blob: 41d3d807c2d1574dee36f8aeeb3c6dd1040ed282 [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"
"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/memoize"
"golang.org/x/tools/internal/span"
)
func New(options func(*source.Options)) source.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, kind source.FileKind) source.FileHandle {
underlying := c.fs.GetFile(uri, kind)
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(ctx context.Context) source.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 }