Merge pull request #715 from serde-rs/nostd

Support serde_derive on no_std

.travis.yml

@@ -18,6 +18,7 @@ script:
 - (cd testing && travis-cargo --skip nightly test)
 - (cd testing && travis-cargo --only nightly test -- --features unstable-testing)
 - (cd serde_derive && travis-cargo --only nightly test)
+- (cd serde_derive/no-std-tests && travis-cargo --only nightly build)
 #- (cd examples/serde-syntex-example && travis-cargo --skip nightly run)
 #- (cd examples/serde-syntex-example && travis-cargo --only nightly run -- --no-default-features --features unstable)
 - (cd serde && travis-cargo --only stable doc)

serde/src/export.rs

@@ -0,0 +1,33 @@
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::String;
+
+#[cfg(feature = "std")]
+use std::borrow::Cow;
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::borrow::Cow;
+
+pub use core::default::Default;
+pub use core::fmt;
+pub use core::marker::PhantomData;
+pub use core::result::Result;
+
+#[cfg(any(feature = "collections", feature = "std"))]
+pub fn from_utf8_lossy(bytes: &[u8]) -> Cow<str> {
+    String::from_utf8_lossy(bytes)
+}
+
+// The generated code calls this like:
+//
+//     let value = &_serde::export::from_utf8_lossy(bytes);
+//     Err(_serde::de::Error::unknown_variant(value, VARIANTS))
+//
+// so it is okay for the return type to be different from the std case as long
+// as the above works.
+#[cfg(not(any(feature = "collections", feature = "std")))]
+pub fn from_utf8_lossy(bytes: &[u8]) -> &str {
+    use core::str;
+    // Three unicode replacement characters if it fails. They look like a
+    // white-on-black question mark. The user will recognize it as invalid
+    // UTF-8.
+    str::from_utf8(bytes).unwrap_or("\u{fffd}\u{fffd}\u{fffd}")
+}

serde/src/lib.rs

@@ -31,7 +31,7 @@ extern crate core as actual_core;
 #[cfg(feature = "std")]
 mod core {
     pub use std::{ops, hash, fmt, cmp, marker, mem, i8, i16, i32, i64, u8, u16, u32, u64, isize,
-            usize, f32, f64, char, str, num, slice, iter, cell};
+            usize, f32, f64, char, str, num, slice, iter, cell, default, result};
     #[cfg(feature = "unstable")]
     pub use actual_core::nonzero;
 }
@@ -50,3 +50,7 @@ pub mod ser;
 #[cfg_attr(feature = "std", doc(hidden))]
 pub mod error;
 mod utils;
+
+// Generated code uses these to support no_std. Not public API.
+#[doc(hidden)]
+pub mod export;

serde_codegen/src/de.rs

@@ -36,7 +36,7 @@ pub fn expand_derive_deserialize(item: &syn::MacroInput) -> Result<Tokens, Strin
             extern crate serde as _serde;
             #[automatically_derived]
             impl #impl_generics _serde::Deserialize for #ty #where_clause {
-                fn deserialize<__D>(deserializer: __D) -> ::std::result::Result<#ty, __D::Error>
+                fn deserialize<__D>(deserializer: __D) -> _serde::export::Result<#ty, __D::Error>
                     where __D: _serde::Deserializer
                 #body
             }
@@ -158,11 +158,11 @@ fn deserialize_visitor(generics: &syn::Generics) -> (Tokens, Tokens, Tokens) {
         let phantom_types = generics.lifetimes.iter()
             .map(|lifetime_def| {
                 let lifetime = &lifetime_def.lifetime;
-                quote!(::std::marker::PhantomData<& #lifetime ()>)
+                quote!(_serde::export::PhantomData<& #lifetime ()>)
             }).chain(generics.ty_params.iter()
                 .map(|ty_param| {
                     let ident = &ty_param.ident;
-                    quote!(::std::marker::PhantomData<#ident>)
+                    quote!(_serde::export::PhantomData<#ident>)
                 }));
 
         let all_params = generics.lifetimes.iter()
@@ -182,7 +182,7 @@ fn deserialize_visitor(generics: &syn::Generics) -> (Tokens, Tokens, Tokens) {
             Some(quote!(::<#(#ty_param_idents),*>))
         };
 
