--- /dev/null
+// Copyright 2020 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.
+
+package completion
+
+import (
+ "context"
+ "fmt"
+ "go/ast"
+ "go/parser"
+ "go/scanner"
+ "go/token"
+ "go/types"
+ "path/filepath"
+ "strings"
+
+ "golang.org/x/tools/internal/lsp/fuzzy"
+ "golang.org/x/tools/internal/lsp/protocol"
+ "golang.org/x/tools/internal/lsp/source"
+ "golang.org/x/tools/internal/span"
+ errors "golang.org/x/xerrors"
+)
+
+// packageClauseCompletions offers completions for a package declaration when
+// one is not present in the given file.
+func packageClauseCompletions(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle, pos protocol.Position) ([]CompletionItem, *Selection, error) {
+ // We know that the AST for this file will be empty due to the missing
+ // package declaration, but parse it anyway to get a mapper.
+ pgf, err := snapshot.ParseGo(ctx, fh, source.ParseFull)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ cursorSpan, err := pgf.Mapper.PointSpan(pos)
+ if err != nil {
+ return nil, nil, err
+ }
+ rng, err := cursorSpan.Range(pgf.Mapper.Converter)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ surrounding, err := packageCompletionSurrounding(snapshot.FileSet(), fh, pgf, rng.Start)
+ if err != nil {
+ return nil, nil, errors.Errorf("invalid position for package completion: %w", err)
+ }
+
+ packageSuggestions, err := packageSuggestions(ctx, snapshot, fh.URI(), "")
+ if err != nil {
+ return nil, nil, err
+ }
+
+ var items []CompletionItem
+ for _, pkg := range packageSuggestions {
+ insertText := fmt.Sprintf("package %s", pkg.name)
+ items = append(items, CompletionItem{
+ Label: insertText,
+ Kind: protocol.ModuleCompletion,
+ InsertText: insertText,
+ Score: pkg.score,
+ })
+ }
+
+ return items, surrounding, nil
+}
+
+// packageCompletionSurrounding returns surrounding for package completion if a
+// package completions can be suggested at a given position. A valid location
+// for package completion is above any declarations or import statements.
+func packageCompletionSurrounding(fset *token.FileSet, fh source.FileHandle, pgf *source.ParsedGoFile, pos token.Pos) (*Selection, error) {
+ src, err := fh.Read()
+ if err != nil {
+ return nil, err
+ }
+ // If the file lacks a package declaration, the parser will return an empty
+ // AST. As a work-around, try to parse an expression from the file contents.
+ expr, _ := parser.ParseExprFrom(fset, fh.URI().Filename(), src, parser.Mode(0))
+ if expr == nil {
+ return nil, fmt.Errorf("unparseable file (%s)", fh.URI())
+ }
+ tok := fset.File(expr.Pos())
+ cursor := tok.Pos(pgf.Tok.Offset(pos))
+ m := &protocol.ColumnMapper{
+ URI: pgf.URI,
+ Content: src,
+ Converter: span.NewContentConverter(fh.URI().Filename(), src),
+ }
+
+ // If we were able to parse out an identifier as the first expression from
+ // the file, it may be the beginning of a package declaration ("pack ").
+ // We can offer package completions if the cursor is in the identifier.
+ if name, ok := expr.(*ast.Ident); ok {
+ if cursor >= name.Pos() && cursor <= name.End() {
+ if !strings.HasPrefix(PACKAGE, name.Name) {
+ return nil, fmt.Errorf("cursor in non-matching ident")
+ }
+ return &Selection{
+ content: name.Name,
+ cursor: cursor,
+ MappedRange: source.NewMappedRange(fset, m, name.Pos(), name.End()),
+ }, nil
+ }
+ }
+
+ // The file is invalid, but it contains an expression that we were able to
+ // parse. We will use this expression to construct the cursor's
+ // "surrounding".
+
+ // First, consider the possibility that we have a valid "package" keyword
+ // with an empty package name ("package "). "package" is parsed as an
+ // *ast.BadDecl since it is a keyword. This logic would allow "package" to
+ // appear on any line of the file as long as it's the first code expression
+ // in the file.
+ lines := strings.Split(string(src), "\n")
+ cursorLine := tok.Line(cursor)
+ if cursorLine <= 0 || cursorLine > len(lines) {
+ return nil, fmt.Errorf("invalid line number")
+ }
+ if fset.Position(expr.Pos()).Line == cursorLine {
+ words := strings.Fields(lines[cursorLine-1])
+ if len(words) > 0 && words[0] == PACKAGE {
+ content := PACKAGE
+ // Account for spaces if there are any.
+ if len(words) > 1 {
+ content += " "
+ }
+
+ start := expr.Pos()
+ end := token.Pos(int(expr.Pos()) + len(content) + 1)
+ // We have verified that we have a valid 'package' keyword as our
+ // first expression. Ensure that cursor is in this keyword or
+ // otherwise fallback to the general case.
+ if cursor >= start && cursor <= end {
+ return &Selection{
+ content: content,
+ cursor: cursor,
+ MappedRange: source.NewMappedRange(fset, m, start, end),
+ }, nil
+ }
+ }
+ }
+
+ // If the cursor is after the start of the expression, no package
+ // declaration will be valid.
