diff options
Diffstat (limited to 'vendor/golang.org/x/tools/imports/imports.go')
-rw-r--r-- | vendor/golang.org/x/tools/imports/imports.go | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/imports/imports.go b/vendor/golang.org/x/tools/imports/imports.go new file mode 100644 index 00000000..a4cbf5c7 --- /dev/null +++ b/vendor/golang.org/x/tools/imports/imports.go @@ -0,0 +1,310 @@ +// 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. + +//go:generate go run mkstdlib.go + +// Package imports implements a Go pretty-printer (like package "go/format") +// that also adds or removes import statements as necessary. +package imports // import "golang.org/x/tools/imports" + +import ( + "bufio" + "bytes" + "fmt" + "go/ast" + "go/format" + "go/parser" + "go/printer" + "go/token" + "io" + "io/ioutil" + "regexp" + "strconv" + "strings" + + "golang.org/x/tools/go/ast/astutil" +) + +// Options specifies options for processing files. +type Options struct { + Fragment bool // Accept fragment of a source file (no package statement) + AllErrors bool // Report all errors (not just the first 10 on different lines) + + Comments bool // Print comments (true if nil *Options provided) + TabIndent bool // Use tabs for indent (true if nil *Options provided) + TabWidth int // Tab width (8 if nil *Options provided) + + FormatOnly bool // Disable the insertion and deletion of imports +} + +// Process formats and adjusts imports for the provided file. +// If opt is nil the defaults are used. +// +// Note that filename's directory influences which imports can be chosen, +// so it is important that filename be accurate. +// To process data ``as if'' it were in filename, pass the data as a non-nil src. +func Process(filename string, src []byte, opt *Options) ([]byte, error) { + if opt == nil { + opt = &Options{Comments: true, TabIndent: true, TabWidth: 8} + } + if src == nil { + b, err := ioutil.ReadFile(filename) + if err != nil { + return nil, err + } + src = b + } + + fileSet := token.NewFileSet() + file, adjust, err := parse(fileSet, filename, src, opt) + if err != nil { + return nil, err + } + + if !opt.FormatOnly { + _, err = fixImports(fileSet, file, filename) + if err != nil { + return nil, err + } + } + + sortImports(fileSet, file) + imps := astutil.Imports(fileSet, file) + var spacesBefore []string // import paths we need spaces before + for _, impSection := range imps { + // Within each block of contiguous imports, see if any + // import lines are in different group numbers. If so, + // we'll need to put a space between them so it's + // compatible with gofmt. + lastGroup := -1 + for _, importSpec := range impSection { + importPath, _ := strconv.Unquote(importSpec.Path.Value) + groupNum := importGroup(importPath) + if groupNum != lastGroup && lastGroup != -1 { + spacesBefore = append(spacesBefore, importPath) + } + lastGroup = groupNum + } + + } + + printerMode := printer.UseSpaces + if opt.TabIndent { + printerMode |= printer.TabIndent + } + printConfig := &printer.Config{Mode: printerMode, Tabwidth: opt.TabWidth} + + var buf bytes.Buffer + err = printConfig.Fprint(&buf, fileSet, file) + if err != nil { + return nil, err + } + out := buf.Bytes() + if adjust != nil { + out = adjust(src, out) + } + if len(spacesBefore) > 0 { + out, err = addImportSpaces(bytes.NewReader(out), spacesBefore) + if err != nil { + return nil, err + } + } + + out, err = format.Source(out) + if err != nil { + return nil, err + } + return out, nil +} + +// parse parses src, which was read from filename, +// as a Go source file or statement list. +func parse(fset *token.FileSet, filename string, src []byte, opt *Options) (*ast.File, func(orig, src []byte) []byte, error) { + parserMode := parser.Mode(0) + if opt.Comments { + parserMode |= parser.ParseComments + } + if opt.AllErrors { + parserMode |= parser.AllErrors + } + + // Try as whole source file. + file, err := parser.ParseFile(fset, filename, src, parserMode) + if err == nil { + return file, nil, nil + } + // If the error is that the source file didn't begin with a + // package line and we accept fragmented input, fall through to + // try as a source fragment. Stop and return on any other error. + if !opt.Fragment || !strings.Contains(err.Error(), "expected 'package'") { + return nil, nil, err + } + + // If this is a declaration list, make it a source file + // by inserting a package clause. + // Insert using a ;, not a newline, so that