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go/internal/lsp/cache/cache.go
Rob Findley c4d4ea9c79 internal/lsp/cache: return concrete types where possible
For testability, and to allow the exchange of debug information when
forwarding the LSP, it will be necessary to access debug information
stored in cache objects. This is cumbersome to do if our constructors
return source interfaces rather than concrete types.

This CL changes cache.New and (*Cache).NewSession to return concrete
types. This required removing NewSession from source.Cache. I would
argue that this makes sense from a philosophical perspective: everything
in the source package operates in a context where the Session and Cache
already exist.

Updates golang/go#34111

Change-Id: I01721db827d51117f9479f1544b15cedae0c5921
Reviewed-on: https://go-review.googlesource.com/c/tools/+/220077
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
2020-02-19 18:42:16 +00:00

123 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"
"reflect"
"strconv"
"sync/atomic"
"golang.org/x/tools/internal/lsp/debug"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/span"
)
func New(options func(*source.Options)) *Cache {
index := atomic.AddInt64(&cacheIndex, 1)
c := &Cache{
fs: &nativeFileSystem{},
id: strconv.FormatInt(index, 10),
fset: token.NewFileSet(),
options: options,
}
debug.AddCache(debugCache{c})
return c
}
type Cache struct {
fs source.FileSystem
id string
fset *token.FileSet
options func(*source.Options)
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() *Session {
index := atomic.AddInt64(&sessionIndex, 1)
s := &Session{
cache: c,
id: strconv.FormatInt(index, 10),
options: source.DefaultOptions(),
overlays: make(map[span.URI]*overlay),
}
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) 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 }
func (c debugCache) MemStats() map[reflect.Type]int { return c.store.Stats() }