diff options
Diffstat (limited to 'internal/lsp/source/identifier.go')
-rw-r--r-- | internal/lsp/source/identifier.go | 576 |
1 files changed, 0 insertions, 576 deletions
diff --git a/internal/lsp/source/identifier.go b/internal/lsp/source/identifier.go deleted file mode 100644 index bf4941f18..000000000 --- a/internal/lsp/source/identifier.go +++ /dev/null @@ -1,576 +0,0 @@ -// 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 source - -import ( - "context" - "fmt" - "go/ast" - "go/parser" - "go/token" - "go/types" - "sort" - "strconv" - - "golang.org/x/tools/go/ast/astutil" - "golang.org/x/tools/internal/event" - "golang.org/x/tools/internal/lsp/protocol" - "golang.org/x/tools/internal/span" - "golang.org/x/tools/internal/typeparams" - errors "golang.org/x/xerrors" -) - -// IdentifierInfo holds information about an identifier in Go source. -type IdentifierInfo struct { - Name string - Snapshot Snapshot - MappedRange - - Type struct { - MappedRange - Object types.Object - } - - Inferred *types.Signature - - Declaration Declaration - - ident *ast.Ident - - // For struct fields or embedded interfaces, enclosing is the object - // corresponding to the outer type declaration, if it is exported, for use in - // documentation links. - enclosing *types.TypeName - - pkg Package - qf types.Qualifier -} - -func (i *IdentifierInfo) IsImport() bool { - _, ok := i.Declaration.node.(*ast.ImportSpec) - return ok -} - -type Declaration struct { - MappedRange []MappedRange - - // The typechecked node. - node ast.Node - - // Optional: the fully parsed node, to be used for formatting in cases where - // node has missing information. This could be the case when node was parsed - // in ParseExported mode. - fullDecl ast.Decl - - // The typechecked object. - obj types.Object - - // typeSwitchImplicit indicates that the declaration is in an implicit - // type switch. Its type is the type of the variable on the right-hand - // side of the type switch. - typeSwitchImplicit types.Type -} - -// Identifier returns identifier information for a position -// in a file, accounting for a potentially incomplete selector. -func Identifier(ctx context.Context, snapshot Snapshot, fh FileHandle, pos protocol.Position) (*IdentifierInfo, error) { - ctx, done := event.Start(ctx, "source.Identifier") - defer done() - - pkgs, err := snapshot.PackagesForFile(ctx, fh.URI(), TypecheckAll, false) - if err != nil { - return nil, err - } - if len(pkgs) == 0 { - return nil, fmt.Errorf("no packages for file %v", fh.URI()) - } - sort.Slice(pkgs, func(i, j int) bool { - // Prefer packages with a more complete parse mode. - if pkgs[i].ParseMode() != pkgs[j].ParseMode() { - return pkgs[i].ParseMode() > pkgs[j].ParseMode() - } - return len(pkgs[i].CompiledGoFiles()) < len(pkgs[j].CompiledGoFiles()) - }) - var findErr error - for _, pkg := range pkgs { - pgf, err := pkg.File(fh.URI()) - if err != nil { - return nil, err - } - spn, err := pgf.Mapper.PointSpan(pos) - if err != nil { - return nil, err - } - rng, err := spn.Range(pgf.Mapper.Converter) - if err != nil { - return nil, err - } - var ident *IdentifierInfo - ident, findErr = findIdentifier(ctx, snapshot, pkg, pgf, rng.Start) - if findErr == nil { - return ident, nil - } - } - return nil, findErr -} - -// ErrNoIdentFound is error returned when no identifer is found at a particular position -var ErrNoIdentFound = errors.New("no identifier found") - -func findIdentifier(ctx context.Context, snapshot Snapshot, pkg Package, pgf *ParsedGoFile, pos token.Pos) (*IdentifierInfo, error) { - file := pgf.File - // Handle import specs separately, as there is no formal position for a - // package declaration. - if result, err := importSpec(snapshot, pkg, file, pos); result != nil || err != nil { - return result, err - } - path := pathEnclosingObjNode(file, pos) - if path == nil { - return nil, ErrNoIdentFound - } - - qf := Qualifier(file, pkg.GetTypes(), pkg.GetTypesInfo()) - - ident, _ := path[0].