internal/memoize: delete Generation and Bind

Now that the lifetime of all handles in the store is
determined by reference counting, we no longer need
the generation feature.

The Arg interface, renamed RefCounted, is now optional,
and causes the lifetime of the argument to be extended
for the duration of the Function call.  This is important
when the Get(ctx) context is cancelled, causing the
function call to outlive Get: if Get's reference to
the argument was borrowed, it needs to increase the
refcount to prevent premature destruction.

Also:
- add missing snapshot.release() call in
  importsState.populateProcessEnv.
- remove the --memoize_panic_on_destroyed flag.

Change-Id: I0b3d37c16f8b3f550bb10120c066b628c3db244b
Reviewed-on: https://go-review.googlesource.com/c/tools/+/416076
Run-TryBot: Alan Donovan <adonovan@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/internal/lsp/cache/parse.go b/internal/lsp/cache/parse.go
index c8c751f0b..ef588c605 100644
--- a/internal/lsp/cache/parse.go
+++ b/internal/lsp/cache/parse.go
@@ -59,7 +59,7 @@ func (s *snapshot) ParseGo(ctx context.Context, fh source.FileHandle, mode sourc
 
 	// cache miss?
 	if !hit {
-		handle, release := s.generation.GetHandle(key, func(ctx context.Context, arg memoize.Arg) interface{} {
+		handle, release := s.store.Handle(key, func(ctx context.Context, arg interface{}) interface{} {
 			parsed, err := parseGoImpl(ctx, arg.(*snapshot).FileSet(), fh, mode)
 			return parseGoResult{parsed, err}
 		})
@@ -77,7 +77,7 @@ func (s *snapshot) ParseGo(ctx context.Context, fh source.FileHandle, mode sourc
 	}
 
 	// Await result.
-	v, err := entry.(*memoize.Handle).Get(ctx, s.generation, s)
+	v, err := s.awaitHandle(ctx, entry.(*memoize.Handle))
 	if err != nil {
 		return nil, err
 	}
@@ -93,7 +93,7 @@ func (s *snapshot) peekParseGoLocked(fh source.FileHandle, mode source.ParseMode
 	if !hit {
 		return nil, nil // no-one has requested this file
 	}
-	v := entry.(*memoize.Handle).Cached(s.generation)
+	v := entry.(*memoize.Handle).Cached()
 	if v == nil {
 		return nil, nil // parsing is still in progress
 	}
@@ -147,12 +147,12 @@ func (s *snapshot) astCacheData(ctx context.Context, spkg source.Package, pos to
 	// the search Pos.)
 	//
 	// A representative benchmark would help.
-	astHandle, release := s.generation.GetHandle(astCacheKey{pkgHandle.key, pgf.URI}, func(ctx context.Context, arg memoize.Arg) interface{} {
+	astHandle, release := s.store.Handle(astCacheKey{pkgHandle.key, pgf.URI}, func(ctx context.Context, arg interface{}) interface{} {
 		return buildASTCache(pgf)
 	})
 	defer release()
 
-	d, err := astHandle.Get(ctx, s.generation, s)
+	d, err := s.awaitHandle(ctx, astHandle)
 	if err != nil {
 		return nil, err
 	}