--- /dev/null
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Hacked up copy of go/ast/import.go
+
+package imports
+
+import (
+ "go/ast"
+ "go/token"
+ "sort"
+ "strconv"
+)
+
+// 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(localPrefix string, 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(localPrefix, fset, f, d.Specs[i:j])...)
+ i = j
+ }
+ }
+ specs = append(specs, sortSpecs(localPrefix, 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)
+ }
+ }
+ }
+}
+
+// mergeImports merges all the import declarations into the first one.
+// Taken from golang.org/x/tools/ast/astutil.
+func mergeImports(fset *token.FileSet, f *ast.File) {
+ if len(f.Decls) <= 1 {
+ return
+ }
+
+ // Merge all the import declarations into the first one.
+ var first *ast.GenDecl
+ for i := 0; i < len(f.Decls); i++ {
+ decl := f.Decls[i]
+ 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.
+ }
+ // We now know there is more than one package in this import
+ // declaration. Ensure that it ends up parenthesized.
+ first.Lparen = first.Pos()
+ // 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:]...)
+ i--
+ }
+}
+
+// declImports reports whether gen contains an import of path.
+// Taken from golang.org/x/tools/ast/astutil.
+func declImports(gen *ast.GenDecl, path string) bool {
+ if gen.Tok != token.IMPORT {
+ return false
+ }
+ for _, spec := range gen.Specs {
+ impspec := spec.(*ast.ImportSpec)
+ if importPath(impspec) == path {
+ return true
+ }
+ }
+ return false
+}
+
+func importPath(s ast.Spec) string {
+ t, err := strconv.Unquote(s.(*ast.ImportSpec).Path.Value)
+ if err == nil {
+ return t
+ }
+ return ""
+}
+
+func importName(s ast.Spec) string {
+ n := s.(*ast.ImportSpec).Name
+ if n == nil {
+ return ""
+ }
+ return n.Name
+}
+
+func importComment(s ast.Spec) string {
+ c := s.(*ast.ImportSpec).Comment
+ if c == nil {
+ return ""
+ }
+ return c.Text()
+}
+
+// collapse indicates whether prev may be removed, leaving only next.
+func collapse(prev, next ast.Spec) bool {
+ if importPath(next) != importPath(prev) || importName(next) != importName(prev) {
+ return false
+ }
+ return prev.(*ast.ImportSpec).Comment == nil
+}
+
+type posSpan struct {
+ Start token.Pos
+ End token.Pos
+}
+
+func sortSpecs(localPrefix string, fset *token.FileSet, f *ast.File, specs []ast.Spec) []ast.Spec {
+ // Can't short-circuit here even if specs are already sorted,
+ // since they might yet need deduplication.
+ // A lone import, however, may be safely ignored.
+ if len(specs) <= 1 {
+ return specs
+ }
+
+ // Record positions for specs.
+ pos := make([]posSpan, len(specs))
+ for i, s := range specs {
+ pos[i] = posSpan{s.Pos(), s.End()}
+ }
+
+ // Identify comments in this range.
+ // Any comment from pos[0].Start to the final line counts.
+ lastLine := fset.Position(pos[len(pos)-1].End).Line
+ cstart := len(f.Comments)
+ cend := len(f.Comments)
+ for i, g := range f.Comments {
+ if g.Pos() < pos[0].Start {
+ continue
+ }
+ if i < cstart {
+ cstart = i
+ }
+ if fset.Position(g.End()).Line > lastLine {
+ cend = i
+ break
+ }
+ }
+ comments := f.Comments[cstart:cend]
+
+ // Assign each comment to the import spec preceding it.
+ importComment := map[*ast.ImportSpec][]*ast.CommentGroup{}
+ specIndex := 0
+ for _, g := range comments {
+ for specIndex+1 < len(specs) && pos[specIndex+1].Start <= g.Pos() {
+ specIndex++
+ }
+ s := specs[specIndex].(*ast.ImportSpec)
+ importComment[s] = append(importComment[s], g)
+ }
+
+ // Sort the import specs by import path.
+ // Remove duplicates, when possible without data loss.
+ // Reassign the import paths to have the same position sequence.
+ // Reassign each comment to abut the end of its spec.
+ // Sort the comments by new position.
+ sort.Sort(byImportSpec{localPrefix, specs})
+
+ // Dedup. Thanks to our sorting, we can just consider
+ // adjacent pairs of imports.
+ deduped := specs[:0]
+ for i, s := range specs {
+ if i == len(specs)-1 || !collapse(s, specs[i+1]) {
+ deduped = append(deduped, s)
+ } else {
+ p := s.Pos()
+ fset.File(p).MergeLine(fset.Position(p).Line)
+ }
+ }
+ specs = deduped
+
+ // Fix up comment positions
+ for i, s := range specs {
+ s := s.(*ast.ImportSpec)
+ if s.Name != nil {
+ s.Name.NamePos = pos[i].Start
+ }
+ s.Path.ValuePos = pos[i].Start
+ s.EndPos = pos[i].End
+ nextSpecPos := pos[i].End
+
+ for _, g := range importComment[s] {
+ for _, c := range g.List {
+ c.Slash = pos[i].End
+ nextSpecPos = c.End()
+ }
+ }
+ if i < len(specs)-1 {
+ pos[i+1].Start = nextSpecPos
+ pos[i+1].End = nextSpecPos
+ }
+ }
+
+ sort.Sort(byCommentPos(comments))
+
+ // Fixup comments can insert blank lines, because import specs are on different lines.
+ // We remove those blank lines here by merging import spec to the first import spec line.
+ firstSpecLine := fset.Position(specs[0].Pos()).Line
+ for _, s := range specs[1:] {
+ p := s.Pos()
+ line := fset.File(p).Line(p)
+ for previousLine := line - 1; previousLine >= firstSpecLine; {
+ fset.File(p).MergeLine(previousLine)
+ previousLine--
+ }
+ }
+ return specs
+}
+
+type byImportSpec struct {
+ localPrefix string
+ specs []ast.Spec // slice of *ast.ImportSpec
+}
+
+func (x byImportSpec) Len() int { return len(x.specs) }
+func (x byImportSpec) Swap(i, j int) { x.specs[i], x.specs[j] = x.specs[j], x.specs[i] }
+func (x byImportSpec) Less(i, j int) bool {
+ ipath := importPath(x.specs[i])
+ jpath := importPath(x.specs[j])
+
+ igroup := importGroup(x.localPrefix, ipath)
+ jgroup := importGroup(x.localPrefix, jpath)
+ if igroup != jgroup {
+ return igroup < jgroup
+ }
+
+ if ipath != jpath {
+ return ipath < jpath
+ }
+ iname := importName(x.specs[i])
+ jname := importName(x.specs[j])
+
+ if iname != jname {
+ return iname < jname
+ }
+ return importComment(x.specs[i]) < importComment(x.specs[j])
+}
+
+type byCommentPos []*ast.CommentGroup
+
+func (x byCommentPos) Len() int { return len(x) }
+func (x byCommentPos) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+func (x byCommentPos) Less(i, j int) bool { return x[i].Pos() < x[j].Pos() }
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