(*ast.Ident) - if ident == nil { - return nil, ErrNoIdentFound - } - // Special case for package declarations, since they have no - // corresponding types.Object. - if ident == file.Name { - rng, err := posToMappedRange(snapshot, pkg, file.Name.Pos(), file.Name.End()) - if err != nil { - return nil, err - } - var declAST *ast.File - for _, pgf := range pkg.CompiledGoFiles() { - if pgf.File.Doc != nil { - declAST = pgf.File - } - } - // If there's no package documentation, just use current file. - if declAST == nil { - declAST = file - } - declRng, err := posToMappedRange(snapshot, pkg, declAST.Name.Pos(), declAST.Name.End()) - if err != nil { - return nil, err - } - return &IdentifierInfo{ - Name: file.Name.Name, - ident: file.Name, - MappedRange: rng, - pkg: pkg, - qf: qf, - Snapshot: snapshot, - Declaration: Declaration{ - node: declAST.Name, - MappedRange: []MappedRange{declRng}, - }, - }, nil - } - - result := &IdentifierInfo{ - Snapshot: snapshot, - qf: qf, - pkg: pkg, - ident: ident, - enclosing: searchForEnclosing(pkg.GetTypesInfo(), path), - } - - result.Name = result.ident.Name - var err error - if result.MappedRange, err = posToMappedRange(snapshot, pkg, result.ident.Pos(), result.ident.End()); err != nil { - return nil, err - } - - result.Declaration.obj = pkg.GetTypesInfo().ObjectOf(result.ident) - if result.Declaration.obj == nil { - // If there was no types.Object for the declaration, there might be an - // implicit local variable declaration in a type switch. - if objs, typ := typeSwitchImplicits(pkg, path); len(objs) > 0 { - // There is no types.Object for the declaration of an implicit local variable, - // but all of the types.Objects associated with the usages of this variable can be - // used to connect it back to the declaration. - // Preserve the first of these objects and treat it as if it were the declaring object. - result.Declaration.obj = objs[0] - result.Declaration.typeSwitchImplicit = typ - } else { - // Probably a type error. - return nil, errors.Errorf("%w for ident %v", errNoObjectFound, result.Name) - } - } - - // Handle builtins separately. - if result.Declaration.obj.Parent() == types.Universe { - builtin, err := snapshot.BuiltinFile(ctx) - if err != nil { - return nil, err - } - builtinObj := builtin.File.Scope.Lookup(result.Name) - if builtinObj == nil { - return nil, fmt.Errorf("no builtin object for %s", result.Name) - } - decl, ok := builtinObj.Decl.(ast.Node) - if !ok { - return nil, errors.Errorf("no declaration for %s", result.Name) - } - result.Declaration.node = decl - if typeSpec, ok := decl.(*ast.TypeSpec); ok { - // Find the GenDecl (which has the doc comments) for the TypeSpec. - result.Declaration.fullDecl = findGenDecl(builtin.File, typeSpec) - } - - // The builtin package isn't in the dependency graph, so the usual - // utilities won't work here. - rng := NewMappedRange(snapshot.FileSet(), builtin.Mapper, decl.Pos(), decl.Pos()+token.Pos(len(result.Name))) - result.Declaration.MappedRange = append(result.Declaration.MappedRange, rng) - return result, nil - } - - // (error).Error is a special case of builtin. Lots of checks to confirm - // that this is the builtin Error. - if obj := result.Declaration.obj; obj.Parent() == nil && obj.Pkg() == nil && obj.Name() == "Error" { - if _, ok := obj.Type().(*types.Signature); ok { - builtin, err := snapshot.BuiltinFile(ctx) - if err != nil { - return nil, err - } - // Look up "error" and then navigate to its only method. - // The Error method does not appear in the builtin package's scope.log.Pri - const errorName = "error" - builtinObj := builtin.File.Scope.Lookup(errorName) - if builtinObj == nil { - return nil, fmt.Errorf("no builtin object for %s", errorName) - } - decl, ok := builtinObj.Decl.(ast.Node) - if !ok { - return nil, errors.Errorf("no declaration for %s", errorName) - } - spec, ok := decl.(*ast.TypeSpec) - if !ok { - return nil, fmt.Errorf("no type spec for %s", errorName) - } - iface, ok := spec.Type.(*ast.InterfaceType) - if !ok { - return nil, fmt.Errorf("%s is not an interface", errorName) - } - if iface.Methods.NumFields() != 1 { - return nil, fmt.Errorf("expected 1 method for %s, got %v", errorName, iface.Methods.NumFields()) - } - method := iface.Methods.List[0] - if len(method.Names) != 1 { - return nil, fmt.Errorf("expected 1 name for %v, got %v", method, len(method.Names)) - } - name := method.Names[0].Name - result.Declaration.node = method - rng := NewMappedRange(snapshot.FileSet(), builtin.Mapper, method.Pos(), method.Pos()+token.Pos(len(name))) - result.Declaration.MappedRange = append(result.Declaration.MappedRange, rng) - return result, nil - } - } - - // If the original position was an embedded field, we want to jump - // to the field's type definition, not the field's definition. - if v, ok := result.Declaration.obj.