Simplify mmap.

internal/util/mmap.go

@@ -12,22 +12,13 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+func withMmappedAllocator(ctx context.Context) context.Context {
+	return experimental.WithMemoryAllocator(ctx,
+		experimental.MemoryAllocatorFunc(mmappedAllocator))
+}
+
 type mmapState struct {
 	regions []*MappedRegion
-	enabled bool
-}
-
-func (s *mmapState) init(ctx context.Context, enabled bool) context.Context {
-	if s.enabled = enabled; enabled {
-		return experimental.WithMemoryAllocator(ctx,
-			experimental.MemoryAllocatorFunc(mmappedAllocator))
-	}
-	return ctx
-}
-
-func CanMapFiles(ctx context.Context) bool {
-	s := ctx.Value(moduleKey{}).(*moduleState)
-	return s.mmapState.enabled
 }
 
 func (s *mmapState) new(ctx context.Context, mod api.Module, size int32) *MappedRegion {

internal/util/mmap_other.go

@@ -6,10 +6,6 @@ import "context"
 
 type mmapState struct{}
 
-func (s *mmapState) init(ctx context.Context, _ bool) context.Context {
+func withMmappedAllocator(ctx context.Context) context.Context {
 	return ctx
 }
-
-func CanMapFiles(ctx context.Context) bool {
-	return false
-}

internal/util/module.go

@@ -12,10 +12,10 @@ type moduleState struct {
 	mmapState
 }
 
-func NewContext(ctx context.Context, mappableMemory bool) context.Context {
+func NewContext(ctx context.Context) context.Context {
 	state := new(moduleState)
-	ctx = context.WithValue(ctx, moduleKey{}, state)
+	ctx = withMmappedAllocator(ctx)
 	ctx = experimental.WithCloseNotifier(ctx, state)
-	ctx = state.mmapState.init(ctx, mappableMemory)
+	ctx = context.WithValue(ctx, moduleKey{}, state)
 	return ctx
 }