| // Copyright 2018 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 provides core functionality for code completion in Go |
| // editors and tools. |
| package completion |
| |
| import ( |
| "context" |
| "fmt" |
| "go/ast" |
| "go/constant" |
| "go/scanner" |
| "go/token" |
| "go/types" |
| "math" |
| "sort" |
| "strconv" |
| "strings" |
| "sync" |
| "time" |
| "unicode" |
| |
| "golang.org/x/tools/go/ast/astutil" |
| "golang.org/x/tools/internal/event" |
| "golang.org/x/tools/internal/imports" |
| "golang.org/x/tools/internal/lsp/fuzzy" |
| "golang.org/x/tools/internal/lsp/protocol" |
| "golang.org/x/tools/internal/lsp/snippet" |
| "golang.org/x/tools/internal/lsp/source" |
| errors "golang.org/x/xerrors" |
| ) |
| |
| type CompletionItem struct { |
| // Label is the primary text the user sees for this completion item. |
| Label string |
| |
| // Detail is supplemental information to present to the user. |
| // This often contains the type or return type of the completion item. |
| Detail string |
| |
| // InsertText is the text to insert if this item is selected. |
| // Any of the prefix that has already been typed is not trimmed. |
| // The insert text does not contain snippets. |
| InsertText string |
| |
| Kind protocol.CompletionItemKind |
| |
| // An optional array of additional TextEdits that are applied when |
| // selecting this completion. |
| // |
| // Additional text edits should be used to change text unrelated to the current cursor position |
| // (for example adding an import statement at the top of the file if the completion item will |
| // insert an unqualified type). |
| AdditionalTextEdits []protocol.TextEdit |
| |
| // Depth is how many levels were searched to find this completion. |
| // For example when completing "foo<>", "fooBar" is depth 0, and |
| // "fooBar.Baz" is depth 1. |
| Depth int |
| |
| // Score is the internal relevance score. |
| // A higher score indicates that this completion item is more relevant. |
| Score float64 |
| |
| // snippet is the LSP snippet for the completion item. The LSP |
| // specification contains details about LSP snippets. For example, a |
| // snippet for a function with the following signature: |
| // |
| // func foo(a, b, c int) |
| // |
| // would be: |
| // |
| // foo(${1:a int}, ${2: b int}, ${3: c int}) |
| // |
| // If Placeholders is false in the CompletionOptions, the above |
| // snippet would instead be: |
| // |
| // foo(${1:}) |
| snippet *snippet.Builder |
| |
| // Documentation is the documentation for the completion item. |
| Documentation string |
| |
| // obj is the object from which this candidate was derived, if any. |
| // obj is for internal use only. |
| obj types.Object |
| } |
| |
| // completionOptions holds completion specific configuration. |
| type completionOptions struct { |
| unimported bool |
| documentation bool |
| fullDocumentation bool |
| placeholders bool |
| literal bool |
| matcher source.Matcher |
| budget time.Duration |
| } |
| |
| // Snippet is a convenience returns the snippet if available, otherwise |
| // the InsertText. |
| // used for an item, depending on if the callee wants placeholders or not. |
| func (i *CompletionItem) Snippet() string { |
| if i.snippet != nil { |
| return i.snippet.String() |
| } |
| return i.InsertText |
| } |
| |
| // Scoring constants are used for weighting the relevance of different candidates. |
| const ( |
| // stdScore is the base score for all completion items. |
| stdScore float64 = 1.0 |
| |
| // highScore indicates a very relevant completion item. |
| highScore float64 = 10.0 |
| |
| // lowScore indicates an irrelevant or not useful completion item. |
| lowScore float64 = 0.01 |
| ) |
| |
| // matcher matches a candidate's label against the user input. The |
| // returned score reflects the quality of the match. A score of zero |
| // indicates no match, and a score of one means a perfect match. |
| type matcher interface { |
| Score(candidateLabel string) (score float32) |
| } |
| |
| // prefixMatcher implements case sensitive prefix matching. |
| type prefixMatcher string |
| |
| func (pm prefixMatcher) Score(candidateLabel string) float32 { |
| if strings.HasPrefix(candidateLabel, string(pm)) { |
| return 1 |
| } |
| return -1 |
| } |
| |
| // insensitivePrefixMatcher implements case insensitive prefix matching. |
| type insensitivePrefixMatcher string |
| |
| func (ipm insensitivePrefixMatcher) Score(candidateLabel string) float32 { |
| if strings.HasPrefix(strings.ToLower(candidateLabel), string(ipm)) { |
| return 1 |
| } |
| return -1 |
| } |
| |
| // completer contains the necessary information for a single completion request. |
| type completer struct { |
| snapshot source.Snapshot |
| pkg source.Package |
| qf types.Qualifier |
| opts *completionOptions |
| |
| // completionContext contains information about the trigger for this |
| // completion request. |
| completionContext completionContext |
| |
| // fh is a handle to the file associated with this completion request. |
| fh source.FileHandle |
| |
| // filename is the name of the file associated with this completion request. |
| filename string |
| |
| // file is the AST of the file associated with this completion request. |
| file *ast.File |
| |
| // pos is the position at which the request was triggered. |
| pos token.Pos |
| |
| // path is the path of AST nodes enclosing the position. |
| path []ast.Node |
| |
| // seen is the map that ensures we do not return duplicate results. |
| seen map[types.Object]bool |
| |
| // items is the list of completion items returned. |
| items []CompletionItem |
| |
| // completionCallbacks is a list of callbacks to collect completions that |
| // require expensive operations. This includes operations where we search |
| // through the entire module cache. |
| completionCallbacks []func(opts *imports.Options) error |
| |
| // surrounding describes the identifier surrounding the position. |
| surrounding *Selection |
| |
| // inference contains information we've inferred about ideal |
| // candidates such as the candidate's type. |
| inference candidateInference |
| |
| // enclosingFunc contains information about the function enclosing |
| // the position. |
| enclosingFunc *funcInfo |
| |
| // enclosingCompositeLiteral contains information about the composite literal |
| // enclosing the position. |
| enclosingCompositeLiteral *compLitInfo |
| |
| // deepState contains the current state of our deep completion search. |
| deepState deepCompletionState |
| |
| // matcher matches the candidates against the surrounding prefix. |
| matcher matcher |
| |
| // methodSetCache caches the types.NewMethodSet call, which is relatively |
| // expensive and can be called many times for the same type while searching |
| // for deep completions. |
| methodSetCache map[methodSetKey]*types.MethodSet |
| |
| // mapper converts the positions in the file from which the completion originated. |
| mapper *protocol.ColumnMapper |
| |
| // startTime is when we started processing this completion request. It does |
| // not include any time the request spent in the queue. |
| startTime time.Time |
| } |
| |
| // funcInfo holds info about a function object. |
| type funcInfo struct { |
| // sig is the function declaration enclosing the position. |
| sig *types.Signature |
| |
| // body is the function's body. |
| body *ast.BlockStmt |
| } |
| |
| type compLitInfo struct { |
| // cl is the *ast.CompositeLit enclosing the position. |
| cl *ast.CompositeLit |
| |
| // clType is the type of cl. |
| clType types.Type |
| |
| // kv is the *ast.KeyValueExpr enclosing the position, if any. |
| kv *ast.KeyValueExpr |
| |
| // inKey is true if we are certain the position is in the key side |
| // of a key-value pair. |
| inKey bool |
| |
| // maybeInFieldName is true if inKey is false and it is possible |
| // we are completing a struct field name. For example, |
| // "SomeStruct{<>}" will be inKey=false, but maybeInFieldName=true |
| // because we _could_ be completing a field name. |
| maybeInFieldName bool |
| } |
| |
| type importInfo struct { |
| importPath string |
| name string |
| pkg source.Package |
| } |
| |
| type methodSetKey struct { |
| typ types.Type |
| addressable bool |
| } |
| |
| type completionContext struct { |
| // triggerCharacter is the character used to trigger completion at current |
| // position, if any. |
| triggerCharacter string |
| |
| // triggerKind is information about how a completion was triggered. |
| triggerKind protocol.CompletionTriggerKind |
| |
| // commentCompletion is true if we are completing a comment. |
| commentCompletion bool |
| |
| // packageCompletion is true if we are completing a package name. |
| packageCompletion bool |
| } |
| |
| // A Selection represents the cursor position and surrounding identifier. |
| type Selection struct { |
| content string |
| cursor token.Pos |
| source.MappedRange |
| } |
| |
| func (p Selection) Content() string { |
| return p.content |
| } |
| |
| func (p Selection) Start() token.Pos { |
| return p.MappedRange.SpanRange().Start |
| } |
| |
| func (p Selection) End() token.Pos { |
| return p.MappedRange.SpanRange().End |
| } |
| |
| func (p Selection) Prefix() string { |
| return p.content[:p.cursor-p.SpanRange().Start] |
| } |
| |
| func (p Selection) Suffix() string { |
| return p.content[p.cursor-p.SpanRange().Start:] |
| } |
| |
| func (c *completer) setSurrounding(ident *ast.Ident) { |
| if c.surrounding != nil { |
| return |
| } |
| if !(ident.Pos() <= c.pos && c.pos <= ident.End()) { |
| return |
| } |
| |
| c.surrounding = &Selection{ |
| content: ident.Name, |
| cursor: c.pos, |
| // Overwrite the prefix only. |
| MappedRange: source.NewMappedRange(c.snapshot.FileSet(), c.mapper, ident.Pos(), ident.End()), |
| } |
| |
| c.setMatcherFromPrefix(c.surrounding.Prefix()) |
| } |
| |
| func (c *completer) setMatcherFromPrefix(prefix string) { |
| switch c.opts.matcher { |
| case source.Fuzzy: |
| c.matcher = fuzzy.NewMatcher(prefix) |
| case source.CaseSensitive: |
| c.matcher = prefixMatcher(prefix) |
| default: |
| c.matcher = insensitivePrefixMatcher(strings.ToLower(prefix)) |
| } |
| } |
| |
| func (c *completer) getSurrounding() *Selection { |
| if c.surrounding == nil { |
| c.surrounding = &Selection{ |
| content: "", |
| cursor: c.pos, |
| MappedRange: source.NewMappedRange(c.snapshot.FileSet(), c.mapper, c.pos, c.pos), |
| } |
| } |
| return c.surrounding |
| } |
| |
| // candidate represents a completion candidate. |
| type candidate struct { |
| // obj is the types.Object to complete to. |
| obj types.Object |
| |
| // score is used to rank candidates. |
| score float64 |
| |
| // name is the deep object name path, e.g. "foo.bar" |
| name string |
| |
| // detail is additional information about this item. If not specified, |