(*types.Var); ok && v.Embedded() { - // types.Info.Uses contains the embedded field's *types.TypeName. - if typeName := pkg.GetTypesInfo().Uses[ident]; typeName != nil { - result.Declaration.obj = typeName - } - } - - rng, err := objToMappedRange(snapshot, pkg, result.Declaration.obj) - if err != nil { - return nil, err - } - result.Declaration.MappedRange = append(result.Declaration.MappedRange, rng) - - declPkg, err := FindPackageFromPos(ctx, snapshot, result.Declaration.obj.Pos()) - if err != nil { - return nil, err - } - if result.Declaration.node, err = snapshot.PosToDecl(ctx, declPkg, result.Declaration.obj.Pos()); err != nil { - return nil, err - } - // Ensure that we have the full declaration, in case the declaration was - // parsed in ParseExported and therefore could be missing information. - if result.Declaration.fullDecl, err = fullNode(snapshot, result.Declaration.obj, declPkg); err != nil { - return nil, err - } - typ := pkg.GetTypesInfo().TypeOf(result.ident) - if typ == nil { - return result, nil - } - - result.Inferred = inferredSignature(pkg.GetTypesInfo(), ident) - - result.Type.Object = typeToObject(typ) - if result.Type.Object != nil { - // Identifiers with the type "error" are a special case with no position. - if hasErrorType(result.Type.Object) { - return result, nil - } - if result.Type.MappedRange, err = objToMappedRange(snapshot, pkg, result.Type.Object); err != nil { - return nil, err - } - } - return result, nil -} - -// findGenDecl determines the parent ast.GenDecl for a given ast.Spec. -func findGenDecl(f *ast.File, spec ast.Spec) *ast.GenDecl { - for _, decl := range f.Decls { - if genDecl, ok := decl.(*ast.GenDecl); ok { - if genDecl.Pos() <= spec.Pos() && genDecl.End() >= spec.End() { - return genDecl - } - } - } - return nil -} - -// fullNode tries to extract the full spec corresponding to obj's declaration. -// If the package was not parsed in full, the declaration file will be -// re-parsed to ensure it has complete syntax. -func fullNode(snapshot Snapshot, obj types.Object, pkg Package) (ast.Decl, error) { - // declaration in a different package... make sure we have full AST information. - tok := snapshot.FileSet().File(obj.Pos()) - uri := span.URIFromPath(tok.Name()) - pgf, err := pkg.File(uri) - if err != nil { - return nil, err - } - file := pgf.File - pos := obj.Pos() - if pgf.Mode != ParseFull { - fset := snapshot.FileSet() - file2, _ := parser.ParseFile(fset, tok.Name(), pgf.Src, parser.AllErrors|parser.ParseComments) - if file2 != nil { - offset, err := Offset(tok, obj.Pos()) - if err != nil { - return nil, err - } - file = file2 - tok2 := fset.File(file2.Pos()) - pos = tok2.Pos(offset) - } - } - path, _ := astutil.PathEnclosingInterval(file, pos, pos) - for _, n := range path { - if decl, ok := n.(ast.Decl); ok { - return decl, nil - } - } - return nil, nil -} - -// inferredSignature determines the resolved non-generic signature for an -// identifier in an instantiation expression. -// -// If no such signature exists, it returns nil. -func inferredSignature(info *types.Info, id *ast.Ident) *types.Signature { - inst := typeparams.GetInstances(info)[id] - sig, _ := inst.Type.(*types.Signature) - return sig -} - -func searchForEnclosing(info *types.Info, path []ast.Node) *types.TypeName { - for _, n := range path { - switch n := n.(type) { - case *ast.SelectorExpr: - if sel, ok := info.Selections[n]; ok { - recv := Deref(sel.Recv()) - - // Keep track of the last exported type seen. - var exported *types.TypeName - if named, ok := recv.(*types.Named); ok && named.Obj().Exported() { - exported = named.Obj() - } - // We don't want the last element, as that's the field or - // method itself. - for _, index := range sel.Index()[:len(sel.Index())-1] { - if r, ok := recv.Underlying().(*types.Struct); ok { - recv = Deref(r.Field(index).Type()) - if named, ok := recv.(*types.Named); ok && named.Obj().Exported() { - exported = named.Obj() - } - } - } - return exported - } - case *ast.CompositeLit: - if t, ok := info.Types[n]; ok { - if named, _ := t.Type.(*types.Named); named != nil { - return named.Obj() - } - } - case *ast.TypeSpec: - if _, ok := n.Type.(*ast.StructType); ok { - if t, ok := info.Defs[n.Name]; ok { - if tname, _ := t.(*types.TypeName); tname != nil { - return tname - } - } - } - } - } - return nil -} - -func typeToObject(typ types.Type) types.Object { - switch typ := typ.