blob: 806499aabbddaa7e91d869323d267c1ab13aacce [file] [log] [blame]
// Copyright 2019 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 cache
import (
"context"
"io/ioutil"
"os"
"golang.org/x/tools/internal/lsp/debug/tag"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/span"
"golang.org/x/tools/internal/telemetry/event"
errors "golang.org/x/xerrors"
)
// ioLimit limits the number of parallel file reads per process.
var ioLimit = make(chan struct{}, 128)
// nativeFileSystem implements FileSystem reading from the normal os file system.
type nativeFileSystem struct{}
// nativeFileHandle implements FileHandle for nativeFileSystem
type nativeFileHandle struct {
fs *nativeFileSystem
identity source.FileIdentity
}
func (fs *nativeFileSystem) GetFile(uri span.URI) source.FileHandle {
return &nativeFileHandle{
fs: fs,
identity: source.FileIdentity{
URI: uri,
Identifier: identifier(uri.Filename()),
Kind: source.DetectLanguage("", uri.Filename()),
},
}
}
func (h *nativeFileHandle) FileSystem() source.FileSystem {
return h.fs
}
func (h *nativeFileHandle) Identity() source.FileIdentity {
return h.identity
}
func (h *nativeFileHandle) Read(ctx context.Context) ([]byte, string, error) {
ctx, done := event.StartSpan(ctx, "cache.nativeFileHandle.Read", tag.File.Of(h.identity.URI.Filename()))
_ = ctx
defer done()
ioLimit <- struct{}{}
defer func() { <-ioLimit }()
if id := identifier(h.identity.URI.Filename()); id != h.identity.Identifier {
return nil, "", errors.Errorf("%s: file has been modified", h.identity.URI.Filename())
}
data, err := ioutil.ReadFile(h.identity.URI.Filename())
if err != nil {
return nil, "", err
}
return data, hashContents(data), nil
}
func identifier(filename string) string {
if fi, err := os.Stat(filename); err == nil {
return fi.ModTime().String()
}
return "DOES NOT EXIST"
}