| // defaults to type string for the object. |
| detail string |
| |
| // path holds the path from the search root (excluding the candidate |
| // itself) for a deep candidate. |
| path []types.Object |
| |
| // names tracks the names of objects from search root (excluding the |
| // candidate itself) for a deep candidate. This also includes |
| // expanded calls for function invocations. |
| names []string |
| |
| // expandFuncCall is true if obj should be invoked in the completion. |
| // For example, expandFuncCall=true yields "foo()", expandFuncCall=false yields "foo". |
| expandFuncCall bool |
| |
| // takeAddress is true if the completion should take a pointer to obj. |
| // For example, takeAddress=true yields "&foo", takeAddress=false yields "foo". |
| takeAddress bool |
| |
| // addressable is true if a pointer can be taken to the candidate. |
| addressable bool |
| |
| // makePointer is true if the candidate type name T should be made into *T. |
| makePointer bool |
| |
| // dereference is a count of how many times to dereference the candidate obj. |
| // For example, dereference=2 turns "foo" into "**foo" when formatting. |
| dereference int |
| |
| // variadic is true if this candidate fills a variadic param and |
| // needs "..." appended. |
| variadic bool |
| |
| // imp is the import that needs to be added to this package in order |
| // for this candidate to be valid. nil if no import needed. |
| imp *importInfo |
| } |
| |
| // ErrIsDefinition is an error that informs the user they got no |
| // completions because they tried to complete the name of a new object |
| // being defined. |
| type ErrIsDefinition struct { |
| objStr string |
| } |
| |
| func (e ErrIsDefinition) Error() string { |
| msg := "this is a definition" |
| if e.objStr != "" { |
| msg += " of " + e.objStr |
| } |
| return msg |
| } |
| |
| // Completion returns a list of possible candidates for completion, given a |
| // a file and a position. |
| // |
| // The selection is computed based on the preceding identifier and can be used by |
| // the client to score the quality of the completion. For instance, some clients |
| // may tolerate imperfect matches as valid completion results, since users may make typos. |
| func Completion(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle, protoPos protocol.Position, protoContext protocol.CompletionContext) ([]CompletionItem, *Selection, error) { |
| ctx, done := event.Start(ctx, "completion.Completion") |
| defer done() |
| |
| startTime := time.Now() |
| |
| pkg, pgf, err := source.GetParsedFile(ctx, snapshot, fh, source.NarrowestPackage) |
| if err != nil || pgf.File.Package == token.NoPos { |
| // If we can't parse this file or find position for the package |
| // keyword, it may be missing a package declaration. Try offering |
| // suggestions for the package declaration. |
| // Note that this would be the case even if the keyword 'package' is |
| // present but no package name exists. |
| items, surrounding, innerErr := packageClauseCompletions(ctx, snapshot, fh, protoPos) |
| if innerErr != nil { |
| // return the error for GetParsedFile since it's more relevant in this situation. |
| return nil, nil, errors.Errorf("getting file for Completion: %w (package completions: %v)", err, innerErr) |
| |
| } |
| return items, surrounding, nil |
| } |
| spn, err := pgf.Mapper.PointSpan(protoPos) |
| if err != nil { |
| return nil, nil, err |
| } |
| rng, err := spn.Range(pgf.Mapper.Converter) |
| if err != nil { |
| return nil, nil, err |
| } |
| // Completion is based on what precedes the cursor. |
| // Find the path to the position before pos. |
| path, _ := astutil.PathEnclosingInterval(pgf.File, rng.Start-1, rng.Start-1) |
| if path == nil { |
| return nil, nil, errors.Errorf("cannot find node enclosing position") |
| } |
| |
| pos := rng.Start |
| |
| // Check if completion at this position is valid. If not, return early. |
| switch n := path[0].(type) { |
| case *ast.BasicLit: |
| // Skip completion inside literals except for ImportSpec |
| if len(path) > 1 { |
| if _, ok := path[1].(*ast.ImportSpec); ok { |
| break |
| } |
| } |
| return nil, nil, nil |
| case *ast.CallExpr: |
| if n.Ellipsis.IsValid() && pos > n.Ellipsis && pos <= n.Ellipsis+token.Pos(len("...")) { |
| // Don't offer completions inside or directly after "...". For |
| // example, don't offer completions at "<>" in "foo(bar...<>"). |
| return nil, nil, nil |
| } |
| case *ast.Ident: |
| // reject defining identifiers |
| if obj, ok := pkg.GetTypesInfo().Defs[n]; ok { |
| if v, ok := obj.(*types.Var); ok && v.IsField() && v.Embedded() { |
| // An anonymous field is also a reference to a type. |
| } else if pgf.File.Name == n { |
| // Don't skip completions if Ident is for package name. |
| break |
| } else { |
| objStr := "" |
| if obj != nil { |
| qual := types.RelativeTo(pkg.GetTypes()) |
| objStr = types.ObjectString(obj, qual) |
| } |
| return nil, nil, ErrIsDefinition{objStr: objStr} |
| } |
| } |
| } |
| |
| opts := snapshot.View().Options() |
| c := &completer{ |
| pkg: pkg, |
| snapshot: snapshot, |
| qf: source.Qualifier(pgf.File, pkg.GetTypes(), pkg.GetTypesInfo()), |
| completionContext: completionContext{ |
| triggerCharacter: protoContext.TriggerCharacter, |
| triggerKind: protoContext.TriggerKind, |
| }, |
| fh: fh, |
| filename: fh.URI().Filename(), |
| file: pgf.File, |
| path: path, |
| pos: pos, |
| seen: make(map[types.Object]bool), |
| enclosingFunc: enclosingFunction(path, pkg.GetTypesInfo()), |
| enclosingCompositeLiteral: enclosingCompositeLiteral(path, rng.Start, pkg.GetTypesInfo()), |
| deepState: deepCompletionState{ |
| enabled: opts.DeepCompletion, |
| }, |
| opts: &completionOptions{ |
| matcher: opts.Matcher, |
| unimported: opts.CompleteUnimported, |
| documentation: opts.CompletionDocumentation && opts.HoverKind != source.NoDocumentation, |
| fullDocumentation: opts.HoverKind == source.FullDocumentation, |
| placeholders: opts.UsePlaceholders, |
| literal: opts.LiteralCompletions && opts.InsertTextFormat == protocol.SnippetTextFormat, |
| budget: opts.CompletionBudget, |
| }, |
| // default to a matcher that always matches |
| matcher: prefixMatcher(""), |
| methodSetCache: make(map[methodSetKey]*types.MethodSet), |
| mapper: pgf.Mapper, |
| startTime: startTime, |
| } |
| |
| var cancel context.CancelFunc |
| if c.opts.budget == 0 { |
| ctx, cancel = context.WithCancel(ctx) |
| } else { |
| // timeoutDuration is the completion budget remaining. If less than |
| // 10ms, set to 10ms |
| timeoutDuration := time.Until(c.startTime.Add(c.opts.budget)) |
| if timeoutDuration < 10*time.Millisecond { |
| timeoutDuration = 10 * time.Millisecond |
| } |
| ctx, cancel = context.WithTimeout(ctx, timeoutDuration) |
| } |
| defer cancel() |
| |
| if surrounding := c.containingIdent(pgf.Src); surrounding != nil { |
| c.setSurrounding(surrounding) |
| } |
| |
| c.inference = expectedCandidate(ctx, c) |
| |
| err = c.collectCompletions(ctx) |
| if err != nil { |
| return nil, nil, err |
| } |
| |
| // Deep search collected candidates and their members for more candidates. |
| c.deepSearch(ctx) |
| c.deepState.searchQueue = nil |
| |
| for _, callback := range c.completionCallbacks { |
| if err := c.snapshot.RunProcessEnvFunc(ctx, callback); err != nil { |
| return nil, nil, err |
| } |
| } |
| |
| // Search candidates populated by expensive operations like |
| // unimportedMembers etc. for more completion items. |
| c.deepSearch(ctx) |
| |
| // Statement candidates offer an entire statement in certain contexts, as |
| // opposed to a single object. Add statement candidates last because they |
| // depend on other candidates having already been collected. |
| c.addStatementCandidates() |
| |
| c.sortItems() |
| return c.items, c.getSurrounding(), nil |
| } |
| |
| // collectCompletions adds possible completion candidates to either the deep |
| // search queue or completion items directly for different completion contexts. |
| func (c *completer) collectCompletions(ctx context.Context) error { |
| // Inside import blocks, return completions for unimported packages. |
| for _, importSpec := range c.file.Imports { |
| if !(importSpec.Path.Pos() <= c.pos && c.pos <= importSpec.Path.End()) { |
| continue |
| } |
| return c.populateImportCompletions(ctx, importSpec) |
| } |
| |
| // Inside comments, offer completions for the name of the relevant symbol. |
| for _, comment := range c.file.Comments { |
| if comment.Pos() < c.pos && c.pos <= comment.End() { |
| c.populateCommentCompletions(ctx, comment) |
| return nil |
| } |
| } |
| |
| // Struct literals are handled entirely separately. |
| if c.wantStructFieldCompletions() { |
| // If we are definitely completing a struct field name, deep completions |
| // don't make sense. |
| if c.enclosingCompositeLiteral.inKey { |
| c.deepState.enabled = false |
| } |
| return c.structLiteralFieldName(ctx) |
| } |
| |
| if lt := c.wantLabelCompletion(); lt != labelNone { |
| c.labels(lt) |
| return nil |
| } |
| |
| if c.emptySwitchStmt() { |
| // Empty switch statements only admit "default" and "case" keywords. |
| c.addKeywordItems(map[string]bool{}, highScore, CASE, DEFAULT) |
| return nil |
| } |
| |
| switch n := c.path[0].(type) { |
| case *ast.Ident: |
| if c.file.Name == n { |
| return c.packageNameCompletions(ctx, c.fh.URI(), n) |
| } else if sel, ok := c.path[1].(*ast.SelectorExpr); ok && sel.Sel == n { |
| // Is this the Sel part of a selector? |
| return c.selector(ctx, sel) |
| } |
| return c.lexical(ctx) |
| // The function name hasn't been typed yet, but the parens are there: |
| // recv.‸(arg) |
| case *ast.TypeAssertExpr: |
| // Create a fake selector expression. |
| return c.selector(ctx, &ast.SelectorExpr{X: n.X}) |
| case *ast.SelectorExpr: |
| return c.selector(ctx, n) |
| // At the file scope, only keywords are allowed. |
| case *ast.BadDecl, *ast.File: |
| c.addKeywordCompletions() |
| default: |
| // fallback to lexical completions |
| return c.lexical(ctx) |
| } |
| |
| return nil |
| } |
| |
| // containingIdent returns the *ast.Ident containing pos, if any. It |
| // synthesizes an *ast.Ident to allow completion in the face of |
| // certain syntax errors. |
| func (c *completer) containingIdent(src []byte) *ast.Ident { |
| // In the normal case, our leaf AST node is the identifer being completed. |
| if ident, ok := c.path[0].(*ast.Ident); ok { |
| return ident |
| } |
| |
| pos, tkn, lit := c.scanToken(src) |
| if !pos.IsValid() { |
| return nil |
| } |
| |
| fakeIdent := &ast.Ident{Name: lit, NamePos: pos} |
| |
| if _, isBadDecl := c.path[0].(*ast.BadDecl); isBadDecl { |
| // You don't get *ast.Idents at the file level, so look for bad |
| // decls and use the manually extracted token. |
| return fakeIdent |
