Merge branch 'feature/inhibit' of https://github.com/dtolnay/serde into dtolnay-feature/inhibit

This commit is contained in:
Erick Tryzelaar 2016-04-12 08:41:02 -07:00
commit bc2324fba7
3 changed files with 238 additions and 24 deletions

View File

@ -377,7 +377,7 @@ fn get_renames(cx: &ExtCtxt,
Ok((ser_name, de_name))
}
fn get_serde_meta_items(attr: &ast::Attribute) -> Option<&[P<ast::MetaItem>]> {
pub fn get_serde_meta_items(attr: &ast::Attribute) -> Option<&[P<ast::MetaItem>]> {
match attr.node.value.node {
ast::MetaItemKind::List(ref name, ref items) if name == &"serde" => {
attr::mark_used(&attr);

View File

@ -1,3 +1,5 @@
use std::collections::HashSet;
use aster;
use syntax::ast::{
@ -10,6 +12,7 @@ use syntax::codemap::Span;
use syntax::ext::base::{Annotatable, ExtCtxt};
use syntax::ext::build::AstBuilder;
use syntax::ptr::P;
use syntax::visit;
use attr;
use error::Error;
@ -60,11 +63,7 @@ fn serialize_item(
}
};
let impl_generics = builder.from_generics(generics.clone())
.add_ty_param_bound(
builder.path().global().ids(&["serde", "ser", "Serialize"]).build()
)
.build();
let impl_generics = build_impl_generics(cx, builder, item, generics);
let ty = builder.ty().path()
.segment(item.ident).with_generics(impl_generics.clone()).build()
@ -89,6 +88,157 @@ fn serialize_item(
).unwrap())
}
// All the generics in the input, plus a bound `T: Serialize` for each generic
// field type that will be serialized by us.
fn build_impl_generics(
cx: &ExtCtxt,
builder: &aster::AstBuilder,
item: &Item,
generics: &ast::Generics,
) -> ast::Generics {
let serialize_path = builder.path()
.global()
.ids(&["serde", "ser", "Serialize"])
.build();
builder.from_generics(generics.clone())
.with_predicates(
all_variants(cx, item).iter()
.flat_map(|variant_data| all_struct_fields(variant_data))
.filter(|field| serialized_by_us(field))
.map(|field| &field.ty)
// TODO this filter can be removed later, see comment on function
.filter(|ty| contains_generic(ty, generics))
.map(|ty| strip_reference(ty))
.map(|ty| builder.where_predicate()
// the type that is being bounded i.e. T
.bound().build(ty.clone())
// the bound i.e. Serialize
.bound().trait_(serialize_path.clone()).build()
.build()))
.build()
}
fn all_variants<'a>(cx: &ExtCtxt, item: &'a Item) -> Vec<&'a ast::VariantData> {
match item.node {
ast::ItemKind::Struct(ref variant_data, _) => {
vec![variant_data]
}
ast::ItemKind::Enum(ref enum_def, _) => {
enum_def.variants.iter()
.map(|variant| &variant.node.data)
.collect()
}
_ => {
cx.span_bug(item.span,
"expected Item to be Struct or Enum in #[derive(Serialize)]");
}
}
}
fn all_struct_fields(variant_data: &ast::VariantData) -> &[ast::StructField] {
match *variant_data {
ast::VariantData::Struct(ref fields, _) |
ast::VariantData::Tuple(ref fields, _) => {
fields
}
ast::VariantData::Unit(_) => {
