gopls/internal/template: use protocol.Mapper and simplify

This CL replaces all the complex bookkeeping logic with
the existing protocol.Mapper. This fixes the associated
bug.

Details:
- eliminate parsed.{nls,lastnl,check,nonASCII}.
- use UTF-16 or byte offsets, never runes.
- propagate all Mapper errors upwards and handle them properly.
- eliminate unnecessary "multiline" token distinction
  and alternative logic. Mapper works fine.
- remove tests that reduced to tests of Mapper.
- remove append to file.Handle.Content buffer (a data race).

The only behavior changes to tests are:
- the extent of a string token "foo" now includes its quote marks
- the length of an identifier or literal is in bytes, not runes

Also:
- use clearer variable names.
- mark existing comments as TODO where appropriate.
- move symAtPosition
- rename findWordAt -> wordAt

Fixes golang/go#74635

Change-Id: Ia25b7dcbe28e3bc472ae103bd85f71e3c09e3a30
Reviewed-on: https://go-review.googlesource.com/c/tools/+/688937
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
9 files changed
tree: c68621487ca63e959da35b14fd7be2cf2eb5e40a
  1. benchmark/
  2. blog/
  3. cmd/
  4. container/
  5. copyright/
  6. cover/
  7. go/
  8. godoc/
  9. gopls/
  10. imports/
  11. internal/
  12. playground/
  13. present/
  14. refactor/
  15. txtar/
  16. .gitattributes
  17. .gitignore
  18. .prettierrc
  19. codereview.cfg
  20. CONTRIBUTING.md
  21. go.mod
  22. go.sum
  23. LICENSE
  24. PATENTS
  25. README.md
README.md

Go Tools

PkgGoDev

This repository provides the golang.org/x/tools module, comprising various tools and packages mostly for static analysis of Go programs, some of which are listed below. Use the “Go reference” link above for more information about any package.

It also contains the golang.org/x/tools/gopls module, whose root package is a language-server protocol (LSP) server for Go. An LSP server analyses the source code of a project and responds to requests from a wide range of editors such as VSCode and Vim, allowing them to support IDE-like functionality.

Selected commands:

  • cmd/goimports formats a Go program like go fmt and additionally inserts import statements for any packages required by the file after it is edited.
  • cmd/callgraph prints the call graph of a Go program.
  • cmd/digraph is a utility for manipulating directed graphs in textual notation.
  • cmd/stringer generates declarations (including a String method) for “enum” types.
  • cmd/toolstash is a utility to simplify working with multiple versions of the Go toolchain.

These commands may be fetched with a command such as

go install golang.org/x/tools/cmd/goimports@latest

Selected packages:

  • go/ssa provides a static single-assignment form (SSA) intermediate representation (IR) for Go programs, similar to a typical compiler, for use by analysis tools.

  • go/packages provides a simple interface for loading, parsing, and type checking a complete Go program from source code.

  • go/analysis provides a framework for modular static analysis of Go programs.

  • go/callgraph provides call graphs of Go programs using a variety of algorithms with different trade-offs.

  • go/ast/inspector provides an optimized means of traversing a Go parse tree for use in analysis tools.

  • go/cfg provides a simple control-flow graph (CFG) for a Go function.

  • go/gcexportdata and go/gccgoexportdata read and write the binary files containing type information used by the standard and gccgo compilers.

  • go/types/objectpath provides a stable naming scheme for named entities (“objects”) in the go/types API.

Numerous other packages provide more esoteric functionality.

Contributing

This repository uses Gerrit for code changes. To learn how to submit changes, see https://go.dev/doc/contribute.

The git repository is https://go.googlesource.com/tools.

The main issue tracker for the tools repository is located at https://go.dev/issues. Prefix your issue with “x/tools/(your subdir):” in the subject line, so it is easy to find.

JavaScript and CSS Formatting

This repository uses prettier to format JS and CSS files.

The version of prettier used is 1.18.2.

It is encouraged that all JS and CSS code be run through this before submitting a change. However, it is not a strict requirement enforced by CI.