(type) { - case *types.Named: - return typ.Obj() - case *types.Pointer: - return typeToObject(typ.Elem()) - case *types.Array: - return typeToObject(typ.Elem()) - case *types.Slice: - return typeToObject(typ.Elem()) - case *types.Chan: - return typeToObject(typ.Elem()) - case *types.Signature: - // Try to find a return value of a named type. If there's only one - // such value, jump to its type definition. - var res types.Object - - results := typ.Results() - for i := 0; i < results.Len(); i++ { - obj := typeToObject(results.At(i).Type()) - if obj == nil || hasErrorType(obj) { - // Skip builtins. - continue - } - if res != nil { - // The function/method must have only one return value of a named type. - return nil - } - - res = obj - } - return res - default: - return nil - } -} - -func hasErrorType(obj types.Object) bool { - return types.IsInterface(obj.Type()) && obj.Pkg() == nil && obj.Name() == "error" -} - -// importSpec handles positions inside of an *ast.ImportSpec. -func importSpec(snapshot Snapshot, pkg Package, file *ast.File, pos token.Pos) (*IdentifierInfo, error) { - var imp *ast.ImportSpec - for _, spec := range file.Imports { - if spec.Path.Pos() <= pos && pos < spec.Path.End() { - imp = spec - } - } - if imp == nil { - return nil, nil - } - importPath, err := strconv.Unquote(imp.Path.Value) - if err != nil { - return nil, errors.Errorf("import path not quoted: %s (%v)", imp.Path.Value, err) - } - result := &IdentifierInfo{ - Snapshot: snapshot, - Name: importPath, - pkg: pkg, - } - if result.MappedRange, err = posToMappedRange(snapshot, pkg, imp.Path.Pos(), imp.Path.End()); err != nil { - return nil, err - } - // Consider the "declaration" of an import spec to be the imported package. - importedPkg, err := pkg.GetImport(importPath) - if err != nil { - return nil, err - } - // Return all of the files in the package as the definition of the import spec. - for _, dst := range importedPkg.GetSyntax() { - rng, err := posToMappedRange(snapshot, pkg, dst.Pos(), dst.End()) - if err != nil { - return nil, err - } - result.Declaration.MappedRange = append(result.Declaration.MappedRange, rng) - } - - result.Declaration.node = imp - return result, nil -} - -// typeSwitchImplicits returns all the implicit type switch objects that -// correspond to the leaf *ast.Ident. It also returns the original type -// associated with the identifier (outside of a case clause). -func typeSwitchImplicits(pkg Package, path []ast.Node) ([]types.Object, types.Type) { - ident, _ := path[0].(*ast.Ident) - if ident == nil { - return nil, nil - } - - var ( - ts *ast.TypeSwitchStmt - assign *ast.AssignStmt - cc *ast.CaseClause - obj = pkg.GetTypesInfo().ObjectOf(ident) - ) - - // Walk our ancestors to determine if our leaf ident refers to a - // type switch variable, e.g. the "a" from "switch a := b.(type)". -Outer: - for i := 1; i < len(path); i++ { - switch n := path[i].(type) { - case *ast.AssignStmt: - // Check if ident is the "a" in "a := foo.(type)". The "a" in - // this case has no types.Object, so check for ident equality. - if len(n.Lhs) == 1 && n.Lhs[0] == ident { - assign = n - } - case *ast.CaseClause: - // Check if ident is a use of "a" within a case clause. Each - // case clause implicitly maps "a" to a different types.Object, - // so check if ident's object is the case clause's implicit - // object. - if obj != nil && pkg.GetTypesInfo().Implicits[n] == obj { - cc = n - } - case *ast.TypeSwitchStmt: - // Look for the type switch that owns our previously found - // *ast.AssignStmt or *ast.CaseClause. - if n.Assign == assign { - ts = n - break Outer - } - - for _, stmt := range n.Body.List { - if stmt == cc { - ts = n - break Outer - } - } - } - } - if ts == nil { - return nil, nil - } - // Our leaf ident refers to a type switch variable. Fan out to the - // type switch's implicit case clause objects. - var objs []types.Object - for _, cc := range ts.Body.List { - if ccObj := pkg.GetTypesInfo().Implicits[cc]; ccObj != nil { - objs = append(objs, ccObj) - } - } - // The right-hand side of a type switch should only have one - // element, and we need to track its type in order to generate - // hover information for implicit type switch variables. - var typ types.Type - if assign, ok := ts.Assign.(*ast.AssignStmt); ok && len(assign.Rhs) == 1 { - if rhs := assign.Rhs[0].(*ast.TypeAssertExpr); ok { - typ = pkg.GetTypesInfo().TypeOf(rhs.X) - } - } - return objs, typ -} |