&[]
}
}
}
// Fields with a `skip_serializing` or `serialize_with` attribute are not
// serialized by us. All other fields may need a `T: Serialize` bound where T is
// the type of the field.
fn serialized_by_us(field: &ast::StructField) -> bool {
for meta_items in field.attrs.iter().filter_map(attr::get_serde_meta_items) {
for meta_item in meta_items {
match meta_item.node {
ast::MetaItemKind::Word(ref name) if name == &"skip_serializing" => {
return false
}
ast::MetaItemKind::NameValue(ref name, _) if name == &"serialize_with" => {
return false
}
_ => {}
}
}
}
true
}
// Rust <1.7 enforces that `where` clauses involve generic type parameters. The
// corresponding compiler error is E0193. It is no longer enforced in Rust >=1.7
// so this filtering can be removed in the future when we stop supporting <1.7.
//
// E0193 means we must not generate a `where` clause like `i32: Serialize`
// because even though i32 implements Serialize, i32 is not a generic type
// parameter. Clauses like `T: Serialize` and `Option<T>: Serialize` are okay.
// This function decides whether a given type references any of the generic type
// parameters in the input `Generics`.
fn contains_generic(ty: &ast::Ty, generics: &ast::Generics) -> bool {
struct FindGeneric<'a> {
generic_names: &'a HashSet<ast::Name>,
found_generic: bool,
}
impl<'a, 'v> visit::Visitor<'v> for FindGeneric<'a> {
fn visit_path(&mut self, path: &'v ast::Path, _id: ast::NodeId) {
if !path.global
&& path.segments.len() == 1
&& self.generic_names.contains(&path.segments[0].identifier.name) {
self.found_generic = true;
} else {
visit::walk_path(self, path);
}
}
}
let generic_names: HashSet<_> = generics.ty_params.iter()
.map(|ty_param| ty_param.ident.name)
.collect();
let mut visitor = FindGeneric {
generic_names: &generic_names,
found_generic: false,
};
visit::walk_ty(&mut visitor, ty);
visitor.found_generic
}
// This is required to handle types that use both a reference and a value of
// the same type, as in:
//
// enum Test<'a, T> where T: 'a {
// Lifetime(&'a T),
// NoLifetime(T),
// }
//
// Preserving references, we would generate an impl like:
//
// impl<'a, T> Serialize for Test<'a, T>
// where &'a T: Serialize,
// T: Serialize { ... }
//
// And taking a reference to one of the elements would fail with:
//
// error: cannot infer an appropriate lifetime for pattern due
// to conflicting requirements [E0495]
// Test::NoLifetime(ref v) => { ... }
// ^~~~~
//
// Instead, we strip references before adding `T: Serialize` bounds in order to
// generate:
//
// impl<'a, T> Serialize for Test<'a, T>
// where T: Serialize { ... }
fn strip_reference(ty: &P<ast::Ty>) -> &P<ast::Ty> {
match ty.node {
ast::TyKind::Rptr(_, ref mut_ty) => &mut_ty.ty,
_ => ty
}
}
fn serialize_body(
cx: &ExtCtxt,
builder: &aster::AstBuilder,

