Add ability to seal enum classes in Dart

serde-generate/src/config.rs

@@ -1,7 +1,7 @@
 // Copyright (c) Facebook, Inc. and its affiliates
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-use std::collections::{BTreeMap, BTreeSet};
+use std::collections::{BTreeMap, BTreeSet, HashMap};
 
 /// Code generation options meant to be supported by all languages.
 #[derive(Clone, Debug)]
@@ -12,7 +12,7 @@ pub struct CodeGeneratorConfig {
     pub external_definitions: ExternalDefinitions,
     pub comments: DocComments,
     pub custom_code: CustomCode,
-    pub c_style_enums: bool,
+    pub enums: EnumConfig,
     pub package_manifest: bool,
 }
 
@@ -36,6 +36,18 @@ pub type CustomCode = std::collections::BTreeMap<
     /* custom code */ String,
 >;
 
+/// Configure the generation style of enums.
+#[derive(Clone, Debug)]
+pub struct EnumConfig {
+    // Generate [enum] if `true` or classes if `false`
+    pub c_style: bool,
+    // Generate sealed class if `true` or abstract class if `false`
+    pub sealed: bool,
+    // If `sealed_enums` is true then the listed names will be abstract,
+    // if `sealed_enums` is false then the listed names will be sealed.
+    pub output_type: HashMap<&'static str, &'static str>,
+}
+
 /// How to copy generated source code and available runtimes for a given language.
 pub trait SourceInstaller {
     type Error;
@@ -67,7 +79,11 @@ impl CodeGeneratorConfig {
             external_definitions: BTreeMap::new(),
             comments: BTreeMap::new(),
             custom_code: BTreeMap::new(),
-            c_style_enums: false,
+            enums: EnumConfig {
+                c_style: false,
+                sealed: false,
+                output_type: HashMap::new(),
+            },
             package_manifest: true,
         }
     }
@@ -116,7 +132,23 @@ impl CodeGeneratorConfig {
     /// Generate C-style enums (without variant data) as the target language
     /// native enum type in supported languages.
     pub fn with_c_style_enums(mut self, c_style_enums: bool) -> Self {
-        self.c_style_enums = c_style_enums;
+        self.enums.c_style = c_style_enums;
+        self
+    }
+
+    /// For complex enums generate sealed enum classes instead of abstract classes
+    pub fn with_sealed_enums(mut self, sealed: bool) -> Self {
+        self.enums.sealed = sealed;
+        self
+    }
+
+    /// Generate abstract or sealed classes for data enums  based on `with_sealed_enums`
+    /// but allow item by item overrides.
+    pub fn with_enum_type_overrides(
+        mut self,
+        overrides: HashMap<&'static str, &'static str>,
+    ) -> Self {
+        self.enums.output_type = overrides;
         self
     }
 

serde-generate/src/cpp.rs

@@ -40,7 +40,7 @@ struct CppEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a C++ code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("C++ does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();

serde-generate/src/csharp.rs

@@ -83,7 +83,7 @@ impl<'a> CodeGenerator<'a> {
         // When we find an enum with all Unit variants, we ser/de as a regular C# enum.
         // We keep track of this so we can use the enum's extension class for ser/de since enums can't have methods.
         let mut cstyle_enum_names = Vec::new();
-        if self.config.c_style_enums {
+        if self.config.enums.c_style {
             for (name, format) in registry {
                 if let ContainerFormat::Enum(variants) = format {
                     if variants.values().all(|f| f.value == VariantFormat::Unit) {
@@ -1214,7 +1214,7 @@ impl crate::SourceInstaller for Installer {
         <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     </ItemGroup>
     <ItemGroup>
-{}    
+{}
     </ItemGroup>
 </Project>
 "#,

serde-generate/src/dart.rs

@@ -192,7 +192,7 @@ where
     // in Dart enums cannot have a static method added to them
     // yet so we must call the extension class instead
     fn get_class(&self, name: &str) -> String {
-        if self.generator.config.c_style_enums {
+        if self.generator.config.enums.c_style {
             use ContainerFormat::Enum;
             match self.get_field_container_type(name) {
                 // if we have an enum AND all of that enum's members are Unit
@@ -583,12 +583,19 @@ return obj;
             Struct(fields) => fields.clone(),
             Enum(variants) => {
                 // When we find an enum with all Unit variants, we ser/de as a regular Dart enum.
-                if self.generator.config.c_style_enums
+                if ((self.generator.config.enums.c_style
+                    && !self.generator.config.enums.output_type.contains_key(name))
+                    || self.generator.config.enums.output_type.get(name) == Some(&"enum"))
                     && variants.values().all(|f| f.value == VariantFormat::Unit)
                 {
                     self.output_enum_container(name, variants)?;
+                } else if (self.generator.config.enums.sealed
+                    && !self.generator.config.enums.output_type.contains_key(name))
+                    || self.generator.config.enums.output_type.get(name) == Some(&"sealed")
+                {
+                    self.output_enum_class_container(name, variants, "sealed")?;
                 } else {
-                    self.output_enum_class_container(name, variants)?;
+                    self.output_enum_class_container(name, variants, "abstract")?;
                 }
                 return Ok(());
             }
@@ -1052,12 +1059,14 @@ switch (this) {{"#,
         &mut self,
         name: &str,
         variants: &BTreeMap<u32, Named<VariantFormat>>,
+        class_type: &str,
     ) -> Result<()> {
         writeln!(self.out)?;
         self.output_comment(name)?;
         writeln!(
             self.out,
-            "abstract class {} {{",
+            "{} class {} {{",
+            class_type,
             self.quote_qualified_name(name)
         )?;
         self.enter_class(name);

serde-generate/src/golang.rs

@@ -39,7 +39,7 @@ struct GoEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a Go code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("Go does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();

serde-generate/src/java.rs

@@ -42,7 +42,7 @@ struct JavaEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a Java code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("Java does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();

serde-generate/src/ocaml.rs

@@ -30,7 +30,7 @@ struct OCamlEmitter<'a, T> {
 
 impl<'a> CodeGenerator<'a> {
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("OCaml does not support generating c-style enums");
         }
         Self {

serde-generate/src/python3.rs

@@ -37,7 +37,7 @@ struct PythonEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a Python code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("Python 3 does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();

serde-generate/src/solidity.rs

@@ -1455,7 +1455,7 @@ impl SolRegistry {
 impl<'a> CodeGenerator<'a> {
     /// Create a solidity code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("Solidity does not support generating c-style enums");
         }
         Self { config }

serde-generate/src/swift.rs

@@ -39,7 +39,7 @@ struct SwiftEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a Swift code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("Swift does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();

serde-generate/src/typescript.rs

@@ -38,7 +38,7 @@ struct TypeScriptEmitter<'a, T> {
 impl<'a> CodeGenerator<'a> {
     /// Create a TypeScript code generator for the given config.
     pub fn new(config: &'a CodeGeneratorConfig) -> Self {
-        if config.c_style_enums {
+        if config.enums.c_style {
             panic!("TypeScript does not support generating c-style enums");
         }
         let mut external_qualified_names = HashMap::new();