Optimize YamlParser with move semantics

- Improved the efficiency of the `YamlParser` by utilizing move semantics for the `Document` class in `Yaml.h`.
- Updated `YamlParser.cpp` to call `GetRoot` with `std::move(doc).GetRoot()` to avoid unnecessary copying.
- Modified `GetRoot` in `Yaml.h` to return an r-value reference (`Node&&`).
- Also, updated `GetSchemaHeader` to return a constant reference (`const DocumentSchemaHeader&`) to reduce copying.

src/AppInstallerCommonCore/Manifest/YamlParser.cpp

@@ -528,7 +528,7 @@ namespace AppInstaller::Manifest::YamlParser
 
                     YamlManifestInfo manifestInfo;
                     YAML::Document doc = YAML::LoadDocument(file.path());
-                    manifestInfo.Root = doc.GetRoot();
+                    manifestInfo.Root = std::move(doc).GetRoot();
                     manifestInfo.DocumentSchemaHeader = doc.GetSchemaHeader();
                     manifestInfo.FileName = file.path().filename().u8string();
                     docList.emplace_back(std::move(manifestInfo));
@@ -538,7 +538,7 @@ namespace AppInstaller::Manifest::YamlParser
             {
                 YamlManifestInfo manifestInfo;
                 YAML::Document doc = YAML::LoadDocument(inputPath, manifestInfo.StreamSha256);
-                manifestInfo.Root = doc.GetRoot();
+                manifestInfo.Root = std::move(doc).GetRoot();
                 manifestInfo.DocumentSchemaHeader = doc.GetSchemaHeader();
                 manifestInfo.FileName = inputPath.filename().u8string();
                 docList.emplace_back(std::move(manifestInfo));
@@ -563,7 +563,7 @@ namespace AppInstaller::Manifest::YamlParser
         {
             YamlManifestInfo manifestInfo;
             YAML::Document doc = YAML::LoadDocument(input);
-            manifestInfo.Root = doc.GetRoot();
+            manifestInfo.Root = std::move(doc).GetRoot();
             manifestInfo.DocumentSchemaHeader = doc.GetSchemaHeader();
             docList.emplace_back(std::move(manifestInfo));
         }

src/AppInstallerSharedLib/Public/winget/Yaml.h

@@ -253,9 +253,10 @@ namespace AppInstaller::YAML
         Document() = default;
         Document(Node root, DocumentSchemaHeader schemaHeader) : m_root(std::move(root)), m_schemaHeader(std::move(schemaHeader)) {}
 
+        const DocumentSchemaHeader& GetSchemaHeader() const { return m_schemaHeader; }
+
         // Return r-values for move semantics
-        Node GetRoot() const { return m_root; }
-        DocumentSchemaHeader GetSchemaHeader() const { return m_schemaHeader; }
+        Node&& GetRoot() && { return std::move(m_root); }
 
     private:
         Node m_root;