Merge pull request #127 from itchyny/refactor-struct-info-derive-buil…

…der-attr

Refactor implementations of StructInfo::derive and TypeBuilderAttr

typed-builder-macro/src/builder_attr.rs

@@ -0,0 +1,202 @@
+use proc_macro2::TokenStream;
+use quote::{quote, ToTokens};
+use syn::parse::Error;
+
+use crate::field_info::FieldBuilderAttr;
+use crate::mutator::Mutator;
+use crate::util::{path_to_single_string, ApplyMeta, AttrArg};
+
+#[derive(Debug, Default, Clone)]
+pub struct CommonDeclarationSettings {
+    pub vis: Option<syn::Visibility>,
+    pub name: Option<syn::Expr>,
+    pub doc: Option<syn::Expr>,
+}
+
+impl ApplyMeta for CommonDeclarationSettings {
+    fn apply_meta(&mut self, expr: AttrArg) -> Result<(), Error> {
+        match expr.name().to_string().as_str() {
+            "vis" => {
+                let expr_str = expr.key_value()?.parse_value::<syn::LitStr>()?.value();
+                self.vis = Some(syn::parse_str(&expr_str)?);
+                Ok(())
+            }
+            "name" => {
+                self.name = Some(expr.key_value()?.parse_value()?);
+                Ok(())
+            }
+            "doc" => {
+                self.doc = Some(expr.key_value()?.parse_value()?);
+                Ok(())
+            }
+            _ => Err(Error::new_spanned(
+                expr.name(),
+                format!("Unknown parameter {:?}", expr.name().to_string()),
+            )),
+        }
+    }
+}
+
+impl CommonDeclarationSettings {
+    pub fn get_name(&self) -> Option<TokenStream> {
+        self.name.as_ref().map(|name| name.to_token_stream())
+    }
+
+    pub fn get_doc_or(&self, gen_doc: impl FnOnce() -> String) -> TokenStream {
+        if let Some(ref doc) = self.doc {
+            quote!(#[doc = #doc])
+        } else {
+            let doc = gen_doc();
+            quote!(#[doc = #doc])
+        }
+    }
+}
+
+/// Setting of the `into` argument.
+#[derive(Debug, Clone)]
+pub enum IntoSetting {
+    /// Do not run any conversion on the built value.
+    NoConversion,
+    /// Convert the build value into the generic parameter passed to the `build` method.
+    GenericConversion,
+    /// Convert the build value into a specific type specified in the attribute.
+    TypeConversionToSpecificType(syn::TypePath),
+}
+
+impl Default for IntoSetting {
+    fn default() -> Self {
+        Self::NoConversion
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct BuildMethodSettings {
+    pub common: CommonDeclarationSettings,
+
+    /// Whether to convert the built type into another while finishing the build.
+    pub into: IntoSetting,
+}
+
+impl ApplyMeta for BuildMethodSettings {
+    fn apply_meta(&mut self, expr: AttrArg) -> Result<(), Error> {
+        match expr.name().to_string().as_str() {
+            "into" => match expr {
+                AttrArg::Flag(_) => {
+                    self.into = IntoSetting::GenericConversion;
+                    Ok(())
+                }
+                AttrArg::KeyValue(key_value) => {
+                    let type_path = key_value.parse_value::<syn::TypePath>()?;
+                    self.into = IntoSetting::TypeConversionToSpecificType(type_path);
+                    Ok(())
+                }
+                _ => Err(expr.incorrect_type()),
+            },
+            _ => self.common.apply_meta(expr),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct TypeBuilderAttr<'a> {
+    /// Whether to show docs for the `TypeBuilder` type (rather than hiding them).
+    pub doc: bool,
+
+    /// Customize builder method, ex. visibility, name
+    pub builder_method: CommonDeclarationSettings,
+
+    /// Customize builder type, ex. visibility, name
+    pub builder_type: CommonDeclarationSettings,
+
+    /// Customize build method, ex. visibility, name
+    pub build_method: BuildMethodSettings,
+
+    pub field_defaults: FieldBuilderAttr<'a>,
+
+    pub crate_module_path: syn::Path,
+
+    /// Functions that are able to mutate fields in the builder that are already set
+    pub mutators: Vec<Mutator>,
+}
+
+impl Default for TypeBuilderAttr<'_> {
+    fn default() -> Self {
+        Self {
+            doc: Default::default(),
+            builder_method: Default::default(),
+            builder_type: Default::default(),
+            build_method: Default::default(),
+            field_defaults: Default::default(),
+            crate_module_path: syn::parse_quote!(::typed_builder),
+            mutators: Default::default(),
+        }
+    }
+}
+
+impl<'a> TypeBuilderAttr<'a> {
+    pub fn new(attrs: &[syn::Attribute]) -> Result<Self, Error> {
+        let mut result = Self::default();
+
+        for attr in attrs {
+            let list = match &attr.meta {
+                syn::Meta::List(list) => {
+                    if path_to_single_string(&list.path).as_deref() != Some("builder") {
+                        continue;
+                    }
+
+                    list
+                }
+                _ => continue,
+            };
+
+            result.apply_subsections(list)?;
+        }
+
+        if result.builder_type.doc.is_some() || result.build_method.common.doc.is_some() {
+            result.doc = true;
+        }
+
+        Ok(result)
+    }
+}
+
+impl ApplyMeta for TypeBuilderAttr<'_> {
+    fn apply_meta(&mut self, expr: AttrArg) -> Result<(), Error> {
+        match expr.name().to_string().as_str() {
+            "crate_module_path" => {
+                let crate_module_path = expr.key_value()?.parse_value::<syn::ExprPath>()?;
+                self.crate_module_path = crate_module_path.path;
+                Ok(())
+            }
+            "builder_method_doc" => Err(Error::new_spanned(
+                expr.name(),
+                "`builder_method_doc` is deprecated - use `builder_method(doc = \"...\")`",
+            )),
+            "builder_type_doc" => Err(Error::new_spanned(
+                expr.name(),
+                "`builder_typemethod_doc` is deprecated - use `builder_type(doc = \"...\")`",
+            )),
+            "build_method_doc" => Err(Error::new_spanned(
+                expr.name(),
+                "`build_method_doc` is deprecated - use `build_method(doc = \"...\")`",
+            )),
+            "doc" => {
+                expr.flag()?;
+                self.doc = true;
+                Ok(())
+            }
+            "mutators" => {
+                self.mutators.extend(expr.sub_attr()?.undelimited()?);
+                Ok(())
+            }
+            "field_defaults" => self.field_defaults.apply_sub_attr(expr.sub_attr()?),
+            "builder_method" => self.builder_method.apply_sub_attr(expr.sub_attr()?),
+            "builder_type" => self.builder_type.apply_sub_attr(expr.sub_attr()?),
+            "build_method" => self.build_method.apply_sub_attr(expr.sub_attr()?),
+            _ => Err(Error::new_spanned(
+                expr.name(),
+                format!("Unknown parameter {:?}", expr.name().to_string()),
+            )),
+        }
+    }
+}