| } else if c.emptySwitchStmt() { |
| // Only keywords are allowed in empty switch statements. |
| // *ast.Idents are not parsed, so we must use the manually |
| // extracted token. |
| return fakeIdent |
| } else if tkn.IsKeyword() { |
| // Otherwise, manually extract the prefix if our containing token |
| // is a keyword. This improves completion after an "accidental |
| // keyword", e.g. completing to "variance" in "someFunc(var<>)". |
| return fakeIdent |
| } |
| |
| return nil |
| } |
| |
| // scanToken scans pgh's contents for the token containing pos. |
| func (c *completer) scanToken(contents []byte) (token.Pos, token.Token, string) { |
| tok := c.snapshot.FileSet().File(c.pos) |
| |
| var s scanner.Scanner |
| s.Init(tok, contents, nil, 0) |
| for { |
| tknPos, tkn, lit := s.Scan() |
| if tkn == token.EOF || tknPos >= c.pos { |
| return token.NoPos, token.ILLEGAL, "" |
| } |
| |
| if len(lit) > 0 && tknPos <= c.pos && c.pos <= tknPos+token.Pos(len(lit)) { |
| return tknPos, tkn, lit |
| } |
| } |
| } |
| |
| func (c *completer) sortItems() { |
| sort.SliceStable(c.items, func(i, j int) bool { |
| // Sort by score first. |
| if c.items[i].Score != c.items[j].Score { |
| return c.items[i].Score > c.items[j].Score |
| } |
| |
| // Then sort by label so order stays consistent. This also has the |
| // effect of prefering shorter candidates. |
| return c.items[i].Label < c.items[j].Label |
| }) |
| } |
| |
| // emptySwitchStmt reports whether pos is in an empty switch or select |
| // statement. |
| func (c *completer) emptySwitchStmt() bool { |
| block, ok := c.path[0].(*ast.BlockStmt) |
| if !ok || len(block.List) > 0 || len(c.path) == 1 { |
| return false |
| } |
| |
| switch c.path[1].(type) { |
| case *ast.SwitchStmt, *ast.TypeSwitchStmt, *ast.SelectStmt: |
| return true |
| default: |
| return false |
| } |
| } |
| |
| // populateImportCompletions yields completions for an import path around the cursor. |
| // |
| // Completions are suggested at the directory depth of the given import path so |
| // that we don't overwhelm the user with a large list of possibilities. As an |
| // example, a completion for the prefix "golang" results in "golang.org/". |
| // Completions for "golang.org/" yield its subdirectories |
| // (i.e. "golang.org/x/"). The user is meant to accept completion suggestions |
| // until they reach a complete import path. |
| func (c *completer) populateImportCompletions(ctx context.Context, searchImport *ast.ImportSpec) error { |
| // deepSearch is not valuable for import completions. |
| c.deepState.enabled = false |
| |
| importPath := searchImport.Path.Value |
| |
| // Extract the text between the quotes (if any) in an import spec. |
| // prefix is the part of import path before the cursor. |
| prefixEnd := c.pos - searchImport.Path.Pos() |
| prefix := strings.Trim(importPath[:prefixEnd], `"`) |
| |
| // The number of directories in the import path gives us the depth at |
| // which to search. |
| depth := len(strings.Split(prefix, "/")) - 1 |
| |
| content := importPath |
| start, end := searchImport.Path.Pos(), searchImport.Path.End() |
| namePrefix, nameSuffix := `"`, `"` |
| // If a starting quote is present, adjust surrounding to either after the |
| // cursor or after the first slash (/), except if cursor is at the starting |
| // quote. Otherwise we provide a completion including the starting quote. |
| if strings.HasPrefix(importPath, `"`) && c.pos > searchImport.Path.Pos() { |
| content = content[1:] |
| start++ |
| if depth > 0 { |
| // Adjust textEdit start to replacement range. For ex: if current |
| // path was "golang.or/x/to<>ols/internal/", where <> is the cursor |
| // position, start of the replacement range would be after |
| // "golang.org/x/". |
| path := strings.SplitAfter(prefix, "/") |
| numChars := len(strings.Join(path[:len(path)-1], "")) |
| content = content[numChars:] |
| start += token.Pos(numChars) |
| } |
| namePrefix = "" |
| } |
| |
| // We won't provide an ending quote if one is already present, except if |
| // cursor is after the ending quote but still in import spec. This is |
| // because cursor has to be in our textEdit range. |
| if strings.HasSuffix(importPath, `"`) && c.pos < searchImport.Path.End() { |
| end-- |
| content = content[:len(content)-1] |
| nameSuffix = "" |
| } |
| |
| c.surrounding = &Selection{ |
| content: content, |
| cursor: c.pos, |
| MappedRange: source.NewMappedRange(c.snapshot.FileSet(), c.mapper, start, end), |
| } |
| |
| seenImports := make(map[string]struct{}) |
| for _, importSpec := range c.file.Imports { |
| if importSpec.Path.Value == importPath { |
| continue |
| } |
| seenImportPath, err := strconv.Unquote(importSpec.Path.Value) |
| if err != nil { |
| return err |
| } |
| seenImports[seenImportPath] = struct{}{} |
| } |
| |
| var mu sync.Mutex // guard c.items locally, since searchImports is called in parallel |
| seen := make(map[string]struct{}) |
| searchImports := func(pkg imports.ImportFix) { |
| path := pkg.StmtInfo.ImportPath |
| if _, ok := seenImports[path]; ok { |
| return |
| } |
| |
| // Any package path containing fewer directories than the search |
| // prefix is not a match. |
| pkgDirList := strings.Split(path, "/") |
| if len(pkgDirList) < depth+1 { |
| return |
| } |
| pkgToConsider := strings.Join(pkgDirList[:depth+1], "/") |
| |
| name := pkgDirList[depth] |
| // if we're adding an opening quote to completion too, set name to full |
| // package path since we'll need to overwrite that range. |
| if namePrefix == `"` { |
| name = pkgToConsider |
| } |
| |
| score := pkg.Relevance |
| if len(pkgDirList)-1 == depth { |
| score *= highScore |
| } else { |
| // For incomplete package paths, add a terminal slash to indicate that the |
| // user should keep triggering completions. |
| name += "/" |
| pkgToConsider += "/" |
| } |
| |
| if _, ok := seen[pkgToConsider]; ok { |
| return |
| } |
| seen[pkgToConsider] = struct{}{} |
| |
| mu.Lock() |
| defer mu.Unlock() |
| |
| name = namePrefix + name + nameSuffix |
| obj := types.NewPkgName(0, nil, name, types.NewPackage(pkgToConsider, name)) |
| c.deepState.enqueue(candidate{ |
| obj: obj, |
| detail: fmt.Sprintf("%q", pkgToConsider), |
| score: score, |
| }) |
| } |
| |
| c.completionCallbacks = append(c.completionCallbacks, func(opts *imports.Options) error { |
| return imports.GetImportPaths(ctx, searchImports, prefix, c.filename, c.pkg.GetTypes().Name(), opts.Env) |
| }) |
| return nil |
| } |
| |
| // populateCommentCompletions yields completions for comments preceding or in declarations. |
| func (c *completer) populateCommentCompletions(ctx context.Context, comment *ast.CommentGroup) { |
| // If the completion was triggered by a period, ignore it. These types of |
| // completions will not be useful in comments. |
| if c.completionContext.triggerCharacter == "." { |
| return |
| } |
| |
| // Using the comment position find the line after |
| file := c.snapshot.FileSet().File(comment.End()) |
| if file == nil { |
| return |
| } |
| |
| // Deep completion doesn't work properly in comments since we don't |
| // have a type object to complete further. |
| c.deepState.enabled = false |
| c.completionContext.commentCompletion = true |
| |
| // Documentation isn't useful in comments, since it might end up being the |
| // comment itself. |
| c.opts.documentation = false |
| |
| commentLine := file.Line(comment.End()) |
| |
| // comment is valid, set surrounding as word boundaries around cursor |
| c.setSurroundingForComment(comment) |
| |
| // Using the next line pos, grab and parse the exported symbol on that line |
| for _, n := range c.file.Decls { |
| declLine := file.Line(n.Pos()) |
| // if the comment is not in, directly above or on the same line as a declaration |
| if declLine != commentLine && declLine != commentLine+1 && |
| !(n.Pos() <= comment.Pos() && comment.End() <= n.End()) { |
| continue |
| } |
| switch node := n.(type) { |
| // handle const, vars, and types |
| case *ast.GenDecl: |
| for _, spec := range node.Specs { |
| switch spec := spec.(type) { |
| case *ast.ValueSpec: |
| for _, name := range spec.Names { |
| if name.String() == "_" { |
| continue |
| } |
| obj := c.pkg.GetTypesInfo().ObjectOf(name) |
| c.deepState.enqueue(candidate{obj: obj, score: stdScore}) |
| } |
| case *ast.TypeSpec: |
| // add TypeSpec fields to completion |
| switch typeNode := spec.Type.(type) { |
| case *ast.StructType: |
| c.addFieldItems(ctx, typeNode.Fields) |
| case *ast.FuncType: |
| c.addFieldItems(ctx, typeNode.Params) |
| c.addFieldItems(ctx, typeNode.Results) |
| case *ast.InterfaceType: |
| c.addFieldItems(ctx, typeNode.Methods) |
| } |
| |
| if spec.Name.String() == "_" { |
| continue |
| } |
| |
| obj := c.pkg.GetTypesInfo().ObjectOf(spec.Name) |
| // Type name should get a higher score than fields but not highScore by default |
| // since field near a comment cursor gets a highScore |
| score := stdScore * 1.1 |
| // If type declaration is on the line after comment, give it a highScore. |
| if declLine == commentLine+1 { |
| score = highScore |
| } |
| |
| c.deepState.enqueue(candidate{obj: obj, score: score}) |
| } |
| } |
| // handle functions |
| case *ast.FuncDecl: |
| c.addFieldItems(ctx, node.Recv) |
| c.addFieldItems(ctx, node.Type.Params) |
| c.addFieldItems(ctx, node.Type.Results) |
| |
| // collect receiver struct fields |
| if node.Recv != nil { |
| for _, fields := range node.Recv.List { |
| for _, name := range fields.Names { |
| obj := c.pkg.GetTypesInfo().ObjectOf(name) |
| if obj == nil { |
| continue |
| } |
| |
| recvType := obj.Type().Underlying() |
| if ptr, ok := recvType.(*types.Pointer); ok { |
| recvType = ptr.Elem() |
| } |
| recvStruct, ok := recvType.Underlying().(*types.Struct) |
| if !ok { |
| continue |
| } |
| for i := 0; i < recvStruct.NumFields(); i++ { |
| field := recvStruct.Field(i) |
| c.deepState.enqueue(candidate{obj: field, score: lowScore}) |
| } |
| } |
| } |
| } |
| |
| if node.Name.String() == "_" { |
| continue |
| } |
| |
| obj := c.pkg.GetTypesInfo().ObjectOf(node.Name) |
| if obj == nil || obj.Pkg() != nil && obj.Pkg() != c.pkg.GetTypes() { |
| continue |
| } |
| |
| c.deepState.enqueue(candidate{obj: obj, score: highScore}) |
| } |
| } |
| } |
| |
| // sets word boundaries surrounding a cursor for a comment |
| func (c *completer) setSurroundingForComment(comments *ast.CommentGroup) { |
| var cursorComment *ast.Comment |
| for _, comment := range comments.List { |
| if c.pos >= comment.Pos() && c.pos <= comment.End() { |
| cursorComment = comment |
| break |
| } |
| } |
| // if cursor isn't in the comment |
| if cursorComment == nil { |
| return |
| } |
| |
| // index of cursor in comment text |
| cursorOffset := int(c.pos - cursorComment.Pos()) |
| start, end := cursorOffset, cursorOffset |