+ if cursor > expr.Pos() {
+ return nil, fmt.Errorf("cursor after expression")
+ }
+
+ // If the cursor is in a comment, don't offer any completions.
+ if cursorInComment(fset, cursor, src) {
+ return nil, fmt.Errorf("cursor in comment")
+ }
+
+ // The surrounding range in this case is the cursor except for empty file,
+ // in which case it's end of file - 1
+ start, end := cursor, cursor
+ if tok.Size() == 0 {
+ start, end = tok.Pos(0)-1, tok.Pos(0)-1
+ }
+
+ return &Selection{
+ content: "",
+ cursor: cursor,
+ MappedRange: source.NewMappedRange(fset, m, start, end),
+ }, nil
+}
+
+func cursorInComment(fset *token.FileSet, cursor token.Pos, src []byte) bool {
+ var s scanner.Scanner
+ s.Init(fset.File(cursor), src, func(_ token.Position, _ string) {}, scanner.ScanComments)
+ for {
+ pos, tok, lit := s.Scan()
+ if pos <= cursor && cursor <= token.Pos(int(pos)+len(lit)) {
+ return tok == token.COMMENT
+ }
+ if tok == token.EOF {
+ break
+ }
+ }
+ return false
+}
+
+// packageNameCompletions returns name completions for a package clause using
+// the current name as prefix.
+func (c *completer) packageNameCompletions(ctx context.Context, fileURI span.URI, name *ast.Ident) error {
+ cursor := int(c.pos - name.NamePos)
+ if cursor < 0 || cursor > len(name.Name) {
+ return errors.New("cursor is not in package name identifier")
+ }
+
+ c.completionContext.packageCompletion = true
+
+ prefix := name.Name[:cursor]
+ packageSuggestions, err := packageSuggestions(ctx, c.snapshot, fileURI, prefix)
+ if err != nil {
+ return err
+ }
+
+ for _, pkg := range packageSuggestions {
+ c.deepState.enqueue(pkg)
+ }
+ return nil
+}
+
+// packageSuggestions returns a list of packages from workspace packages that
+// have the given prefix and are used in the same directory as the given
+// file. This also includes test packages for these packages (<pkg>_test) and
+// the directory name itself.
+func packageSuggestions(ctx context.Context, snapshot source.Snapshot, fileURI span.URI, prefix string) ([]candidate, error) {
+ workspacePackages, err := snapshot.WorkspacePackages(ctx)
+ if err != nil {
+ return nil, err
+ }
+
+ dirPath := filepath.Dir(string(fileURI))
+ dirName := filepath.Base(dirPath)
+
+ seenPkgs := make(map[string]struct{})
+
+ toCandidate := func(name string, score float64) candidate {
+ obj := types.NewPkgName(0, nil, name, types.NewPackage("", name))
+ return candidate{obj: obj, name: name, detail: name, score: score}
+ }
+
+ matcher := fuzzy.NewMatcher(prefix)
+
+ // The `go` command by default only allows one package per directory but we
+ // support multiple package suggestions since gopls is build system agnostic.
+ var packages []candidate
+ for _, pkg := range workspacePackages {
+ if pkg.Name() == "main" || pkg.Name() == "" {
+ continue
+ }
+ if _, ok := seenPkgs[pkg.Name()]; ok {
+ continue
+ }
+
+ // Only add packages that are previously used in the current directory.
+ var relevantPkg bool
+ for _, pgf := range pkg.CompiledGoFiles() {
+ if filepath.Dir(string(pgf.URI)) == dirPath {
+ relevantPkg = true
+ break
+ }
+ }
+ if !relevantPkg {
+ continue
+ }
+
+ // Add a found package used in current directory as a high relevance
+ // suggestion and the test package for it as a medium relevance
+ // suggestion.
+ if score := float64(matcher.Score(pkg.Name())); score > 0 {
+ packages = append(packages, toCandidate(pkg.Name(), score*highScore))
+ }
+ seenPkgs[pkg.Name()] = struct{}{}
+
+ testPkgName := pkg.Name() + "_test"
+ if _, ok := seenPkgs[testPkgName]; ok || strings.HasSuffix(pkg.Name(), "_test") {
+ continue
+ }
+ if score := float64(matcher.Score(testPkgName)); score > 0 {
+ packages = append(packages, toCandidate(testPkgName, score*stdScore))
+ }
+ seenPkgs[testPkgName] = struct{}{}
+ }
+
+ // Add current directory name as a low relevance suggestion.
+ if _, ok := seenPkgs[dirName]; !ok {
+ if score := float64(matcher.Score(dirName)); score > 0 {
+ packages = append(packages, toCandidate(dirName, score*lowScore))
+ }
+
+ testDirName := dirName + "_test"
+ if score := float64(matcher.Score(testDirName)); score > 0 {
+ packages = append(packages, toCandidate(testDirName, score*lowScore))
+ }
+ }
+
+ if score := float64(matcher.Score("main")); score > 0 {
+ packages = append(packages, toCandidate("main", score*lowScore))
+ }
+
+ return packages, nil
+}
projects / dotfiles / .git / blobdiff