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author | Michael Muré <batolettre@gmail.com> | 2018-08-14 14:48:41 +0200 |
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committer | Michael Muré <batolettre@gmail.com> | 2018-08-14 14:48:41 +0200 |
commit | 5c568a362b73cf163b06bc7371982f9a7ceaaf29 (patch) | |
tree | 755b61f969913b5290f3d56f4cfba4070b8155bc /vendor/golang.org/x/tools/imports/sortimports.go | |
parent | ef0d8fa108fbdef24997a84a3c6ecbf21cbc0a9e (diff) | |
download | git-bug-5c568a362b73cf163b06bc7371982f9a7ceaaf29.tar.gz |
gqlgen: add a small program to go:generate the code
Diffstat (limited to 'vendor/golang.org/x/tools/imports/sortimports.go')
-rw-r--r-- | vendor/golang.org/x/tools/imports/sortimports.go | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/imports/sortimports.go b/vendor/golang.org/x/tools/imports/sortimports.go new file mode 100644 index 00000000..f3dd56c7 --- /dev/null +++ b/vendor/golang.org/x/tools/imports/sortimports.go @@ -0,0 +1,230 @@ +// 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(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) + } + } + } +} + +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(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(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 []ast.Spec // slice of *ast.ImportSpec + +func (x byImportSpec) Len() int { return len(x) } +func (x byImportSpec) Swap(i, j int) { x[i], x[j] = x[j], x[i] } +func (x byImportSpec) Less(i, j int) bool { + ipath := importPath(x[i]) + jpath := importPath(x[j]) + + igroup := importGroup(ipath) + jgroup := importGroup(jpath) + if igroup != jgroup { + return igroup < jgroup + } + + if ipath != jpath { + return ipath < jpath + } + iname := importName(x[i]) + jname := importName(x[j]) + + if iname != jname { + return iname < jname + } + return importComment(x[i]) < importComment(x[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() } |