| for start > 0 && isValidIdentifierChar(cursorComment.Text[start-1]) { |
| start-- |
| } |
| for end < len(cursorComment.Text) && isValidIdentifierChar(cursorComment.Text[end]) { |
| end++ |
| } |
| |
| c.surrounding = &Selection{ |
| content: cursorComment.Text[start:end], |
| cursor: c.pos, |
| MappedRange: source.NewMappedRange(c.snapshot.FileSet(), c.mapper, |
| token.Pos(int(cursorComment.Slash)+start), token.Pos(int(cursorComment.Slash)+end)), |
| } |
| c.setMatcherFromPrefix(c.surrounding.Prefix()) |
| } |
| |
| // isValidIdentifierChar returns true if a byte is a valid go identifier character |
| // i.e unicode letter or digit or undescore |
| func isValidIdentifierChar(char byte) bool { |
| charRune := rune(char) |
| return unicode.In(charRune, unicode.Letter, unicode.Digit) || char == '_' |
| } |
| |
| // adds struct fields, interface methods, function declaration fields to completion |
| func (c *completer) addFieldItems(ctx context.Context, fields *ast.FieldList) { |
| if fields == nil { |
| return |
| } |
| |
| cursor := c.surrounding.cursor |
| for _, field := range fields.List { |
| for _, name := range field.Names { |
| if name.String() == "_" { |
| continue |
| } |
| obj := c.pkg.GetTypesInfo().ObjectOf(name) |
| if obj == nil { |
| continue |
| } |
| |
| // if we're in a field comment/doc, score that field as more relevant |
| score := stdScore |
| if field.Comment != nil && field.Comment.Pos() <= cursor && cursor <= field.Comment.End() { |
| score = highScore |
| } else if field.Doc != nil && field.Doc.Pos() <= cursor && cursor <= field.Doc.End() { |
| score = highScore |
| } |
| |
| c.deepState.enqueue(candidate{obj: obj, score: score}) |
| } |
| } |
| } |
| |
| func (c *completer) wantStructFieldCompletions() bool { |
| clInfo := c.enclosingCompositeLiteral |
| if clInfo == nil { |
| return false |
| } |
| |
| return clInfo.isStruct() && (clInfo.inKey || clInfo.maybeInFieldName) |
| } |
| |
| func (c *completer) wantTypeName() bool { |
| return !c.completionContext.commentCompletion && c.inference.typeName.wantTypeName |
| } |
| |
| // See https://golang.org/issue/36001. Unimported completions are expensive. |
| const ( |
| maxUnimportedPackageNames = 5 |
| unimportedMemberTarget = 100 |
| ) |
| |
| // selector finds completions for the specified selector expression. |
| func (c *completer) selector(ctx context.Context, sel *ast.SelectorExpr) error { |
| c.inference.objChain = objChain(c.pkg.GetTypesInfo(), sel.X) |
| |
| // Is sel a qualified identifier? |
| if id, ok := sel.X.(*ast.Ident); ok { |
| if pkgName, ok := c.pkg.GetTypesInfo().Uses[id].(*types.PkgName); ok { |
| candidates := c.packageMembers(pkgName.Imported(), stdScore, nil) |
| for _, cand := range candidates { |
| c.deepState.enqueue(cand) |
| } |
| return nil |
| } |
| } |
| |
| // Invariant: sel is a true selector. |
| tv, ok := c.pkg.GetTypesInfo().Types[sel.X] |
| if ok { |
| candidates := c.methodsAndFields(tv.Type, tv.Addressable(), nil) |
| for _, cand := range candidates { |
| c.deepState.enqueue(cand) |
| } |
| return nil |
| } |
| |
| // Try unimported packages. |
| if id, ok := sel.X.(*ast.Ident); ok && c.opts.unimported { |
| if err := c.unimportedMembers(ctx, id); err != nil { |
| return err |
| } |
| } |
| return nil |
| } |
| |
| func (c *completer) unimportedMembers(ctx context.Context, id *ast.Ident) error { |
| // Try loaded packages first. They're relevant, fast, and fully typed. |
| known, err := c.snapshot.CachedImportPaths(ctx) |
| if err != nil { |
| return err |
| } |
| |
| var paths []string |
| for path, pkg := range known { |
| if pkg.GetTypes().Name() != id.Name { |
| continue |
| } |
| paths = append(paths, path) |
| } |
| |
| var relevances map[string]float64 |
| if len(paths) != 0 { |
| if err := c.snapshot.RunProcessEnvFunc(ctx, func(opts *imports.Options) error { |
| var err error |
| relevances, err = imports.ScoreImportPaths(ctx, opts.Env, paths) |
| return err |
| }); err != nil { |
| return err |
| } |
| } |
| sort.Slice(paths, func(i, j int) bool { |
| return relevances[paths[i]] > relevances[paths[j]] |
| }) |
| |
| for _, path := range paths { |
| pkg := known[path] |
| if pkg.GetTypes().Name() != id.Name { |
| continue |
| } |
| imp := &importInfo{ |
| importPath: path, |
| pkg: pkg, |
| } |
| if imports.ImportPathToAssumedName(path) != pkg.GetTypes().Name() { |
| imp.name = pkg.GetTypes().Name() |
| } |
| candidates := c.packageMembers(pkg.GetTypes(), unimportedScore(relevances[path]), imp) |
| for _, cand := range candidates { |
| c.deepState.enqueue(cand) |
| } |
| if len(c.items) >= unimportedMemberTarget { |
| return nil |
| } |
| } |
| |
| ctx, cancel := context.WithCancel(ctx) |
| |
| var mu sync.Mutex |
| add := func(pkgExport imports.PackageExport) { |
| mu.Lock() |
| defer mu.Unlock() |
| if _, ok := known[pkgExport.Fix.StmtInfo.ImportPath]; ok { |
| return // We got this one above. |
| } |
| |
| // Continue with untyped proposals. |
| pkg := types.NewPackage(pkgExport.Fix.StmtInfo.ImportPath, pkgExport.Fix.IdentName) |
| for _, export := range pkgExport.Exports { |
| score := unimportedScore(pkgExport.Fix.Relevance) |
| c.deepState.enqueue(candidate{ |
| obj: types.NewVar(0, pkg, export, nil), |
| score: score, |
| imp: &importInfo{ |
| importPath: pkgExport.Fix.StmtInfo.ImportPath, |
| name: pkgExport.Fix.StmtInfo.Name, |
| }, |
| }) |
| } |
| if len(c.items) >= unimportedMemberTarget { |
| cancel() |
| } |
| } |
| |
| c.completionCallbacks = append(c.completionCallbacks, func(opts *imports.Options) error { |
| defer cancel() |
| return imports.GetPackageExports(ctx, add, id.Name, c.filename, c.pkg.GetTypes().Name(), opts.Env) |
| }) |
| return nil |
| } |
| |
| // unimportedScore returns a score for an unimported package that is generally |
| // lower than other candidates. |
| func unimportedScore(relevance float64) float64 { |
| return (stdScore + .1*relevance) / 2 |
| } |
| |
| func (c *completer) packageMembers(pkg *types.Package, score float64, imp *importInfo) []candidate { |
| var candidates []candidate |
| scope := pkg.Scope() |
| for _, name := range scope.Names() { |
| obj := scope.Lookup(name) |
| candidates = append(candidates, candidate{ |
| obj: obj, |
| score: score, |
| imp: imp, |
| addressable: isVar(obj), |
| }) |
| } |
| return candidates |
| } |
| |
| func (c *completer) methodsAndFields(typ types.Type, addressable bool, imp *importInfo) []candidate { |
| mset := c.methodSetCache[methodSetKey{typ, addressable}] |
| if mset == nil { |
| if addressable && !types.IsInterface(typ) && !isPointer(typ) { |
| // Add methods of *T, which includes methods with receiver T. |
| mset = types.NewMethodSet(types.NewPointer(typ)) |
| } else { |
| // Add methods of T. |
| mset = types.NewMethodSet(typ) |
| } |
| c.methodSetCache[methodSetKey{typ, addressable}] = mset |
| } |
| |
| var candidates []candidate |
| for i := 0; i < mset.Len(); i++ { |
| candidates = append(candidates, candidate{ |
| obj: mset.At(i).Obj(), |
| score: stdScore, |
| imp: imp, |
| addressable: addressable || isPointer(typ), |
| }) |
| } |
| |
| // Add fields of T. |
| eachField(typ, func(v *types.Var) { |
| candidates = append(candidates, candidate{ |
| obj: v, |
| score: stdScore - 0.01, |
| imp: imp, |
| addressable: addressable || isPointer(typ), |
| }) |
| }) |
| |
| return candidates |
| } |
| |
| // lexical finds completions in the lexical environment. |
| func (c *completer) lexical(ctx context.Context) error { |
| scopes := source.CollectScopes(c.pkg.GetTypesInfo(), c.path, c.pos) |
| scopes = append(scopes, c.pkg.GetTypes().Scope(), types.Universe) |
| |
| var ( |
| builtinIota = types.Universe.Lookup("iota") |
| builtinNil = types.Universe.Lookup("nil") |
| ) |
| |
| // Track seen variables to avoid showing completions for shadowed variables. |
| // This works since we look at scopes from innermost to outermost. |
| seen := make(map[string]struct{}) |
| |
| // Process scopes innermost first. |
| for i, scope := range scopes { |
| if scope == nil { |
| continue |
| } |
| |
| Names: |
| for _, name := range scope.Names() { |
| declScope, obj := scope.LookupParent(name, c.pos) |
| if declScope != scope { |
| continue // Name was declared in some enclosing scope, or not at all. |
| } |
| |
| // If obj's type is invalid, find the AST node that defines the lexical block |
| // containing the declaration of obj. Don't resolve types for packages. |
| if !isPkgName(obj) && !typeIsValid(obj.Type()) { |
| // Match the scope to its ast.Node. If the scope is the package scope, |
| // use the *ast.File as the starting node. |
| var node ast.Node |
| if i < len(c.path) { |
| node = c.path[i] |
| } else if i == len(c.path) { // use the *ast.File for package scope |
| node = c.path[i-1] |
| } |
| if node != nil { |
| if resolved := resolveInvalid(c.snapshot.FileSet(), obj, node, c.pkg.GetTypesInfo()); resolved != nil { |
| obj = resolved |
| } |
| } |
| } |
| |
| // Don't use LHS of value spec in RHS. |
| if vs := enclosingValueSpec(c.path); vs != nil { |
| for _, ident := range vs.Names { |
| if obj.Pos() == ident.Pos() { |
| continue Names |
| } |
| } |
| } |
| |
| // Don't suggest "iota" outside of const decls. |
| if obj == builtinIota && !c.inConstDecl() { |
| continue |
| } |
| |
| // Rank outer scopes lower than inner. |
| score := stdScore * math.Pow(.99, float64(i)) |
| |
| // Dowrank "nil" a bit so it is ranked below more interesting candidates. |
| if obj == builtinNil { |
| score /= 2 |
| } |
| |
| // If we haven't already added a candidate for an object with this name. |
| if _, ok := seen[obj.Name()]; !ok { |
| seen[obj.Name()] = struct{}{} |
| c.deepState.enqueue(candidate{ |
| obj: obj, |
| score: score, |
| addressable: isVar(obj), |
| }) |
| } |
| } |
| } |
| |
| if c.inference.objType != nil { |
| if named, _ := source.Deref(c.inference.objType).(*types.Named); named != nil { |
| // If we expected a named type, check the type's package for |
| // completion items. This is useful when the current file hasn't |
| // imported the type's package yet. |
| |
| if named.Obj() != nil && named.Obj().Pkg() != nil { |
| pkg := named.Obj().Pkg() |
| |
| // Make sure the package name isn't already in use by another |
| // object, and that this file doesn't import the package yet. |
| if _, ok := seen[pkg.Name()]; !ok && pkg != c.pkg.GetTypes() && !alreadyImports(c.file, pkg.Path()) { |
| seen[pkg.Name()] = struct{}{} |
| obj := types.NewPkgName(0, nil, pkg.Name(), pkg) |
| imp := &importInfo{ |
| importPath: pkg.Path(), |
| } |
| if imports.ImportPathToAssumedName(pkg.Path()) != pkg.Name() { |
| imp.name = pkg.Name() |
| } |
| c.deepState.enqueue(candidate{ |
| obj: obj, |
| score: stdScore, |
| imp: imp, |
| }) |
| } |
| } |
| } |
| } |
| |
| if c.opts.unimported { |
