectErrs = append(inspectErrs, err.Error())
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} else {
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values = append(values, vs...)
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}
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return false
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})
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}
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if len(inspectErrs) > 0 {
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return nil, fmt.Errorf("inspecting code:\n\t%v", strings.Join(inspectErrs, "\n\t"))
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}
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if len(values) == 0 {
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return nil, fmt.Errorf("no values defined for type %s", typeName)
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}
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return values, nil
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}
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func (pkg *Package) valuesOfTypeIn(typeName string, decl *ast.GenDecl) ([]string, error) {
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var values []string
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// The name of the type of the constants we are declaring.
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// Can change if this is a multi-element declaration.
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typ := ""
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// Loop over the elements of the declaration. Each element is a ValueSpec:
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// a list of names possibly followed by a type, possibly followed by values.
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// If the type and value are both missing, we carry down the type (and value,
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// but the "go/types" package takes care of that).
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for _, spec := range decl.Specs {
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vspec := spec.(*ast.ValueSpec) // Guaranteed to succeed as this is CONST.
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if vspec.Type == nil && len(vspec.Values) > 0 {
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// "X = 1". With no type but a value, the constant is untyped.
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// Skip this vspec and reset the remembered type.
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typ = ""
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continue
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}
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if vspec.Type != nil {
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// "X T". We have a type. Remember it.
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ident, ok := vspec.Type.(*ast.Ident)
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if !ok {
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continue
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}
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typ = ident.Name
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}
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if typ != typeName {
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// This is not the type we're looking for.
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continue
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}
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// We now have a list of names (from one line of source code) all being
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// declared with the desired type.
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// Grab their names and actual values and store them in f.values.
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for _, name := range vspec.Names {
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if name.Name == "_" {
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continue
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}
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// This dance lets the type checker find the values for us. It's a
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// bit tricky: look up the object declared by the name, find its
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// types.Const, and extract its value.
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obj, ok := pkg.defs[name]
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if !ok {
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return nil, fmt.Errorf("no value for constant %s", name)
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}
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info := obj.Type().Underlying().(*types.Basic).Info()
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if info&types.IsInteger == 0 {
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return nil, fmt.Errorf("can't handle non-integer constant type %s", typ)
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}
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value := obj.(*types.Const).Val() // Guaranteed to succeed as this is CONST.
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if value.Kind() != exact.Int {
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log.Fatalf("can't happen: constant is not an integer %s", name)
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}
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values = append(values, name.Name)
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}
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}
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return values, nil
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}
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