// Transform applies the transformation to the specified parsed file,
// whose type information is supplied in info, and returns the number
// of replacements that were made.
//
// It mutates the AST in place (the identity of the root node is
// unchanged), and may add nodes for which no type information is
// available in info.
//
// Derived from rewriteFile in $GOROOT/src/cmd/gofmt/rewrite.go.
//
func (tr *Transformer) Transform(info *types.Info, pkg *types.Package, file *ast.File) int {
if !tr.seenInfos[info] {
tr.seenInfos[info] = true
mergeTypeInfo(&tr.info.Info, info)
}
tr.currentPkg = pkg
tr.nsubsts = 0
if tr.verbose {
fmt.Fprintf(os.Stderr, "before: %s\n", astString(tr.fset, tr.before))
fmt.Fprintf(os.Stderr, "after: %s\n", astString(tr.fset, tr.after))
}
var f func(rv reflect.Value) reflect.Value
f = func(rv reflect.Value) reflect.Value {
// don't bother if val is invalid to start with
if !rv.IsValid() {
return reflect.Value{}
}
rv = apply(f, rv)
e := rvToExpr(rv)
if e != nil {
savedEnv := tr.env
tr.env = make(map[string]ast.Expr) // inefficient! Use a slice of k/v pairs
if tr.matchExpr(tr.before, e) {
if tr.verbose {
fmt.Fprintf(os.Stderr, "%s matches %s",
astString(tr.fset, tr.before), astString(tr.fset, e))
if len(tr.env) > 0 {
fmt.Fprintf(os.Stderr, " with:")
for name, ast := range tr.env {
fmt.Fprintf(os.Stderr, " %s->%s",
name, astString(tr.fset, ast))
}
}
fmt.Fprintf(os.Stderr, "\n")
}
tr.nsubsts++
// Clone the replacement tree, performing parameter substitution.
// We update all positions to n.Pos() to aid comment placement.
rv = tr.subst(tr.env, reflect.ValueOf(tr.after),
reflect.ValueOf(e.Pos()))
}
tr.env = savedEnv
}
return rv
}
file2 := apply(f, reflect.ValueOf(file)).Interface().(*ast.File)
// By construction, the root node is unchanged.
if file != file2 {
panic("BUG")
}
// Add any necessary imports.
// TODO(adonovan): remove no-longer needed imports too.
if tr.nsubsts > 0 {
pkgs := make(map[string]*types.Package)
for obj := range tr.importedObjs {
pkgs[obj.Pkg().Path()] = obj.Pkg()
}
for _, imp := range file.Imports {
path, _ := strconv.Unquote(imp.Path.Value)
delete(pkgs, path)
}
delete(pkgs, pkg.Path()) // don't import self
// NB: AddImport may completely replace the AST!
// It thus renders info and tr.info no longer relevant to file.
var paths []string
for path := range pkgs {
paths = append(paths, path)
}
sort.Strings(paths)
for _, path := range paths {
astutil.AddImport(tr.fset, file, path)
}
}
tr.currentPkg = nil
return tr.nsubsts
}
func fixImports(fset *token.FileSet, f *ast.File) (added []string, err error) {
// refs are a set of possible package references currently unsatisfied by imports.
// first key: either base package (e.g. "fmt") or renamed package
// second key: referenced package symbol (e.g. "Println")
refs := make(map[string]map[string]bool)
// decls are the current package imports. key is base package or renamed package.
decls := make(map[string]*ast.ImportSpec)
// collect potential uses of packages.
var visitor visitFn
visitor = visitFn(func(node ast.Node) ast.Visitor {
if node == nil {
return visitor
}
switch v := node.(type) {
case *ast.ImportSpec:
if v.Name != nil {
decls[v.Name.Name] = v
} else {
local := importPathToName(strings.Trim(v.Path.Value, `\"`))
decls[local] = v
}
case *ast.SelectorExpr:
xident, ok := v.X.(*ast.Ident)
if !ok {
break
}
if xident.Obj != nil {
// if the parser can resolve it, it's not a package ref
break
}
pkgName := xident.Name
if refs[pkgName] == nil {
refs[pkgName] = make(map[string]bool)
}
if decls[pkgName] == nil {
refs[pkgName][v.Sel.Name] = true
}
}
return visitor
})
ast.Walk(visitor, f)
// Search for imports matching potential package references.
searches := 0
type result struct {
ipath string
name string
err error
}
results := make(chan result)
for pkgName, symbols := range refs {
if len(symbols) == 0 {
continue // skip over packages already imported
}
go func(pkgName string, symbols map[string]bool) {
ipath, rename, err := findImport(pkgName, symbols)
r := result{ipath: ipath, err: err}
if rename {
r.name = pkgName
}
results <- r
}(pkgName, symbols)
searches++
}
for i := 0; i < searches; i++ {
result := <-results
if result.err != nil {
return nil, result.err
}
if result.ipath != "" {
if result.name != "" {
astutil.AddNamedImport(fset, f, result.name, result.ipath)
} else {
astutil.AddImport(fset, f, result.ipath)
}
added = append(added, result.ipath)
}
}
// Nil out any unused ImportSpecs, to be removed in following passes
unusedImport := map[string]bool{}
for pkg, is := range decls {
if refs[pkg] == nil && pkg != "_" && pkg != "." {
unusedImport[strings.Trim(is.Path.Value, `"`)] = true
}
}
for ipath := range unusedImport {
if ipath == "C" {
// Don't remove cgo stuff.
continue
}
astutil.DeleteImport(fset, f, ipath)
}
return added, nil
}