Migrate dagger.#Secret and dagger.#Stream to new format

- Refactored to keep every transformation of built-in types (e.g. FS,
  Secret, etc) to/from CUE in the same place (plancontext)
- dagger.#Service and dagger.#Secret are now following the new FS-like format
  (e.g. `_service: id: string`)
- Backward compatibility
- dagger.#Stream is now an alias for dagger.#Service

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

plancontext/localdir.go

@@ -5,41 +5,16 @@ import (
 	"sync"
 )
 
-type LocalDir struct {
-	Path string
-}
-
 type localDirContext struct {
 	l     sync.RWMutex
-	store map[ContextKey]*LocalDir
+	store []string
 }
 
-func (c *localDirContext) Register(directory *LocalDir) ContextKey {
+func (c *localDirContext) Add(dir string) {
 	c.l.Lock()
 	defer c.l.Unlock()
 
-	id := hashID(directory)
-	c.store[id] = directory
-	return id
-}
-
-func (c *localDirContext) Get(id ContextKey) *LocalDir {
-	c.l.RLock()
-	defer c.l.RUnlock()
-
-	return c.store[id]
-}
-
-func (c *localDirContext) List() []*LocalDir {
-	c.l.RLock()
-	defer c.l.RUnlock()
-
-	directories := make([]*LocalDir, 0, len(c.store))
-	for _, d := range c.store {
-		directories = append(directories, d)
-	}
-
-	return directories
+	c.store = append(c.store, dir)
 }
 
 func (c *localDirContext) Paths() (map[string]string, error) {
@@ -48,12 +23,12 @@ func (c *localDirContext) Paths() (map[string]string, error) {
 
 	directories := make(map[string]string)
 	for _, d := range c.store {
-		abs, err := filepath.Abs(d.Path)
+		abs, err := filepath.Abs(d)
 		if err != nil {
 			return nil, err
 		}
 
-		directories[d.Path] = abs
+		directories[d] = abs
 	}
 
 	return directories, nil