parse errors are on + // the correct line. + const prefix = "package main;" + psrc := append([]byte(prefix), src...) + file, err = parser.ParseFile(fset, filename, psrc, parserMode) + if err == nil { + // Gofmt will turn the ; into a \n. + // Do that ourselves now and update the file contents, + // so that positions and line numbers are correct going forward. + psrc[len(prefix)-1] = '\n' + fset.File(file.Package).SetLinesForContent(psrc) + + // If a main function exists, we will assume this is a main + // package and leave the file. + if containsMainFunc(file) { + return file, nil, nil + } + + adjust := func(orig, src []byte) []byte { + // Remove the package clause. + src = src[len(prefix):] + return matchSpace(orig, src) + } + return file, adjust, nil + } + // If the error is that the source file didn't begin with a + // declaration, fall through to try as a statement list. + // Stop and return on any other error. + if !strings.Contains(err.Error(), "expected declaration") { + return nil, nil, err + } + + // If this is a statement list, make it a source file + // by inserting a package clause and turning the list + // into a function body. This handles expressions too. + // Insert using a ;, not a newline, so that the line numbers + // in fsrc match the ones in src. + fsrc := append(append([]byte("package p; func _() {"), src...), '}') + file, err = parser.ParseFile(fset, filename, fsrc, parserMode) + if err == nil { + adjust := func(orig, src []byte) []byte { + // Remove the wrapping. + // Gofmt has turned the ; into a \n\n. + src = src[len("package p\n\nfunc _() {"):] + src = src[:len(src)-len("}\n")] + // Gofmt has also indented the function body one level. + // Remove that indent. + src = bytes.Replace(src, []byte("\n\t"), []byte("\n"), -1) + return matchSpace(orig, src) + } + return file, adjust, nil + } + + // Failed, and out of options. + return nil, nil, err +} + +// containsMainFunc checks if a file contains a function declaration with the +// function signature 'func main()' +func containsMainFunc(file *ast.File) bool { + for _, decl := range file.Decls { + if f, ok := decl.(*ast.FuncDecl); ok { + if f.Name.Name != "main" { + continue + } + + if len(f.Type.Params.List) != 0 { + continue + } + + if f.Type.Results != nil && len(f.Type.Results.List) != 0 { + continue + } + + return true + } + } + + return false +} + +func cutSpace(b []byte) (before, middle, after []byte) { + i := 0 + for i < len(b) && (b[i] == ' ' || b[i] == '\t' || b[i] == '\n') { + i++ + } + j := len(b) + for j > 0 && (b[j-1] == ' ' || b[j-1] == '\t' || b[j-1] == '\n') { + j-- + } + if i <= j { + return b[:i], b[i:j], b[j:] + } + return nil, nil, b[j:] +} + +// matchSpace reformats src to use the same space context as orig. +// 1) If orig begins with blank lines, matchSpace inserts them at the beginning of src. +// 2) matchSpace copies the indentation of the first non-blank line in orig +// to every non-blank line in src. +// 3) matchSpace copies the trailing space from orig and uses it in place +// of src's trailing space. +func matchSpace(orig []byte, src []byte) []byte { + before, _, after := cutSpace(orig) + i := bytes.LastIndex(before, []byte{'\n'}) + before, indent := before[:i+1], before[i+1:] + + _, src, _ = cutSpace(src) + + var b bytes.Buffer + b.Write(before) + for len(src) > 0 { + line := src + if i := bytes.IndexByte(line, '\n'); i >= 0 { + line, src = line[:i+1], line[i+1:] + } else { + src = nil + } + if len(line) > 0 && line[0] != '\n' { // not blank + b.Write(indent) + } + b.Write(line) + } + b.Write(after) + return b.Bytes() +} + +var impLine = regexp.MustCompile(`^\s+(?:[\w\.]+\s+)?"(.+)"`) + +func addImportSpaces(r io.Reader, breaks []string) ([]byte, error) { + var out bytes.Buffer + in := bufio.NewReader(r) + inImports := false + done := false + for { + s, err := in.ReadString('\n') + if err == io.EOF { + break + } else if err != nil { + return nil, err + } + + if !inImports && !done && strings.HasPrefix(s, "import") { + inImports = true + } + if inImports && (strings.HasPrefix(s, "var") || + strings.HasPrefix(s, "func") || + strings.HasPrefix(s, "const") || + strings.HasPrefix(s, "type")) { + done = true + inImports = false + } + if inImports && len(breaks) > 0 { + if m := impLine.FindStringSubmatch(s); m != nil { + if m[1] == breaks[0] { + out.WriteByte('\n') + breaks = breaks[1:] + } + } + } + + fmt.Fprint(&out, s) + } + return out.Bytes(), nil +} |