typed-builder-macro/src/lib.rs

@@ -1,7 +1,7 @@
 use proc_macro2::TokenStream;
-use quote::quote;
 use syn::{parse::Error, parse_macro_input, spanned::Spanned, DeriveInput};
 
+mod builder_attr;
 mod field_info;
 mod mutator;
 mod struct_info;
@@ -19,34 +19,7 @@ pub fn derive_typed_builder(input: proc_macro::TokenStream) -> proc_macro::Token
 fn impl_my_derive(ast: &syn::DeriveInput) -> Result<TokenStream, Error> {
     let data = match &ast.data {
         syn::Data::Struct(data) => match &data.fields {
-            syn::Fields::Named(fields) => {
-                let struct_info = struct_info::StructInfo::new(ast, fields.named.iter())?;
-                let builder_creation = struct_info.builder_creation_impl()?;
-                let fields = struct_info
-                    .setter_fields()
-                    .map(|f| struct_info.field_impl(f))
-                    .collect::<Result<TokenStream, _>>()?;
-                let required_fields = struct_info
-                    .setter_fields()
-                    .filter(|f| f.builder_attr.default.is_none())
-                    .map(|f| struct_info.required_field_impl(f));
-                let mutators = struct_info
-                    .fields
-                    .iter()
-                    .flat_map(|f| &f.builder_attr.mutators)
-                    .chain(&struct_info.builder_attr.mutators)
-                    .map(|m| struct_info.mutator_impl(m))
-                    .collect::<Result<TokenStream, _>>()?;
-                let build_method = struct_info.build_method_impl();
-
-                quote! {
-                    #builder_creation
-                    #fields
-                    #(#required_fields)*
-                    #mutators
-                    #build_method
-                }
-            }
+            syn::Fields::Named(fields) => struct_info::StructInfo::new(ast, fields.named.iter())?.derive()?,
             syn::Fields::Unnamed(_) => return Err(Error::new(ast.span(), "TypedBuilder is not supported for tuple structs")),
             syn::Fields::Unit => return Err(Error::new(ast.span(), "TypedBuilder is not supported for unit structs")),
         },