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go/internal/lsp/cache/cache.go
Rebecca Stambler 252024b829 internal/lsp: separate refactorings out of memoization CL
This change just separates minor changes made along the course of the
memoization CL out into their own change. This will clean up the diffs
in the memoization CL.

Change-Id: I7d59e05ba6472af5f1bf516b1e5b879a5815b9a5
Reviewed-on: https://go-review.googlesource.com/c/tools/+/183250
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
2019-06-25 16:04:30 +00:00

125 lines
2.6 KiB
Go

// 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"
"crypto/sha1"
"fmt"
"go/token"
"strconv"
"sync/atomic"
"golang.org/x/tools/internal/lsp/debug"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/lsp/xlog"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/span"
)
func New() source.Cache {
index := atomic.AddInt64(&cacheIndex, 1)
c := &cache{
fs: &nativeFileSystem{},
id: strconv.FormatInt(index, 10),
fset: token.NewFileSet(),
}
debug.AddCache(debugCache{c})
return c
}
type cache struct {
fs source.FileSystem
id string
fset *token.FileSet
store memoize.Store
}
type fileKey struct {
identity source.FileIdentity
}
type fileHandle struct {
cache *cache
underlying source.FileHandle
handle *memoize.Handle
}
type fileData struct {
memoize.NoCopy
bytes []byte
hash string
err error
}
func (c *cache) GetFile(uri span.URI) source.FileHandle {
underlying := c.fs.GetFile(uri)
key := fileKey{
identity: underlying.Identity(),
}
h := c.store.Bind(key, func(ctx context.Context) interface{} {
data := &fileData{}
data.bytes, data.hash, data.err = underlying.Read(ctx)
return data
})
return &fileHandle{
cache: c,
underlying: underlying,
handle: h,
}
}
func (c *cache) NewSession(log xlog.Logger) source.Session {
index := atomic.AddInt64(&sessionIndex, 1)
s := &session{
cache: c,
id: strconv.FormatInt(index, 10),
log: log,
overlays: make(map[span.URI]*overlay),
filesWatchMap: NewWatchMap(),
}
debug.AddSession(debugSession{s})
return s
}
func (c *cache) FileSet() *token.FileSet {
return c.fset
}
func (h *fileHandle) FileSystem() source.FileSystem {
return h.cache
}
func (h *fileHandle) Identity() source.FileIdentity {
return h.underlying.Identity()
}
func (h *fileHandle) Kind() source.FileKind {
return h.underlying.Kind()
}
func (h *fileHandle) Read(ctx context.Context) ([]byte, string, error) {
v := h.handle.Get(ctx)
if v == nil {
return nil, "", ctx.Err()
}
data := v.(*fileData)
return data.bytes, data.hash, data.err
}
func hashContents(contents []byte) string {
// TODO: consider whether sha1 is the best choice here
// This hash is used for internal identity detection only
return fmt.Sprintf("%x", sha1.Sum(contents))
}
var cacheIndex, sessionIndex, viewIndex int64
type debugCache struct{ *cache }
func (c *cache) ID() string { return c.id }
func (c debugCache) FileSet() *token.FileSet { return c.fset }