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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"
errors "golang.org/x/xerrors"
)
type Command struct {
Name, Title string
// appliesFn is an optional field to indicate whether or not a command can
// be applied to the given inputs. If it returns false, we should not
// suggest this command for these inputs.
appliesFn AppliesFunc
// suggestedFixFn is an optional field to generate the edits that the
// command produces for the given inputs.
suggestedFixFn SuggestedFixFunc
}
type AppliesFunc func(fset *token.FileSet, rng span.Range, src []byte, file *ast.File, pkg *types.Package, info *types.Info) bool
// 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.
type SuggestedFixFunc func(fset *token.FileSet, rng span.Range, src []byte, file *ast.File, pkg *types.Package, info *types.Info) (*analysis.SuggestedFix, error)
// Commands are the commands currently supported by gopls.
var Commands = []*Command{
CommandGenerate,
CommandFillStruct,
CommandRegenerateCgo,
CommandTest,
CommandTidy,
CommandUndeclaredName,
CommandUpgradeDependency,
CommandVendor,
CommandExtractVariable,
CommandExtractFunction,
CommandToggleDetails,
}
var (
// CommandTest runs `go test` for a specific test function.
CommandTest = &Command{
Name: "test",
Title: "Run test(s)",
}
// CommandGenerate runs `go generate` for a given directory.
CommandGenerate = &Command{
Name: "generate",
Title: "Run go generate",
}
// CommandTidy runs `go mod tidy` for a module.
CommandTidy = &Command{
Name: "tidy",
Title: "Run go mod tidy",
}
// CommandVendor runs `go mod vendor` for a module.
CommandVendor = &Command{
Name: "vendor",
Title: "Run go mod vendor",
}
// CommandUpgradeDependency upgrades a dependency.
CommandUpgradeDependency = &Command{
Name: "upgrade_dependency",
Title: "Upgrade dependency",
}
// CommandRegenerateCgo regenerates cgo definitions.
CommandRegenerateCgo = &Command{
Name: "regenerate_cgo",
Title: "Regenerate cgo",
}
// CommandToggleDetails controls calculation of gc annotations.
CommandToggleDetails = &Command{
Name: "gc_details",
Title: "Toggle gc_details",
}
// CommandFillStruct is a gopls command to fill a struct with default
// values.
CommandFillStruct = &Command{
Name: "fill_struct",
suggestedFixFn: fillstruct.SuggestedFix,
}
// CommandUndeclaredName adds a variable declaration for an undeclared
// name.
CommandUndeclaredName = &Command{
Name: "undeclared_name",
suggestedFixFn: undeclaredname.SuggestedFix,
}
// CommandExtractVariable extracts an expression to a variable.
CommandExtractVariable = &Command{
Name: "extract_variable",
Title: "Extract to variable",
suggestedFixFn: extractVariable,
appliesFn: func(_ *token.FileSet, rng span.Range, _ []byte, file *ast.File, _ *types.Package, _ *types.Info) bool {
_, _, ok, _ := canExtractVariable(rng, file)
return ok
},
}
// CommandExtractFunction extracts statements to a function.
CommandExtractFunction = &Command{
Name: "extract_function",
Title: "Extract to function",
suggestedFixFn: extractFunction,
appliesFn: func(fset *token.FileSet, rng span.Range, src []byte, file *ast.File, _ *types.Package, info *types.Info) bool {
_, _, _, _, _, ok, _ := canExtractFunction(fset, rng, src, file, info)
return ok
},
}
)
// Applies reports whether the command c implements a suggested fix that is
// relevant to the given rng.
func (c *Command) Applies(ctx context.Context, snapshot Snapshot, fh FileHandle, pRng protocol.Range) bool {
// If there is no applies function, assume that the command applies.
if c.appliesFn == nil {
return true
}
fset, rng, src, file, _, pkg, info, err := getAllSuggestedFixInputs(ctx, snapshot, fh, pRng)
if err != nil {
return false
}
return c.appliesFn(fset, rng, src, file, pkg, info)
}
// IsSuggestedFix reports whether the given command is intended to work as a
// suggested fix. Suggested fix commands are intended to return edits which are
// then applied to the workspace.
func (c *Command) IsSuggestedFix() bool {
return c.suggestedFixFn != nil
}
// SuggestedFix applies the command's suggested fix to the given file and
// range, returning the resulting edits.
func (c *Command) SuggestedFix(ctx context.Context, snapshot Snapshot, fh VersionedFileHandle, pRng protocol.Range) ([]protocol.TextDocumentEdit, error) {
if c.suggestedFixFn == nil {
return nil, fmt.Errorf("no suggested fix function for %s", c.Name)
}
fset, rng, src, file, m, pkg, info, err := getAllSuggestedFixInputs(ctx, snapshot, fh, pRng)
if err != nil {
return nil, err
}
fix, err := c.suggestedFixFn(fset, rng, src, file, pkg, info)
if err != nil {
return nil, err
}
if fix == nil {
return nil, nil
}
var edits []protocol.TextDocumentEdit
for _, edit := range fix.TextEdits {
rng := span.NewRange(fset, edit.Pos, edit.End)
spn, err := rng.Span()
if err != nil {
return nil, err
}
clRng, err := m.Range(spn)
if err != nil {
return nil, err
}
edits = append(edits, protocol.TextDocumentEdit{
TextDocument: protocol.VersionedTextDocumentIdentifier{
Version: fh.Version(),
TextDocumentIdentifier: protocol.TextDocumentIdentifier{
URI: protocol.URIFromSpanURI(fh.URI()),
},
},
Edits: []protocol.TextEdit{
{
Range: clRng,
NewText: string(edit.NewText),
},
},
})
}
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, *protocol.ColumnMapper, *types.Package, *types.Info, error) {
pkg, pgf, err := getParsedFile(ctx, snapshot, fh, NarrowestPackage)
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, nil, errors.Errorf("getting file for Identifier: %w", err)
}
spn, err := pgf.Mapper.RangeSpan(pRng)
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, nil, err
}
rng, err := spn.Range(pgf.Mapper.Converter)
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, nil, err
}
src, err := fh.Read()
if err != nil {
return nil, span.Range{}, nil, nil, nil, nil, nil, err
}
return snapshot.FileSet(), rng, src, pgf.File, pgf.Mapper, pkg.GetTypes(), pkg.GetTypesInfo(), nil
}