definitions: Implement GSP-86 Add CreateLink (#674)

* definitions: Implement GSP-86 Add CreateLink

* definitions: add more details about the behavior for create_link

* definitions:Implement GSP-86 add virtual_link feature

.gitignore

@@ -19,4 +19,8 @@ bin/
 release/
 coverage/
 coverage.*
-tests/*.yaml
+tests/*.yaml
+
+# Jetbrain IDE
+.idea
+*.iml

definitions/features.toml

@@ -26,3 +26,14 @@ virtual_object_metadata feature is designed for a service that doesn't have nati
 
 This feature was introduced in GSP-109.
 """
+
+[virtual_link]
+description = """
+virtual_link feature is designed for a service that doesn't have native support for link.
+
+- If this feature is enabled, the service will run compatible mode: create link via native methods, but allow read link from old-style link object.
+- If this feature is not enabled, the service will run in native as other service.
+
+This feature was introduced in GSP-86.
+"""
+

definitions/fields.toml

@@ -69,3 +69,6 @@ type = "string"
 
 [w]
 type = "io.Writer"
+
+[target]
+type = "string"

definitions/operations.toml

@@ -286,3 +286,22 @@ will write data into a file.
   - Service that doesn't have native support for `overwrite` SHOULD check and delete the object if exists.
 - A successful write operation SHOULD be complete, which means the object's content and metadata should be the same as specified in write request.
 """
+
+[linker]
+description = "is the interface for link"
+
+[linker.op.create_link]
+params = ["path", "target"]
+results = ["o"]
+description = """
+Will create a link object.
+
+# Behavior
+
+- `path` and `target` COULD be relative or absolute path.
+- If `target` exists, CreateLink will create a link object on the target.
+- If `path` does not exist, the CreateLink will fail, and no link object will be created anywhere.
+- A link object COULD be returned in `Stat` or `List`.
+- CreateLink COULD implement virtual_link feature when service without native support.
+  - Users SHOULD enable this feature by themselves.
+"""

types/operation.generated.go

@@ -274,6 +274,53 @@ func (s UnimplementedFetcher) FetchWithContext(ctx context.Context, path string,
 	return
 }
 
+// Linker is the interface for link
+type Linker interface {
+
+	// CreateLink Will create a link object.
+	//
+	// # Behavior
+	//
+	// - `path` and `target` COULD be relative or absolute path.
+	// - If `target` exists, CreateLink will create a link object on the target.
+	// - If `path` does not exist, the CreateLink will fail, and no link object will be created anywhere.
+	// - A link object COULD be returned in `Stat` or `List`.
+	// - CreateLink COULD implement virtual_link feature when service without native support.
+	//   - Users SHOULD enable this feature by themselves.
+	CreateLink(path string, target string, pairs ...Pair) (o *Object, err error)
+	// CreateLinkWithContext Will create a link object.
+	//
+	// # Behavior
+	//
+	// - `path` and `target` COULD be relative or absolute path.
+	// - If `target` exists, CreateLink will create a link object on the target.
+	// - If `path` does not exist, the CreateLink will fail, and no link object will be created anywhere.
+	// - A link object COULD be returned in `Stat` or `List`.
+	// - CreateLink COULD implement virtual_link feature when service without native support.
+	//   - Users SHOULD enable this feature by themselves.
+	CreateLinkWithContext(ctx context.Context, path string, target string, pairs ...Pair) (o *Object, err error)
+
+	mustEmbedUnimplementedLinker()
+}
+
+// UnimplementedLinker must be embedded to have forward compatible implementations.
+type UnimplementedLinker struct{}
+
+func (s UnimplementedLinker) mustEmbedUnimplementedLinker() {}
+
+func (s UnimplementedLinker) String() string {
+	return "UnimplementedLinker"
+}
+
+func (s UnimplementedLinker) CreateLink(path string, target string, pairs ...Pair) (o *Object, err error) {
+	err = NewOperationNotImplementedError("create_link")
+	return
+}
+func (s UnimplementedLinker) CreateLinkWithContext(ctx context.Context, path string, target string, pairs ...Pair) (o *Object, err error) {
+	err = NewOperationNotImplementedError("create_link")
+	return
+}
+
 // Mover is the interface for Move.
 type Mover interface {