coreapi: path.Mutable

License: MIT
Signed-off-by: Łukasz Magiera <magik6k@gmail.com>

core/coreapi/interface/path.go

@@ -6,13 +6,25 @@ import (
 
 // Path is a generic wrapper for paths used in the API. A path can be resolved
 // to a CID using one of Resolve functions in the API.
-// TODO: figure out/explain namespaces
+//
+// Paths must be prefixed with a valid prefix:
+//
+// * /ipfs - Immutable unixfs path (files)
+// * /ipld - Immutable ipld path (data)
+// * /ipns - Mutable names. Usually resolves to one of the immutable paths
+//TODO: /local (MFS)
 type Path interface {
 	// String returns the path as a string.
 	String() string
 
 	// Namespace returns the first component of the path
 	Namespace() string
+
+	// Mutable returns false if the data pointed to by this path in guaranteed
+	// to not change.
+	//
+	// Note that resolved mutable path can be immutable.
+	Mutable() bool
 }
 
 // ResolvedPath is a resolved Path

core/coreapi/path.go

@@ -97,7 +97,10 @@ func (api *CoreAPI) ParsePath(p string) (coreiface.Path, error) {
 	return &path{path: pp}, nil
 }
 
-func (p *path) String() string { return p.path.String() }
+func (p *path) String() string {
+	return p.path.String()
+}
+
 func (p *path) Namespace() string {
 	if len(p.path.Segments()) < 1 {
 		return ""
@@ -105,5 +108,15 @@ func (p *path) Namespace() string {
 	return p.path.Segments()[0]
 }
 
-func (p *resolvedPath) Cid() *cid.Cid  { return p.cid }
-func (p *resolvedPath) Root() *cid.Cid { return p.root }
+func (p *path) Mutable() bool {
+	//TODO: MFS: check for /local
+	return p.Namespace() == "ipns"
+}
+
+func (p *resolvedPath) Cid() *cid.Cid {
+	return p.cid
+}
+
+func (p *resolvedPath) Root() *cid.Cid {
+	return p.root
+}

core/coreapi/path_test.go

+package coreapi_test
+
+import (
+	"context"
+	"strings"
+	"testing"
+)
+
+func TestMutablePath(t *testing.T) {
+	ctx := context.Background()
+	_, api, err := makeAPI(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// get self /ipns path
+	keys, err := api.Key().List(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !keys[0].Path().Mutable() {
+		t.Error("expected self /ipns path to be mutable")
+	}
+
+	blk, err := api.Block().Put(ctx, strings.NewReader(`foo`))
+	if err != nil {
+		t.Error(err)
+	}
+
+	if blk.Mutable() {
+		t.Error("expected /ipld path to be immutable")
+	}
+}