| if err := c.unimportedPackages(ctx, seen); err != nil { |
| return err |
| } |
| } |
| |
| if t := c.inference.objType; t != nil { |
| t = source.Deref(t) |
| |
| // If we have an expected type and it is _not_ a named type, |
| // handle it specially. Non-named types like "[]int" will never be |
| // considered via a lexical search, so we need to directly inject |
| // them. |
| if _, named := t.(*types.Named); !named { |
| // If our expected type is "[]int", this will add a literal |
| // candidate of "[]int{}". |
| c.literal(ctx, t, nil) |
| |
| if _, isBasic := t.(*types.Basic); !isBasic { |
| // If we expect a non-basic type name (e.g. "[]int"), hack up |
| // a named type whose name is literally "[]int". This allows |
| // us to reuse our object based completion machinery. |
| fakeNamedType := candidate{ |
| obj: types.NewTypeName(token.NoPos, nil, types.TypeString(t, c.qf), t), |
| score: stdScore, |
| } |
| // Make sure the type name matches before considering |
| // candidate. This cuts down on useless candidates. |
| if c.matchingTypeName(&fakeNamedType) { |
| c.deepState.enqueue(fakeNamedType) |
| } |
| } |
| } |
| } |
| |
| // Add keyword completion items appropriate in the current context. |
| c.addKeywordCompletions() |
| |
| return nil |
| } |
| |
| func (c *completer) unimportedPackages(ctx context.Context, seen map[string]struct{}) error { |
| var prefix string |
| if c.surrounding != nil { |
| prefix = c.surrounding.Prefix() |
| } |
| count := 0 |
| |
| known, err := c.snapshot.CachedImportPaths(ctx) |
| if err != nil { |
| return err |
| } |
| var paths []string |
| for path, pkg := range known { |
| if !strings.HasPrefix(pkg.GetTypes().Name(), prefix) { |
| continue |
| } |
| paths = append(paths, path) |
| } |
| |
| var relevances map[string]float64 |
| if len(paths) != 0 { |
| if err := c.snapshot.RunProcessEnvFunc(ctx, func(opts *imports.Options) error { |
| var err error |
| relevances, err = imports.ScoreImportPaths(ctx, opts.Env, paths) |
| return err |
| }); err != nil { |
| return err |
| } |
| } |
| sort.Slice(paths, func(i, j int) bool { |
| return relevances[paths[i]] > relevances[paths[j]] |
| }) |
| |
| for _, path := range paths { |
| pkg := known[path] |
| if _, ok := seen[pkg.GetTypes().Name()]; ok { |
| continue |
| } |
| imp := &importInfo{ |
| importPath: path, |
| pkg: pkg, |
| } |
| if imports.ImportPathToAssumedName(path) != pkg.GetTypes().Name() { |
| imp.name = pkg.GetTypes().Name() |
| } |
| if count >= maxUnimportedPackageNames { |
| return nil |
| } |
| c.deepState.enqueue(candidate{ |
| obj: types.NewPkgName(0, nil, pkg.GetTypes().Name(), pkg.GetTypes()), |
| score: unimportedScore(relevances[path]), |
| imp: imp, |
| }) |
| count++ |
| } |
| |
| ctx, cancel := context.WithCancel(ctx) |
| |
| var mu sync.Mutex |
| add := func(pkg imports.ImportFix) { |
| mu.Lock() |
| defer mu.Unlock() |
| if _, ok := seen[pkg.IdentName]; ok { |
| return |
| } |
| if _, ok := relevances[pkg.StmtInfo.ImportPath]; ok { |
| return |
| } |
| |
| if count >= maxUnimportedPackageNames { |
| cancel() |
| return |
| } |
| |
| // Do not add the unimported packages to seen, since we can have |
| // multiple packages of the same name as completion suggestions, since |
| // only one will be chosen. |
| obj := types.NewPkgName(0, nil, pkg.IdentName, types.NewPackage(pkg.StmtInfo.ImportPath, pkg.IdentName)) |
| c.deepState.enqueue(candidate{ |
| obj: obj, |
| score: unimportedScore(pkg.Relevance), |
| imp: &importInfo{ |
| importPath: pkg.StmtInfo.ImportPath, |
| name: pkg.StmtInfo.Name, |
| }, |
| }) |
| count++ |
| } |
| c.completionCallbacks = append(c.completionCallbacks, func(opts *imports.Options) error { |
| defer cancel() |
| return imports.GetAllCandidates(ctx, add, prefix, c.filename, c.pkg.GetTypes().Name(), opts.Env) |
| }) |
| return nil |
| } |
| |
| // alreadyImports reports whether f has an import with the specified path. |
| func alreadyImports(f *ast.File, path string) bool { |
| for _, s := range f.Imports { |
| if source.ImportPath(s) == path { |
| return true |
| } |
| } |
| return false |
| } |
| |
| func (c *completer) inConstDecl() bool { |
| for _, n := range c.path { |
| if decl, ok := n.(*ast.GenDecl); ok && decl.Tok == token.CONST { |
| return true |
| } |
| } |
| return false |
| } |
| |
| // structLiteralFieldName finds completions for struct field names inside a struct literal. |
| func (c *completer) structLiteralFieldName(ctx context.Context) error { |
| clInfo := c.enclosingCompositeLiteral |
| |
| // Mark fields of the composite literal that have already been set, |
| // except for the current field. |
| addedFields := make(map[*types.Var]bool) |
| for _, el := range clInfo.cl.Elts { |
| if kvExpr, ok := el.(*ast.KeyValueExpr); ok { |
| if clInfo.kv == kvExpr { |
| continue |
| } |
| |
| if key, ok := kvExpr.Key.(*ast.Ident); ok { |
| if used, ok := c.pkg.GetTypesInfo().Uses[key]; ok { |
| if usedVar, ok := used.(*types.Var); ok { |
| addedFields[usedVar] = true |
| } |
| } |
| } |
| } |
| } |
| |
| deltaScore := 0.0001 |
| switch t := clInfo.clType.(type) { |
| case *types.Struct: |
| for i := 0; i < t.NumFields(); i++ { |
| field := t.Field(i) |
| if !addedFields[field] { |
| c.deepState.enqueue(candidate{ |
| obj: field, |
| score: highScore - float64(i)*deltaScore, |
| }) |
| } |
| } |
| |
| // Add lexical completions if we aren't certain we are in the key part of a |
| // key-value pair. |
| if clInfo.maybeInFieldName { |
| return c.lexical(ctx) |
| } |
| default: |
| return c.lexical(ctx) |
| } |
| |
| return nil |
| } |
| |
| func (cl *compLitInfo) isStruct() bool { |
| _, ok := cl.clType.(*types.Struct) |
| return ok |
| } |
| |
| // enclosingCompositeLiteral returns information about the composite literal enclosing the |
| // position. |
| func enclosingCompositeLiteral(path []ast.Node, pos token.Pos, info *types.Info) *compLitInfo { |
| for _, n := range path { |
| switch n := n.(type) { |
| case *ast.CompositeLit: |
| // The enclosing node will be a composite literal if the user has just |
| // opened the curly brace (e.g. &x{<>) or the completion request is triggered |
| // from an already completed composite literal expression (e.g. &x{foo: 1, <>}) |
| // |
| // The position is not part of the composite literal unless it falls within the |
| // curly braces (e.g. "foo.Foo<>Struct{}"). |
| if !(n.Lbrace < pos && pos <= n.Rbrace) { |
| // Keep searching since we may yet be inside a composite literal. |
| // For example "Foo{B: Ba<>{}}". |
| break |
| } |
| |
| tv, ok := info.Types[n] |
| if !ok { |
| return nil |
| } |
| |
| clInfo := compLitInfo{ |
| cl: n, |
| clType: source.Deref(tv.Type).Underlying(), |
| } |
| |
| var ( |
| expr ast.Expr |
| hasKeys bool |
| ) |
| for _, el := range n.Elts { |
| // Remember the expression that the position falls in, if any. |
| if el.Pos() <= pos && pos <= el.End() { |
| expr = el |
| } |
| |
| if kv, ok := el.(*ast.KeyValueExpr); ok { |
| hasKeys = true |
| // If expr == el then we know the position falls in this expression, |
| // so also record kv as the enclosing *ast.KeyValueExpr. |
| if expr == el { |
| clInfo.kv = kv |
| break |
| } |
| } |
| } |
| |
| if clInfo.kv != nil { |
| // If in a *ast.KeyValueExpr, we know we are in the key if the position |
| // is to the left of the colon (e.g. "Foo{F<>: V}". |
| clInfo.inKey = pos <= clInfo.kv.Colon |
| } else if hasKeys { |
| // If we aren't in a *ast.KeyValueExpr but the composite literal has |
| // other *ast.KeyValueExprs, we must be on the key side of a new |
| // *ast.KeyValueExpr (e.g. "Foo{F: V, <>}"). |
| clInfo.inKey = true |
| } else { |
| switch clInfo.clType.(type) { |
| case *types.Struct: |
| if len(n.Elts) == 0 { |
| // If the struct literal is empty, next could be a struct field |
| // name or an expression (e.g. "Foo{<>}" could become "Foo{F:}" |
| // or "Foo{someVar}"). |
| clInfo.maybeInFieldName = true |
| } else if len(n.Elts) == 1 { |
| // If there is one expression and the position is in that expression |
| // and the expression is an identifier, we may be writing a field |
| // name or an expression (e.g. "Foo{F<>}"). |
| _, clInfo.maybeInFieldName = expr.(*ast.Ident) |
| } |
| case *types.Map: |
| // If we aren't in a *ast.KeyValueExpr we must be adding a new key |
| // to the map. |
| clInfo.inKey = true |
| } |
| } |
| |
| return &clInfo |
| default: |
| if breaksExpectedTypeInference(n, pos) { |
| return nil |
| } |
| } |
| } |
| |
| return nil |
| } |
| |
| // enclosingFunction returns the signature and body of the function |
| // enclosing the given position. |
| func enclosingFunction(path []ast.Node, info *types.Info) *funcInfo { |
| for _, node := range path { |
| switch t := node.(type) { |
| case *ast.FuncDecl: |
| if obj, ok := info.Defs[t.Name]; ok { |
| return &funcInfo{ |
| sig: obj.Type().(*types.Signature), |
| body: t.Body, |
| } |
| } |
| case *ast.FuncLit: |
| if typ, ok := info.Types[t]; ok { |
| return &funcInfo{ |
| sig: typ.Type.(*types.Signature), |
| body: t.Body, |
| } |
| } |
| } |
| } |
| return nil |
| } |
| |
| func (c *completer) expectedCompositeLiteralType() types.Type { |
| clInfo := c.enclosingCompositeLiteral |
| switch t := clInfo.clType.(type) { |
| case *types.Slice: |
| if clInfo.inKey { |
| return types.Typ[types.Int] |
| } |
| return t.Elem() |
| case *types.Array: |
| if clInfo.inKey { |
| return types.Typ[types.Int] |
| } |
| return t.Elem() |
| case *types.Map: |
| if clInfo.inKey { |
| return t.Key() |
| } |
| return t.Elem() |
| case *types.Struct: |
| // If we are completing a key (i.e. field name), there is no expected type. |
| if clInfo.inKey { |
| return nil |
| } |
| |
| // If we are in a key-value pair, but not in the key, then we must be on the |
| // value side. The expected type of the value will be determined from the key. |
| if clInfo.kv != nil { |
| if key, ok := clInfo.kv.Key.(*ast.Ident); ok { |
| for i := 0; i < t.NumFields(); i++ { |
| if field := t.Field(i); field.Name() == key.Name { |
| return field.Type() |
| } |
| } |
| } |
| } else { |
| // If we aren't in a key-value pair and aren't in the key, we must be using |
| // implicit field names. |
| |
| // The order of the literal fields must match the order in the struct definition. |
| // Find the element that the position belongs to and suggest that field's type. |
| if i := exprAtPos(c.pos, clInfo.cl.Elts); i < t.NumFields() { |
| return t.Field(i).Type() |
| } |
| } |
| } |
| return nil |
| } |
| |
| // typeModifier represents an operator that changes the expected type. |
| type typeModifier struct { |
| mod typeMod |
| arrayLen int64 |
| } |
| |
| type typeMod int |
| |
| const ( |
| dereference typeMod = iota // pointer indirection: "*" |
| reference // adds level of pointer: "&" for values, "*" for type names |
