parse.go

/*
Copyright 2016 The Kubernetes 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 codegen

import (
	"go/ast"
	"go/build"
	"go/importer"
	"go/parser"
	"go/token"
	"go/types"
	"log"
	"path/filepath"
	"strings"
)

type GoParser struct {
	Package *Package // Package we are scanning.
}

// File holds a single parsed file and associated data.
type File struct {
	pkg  *Package  // Package to which this file belongs.
	file *ast.File // Parsed AST.
	// These fields are reset for each type being generated.
	typeName string // Name of the constant type.
	//values   []Value // Accumulator for constant values of that type.
}

type Package struct {
	dir      string
	Name     string
	defs     map[*ast.Ident]types.Object
	files    []*File
	typesPkg *types.Package
}

// prefixDirectory prepends the directory name on the beginning of each name in the list.
func prefixDirectory(directory string, names []string) []string {
	if directory == "." {
		return names
	}
	ret := make([]string, len(names))
	for i, name := range names {
		ret[i] = filepath.Join(directory, name)
	}
	return ret
}

// parsePackageDir parses the package residing in the directory.
func (g *GoParser) parsePackageDir(directory string) {
	pkg, err := build.Default.ImportDir(directory, 0)
	if err != nil {
		log.Fatalf("cannot process directory %s: %s", directory, err)
	}
	var names []string
	names = append(names, pkg.GoFiles...)
	//names = append(names, pkg.CgoFiles...)
	//names = append(names, pkg.SFiles...)
	names = prefixDirectory(directory, names)
	g.parsePackage(directory, names, nil)
}

// parsePackage analyzes the single package constructed from the named files.
// If text is non-nil, it is a string to be used instead of the content of the file,
// to be used for testing. parsePackage exits if there is an error.
func (g *GoParser) parsePackage(directory string, names []string, text interface{}) {
	var files []*File
	var astFiles []*ast.File
	g.Package = new(Package)
	fs := token.NewFileSet()
	for _, name := range names {
		if !strings.HasSuffix(name, ".go") {
			continue
		}
		parsedFile, err := parser.ParseFile(fs, name, text, 0)
		if err != nil {
			log.Fatalf("parsing package: %s: %s", name, err)
		}
		astFiles = append(astFiles, parsedFile)
		files = append(files, &File{
			file: parsedFile,
			pkg:  g.Package,
		})
	}
	if len(astFiles) == 0 {
		log.Fatalf("%s: no buildable Go files", directory)
	}
	g.Package.Name = astFiles[0].Name.Name
	g.Package.files = files
	g.Package.dir = directory
	// Type check the package.
	g.Package.check(fs, astFiles)
}

// check type-checks the package. The package must be OK to proceed.
func (pkg *Package) check(fs *token.FileSet, astFiles []*ast.File) {
	pkg.defs = make(map[*ast.Ident]types.Object)
	config := types.Config{Importer: importer.For("source", nil), FakeImportC: true}
	info := &types.Info{
		Defs: pkg.defs,
	}
	typesPkg, err := config.Check(pkg.dir, fs, astFiles, info)
	if err != nil {
		log.Fatalf("checking package: %s", err)
	}
	pkg.typesPkg = typesPkg
}