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// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package source
import (
"context"
"fmt"
"go/ast"
"go/token"
"go/types"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/internal/lsp/analysis/fillstruct"
"golang.org/x/tools/internal/lsp/analysis/undeclaredname"
"golang.org/x/tools/internal/lsp/protocol"
"golang.org/x/tools/internal/span"
)
type (
// SuggestedFixFunc is a function used to get the suggested fixes for a given
// gopls command, some of which are provided by go/analysis.Analyzers. Some of
// the analyzers in internal/lsp/analysis are not efficient enough to include
// suggested fixes with their diagnostics, so we have to compute them
// separately. Such analyzers should provide a function with a signature of
// SuggestedFixFunc.
SuggestedFixFunc func(ctx context.Context, snapshot Snapshot, fh VersionedFileHandle, pRng protocol.Range) (*analysis.SuggestedFix, error)
singleFileFixFunc func(fset *token.FileSet, rng span.Range, src []byte, file *ast.File, pkg *types.Package, info *types.Info) (*analysis.SuggestedFix, error)
)
const (
FillStruct = "fill_struct"
StubMethods = "stub_methods"
UndeclaredName = "undeclared_name"
ExtractVariable = "extract_variable"
ExtractFunction = "extract_function"
ExtractMethod = "extract_method"
)
// suggestedFixes maps a suggested fix command id to its handler.
var suggestedFixes = map[string]SuggestedFixFunc{
FillStruct: singleFile(fillstruct.SuggestedFix),
UndeclaredName: singleFile(undeclaredname.SuggestedFix),
ExtractVariable: singleFile(extractVariable),
ExtractFunction: singleFile(extractFunction),
ExtractMethod: singleFile(extractMethod),
StubMethods: stubSuggestedFixFunc,
}
// singleFile calls analyzers that expect inputs for a single file
func singleFile(sf singleFileFixFunc) SuggestedFixFunc {
return func(ctx context.Context, snapshot Snapshot, fh VersionedFileHandle, pRng protocol.Range) (*analysis.SuggestedFix, error) {
fset, rng, src, file, pkg, info, err := getAllSuggestedFixInputs(ctx, snapshot, fh, pRng)
if err != nil {
return nil, err
}
return sf(fset, rng, src, file, pkg, info)
}
}
func SuggestedFixFromCommand(cmd protocol.Command, kind protocol.CodeActionKind) SuggestedFix {
return SuggestedFix{
Title: cmd.Title,
Command: &cmd,
ActionKind: kind,
}
}
// ApplyFix applies the command's suggested fix to the given file and
// range, returning the resulting edits.
func ApplyFix(ctx context.Context, fix string, snapshot Snapshot, fh VersionedFileHandle, pRng protocol.Range) ([]protocol.TextDocumentEdit, error) {
handler, ok := suggestedFixes[fix]
if !ok {
return nil, fmt.Errorf("no suggested fix function for %s", fix)
}
suggestion, err := handler(ctx, snapshot, fh, pRng)
if err != nil {
return nil, err
}
if suggestion == nil {
return nil, nil
}
fset := snapshot.FileSet()
editsPerFile := map[span.URI]*protocol.TextDocumentEdit{}
for _, edit := range suggestion.TextEdits {
spn, err := span.NewRange(fset, edit.Pos, edit.End).Span()
if err != nil {
return nil, err
}
fh, err := snapshot.GetVersionedFile(ctx, spn.URI())
if err != nil {
return nil, err
}
te, ok := editsPerFile[spn.URI()]
if !ok {
te = &protocol.TextDocumentEdit{
TextDocument: protocol.OptionalVersionedTextDocumentIdentifier{
Version: fh.Version(),
TextDocumentIdentifier: protocol.TextDocumentIdentifier{
URI: protocol.URIFromSpanURI(fh.URI()),
},
},
}
editsPerFile[spn.URI()] = te
}
_, pgf, err := GetParsedFile(ctx, snapshot, fh, NarrowestPackage)
if err != nil {
return nil, err
}
rng, err := pgf.Mapper.Range(spn)
if err != nil {
return nil, err
}
te.Edits = append(te.Edits, protocol.TextEdit{
Range: rng,
NewText: string(edit.NewText),
})
}
var edits []protocol.TextDocumentEdit
for _, edit := range editsPerFile {
edits = append(edits, *edit)
}
return edits, nil
}
// getAllSuggestedFixInputs is a helper function to collect all possible needed
// inputs for an AppliesFunc or SuggestedFixFunc.
func getAllSuggestedFixInputs(ctx context.Context, snapshot Snapshot, fh FileHandle, pRng protocol.Range) (*token.FileSet, span.Range, []byte, *ast.File, *types.Package, *types.Info, error) {
pkg, pgf, err := GetParsedFile(ctx, snapshot, fh, NarrowestPackage)
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, fmt.Errorf("getting file for Identifier: %w", err)
}
rng, err := pgf.Mapper.RangeToSpanRange(pRng)
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, err
}
return snapshot.FileSet(), rng, pgf.Src, pgf.File, pkg.GetTypes(), pkg.GetTypesInfo(), nil
}