blob: 3749ed2aefc8609ff007299b69cc1adb6f069dd0 [file] [log] [blame]
// 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 cmd
import (
"bytes"
"context"
"flag"
"fmt"
"go/parser"
"go/token"
"io/ioutil"
"log"
"os"
"unicode/utf8"
"golang.org/x/tools/gopls/internal/lsp"
"golang.org/x/tools/gopls/internal/lsp/protocol"
"golang.org/x/tools/gopls/internal/lsp/source"
"golang.org/x/tools/gopls/internal/span"
)
// generate semantic tokens and interpolate them in the file
// The output is the input file decorated with comments showing the
// syntactic tokens. The comments are stylized:
// /*<arrow><length>,<token type>,[<modifiers]*/
// For most occurrences, the comment comes just before the token it
// describes, and arrow is a right arrow. If the token is inside a string
// the comment comes just after the string, and the arrow is a left arrow.
// <length> is the length of the token in runes, <token type> is one
// of the supported semantic token types, and <modifiers. is a
// (possibly empty) list of token type modifiers.
// There are 3 coordinate systems for lines and character offsets in lines
// LSP (what's returned from semanticTokens()):
// 0-based: the first line is line 0, the first character of a line
// is character 0, and characters are counted as UTF-16 code points
// gopls (and Go error messages):
// 1-based: the first line is line1, the first chararcter of a line
// is character 0, and characters are counted as bytes
// internal (as used in marks, and lines:=bytes.Split(buf, '\n'))
// 0-based: lines and character positions are 1 less than in
// the gopls coordinate system
type semtok struct {
app *Application
}
var colmap *protocol.Mapper
func (c *semtok) Name() string { return "semtok" }
func (c *semtok) Parent() string { return c.app.Name() }
func (c *semtok) Usage() string { return "<filename>" }
func (c *semtok) ShortHelp() string { return "show semantic tokens for the specified file" }
func (c *semtok) DetailedHelp(f *flag.FlagSet) {
fmt.Fprint(f.Output(), `
Example: show the semantic tokens for this file:
$ gopls semtok internal/lsp/cmd/semtok.go
`)
printFlagDefaults(f)
}
// Run performs the semtok on the files specified by args and prints the
// results to stdout in the format described above.
func (c *semtok) Run(ctx context.Context, args ...string) error {
if len(args) != 1 {
return fmt.Errorf("expected one file name, got %d", len(args))
}
// perhaps simpler if app had just had a FlagSet member
origOptions := c.app.options
c.app.options = func(opts *source.Options) {
origOptions(opts)
opts.SemanticTokens = true
}
conn, err := c.app.connect(ctx)
if err != nil {
return err
}
defer conn.terminate(ctx)
uri := span.URIFromPath(args[0])
file := conn.openFile(ctx, uri)
if file.err != nil {
return file.err
}
buf, err := ioutil.ReadFile(args[0])
if err != nil {
return err
}
lines := bytes.Split(buf, []byte{'\n'})
p := &protocol.SemanticTokensRangeParams{
TextDocument: protocol.TextDocumentIdentifier{
URI: protocol.URIFromSpanURI(uri),
},
Range: protocol.Range{Start: protocol.Position{Line: 0, Character: 0},
End: protocol.Position{
Line: uint32(len(lines) - 1),
Character: uint32(len(lines[len(lines)-1]))},
},
}
resp, err := conn.semanticTokens(ctx, p)
if err != nil {
return err
}
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, args[0], buf, 0)
if err != nil {
log.Printf("parsing %s failed %v", args[0], err)
return err
}
tok := fset.File(f.Pos())
if tok == nil {
// can't happen; just parsed this file
return fmt.Errorf("can't find %s in fset", args[0])
}
colmap = protocol.NewMapper(uri, buf)
err = decorate(file.uri.Filename(), resp.Data)
if err != nil {
return err
}
return nil
}
type mark struct {
line, offset int // 1-based, from RangeSpan
len int // bytes, not runes
typ string
mods []string
}
// prefixes for semantic token comments
const (
SemanticLeft = "/*⇐"
SemanticRight = "/*⇒"
)
func markLine(m mark, lines [][]byte) {
l := lines[m.line-1] // mx is 1-based
length := utf8.RuneCount(l[m.offset-1 : m.offset-1+m.len])
splitAt := m.offset - 1
insert := ""
if m.typ == "namespace" && m.offset-1+m.len < len(l) && l[m.offset-1+m.len] == '"' {
// it is the last component of an import spec
// cannot put a comment inside a string
insert = fmt.Sprintf("%s%d,namespace,[]*/", SemanticLeft, length)
splitAt = m.offset + m.len
} else {
// be careful not to generate //*
spacer := ""
if splitAt-1 >= 0 && l[splitAt-1] == '/' {
spacer = " "
}
insert = fmt.Sprintf("%s%s%d,%s,%v*/", spacer, SemanticRight, length, m.typ, m.mods)
}
x := append([]byte(insert), l[splitAt:]...)
l = append(l[:splitAt], x...)
lines[m.line-1] = l
}
func decorate(file string, result []uint32) error {
buf, err := ioutil.ReadFile(file)
if err != nil {
return err
}
marks := newMarks(result)
if len(marks) == 0 {
return nil
}
lines := bytes.Split(buf, []byte{'\n'})
for i := len(marks) - 1; i >= 0; i-- {
mx := marks[i]
markLine(mx, lines)
}
os.Stdout.Write(bytes.Join(lines, []byte{'\n'}))
return nil
}
func newMarks(d []uint32) []mark {
ans := []mark{}
// the following two loops could be merged, at the cost
// of making the logic slightly more complicated to understand
// first, convert from deltas to absolute, in LSP coordinates
lspLine := make([]uint32, len(d)/5)
lspChar := make([]uint32, len(d)/5)
var line, char uint32
for i := 0; 5*i < len(d); i++ {
lspLine[i] = line + d[5*i+0]
if d[5*i+0] > 0 {
char = 0
}
lspChar[i] = char + d[5*i+1]
char = lspChar[i]
line = lspLine[i]
}
// second, convert to gopls coordinates
for i := 0; 5*i < len(d); i++ {
pr := protocol.Range{
Start: protocol.Position{
Line: lspLine[i],
Character: lspChar[i],
},
End: protocol.Position{
Line: lspLine[i],
Character: lspChar[i] + d[5*i+2],
},
}
spn, err := colmap.RangeSpan(pr)
if err != nil {
log.Fatal(err)
}
m := mark{
line: spn.Start().Line(),
offset: spn.Start().Column(),
len: spn.End().Column() - spn.Start().Column(),
typ: lsp.SemType(int(d[5*i+3])),
mods: lsp.SemMods(int(d[5*i+4])),
}
ans = append(ans, m)
}
return ans
}