View File

@ -10,23 +10,33 @@ use token::{
assert_de_tokens_error
};
trait Trait: Sized {
trait MyDefault: Sized {
fn my_default() -> Self;
}
trait ShouldSkip: Sized {
fn should_skip(&self) -> bool;
}
trait SerializeWith: Sized {
fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
where S: Serializer;
}
trait DeserializeWith: Sized {
fn deserialize_with<D>(de: &mut D) -> Result<Self, D::Error>
where D: Deserializer;
}
impl Trait for i32 {
impl MyDefault for i32 {
fn my_default() -> Self { 123 }
}
impl ShouldSkip for i32 {
fn should_skip(&self) -> bool { *self == 123 }
}
impl SerializeWith for i32 {
fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
where S: Serializer
{
@ -36,7 +46,9 @@ impl Trait for i32 {
false.serialize(ser)
}
}
}
impl DeserializeWith for i32 {
fn deserialize_with<D>(de: &mut D) -> Result<Self, D::Error>
where D: Deserializer
{
@ -49,11 +61,11 @@ impl Trait for i32 {
}
#[derive(Debug, PartialEq, Serialize, Deserialize)]
struct DefaultStruct<A, B: Default, C> where C: Trait {
struct DefaultStruct<A, B: Default, C> where C: MyDefault {
a1: A,
#[serde(default)]
a2: B,
#[serde(default="Trait::my_default")]
#[serde(default="MyDefault::my_default")]
a3: C,
}
@ -95,12 +107,12 @@ fn test_default_struct() {
}
#[derive(Debug, PartialEq, Serialize, Deserialize)]
enum DefaultEnum<A, B: Default, C> where C: Trait {
enum DefaultEnum<A, B: Default, C> where C: MyDefault {
Struct {
a1: A,
#[serde(default)]
a2: B,
#[serde(default="Trait::my_default")]
#[serde(default="MyDefault::my_default")]
a3: C,
}
}
@ -389,11 +401,11 @@ fn test_rename_enum() {
}
#[derive(Debug, PartialEq, Serialize)]
struct SkipSerializingStruct<'a, B, C> where C: Trait {
struct SkipSerializingStruct<'a, B, C> where C: ShouldSkip {
a: &'a i8,
#[serde(skip_serializing)]
b: B,
#[serde(skip_serializing_if="Trait::should_skip")]
#[serde(skip_serializing_if="ShouldSkip::should_skip")]
c: C,
}
@ -440,12 +452,12 @@ fn test_skip_serializing_struct() {
}
#[derive(Debug, PartialEq, Serialize)]
enum SkipSerializingEnum<'a, B, C> where C: Trait {
enum SkipSerializingEnum<'a, B, C> where C: ShouldSkip {
Struct {
a: &'a i8,
#[serde(skip_serializing)]
_b: B,
#[serde(skip_serializing_if="Trait::should_skip")]
#[serde(skip_serializing_if="ShouldSkip::should_skip")]
c: C,
}
}
@ -492,10 +504,62 @@ fn test_skip_serializing_enum() {
);
}
#[derive(Debug, PartialEq)]
struct NotSerializeStruct(i8);
#[derive(Debug, PartialEq)]
enum NotSerializeEnum { Trouble }
impl SerializeWith for NotSerializeEnum {
fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
where S: Serializer
{
"trouble".serialize(ser)
}
}
#[derive(Debug, PartialEq, Serialize)]
struct SerializeWithStruct<'a, B> where B: Trait {
struct ContainsNotSerialize<'a, B, C, D> where B: 'a, D: SerializeWith {
a: &'a Option<i8>,
#[serde(skip_serializing)]
b: &'a B,
#[serde(skip_serializing)]
c: Option<C>,
#[serde(serialize_with="SerializeWith::serialize_with")]
d: D,
}
#[test]
fn test_elt_not_serialize() {
let a = 1;
assert_ser_tokens(
&ContainsNotSerialize {
a: &Some(a),
b: &NotSerializeStruct(2),
c: Some(NotSerializeEnum::Trouble),
d: NotSerializeEnum::Trouble,
},
&[
Token::StructStart("ContainsNotSerialize", Some(2)),
Token::StructSep,
Token::Str("a"),
Token::Option(true),
Token::I8(1),
Token::StructSep,
Token::Str("d"),
Token::Str("trouble"),
Token::StructEnd,
]
);
}
#[derive(Debug, PartialEq, Serialize)]
struct SerializeWithStruct<'a, B> where B: SerializeWith {
a: &'a i8,
#[serde(serialize_with="Trait::serialize_with")]
#[serde(serialize_with="SerializeWith::serialize_with")]
b: B,
}
@ -544,10 +608,10 @@ fn test_serialize_with_struct() {
}
#[derive(Debug, PartialEq, Serialize)]
enum SerializeWithEnum<'a, B> where B: Trait {
enum SerializeWithEnum<'a, B> where B: SerializeWith {
Struct {
a: &'a i8,
#[serde(serialize_with="Trait::serialize_with")]
#[serde(serialize_with="SerializeWith::serialize_with")]
b: B,
}
}
@ -597,9 +661,9 @@ fn test_serialize_with_enum() {
}
#[derive(Debug, PartialEq, Deserialize)]
struct DeserializeWithStruct<B> where B: Trait {
struct DeserializeWithStruct<B> where B: DeserializeWith {
a: i8,
#[serde(deserialize_with="Trait::deserialize_with")]
#[serde(deserialize_with="DeserializeWith::deserialize_with")]
b: B,
}
@ -647,10 +711,10 @@ fn test_deserialize_with_struct() {
}
#[derive(Debug, PartialEq, Deserialize)]
enum DeserializeWithEnum<B> where B: Trait {
enum DeserializeWithEnum<B> where B: DeserializeWith {
Struct {
a: i8,
#[serde(deserialize_with="Trait::deserialize_with")]
#[serde(deserialize_with="DeserializeWith::deserialize_with")]
b: B,
}
}