| chanRead // channel read operator ("<-") |
| slice // make a slice type ("[]" in "[]int") |
| array // make an array type ("[2]" in "[2]int") |
| ) |
| |
| type objKind int |
| |
| const ( |
| kindAny objKind = 0 |
| kindArray objKind = 1 << iota |
| kindSlice |
| kindChan |
| kindMap |
| kindStruct |
| kindString |
| kindInt |
| kindBool |
| kindBytes |
| kindPtr |
| kindFloat |
| kindComplex |
| kindError |
| kindStringer |
| kindFunc |
| ) |
| |
| // penalizedObj represents an object that should be disfavored as a |
| // completion candidate. |
| type penalizedObj struct { |
| // objChain is the full "chain", e.g. "foo.bar().baz" becomes |
| // []types.Object{foo, bar, baz}. |
| objChain []types.Object |
| // penalty is score penalty in the range (0, 1). |
| penalty float64 |
| } |
| |
| // candidateInference holds information we have inferred about a type that can be |
| // used at the current position. |
| type candidateInference struct { |
| // objType is the desired type of an object used at the query position. |
| objType types.Type |
| |
| // objKind is a mask of expected kinds of types such as "map", "slice", etc. |
| objKind objKind |
| |
| // variadic is true if we are completing the initial variadic |
| // parameter. For example: |
| // append([]T{}, <>) // objType=T variadic=true |
| // append([]T{}, T{}, <>) // objType=T variadic=false |
| variadic bool |
| |
| // modifiers are prefixes such as "*", "&" or "<-" that influence how |
| // a candidate type relates to the expected type. |
| modifiers []typeModifier |
| |
| // convertibleTo is a type our candidate type must be convertible to. |
| convertibleTo types.Type |
| |
| // typeName holds information about the expected type name at |
| // position, if any. |
| typeName typeNameInference |
| |
| // assignees are the types that would receive a function call's |
| // results at the position. For example: |
| // |
| // foo := 123 |
| // foo, bar := <> |
| // |
| // at "<>", the assignees are [int, <invalid>]. |
| assignees []types.Type |
| |
| // variadicAssignees is true if we could be completing an inner |
| // function call that fills out an outer function call's variadic |
| // params. For example: |
| // |
| // func foo(int, ...string) {} |
| // |
| // foo(<>) // variadicAssignees=true |
| // foo(bar<>) // variadicAssignees=true |
| // foo(bar, baz<>) // variadicAssignees=false |
| variadicAssignees bool |
| |
| // penalized holds expressions that should be disfavored as |
| // candidates. For example, it tracks expressions already used in a |
| // switch statement's other cases. Each expression is tracked using |
| // its entire object "chain" allowing differentiation between |
| // "a.foo" and "b.foo" when "a" and "b" are the same type. |
| penalized []penalizedObj |
| |
| // objChain contains the chain of objects representing the |
| // surrounding *ast.SelectorExpr. For example, if we are completing |
| // "foo.bar.ba<>", objChain will contain []types.Object{foo, bar}. |
| objChain []types.Object |
| } |
| |
| // typeNameInference holds information about the expected type name at |
| // position. |
| type typeNameInference struct { |
| // wantTypeName is true if we expect the name of a type. |
| wantTypeName bool |
| |
| // modifiers are prefixes such as "*", "&" or "<-" that influence how |
| // a candidate type relates to the expected type. |
| modifiers []typeModifier |
| |
| // assertableFrom is a type that must be assertable to our candidate type. |
| assertableFrom types.Type |
| |
| // wantComparable is true if we want a comparable type. |
| wantComparable bool |
| |
| // seenTypeSwitchCases tracks types that have already been used by |
| // the containing type switch. |
| seenTypeSwitchCases []types.Type |
| |
| // compLitType is true if we are completing a composite literal type |
| // name, e.g "foo<>{}". |
| compLitType bool |
| } |
| |
| // expectedCandidate returns information about the expected candidate |
| // for an expression at the query position. |
| func expectedCandidate(ctx context.Context, c *completer) (inf candidateInference) { |
| inf.typeName = expectTypeName(c) |
| |
| if c.enclosingCompositeLiteral != nil { |
| inf.objType = c.expectedCompositeLiteralType() |
| } |
| |
| Nodes: |
| for i, node := range c.path { |
| switch node := node.(type) { |
| case *ast.BinaryExpr: |
| // Determine if query position comes from left or right of op. |
| e := node.X |
| if c.pos < node.OpPos { |
| e = node.Y |
| } |
| if tv, ok := c.pkg.GetTypesInfo().Types[e]; ok { |
| switch node.Op { |
| case token.LAND, token.LOR: |
| // Don't infer "bool" type for "&&" or "||". Often you want |
| // to compose a boolean expression from non-boolean |
| // candidates. |
| default: |
| inf.objType = tv.Type |
| } |
| break Nodes |
| } |
| case *ast.AssignStmt: |
| // Only rank completions if you are on the right side of the token. |
| if c.pos > node.TokPos { |
| i := exprAtPos(c.pos, node.Rhs) |
| if i >= len(node.Lhs) { |
| i = len(node.Lhs) - 1 |
| } |
| if tv, ok := c.pkg.GetTypesInfo().Types[node.Lhs[i]]; ok { |
| inf.objType = tv.Type |
| } |
| |
| // If we have a single expression on the RHS, record the LHS |
| // assignees so we can favor multi-return function calls with |
| // matching result values. |
| if len(node.Rhs) <= 1 { |
| for _, lhs := range node.Lhs { |
| inf.assignees = append(inf.assignees, c.pkg.GetTypesInfo().TypeOf(lhs)) |
| } |
| } else { |
| // Otherwse, record our single assignee, even if its type is |
| // not available. We use this info to downrank functions |
| // with the wrong number of result values. |
| inf.assignees = append(inf.assignees, c.pkg.GetTypesInfo().TypeOf(node.Lhs[i])) |
| } |
| } |
| return inf |
| case *ast.ValueSpec: |
| if node.Type != nil && c.pos > node.Type.End() { |
| inf.objType = c.pkg.GetTypesInfo().TypeOf(node.Type) |
| } |
| return inf |
| case *ast.CallExpr: |
| // Only consider CallExpr args if position falls between parens. |
| if node.Lparen < c.pos && c.pos <= node.Rparen { |
| // For type conversions like "int64(foo)" we can only infer our |
| // desired type is convertible to int64. |
| if typ := typeConversion(node, c.pkg.GetTypesInfo()); typ != nil { |
| inf.convertibleTo = typ |
| break Nodes |
| } |
| |
| if tv, ok := c.pkg.GetTypesInfo().Types[node.Fun]; ok { |
| if sig, ok := tv.Type.(*types.Signature); ok { |
| numParams := sig.Params().Len() |
| if numParams == 0 { |
| return inf |
| } |
| |
| exprIdx := exprAtPos(c.pos, node.Args) |
| |
| // If we have one or zero arg expressions, we may be |
| // completing to a function call that returns multiple |
| // values, in turn getting passed in to the surrounding |
| // call. Record the assignees so we can favor function |
| // calls that return matching values. |
| if len(node.Args) <= 1 && exprIdx == 0 { |
| for i := 0; i < sig.Params().Len(); i++ { |
| inf.assignees = append(inf.assignees, sig.Params().At(i).Type()) |
| } |
| |
| // Record that we may be completing into variadic parameters. |
| inf.variadicAssignees = sig.Variadic() |
| } |
| |
| // Make sure not to run past the end of expected parameters. |
| if exprIdx >= numParams { |
| inf.objType = sig.Params().At(numParams - 1).Type() |
| } else { |
| inf.objType = sig.Params().At(exprIdx).Type() |
| } |
| |
| if sig.Variadic() && exprIdx >= (numParams-1) { |
| // If we are completing a variadic param, deslice the variadic type. |
| inf.objType = deslice(inf.objType) |
| // Record whether we are completing the initial variadic param. |
| inf.variadic = exprIdx == numParams-1 && len(node.Args) <= numParams |
| |
| // Check if we can infer object kind from printf verb. |
| inf.objKind |= printfArgKind(c.pkg.GetTypesInfo(), node, exprIdx) |
| } |
| } |
| } |
| |
| if funIdent, ok := node.Fun.(*ast.Ident); ok { |
| obj := c.pkg.GetTypesInfo().ObjectOf(funIdent) |
| |
| if obj != nil && obj.Parent() == types.Universe { |
| // Defer call to builtinArgType so we can provide it the |
| // inferred type from its parent node. |
| defer func() { |
| inf = c.builtinArgType(obj, node, inf) |
| inf.objKind = c.builtinArgKind(ctx, obj, node) |
| }() |
| |
| // The expected type of builtin arguments like append() is |
| // the expected type of the builtin call itself. For |
| // example: |
| // |
| // var foo []int = append(<>) |
| // |
| // To find the expected type at <> we "skip" the append() |
| // node and get the expected type one level up, which is |
| // []int. |
| continue Nodes |
| } |
| } |
| |
| return inf |
| } |
| case *ast.ReturnStmt: |
| if c.enclosingFunc != nil { |
| sig := c.enclosingFunc.sig |
| // Find signature result that corresponds to our return statement. |
| if resultIdx := exprAtPos(c.pos, node.Results); resultIdx < len(node.Results) { |
| if resultIdx < sig.Results().Len() { |
| inf.objType = sig.Results().At(resultIdx).Type() |
| } |
| } |
| } |
| return inf |
| case *ast.CaseClause: |
| if swtch, ok := findSwitchStmt(c.path[i+1:], c.pos, node).(*ast.SwitchStmt); ok { |
| if tv, ok := c.pkg.GetTypesInfo().Types[swtch.Tag]; ok { |
| inf.objType = tv.Type |
| |
| // Record which objects have already been used in the case |
| // statements so we don't suggest them again. |
| for _, cc := range swtch.Body.List { |
| for _, caseExpr := range cc.(*ast.CaseClause).List { |
| // Don't record the expression we are currently completing. |
| if caseExpr.Pos() < c.pos && c.pos <= caseExpr.End() { |
| continue |
| } |
| |
| if objs := objChain(c.pkg.GetTypesInfo(), caseExpr); len(objs) > 0 { |
| inf.penalized = append(inf.penalized, penalizedObj{objChain: objs, penalty: 0.1}) |
| } |
| } |
| } |
| } |
| } |
| return inf |
| case *ast.SliceExpr: |
| // Make sure position falls within the brackets (e.g. "foo[a:<>]"). |
| if node.Lbrack < c.pos && c.pos <= node.Rbrack { |
| inf.objType = types.Typ[types.Int] |
| } |
| return inf |
| case *ast.IndexExpr: |
| // Make sure position falls within the brackets (e.g. "foo[<>]"). |
| if node.Lbrack < c.pos && c.pos <= node.Rbrack { |
| if tv, ok := c.pkg.GetTypesInfo().Types[node.X]; ok { |
| switch t := tv.Type.Underlying().(type) { |
| case *types.Map: |
| inf.objType = t.Key() |
| case *types.Slice, *types.Array: |
| inf.objType = types.Typ[types.Int] |
| } |
| } |
| } |
| return inf |
| case *ast.SendStmt: |
| // Make sure we are on right side of arrow (e.g. "foo <- <>"). |
| if c.pos > node.Arrow+1 { |
| if tv, ok := c.pkg.GetTypesInfo().Types[node.Chan]; ok { |
| if ch, ok := tv.Type.Underlying().(*types.Chan); ok { |
| inf.objType = ch.Elem() |
| } |
| } |
| } |
| return inf |
| case *ast.RangeStmt: |
| if source.NodeContains(node.X, c.pos) { |
| inf.objKind |= kindSlice | kindArray | kindMap | kindString |
| if node.Value == nil { |
| inf.objKind |= kindChan |
| } |
| } |
| return inf |
