func removeEmptyDeclGroups(f *ast.File) {
i := 0
for _, d := range f.Decls {
if g, ok := d.(*ast.GenDecl); !ok || !isEmpty(f, g) {
f.Decls[i] = d
i++
}
}
f.Decls = f.Decls[:i]
}
// fileExports removes unexported declarations from src in place.
//
func (r *reader) fileExports(src *ast.File) {
j := 0
for _, d := range src.Decls {
if r.filterDecl(d) {
src.Decls[j] = d
j++
}
}
src.Decls = src.Decls[0:j]
}
// sortImports sorts runs of consecutive import lines in import blocks in f.
// It also removes duplicate imports when it is possible to do so without data loss.
func sortImports(fset *token.FileSet, f *ast.File) {
for i, d := range f.Decls {
d, ok := d.(*ast.GenDecl)
if !ok || d.Tok != token.IMPORT {
// Not an import declaration, so we're done.
// Imports are always first.
break
}
if len(d.Specs) == 0 {
// Empty import block, remove it.
f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
}
if !d.Lparen.IsValid() {
// Not a block: sorted by default.
continue
}
// Identify and sort runs of specs on successive lines.
i := 0
specs := d.Specs[:0]
for j, s := range d.Specs {
if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
// j begins a new run. End this one.
specs = append(specs, sortSpecs(fset, f, d.Specs[i:j])...)
i = j
}
}
specs = append(specs, sortSpecs(fset, f, d.Specs[i:])...)
d.Specs = specs
// Deduping can leave a blank line before the rparen; clean that up.
if len(d.Specs) > 0 {
lastSpec := d.Specs[len(d.Specs)-1]
lastLine := fset.Position(lastSpec.Pos()).Line
if rParenLine := fset.Position(d.Rparen).Line; rParenLine > lastLine+1 {
fset.File(d.Rparen).MergeLine(rParenLine - 1)
}
}
}
}
// AddNamedImport adds the import path to the file f, if absent.
// If name is not empty, it is used to rename the import.
//
// For example, calling
// AddNamedImport(fset, f, "pathpkg", "path")
// adds
// import pathpkg "path"
func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
if imports(f, ipath) {
return false
}
newImport := &ast.ImportSpec{
Path: &ast.BasicLit{
Kind: token.STRING,
Value: strconv.Quote(ipath),
},
}
if name != "" {
newImport.Name = &ast.Ident{Name: name}
}
// Find an import decl to add to.
// The goal is to find an existing import
// whose import path has the longest shared
// prefix with ipath.
var (
bestMatch = -1 // length of longest shared prefix
lastImport = -1 // index in f.Decls of the file's final import decl
impDecl *ast.GenDecl // import decl containing the best match
impIndex = -1 // spec index in impDecl containing the best match
)
for i, decl := range f.Decls {
gen, ok := decl.(*ast.GenDecl)
if ok && gen.Tok == token.IMPORT {
lastImport = i
// Do not add to import "C", to avoid disrupting the
// association with its doc comment, breaking cgo.
if declImports(gen, "C") {
continue
}
// Match an empty import decl if that's all that is available.
if len(gen.Specs) == 0 && bestMatch == -1 {
impDecl = gen
}
// Compute longest shared prefix with imports in this group.
for j, spec := range gen.Specs {
impspec := spec.(*ast.ImportSpec)
n := matchLen(importPath(impspec), ipath)
if n > bestMatch {
bestMatch = n
impDecl = gen
impIndex = j
}
}
}
}
// If no import decl found, add one after the last import.
if impDecl == nil {
impDecl = &ast.GenDecl{
Tok: token.IMPORT,
}
if lastImport >= 0 {
impDecl.TokPos = f.Decls[lastImport].End()
} else {
// There are no existing imports.
