dagger.#FS support

- Implement dagger.#FS support
- Migrate `context.imports` to dagger.#FS
- Backward compat: dagger.#FS can be passed in lieu of a
  dagger.#Artifact
- For instance, an import (`dagger.#FS`) can be passed to the current
  `yarn.#Package` implementation

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

plancontext/context.go

@@ -15,10 +15,11 @@ type ContextKey string
 // id := ctx.Secrets.Register("mysecret")
 // secret := ctx.Secrets.Get(id)
 type Context struct {
-	Platform    *platformContext
-	Directories *directoryContext
-	Secrets     *secretContext
-	Services    *serviceContext
+	Platform  *platformContext
+	FS        *fsContext
+	LocalDirs *localDirContext
+	Secrets   *secretContext
+	Services  *serviceContext
 }
 
 func New() *Context {
@@ -26,8 +27,11 @@ func New() *Context {
 		Platform: &platformContext{
 			platform: defaultPlatform,
 		},
-		Directories: &directoryContext{
-			store: make(map[ContextKey]*Directory),
+		FS: &fsContext{
+			store: make(map[ContextKey]*FS),
+		},
+		LocalDirs: &localDirContext{
+			store: make(map[ContextKey]*LocalDir),
 		},
 		Secrets: &secretContext{
 			store: make(map[ContextKey]*Secret),

plancontext/directory.go

@@ -1,54 +0,0 @@
-package plancontext
-
-import "sync"
-
-type Directory struct {
-	Path    string
-	Include []string
-	Exclude []string
-}
-
-type directoryContext struct {
-	l     sync.RWMutex
-	store map[ContextKey]*Directory
-}
-
-func (c *directoryContext) Register(directory *Directory) ContextKey {
-	c.l.Lock()
-	defer c.l.Unlock()
-
-	id := hashID(directory)
-	c.store[id] = directory
-	return id
-}
-
-func (c *directoryContext) Get(id ContextKey) *Directory {
-	c.l.RLock()
-	defer c.l.RUnlock()
-
-	return c.store[id]
-}
-
-func (c *directoryContext) List() []*Directory {
-	c.l.RLock()
-	defer c.l.RUnlock()
-
-	directories := make([]*Directory, 0, len(c.store))
-	for _, d := range c.store {
-		directories = append(directories, d)
-	}
-
-	return directories
-}
-
-func (c *directoryContext) Paths() map[string]string {
-	c.l.RLock()
-	defer c.l.RUnlock()
-
-	directories := make(map[string]string)
-	for _, d := range c.store {
-		directories[d.Path] = d.Path
-	}
-
-	return directories
-}

plancontext/fs.go

@@ -0,0 +1,32 @@
+package plancontext
+
+import (
+	"sync"
+
+	bkgw "github.com/moby/buildkit/frontend/gateway/client"
+)
+
+type FS struct {
+	Result bkgw.Reference
+}
+
+type fsContext struct {
+	l     sync.RWMutex
+	store map[ContextKey]*FS
+}
+
+func (c *fsContext) Register(fs *FS) ContextKey {
+	c.l.Lock()
+	defer c.l.Unlock()
+
+	id := hashID(fs)
+	c.store[id] = fs
+	return id
+}
+
+func (c *fsContext) Get(id ContextKey) *FS {
+	c.l.RLock()
+	defer c.l.RUnlock()
+
+	return c.store[id]
+}

plancontext/localdir.go

@@ -0,0 +1,60 @@
+package plancontext
+
+import (
+	"path/filepath"
+	"sync"
+)
+
+type LocalDir struct {
+	Path string
+}
+
+type localDirContext struct {
+	l     sync.RWMutex
+	store map[ContextKey]*LocalDir
+}
+
+func (c *localDirContext) Register(directory *LocalDir) ContextKey {
+	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
+}
+
+func (c *localDirContext) Paths() (map[string]string, error) {
+	c.l.RLock()
+	defer c.l.RUnlock()
+
+	directories := make(map[string]string)
+	for _, d := range c.store {
+		abs, err := filepath.Abs(d.Path)
+		if err != nil {
+			return nil, err
+		}
+
+		directories[d.Path] = abs
+	}
+
+	return directories, nil
+}