-        let phantom_exprs = iter::repeat(quote!(::std::marker::PhantomData)).take(num_phantoms);
+        let phantom_exprs = iter::repeat(quote!(_serde::export::PhantomData)).take(num_phantoms);
 
         (
             quote! {
@@ -208,19 +208,19 @@ fn deserialize_unit_struct(
         impl _serde::de::Visitor for __Visitor {
             type Value = #type_ident;
 
-            fn expecting(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn expecting(&self, formatter: &mut _serde::export::fmt::Formatter) -> _serde::export::fmt::Result {
                 formatter.write_str(#expecting)
             }
 
             #[inline]
-            fn visit_unit<__E>(self) -> ::std::result::Result<#type_ident, __E>
+            fn visit_unit<__E>(self) -> _serde::export::Result<#type_ident, __E>
                 where __E: _serde::de::Error,
             {
                 Ok(#type_ident)
             }
 
             #[inline]
-            fn visit_seq<__V>(self, _: __V) -> ::std::result::Result<#type_ident, __V::Error>
+            fn visit_seq<__V>(self, _: __V) -> _serde::export::Result<#type_ident, __V::Error>
                 where __V: _serde::de::SeqVisitor,
             {
                 Ok(#type_ident)
@@ -297,14 +297,14 @@ fn deserialize_tuple(
         impl #impl_generics _serde::de::Visitor for #visitor_ty #where_clause {
             type Value = #ty;
 
-            fn expecting(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn expecting(&self, formatter: &mut _serde::export::fmt::Formatter) -> _serde::export::fmt::Result {
                 formatter.write_str(#expecting)
             }
 
             #visit_newtype_struct
 
             #[inline]
-            fn visit_seq<__V>(self, #visitor_var: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_seq<__V>(self, #visitor_var: __V) -> _serde::export::Result<#ty, __V::Error>
                 where __V: _serde::de::SeqVisitor
             {
                 #visit_seq
@@ -408,7 +408,7 @@ fn deserialize_newtype_struct(
     };
     quote! {
         #[inline]
-        fn visit_newtype_struct<__E>(self, __e: __E) -> ::std::result::Result<Self::Value, __E::Error>
+        fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::export::Result<Self::Value, __E::Error>
             where __E: _serde::Deserializer,
         {
             Ok(#type_path(#value))
@@ -480,19 +480,19 @@ fn deserialize_struct(
         impl #impl_generics _serde::de::Visitor for #visitor_ty #where_clause {
             type Value = #ty;
 
-            fn expecting(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn expecting(&self, formatter: &mut _serde::export::fmt::Formatter) -> _serde::export::fmt::Result {
                 formatter.write_str(#expecting)
             }
 
             #[inline]
-            fn visit_seq<__V>(self, #visitor_var: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_seq<__V>(self, #visitor_var: __V) -> _serde::export::Result<#ty, __V::Error>
                 where __V: _serde::de::SeqVisitor
             {
                 #visit_seq
             }
 
             #[inline]
-            fn visit_map<__V>(self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_map<__V>(self, mut visitor: __V) -> _serde::export::Result<#ty, __V::Error>
                 where __V: _serde::de::MapVisitor
             {
                 #visit_map
@@ -585,11 +585,11 @@ fn deserialize_item_enum(
         impl #impl_generics _serde::de::Visitor for #visitor_ty #where_clause {
             type Value = #ty;
 
-            fn expecting(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn expecting(&self, formatter: &mut _serde::export::fmt::Formatter) -> _serde::export::fmt::Result {
                 formatter.write_str(#expecting)
             }
 