// Our new import goes after the package declaration and after
// the comment, if any, that starts on the same line as the
// package declaration.
impDecl.TokPos = f.Package
file := fset.File(f.Package)
pkgLine := file.Line(f.Package)
for _, c := range f.Comments {
if file.Line(c.Pos()) > pkgLine {
break
}
impDecl.TokPos = c.End()
}
}
f.Decls = append(f.Decls, nil)
copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
f.Decls[lastImport+1] = impDecl
}
// Insert new import at insertAt.
insertAt := 0
if impIndex >= 0 {
// insert after the found import
insertAt = impIndex + 1
}
impDecl.Specs = append(impDecl.Specs, nil)
copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
impDecl.Specs[insertAt] = newImport
pos := impDecl.Pos()
if insertAt > 0 {
// If there is a comment after an existing import, preserve the comment
// position by adding the new import after the comment.
if spec, ok := impDecl.Specs[insertAt-1].(*ast.ImportSpec); ok && spec.Comment != nil {
pos = spec.Comment.End()
} else {
// Assign same position as the previous import,
// so that the sorter sees it as being in the same block.
pos = impDecl.Specs[insertAt-1].Pos()
}
}
if newImport.Name != nil {
newImport.Name.NamePos = pos
}
newImport.Path.ValuePos = pos
newImport.EndPos = pos
// Clean up parens. impDecl contains at least one spec.
if len(impDecl.Specs) == 1 {
// Remove unneeded parens.
impDecl.Lparen = token.NoPos
} else if !impDecl.Lparen.IsValid() {
// impDecl needs parens added.
impDecl.Lparen = impDecl.Specs[0].Pos()
}
f.Imports = append(f.Imports, newImport)
if len(f.Decls) <= 1 {
return true
}
// Merge all the import declarations into the first one.
var first *ast.GenDecl
for i, decl := range f.Decls {
gen, ok := decl.(*ast.GenDecl)
if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
continue
}
if first == nil {
first = gen
continue // Don't touch the first one.
}
// Move the imports of the other import declaration to the first one.
for _, spec := range gen.Specs {
spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
first.Specs = append(first.Specs, spec)
}
f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
}
return true
}
// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
var delspecs []*ast.ImportSpec
// Find the import nodes that import path, if any.
for i := 0; i < len(f.Decls); i++ {
decl := f.Decls[i]
gen, ok := decl.(*ast.GenDecl)
if !ok || gen.Tok != token.IMPORT {
continue
}
for j := 0; j < len(gen.Specs); j++ {
spec := gen.Specs[j]
impspec := spec.(*ast.ImportSpec)
if impspec.Name == nil && name != "" {
continue
}
if impspec.Name != nil && impspec.Name.Name != name {
continue
}
if importPath(impspec) != path {
continue
}
// We found an import spec that imports path.
// Delete it.
delspecs = append(delspecs, impspec)
deleted = true
copy(gen.Specs[j:], gen.Specs[j+1:])
gen.Specs = gen.Specs[:len(gen.Specs)-1]
// If this was the last import spec in this decl,
// delete the decl, too.
if len(gen.Specs) == 0 {
copy(f.Decls[i:], f.Decls[i+1:])
f.Decls = f.Decls[:len(f.Decls)-1]
i--
break
} else if len(gen.Specs) == 1 {
gen.Lparen = token.NoPos // drop parens
}
if j > 0 {
lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
line := fset.Position(impspec.Path.ValuePos).Line
// We deleted an entry but now there may be
// a blank line-sized hole where the import was.
if line-lastLine > 1 {
// There was a blank line immediately preceding the deleted import,
// so there's no need to close the hole.
// Do nothing.
} else {
// There was no blank line. Close the hole.
fset.File(gen.Rparen).MergeLine(line)
}
}
j--
}
}
// Delete them from f.Imports.
for i := 0; i < len(f.Imports); i++ {
imp := f.Imports[i]
for j, del := range delspecs {
if imp == del {
copy(f.Imports[i:], f.Imports[i+1:])
f.Imports = f.Imports[:len(f.Imports)-1]
copy(delspecs[j:], delspecs[j+1:])
delspecs = delspecs[:len(delspecs)-1]
i--
break
}
}
}
if len(delspecs) > 0 {
panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
}
return
}