Add delete function

Add function to delete a path from a YAML tree.

delete.go

@@ -0,0 +1,106 @@
+// Copyright © 2020 The Homeport Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package ytbx
+
+import (
+	yamlv3 "gopkg.in/yaml.v3"
+)
+
+// Delete removes the section identified by the path from the YAML structure
+func Delete(node *yamlv3.Node, pathString string) (*yamlv3.Node, error) {
+	path, err := ParsePathString(pathString, node)
+	if err != nil {
+		return nil, err
+	}
+
+	switch node.Kind {
+	case yamlv3.DocumentNode:
+		return deletePath(node.Content[0], path)
+
+	default:
+		return deletePath(node, path)
+	}
+}
+
+func deletePath(node *yamlv3.Node, path Path) (*yamlv3.Node, error) {
+	parentPath := Path{
+		DocumentIdx:  path.DocumentIdx,
+		PathElements: path.PathElements[:len(path.PathElements)-1],
+	}
+
+	parent, err := grabByPath(node, parentPath)
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		lastPathElement PathElement  = path.PathElements[len(path.PathElements)-1]
+		deletedNode     *yamlv3.Node = nil
+	)
+
+	switch parent.Kind {
+	case yamlv3.MappingNode:
+		var keyName string = lastPathElement.Name
+		var deleteIdx int = -1
+		for i := 0; i < len(parent.Content); i += 2 {
+			k, v := parent.Content[i], parent.Content[i+1]
+
+			if k.Value == keyName {
+				deleteIdx = i
+				deletedNode = v
+				break
+			}
+		}
+
+		// delete the entry at delete index and the one after that as these two are
+		// the key (first entry) and the value (second entry)
+		parent.Content = append(
+			parent.Content[:deleteIdx],
+			parent.Content[deleteIdx+2:]...,
+		)
+
+		return deletedNode, nil
+
+	case yamlv3.SequenceNode:
+		var deleteIdx int = -1
+		if lastPathElement.isSimpleListElement() {
+			deleteIdx = lastPathElement.Idx
+		} else {
+			deleteIdx, err = getIndexByIdentifierAndName(parent, lastPathElement.Key, lastPathElement.Name)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		deletedNode = parent.Content[deleteIdx]
+
+		// delete the entry that was identified by the deletion index, since it is a
+		// sequence (list), only one entry needs to be deleted
+		parent.Content = append(
+			parent.Content[:deleteIdx],
+			parent.Content[deleteIdx+1:]...,
+		)
+
+		return deletedNode, nil
+	}
+
+	return nil, nil
+}

delete_test.go

@@ -0,0 +1,66 @@
+// Copyright © 2020 The Homeport Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package ytbx_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"github.com/gonvenience/ytbx"
+	"gopkg.in/yaml.v3"
+)
+
+var _ = Describe("Delete from YAML", func() {
+	var example *yaml.Node
+
+	BeforeEach(func() {
+		example = yml(assets("examples", "types.yml"))
+	})
+
+	Context("Delete path from given YAML structure", func() {
+		It("should delete an entry in a map referenced by the path", func() {
+			node, err := ytbx.Delete(example, "/yaml/map/before")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(node.Value).To(BeEquivalentTo("after"))
+			Expect(ytbx.IsPathInTree(example, "/yaml/map/before")).To(BeFalse())
+		})
+
+		It("should delete an entry in a simple list referenced by the path", func() {
+			node, err := ytbx.Delete(example, "/yaml/simple-list/1")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(node.Value).To(BeEquivalentTo("B"))
+
+			list, err := ytbx.Grab(example, "/yaml/simple-list")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(len(list.Content)).To(Equal(4))
+		})
+
+		It("should delete an entry in a named entry list referenced by the path", func() {
+			node, err := ytbx.Delete(example, "/yaml/named-entry-list-using-name/name=C")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(node).To(BeAsNode(yml(`{ name: C, foo: bar }`)))
+
+			list, err := ytbx.Grab(example, "/yaml/named-entry-list-using-name")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(len(list.Content)).To(Equal(4))
+		})
+	})
+})

list_functions.go

@@ -63,16 +63,25 @@ func getEntryFromNamedList(sequenceNode *yamlv3.Node, identifier string, name st
 }
 
 func getEntryByIdentifierAndName(sequenceNode *yamlv3.Node, identifier string, name string) (*yamlv3.Node, error) {
-	for _, mappingNode := range sequenceNode.Content {
+	idx, err := getIndexByIdentifierAndName(sequenceNode, identifier, name)
+	if err != nil {
+		return nil, err
+	}
+
+	return sequenceNode.Content[idx], nil
+}
+
+func getIndexByIdentifierAndName(sequenceNode *yamlv3.Node, identifier string, name string) (int, error) {
+	for idx, mappingNode := range sequenceNode.Content {
 		for i := 0; i < len(mappingNode.Content); i += 2 {
 			k, v := mappingNode.Content[i], mappingNode.Content[i+1]
 			if k.Value == identifier && v.Value == name {
-				return mappingNode, nil
+				return idx, nil
 			}
 		}
 	}
 
-	return nil,
+	return -1,
 		fmt.Errorf("there is no entry %s=%v in the list",
 			identifier,
 			name,