| case *ast.StarExpr: |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: dereference}) |
| case *ast.UnaryExpr: |
| switch node.Op { |
| case token.AND: |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: reference}) |
| case token.ARROW: |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: chanRead}) |
| } |
| case *ast.DeferStmt, *ast.GoStmt: |
| inf.objKind |= kindFunc |
| return inf |
| default: |
| if breaksExpectedTypeInference(node, c.pos) { |
| return inf |
| } |
| } |
| } |
| |
| return inf |
| } |
| |
| // objChain decomposes e into a chain of objects if possible. For |
| // example, "foo.bar().baz" will yield []types.Object{foo, bar, baz}. |
| // If any part can't be turned into an object, return nil. |
| func objChain(info *types.Info, e ast.Expr) []types.Object { |
| var objs []types.Object |
| |
| for e != nil { |
| switch n := e.(type) { |
| case *ast.Ident: |
| obj := info.ObjectOf(n) |
| if obj == nil { |
| return nil |
| } |
| objs = append(objs, obj) |
| e = nil |
| case *ast.SelectorExpr: |
| obj := info.ObjectOf(n.Sel) |
| if obj == nil { |
| return nil |
| } |
| objs = append(objs, obj) |
| e = n.X |
| case *ast.CallExpr: |
| if len(n.Args) > 0 { |
| return nil |
| } |
| e = n.Fun |
| default: |
| return nil |
| } |
| } |
| |
| // Reverse order so the layout matches the syntactic order. |
| for i := 0; i < len(objs)/2; i++ { |
| objs[i], objs[len(objs)-1-i] = objs[len(objs)-1-i], objs[i] |
| } |
| |
| return objs |
| } |
| |
| // applyTypeModifiers applies the list of type modifiers to a type. |
| // It returns nil if the modifiers could not be applied. |
| func (ci candidateInference) applyTypeModifiers(typ types.Type, addressable bool) types.Type { |
| for _, mod := range ci.modifiers { |
| switch mod.mod { |
| case dereference: |
| // For every "*" indirection operator, remove a pointer layer |
| // from candidate type. |
| if ptr, ok := typ.Underlying().(*types.Pointer); ok { |
| typ = ptr.Elem() |
| } else { |
| return nil |
| } |
| case reference: |
| // For every "&" address operator, add another pointer layer to |
| // candidate type, if the candidate is addressable. |
| if addressable { |
| typ = types.NewPointer(typ) |
| } else { |
| return nil |
| } |
| case chanRead: |
| // For every "<-" operator, remove a layer of channelness. |
| if ch, ok := typ.(*types.Chan); ok { |
| typ = ch.Elem() |
| } else { |
| return nil |
| } |
| } |
| } |
| |
| return typ |
| } |
| |
| // applyTypeNameModifiers applies the list of type modifiers to a type name. |
| func (ci candidateInference) applyTypeNameModifiers(typ types.Type) types.Type { |
| for _, mod := range ci.typeName.modifiers { |
| switch mod.mod { |
| case reference: |
| typ = types.NewPointer(typ) |
| case array: |
| typ = types.NewArray(typ, mod.arrayLen) |
| case slice: |
| typ = types.NewSlice(typ) |
| } |
| } |
| return typ |
| } |
| |
| // matchesVariadic returns true if we are completing a variadic |
| // parameter and candType is a compatible slice type. |
| func (ci candidateInference) matchesVariadic(candType types.Type) bool { |
| return ci.variadic && ci.objType != nil && types.AssignableTo(candType, types.NewSlice(ci.objType)) |
| } |
| |
| // findSwitchStmt returns an *ast.CaseClause's corresponding *ast.SwitchStmt or |
| // *ast.TypeSwitchStmt. path should start from the case clause's first ancestor. |
| func findSwitchStmt(path []ast.Node, pos token.Pos, c *ast.CaseClause) ast.Stmt { |
| // Make sure position falls within a "case <>:" clause. |
| if exprAtPos(pos, c.List) >= len(c.List) { |
| return nil |
| } |
| // A case clause is always nested within a block statement in a switch statement. |
| if len(path) < 2 { |
| return nil |
| } |
| if _, ok := path[0].(*ast.BlockStmt); !ok { |
| return nil |
| } |
| switch s := path[1].(type) { |
| case *ast.SwitchStmt: |
| return s |
| case *ast.TypeSwitchStmt: |
| return s |
| default: |
| return nil |
| } |
| } |
| |
| // breaksExpectedTypeInference reports if an expression node's type is unrelated |
| // to its child expression node types. For example, "Foo{Bar: x.Baz(<>)}" should |
| // expect a function argument, not a composite literal value. |
| func breaksExpectedTypeInference(n ast.Node, pos token.Pos) bool { |
| switch n := n.(type) { |
| case *ast.CompositeLit: |
| // Doesn't break inference if pos is in type name. |
| // For example: "Foo<>{Bar: 123}" |
| return !source.NodeContains(n.Type, pos) |
| case *ast.CallExpr: |
| // Doesn't break inference if pos is in func name. |
| // For example: "Foo<>(123)" |
| return !source.NodeContains(n.Fun, pos) |
| case *ast.FuncLit, *ast.IndexExpr, *ast.SliceExpr: |
| return true |
| default: |
| return false |
| } |
| } |
| |
| // expectTypeName returns information about the expected type name at position. |
| func expectTypeName(c *completer) typeNameInference { |
| var inf typeNameInference |
| |
| Nodes: |
| for i, p := range c.path { |
| switch n := p.(type) { |
| case *ast.FieldList: |
| // Expect a type name if pos is in a FieldList. This applies to |
| // FuncType params/results, FuncDecl receiver, StructType, and |
| // InterfaceType. We don't need to worry about the field name |
| // because completion bails out early if pos is in an *ast.Ident |
| // that defines an object. |
| inf.wantTypeName = true |
| break Nodes |
| case *ast.CaseClause: |
| // Expect type names in type switch case clauses. |
| if swtch, ok := findSwitchStmt(c.path[i+1:], c.pos, n).(*ast.TypeSwitchStmt); ok { |
| // The case clause types must be assertable from the type switch parameter. |
| ast.Inspect(swtch.Assign, func(n ast.Node) bool { |
| if ta, ok := n.(*ast.TypeAssertExpr); ok { |
| inf.assertableFrom = c.pkg.GetTypesInfo().TypeOf(ta.X) |
| return false |
| } |
| return true |
| }) |
| inf.wantTypeName = true |
| |
| // Track the types that have already been used in this |
| // switch's case statements so we don't recommend them. |
| for _, e := range swtch.Body.List { |
| for _, typeExpr := range e.(*ast.CaseClause).List { |
| // Skip if type expression contains pos. We don't want to |
| // count it as already used if the user is completing it. |
| if typeExpr.Pos() < c.pos && c.pos <= typeExpr.End() { |
| continue |
| } |
| |
| if t := c.pkg.GetTypesInfo().TypeOf(typeExpr); t != nil { |
| inf.seenTypeSwitchCases = append(inf.seenTypeSwitchCases, t) |
| } |
| } |
| } |
| |
| break Nodes |
| } |
| return typeNameInference{} |
| case *ast.TypeAssertExpr: |
| // Expect type names in type assert expressions. |
| if n.Lparen < c.pos && c.pos <= n.Rparen { |
| // The type in parens must be assertable from the expression type. |
| inf.assertableFrom = c.pkg.GetTypesInfo().TypeOf(n.X) |
| inf.wantTypeName = true |
| break Nodes |
| } |
| return typeNameInference{} |
| case *ast.StarExpr: |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: reference}) |
| case *ast.CompositeLit: |
| // We want a type name if position is in the "Type" part of a |
| // composite literal (e.g. "Foo<>{}"). |
| if n.Type != nil && n.Type.Pos() <= c.pos && c.pos <= n.Type.End() { |
| inf.wantTypeName = true |
| inf.compLitType = true |
| |
| if i < len(c.path)-1 { |
| // Track preceding "&" operator. Technically it applies to |
| // the composite literal and not the type name, but if |
| // affects our type completion nonetheless. |
| if u, ok := c.path[i+1].(*ast.UnaryExpr); ok && u.Op == token.AND { |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: reference}) |
| } |
| } |
| } |
| break Nodes |
| case *ast.ArrayType: |
| // If we are inside the "Elt" part of an array type, we want a type name. |
| if n.Elt.Pos() <= c.pos && c.pos <= n.Elt.End() { |
| inf.wantTypeName = true |
| if n.Len == nil { |
| // No "Len" expression means a slice type. |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: slice}) |
| } else { |
| // Try to get the array type using the constant value of "Len". |
| tv, ok := c.pkg.GetTypesInfo().Types[n.Len] |
| if ok && tv.Value != nil && tv.Value.Kind() == constant.Int { |
| if arrayLen, ok := constant.Int64Val(tv.Value); ok { |
| inf.modifiers = append(inf.modifiers, typeModifier{mod: array, arrayLen: arrayLen}) |
| } |
| } |
| } |
| |
| // ArrayTypes can be nested, so keep going if our parent is an |
| // ArrayType. |
| if i < len(c.path)-1 { |
| if _, ok := c.path[i+1].(*ast.ArrayType); ok { |
| continue Nodes |
| } |
| } |
| |
| break Nodes |
| } |
| case *ast.MapType: |
| inf.wantTypeName = true |
| if n.Key != nil { |
| inf.wantComparable = source.NodeContains(n.Key, c.pos) |
| } else { |
| // If the key is empty, assume we are completing the key if |
| // pos is directly after the "map[". |
| inf.wantComparable = c.pos == n.Pos()+token.Pos(len("map[")) |
| } |
| break Nodes |
| case *ast.ValueSpec: |
| inf.wantTypeName = source.NodeContains(n.Type, c.pos) |
| break Nodes |
| case *ast.TypeSpec: |
| inf.wantTypeName = source.NodeContains(n.Type, c.pos) |
| default: |
| if breaksExpectedTypeInference(p, c.pos) { |
| return typeNameInference{} |
| } |
| } |
| } |
| |
| return inf |
| } |
| |
| func (c *completer) fakeObj(T types.Type) *types.Var { |
| return types.NewVar(token.NoPos, c.pkg.GetTypes(), "", T) |
| } |
| |
| // anyCandType reports whether f returns true for any candidate type |
| // derivable from c. For example, from "foo" we might derive "&foo", |
| // and "foo()". |
| func (c *candidate) anyCandType(f func(t types.Type, addressable bool) bool) bool { |
| if c.obj == nil || c.obj.Type() == nil { |
| return false |
| } |
| |
| objType := c.obj.Type() |
| |
| if f(objType, c.addressable) { |
| return true |
| } |
| |
| // If c is a func type with a single result, offer the result type. |
| if sig, ok := objType.Underlying().(*types.Signature); ok { |
| if sig.Results().Len() == 1 && f(sig.Results().At(0).Type(), false) { |
| // Mark the candidate so we know to append "()" when formatting. |
| c.expandFuncCall = true |
| return true |
| } |
| } |
| |
| var ( |
| seenPtrTypes map[types.Type]bool |
| ptrType = objType |
| ptrDepth int |
| ) |
| |
| // Check if dereferencing c would match our type inference. We loop |
| // since c could have arbitrary levels of pointerness. |
| for { |
| ptr, ok := ptrType.Underlying().(*types.Pointer) |
| if !ok { |
| break |
| } |
| |
| ptrDepth++ |
| |
| // Avoid pointer type cycles. |
| if seenPtrTypes[ptrType] { |
| break |
| } |
| |
| if _, named := ptrType.(*types.Named); named { |
| // Lazily allocate "seen" since it isn't used normally. |
| if seenPtrTypes == nil { |
| seenPtrTypes = make(map[types.Type]bool) |
| } |
| |
| // Track named pointer types we have seen to detect cycles. |
| seenPtrTypes[ptrType] = true |
| } |
| |
| if f(ptr.Elem(), false) { |
| // Mark the candidate so we know to prepend "*" when formatting. |
| c.dereference = ptrDepth |
| return true |
| } |
| |
| ptrType = ptr.Elem() |
| } |
| |
| // Check if c is addressable and a pointer to c matches our type inference. |
| if c.addressable && f(types.NewPointer(objType), false) { |
| // Mark the candidate so we know to prepend "&" when formatting. |
| c.takeAddress = true |
| return true |
| } |
| |
| return false |
| } |
| |
| // matchingCandidate reports whether cand matches our type inferences. |
| // It mutates cand's score in certain cases. |
| func (c *completer) matchingCandidate(cand *candidate) bool { |
| if c.completionContext.commentCompletion { |
| return false |
| } |
| |
| if isTypeName(cand.obj) { |
| return c.matchingTypeName(cand) |
| } else if c.wantTypeName() { |
| // If we want a type, a non-type object never matches. |
| return false |
| } |
| |
| if c.inference.candTypeMatches(cand) { |
| return true |
| } |
| |
| candType := cand.obj.Type() |
| if candType == nil { |
| return false |
| } |
| |
| if sig, ok := candType.Underlying().(*types.Signature); ok { |
| if c.inference.assigneesMatch(cand, sig) { |
| // Invoke the candidate if its results are multi-assignable. |
| cand.expandFuncCall = true |
| return true |
| } |
| } |
| |
| // Default to invoking *types.Func candidates. This is so function |
| // completions in an empty statement (or other cases with no expected type) |
| // are invoked by default. |
| cand.expandFuncCall = isFunc(cand.obj) |
| |
| return false |
| } |
| |
| // candTypeMatches reports whether cand makes a good completion |
| // candidate given the candidate inference. cand's score may be |
| // mutated to downrank the candidate in certain situations. |
| func (ci *candidateInference) candTypeMatches(cand *candidate) bool { |
| var ( |
| expTypes = make([]types.Type, 0, 2) |
| variadicType types.Type |
| ) |
| if ci.objType != nil { |
| expTypes = append(expTypes, ci.objType) |
| |
| if ci.variadic { |
| variadicType = types.NewSlice(ci.objType) |
| expTypes = append(expTypes, variadicType) |
| } |
| } |
| |
| return cand.anyCandType(func(candType types.Type, addressable bool) bool { |
| // Take into account any type modifiers on the expected type. |
| candType = ci.applyTypeModifiers(candType, addressable) |
| if candType == nil { |
| return false |
| } |
| |
| if ci.convertibleTo != nil && types.ConvertibleTo(candType, ci.convertibleTo) { |
| return true |
| } |
| |
| for _, expType := range expTypes { |
| if isEmptyInterface(expType) { |
| continue |
| } |
| |
| matches, untyped := ci.typeMatches(expType, candType) |
| if !matches { |
| continue |
| } |
| |
| if expType == variadicType { |
| cand.variadic = true |
| } |
| |
| // Lower candidate score for untyped conversions. This avoids |
| // ranking untyped constants above candidates with an exact type |
| // match. Don't lower score of builtin constants, e.g. "true". |
| if untyped && !types.Identical(candType, expType) && cand.obj.Parent() != types.Universe { |
| cand.score /= 2 |
| } |
| |
| return true |
| } |
| |
| // If we don't have a specific expected type, fall back to coarser |
| // object kind checks. |
| if ci.objType == nil || isEmptyInterface(ci.objType) { |
| // If we were able to apply type modifiers to our candidate type, |
| // count that as a match. For example: |
| // |
| // var foo chan int |
| // <-fo<> |
| // |
| // We were able to apply the "<-" type modifier to "foo", so "foo" |
| // matches. |
| if len(ci.modifiers) > 0 { |
| return true |
| } |
| |
| // If we didn't have an exact type match, check if our object kind |
| // matches. |
| if ci.kindMatches(candType) { |
| if ci.objKind == kindFunc { |
| cand.expandFuncCall = true |
| } |
| return true |
| } |
| } |
| |
| return false |
| }) |
| } |
| |
| // typeMatches reports whether an object of candType makes a good |
| // completion candidate given the expected type expType. It also |
| // returns a second bool which is true if both types are basic types |
| // of the same kind, and at least one is untyped. |
| func (ci *candidateInference) typeMatches(expType, candType types.Type) (bool, bool) { |
| // Handle untyped values specially since AssignableTo gives false negatives |
| // for them (see https://golang.org/issue/32146). |
| if candBasic, ok := candType.Underlying().(*types.Basic); ok { |
| if wantBasic, ok := expType.Underlying().(*types.Basic); ok { |
| // Make sure at least one of them is untyped. |
| if isUntyped(candType) || isUntyped(expType) { |
| // Check that their constant kind (bool|int|float|complex|string) matches. |
| // This doesn't take into account the constant value, so there will be some |
| // false positives due to integer sign and overflow. |
| if candBasic.Info()&types.IsConstType == wantBasic.Info()&types.IsConstType { |
| return true, true |
| } |
| } |
| } |
| } |
| |
| // AssignableTo covers the case where the types are equal, but also handles |
| // cases like assigning a concrete type to an interface type. |
| return types.AssignableTo(candType, expType), false |
| } |
| |
| // kindMatches reports whether candType's kind matches our expected |
| // kind (e.g. slice, map, etc.). |
| func (ci *candidateInference) kindMatches(candType types.Type) bool { |
| return ci.objKind > 0 && ci.objKind&candKind(candType) > 0 |
| } |
| |
| // assigneesMatch reports whether an invocation of sig matches the |
| // number and type of any assignees. |
| func (ci *candidateInference) assigneesMatch(cand *candidate, sig *types.Signature) bool { |
| if len(ci.assignees) == 0 { |
| return false |
| } |
| |
| // Uniresult functions are always usable and are handled by the |
| // normal, non-assignees type matching logic. |
| if sig.Results().Len() == 1 { |
| return false |
| } |
| |
| var numberOfResultsCouldMatch bool |
| if ci.variadicAssignees { |
| numberOfResultsCouldMatch = sig.Results().Len() >= len(ci.assignees)-1 |
| } else { |
| numberOfResultsCouldMatch = sig.Results().Len() == len(ci.assignees) |
| } |
| |
| // If our signature doesn't return the right number of values, it's |
| // not a match, so downrank it. For example: |
| // |
| // var foo func() (int, int) |
| // a, b, c := <> // downrank "foo()" since it only returns two values |
| if !numberOfResultsCouldMatch { |
| cand.score /= 2 |
| return false |
| } |
| |
| // If at least one assignee has a valid type, and all valid |
| // assignees match the corresponding sig result value, the signature |
| // is a match. |
| allMatch := false |
| for i := 0; i < sig.Results().Len(); i++ { |
| var assignee types.Type |
| |
| // If we are completing into variadic parameters, deslice the |
| // expected variadic type. |
| if ci.variadicAssignees && i >= len(ci.assignees)-1 { |
| assignee = ci.assignees[len(ci.assignees)-1] |
| if elem := deslice(assignee); elem != nil { |
| assignee = elem |
| } |
| } else { |
| assignee = ci.assignees[i] |
| } |
| |
| if assignee == nil { |
| continue |
| } |
| |
| allMatch, _ = ci.typeMatches(assignee, sig.Results().At(i).Type()) |
| if !allMatch { |
| break |
| } |
| } |
| return allMatch |
| } |
| |
| func (c *completer) matchingTypeName(cand *candidate) bool { |
| if !c.wantTypeName() { |
| return false |
| } |
| |
| typeMatches := func(candType types.Type) bool { |
| // Take into account any type name modifier prefixes. |
| candType = c.inference.applyTypeNameModifiers(candType) |
| |
| if from := c.inference.typeName.assertableFrom; from != nil { |
| // Don't suggest the starting type in type assertions. For example, |
| // if "foo" is an io.Writer, don't suggest "foo.(io.Writer)". |
| if types.Identical(from, candType) { |
| return false |
| } |
| |
| if intf, ok := from.Underlying().(*types.Interface); ok { |
| if !types.AssertableTo(intf, candType) { |
| return false |
| } |
| } |
| } |
| |
| if c.inference.typeName.wantComparable && !types.Comparable(candType) { |
| return false |
| } |
| |
| // Skip this type if it has already been used in another type |
| // switch case. |
| for _, seen := range c.inference.typeName.seenTypeSwitchCases { |
| if types.Identical(candType, seen) { |
| return false |
| } |
| } |
| |
| // We can expect a type name and have an expected type in cases like: |
| // |
| // var foo []int |
| // foo = []i<> |
| // |
| // Where our expected type is "[]int", and we expect a type name. |
| if c.inference.objType != nil { |
| return types.AssignableTo(candType, c.inference.objType) |
| } |
| |
| // Default to saying any type name is a match. |
| return true |
| } |
| |
| t := cand.obj.Type() |
| |
| if typeMatches(t) { |
| return true |
| } |
| |
| if !source.IsInterface(t) && typeMatches(types.NewPointer(t)) { |
| if c.inference.typeName.compLitType { |
| // If we are completing a composite literal type as in |
| // "foo<>{}", to make a pointer we must prepend "&". |
| cand.takeAddress = true |
| } else { |
| // If we are completing a normal type name such as "foo<>", to |
| // make a pointer we must prepend "*". |
| cand.makePointer = true |
| } |
| return true |
| } |
| |
| return false |
| } |
| |
| var ( |
| // "interface { Error() string }" (i.e. error) |
| errorIntf = types.Universe.Lookup("error").Type().Underlying().(*types.Interface) |
| |
| // "interface { String() string }" (i.e. fmt.Stringer) |
| stringerIntf = types.NewInterfaceType([]*types.Func{ |
| types.NewFunc(token.NoPos, nil, "String", types.NewSignature( |
| nil, |
| nil, |
| types.NewTuple(types.NewParam(token.NoPos, nil, "", types.Typ[types.String])), |
| false, |
| )), |
| }, nil).Complete() |
| |
| byteType = types.Universe.Lookup("byte").Type() |
| ) |
| |
| // candKind returns the objKind of candType, if any. |
| func candKind(candType types.Type) objKind { |
| var kind objKind |
| |
| switch t := candType.Underlying().(type) { |
| case *types.Array: |
| kind |= kindArray |
| if t.Elem() == byteType { |
| kind |= kindBytes |
| } |
| case *types.Slice: |
| kind |= kindSlice |
| if t.Elem() == byteType { |
| kind |= kindBytes |
| } |
| case *types.Chan: |
| kind |= kindChan |
| case *types.Map: |
| kind |= kindMap |
| case *types.Pointer: |
| kind |= kindPtr |
| |
| // Some builtins handle array pointers as arrays, so just report a pointer |
| // to an array as an array. |
| if _, isArray := t.Elem().Underlying().(*types.Array); isArray { |
| kind |= kindArray |
| } |
| case *types.Basic: |
| switch info := t.Info(); { |
| case info&types.IsString > 0: |
| kind |= kindString |
| case info&types.IsInteger > 0: |
| kind |= kindInt |
| case info&types.IsFloat > 0: |
| kind |= kindFloat |
| case info&types.IsComplex > 0: |
| kind |= kindComplex |
| case info&types.IsBoolean > 0: |
| kind |= kindBool |
| } |
| case *types.Signature: |
| return kindFunc |
| } |
| |
| if types.Implements(candType, errorIntf) { |
| kind |= kindError |
| } |
| |
| if types.Implements(candType, stringerIntf) { |
| kind |= kindStringer |
| } |
| |
| return kind |
| } |