-            fn visit_enum<__V>(self, visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_enum<__V>(self, visitor: __V) -> _serde::export::Result<#ty, __V::Error>
                 where __V: _serde::de::EnumVisitor,
             {
                 #match_variant
@@ -696,7 +696,7 @@ fn deserialize_field_visitor(
         let variant_indices = 0usize..;
         let fallthrough_msg = format!("variant index 0 <= i < {}", fields.len());
         Some(quote! {
-            fn visit_usize<__E>(self, value: usize) -> ::std::result::Result<__Field, __E>
+            fn visit_usize<__E>(self, value: usize) -> _serde::export::Result<__Field, __E>
                 where __E: _serde::de::Error
             {
                 match value {
@@ -731,7 +731,7 @@ fn deserialize_field_visitor(
         Some(quote! {
             // TODO https://github.com/serde-rs/serde/issues/666
             // update this to use str::from_utf8(value).unwrap_or("<22><><EFBFBD>") on no_std
-            let value = &::std::string::String::from_utf8_lossy(value);
+            let value = &_serde::export::from_utf8_lossy(value);
         })
     } else {
         None
@@ -746,7 +746,7 @@ fn deserialize_field_visitor(
 
         impl _serde::Deserialize for __Field {
             #[inline]
-            fn deserialize<__D>(deserializer: __D) -> ::std::result::Result<__Field, __D::Error>
+            fn deserialize<__D>(deserializer: __D) -> _serde::export::Result<__Field, __D::Error>
                 where __D: _serde::Deserializer,
             {
                 struct __FieldVisitor;
@@ -754,13 +754,13 @@ fn deserialize_field_visitor(
                 impl _serde::de::Visitor for __FieldVisitor {
                     type Value = __Field;
 
-                    fn expecting(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+                    fn expecting(&self, formatter: &mut _serde::export::fmt::Formatter) -> _serde::export::fmt::Result {
                         formatter.write_str("field name")
                     }
 
                     #visit_usize
 
-                    fn visit_str<__E>(self, value: &str) -> ::std::result::Result<__Field, __E>
+                    fn visit_str<__E>(self, value: &str) -> _serde::export::Result<__Field, __E>
                         where __E: _serde::de::Error
                     {
                         match value {
@@ -771,7 +771,7 @@ fn deserialize_field_visitor(
                         }
                     }
 
-                    fn visit_bytes<__E>(self, value: &[u8]) -> ::std::result::Result<__Field, __E>
+                    fn visit_bytes<__E>(self, value: &[u8]) -> _serde::export::Result<__Field, __E>
                         where __E: _serde::de::Error
                     {
                         match value {
@@ -981,18 +981,18 @@ fn wrap_deserialize_with(
         quote! {
             struct __SerdeDeserializeWithStruct #impl_generics #where_clause {
                 value: #field_ty,
-                phantom: ::std::marker::PhantomData<#phantom_ty>,
+                phantom: _serde::export::PhantomData<#phantom_ty>,
             }
         },
         quote! {
             impl #impl_generics _serde::Deserialize for #wrapper_ty #where_clause {
-                fn deserialize<__D>(__d: __D) -> ::std::result::Result<Self, __D::Error>
+                fn deserialize<__D>(__d: __D) -> _serde::export::Result<Self, __D::Error>
                     where __D: _serde::Deserializer
                 {
                     let value = try!(#deserialize_with(__d));
                     Ok(__SerdeDeserializeWithStruct {
                         value: value,
-                        phantom: ::std::marker::PhantomData,
+                        phantom: _serde::export::PhantomData,
                     })
                 }
             }
@@ -1004,7 +1004,7 @@ fn wrap_deserialize_with(
 fn expr_is_missing(attrs: &attr::Field) -> Tokens {
     match *attrs.default() {
         attr::FieldDefault::Default => {
-            return quote!(::std::default::Default::default());
+            return quote!(_serde::export::Default::default());
         }
         attr::FieldDefault::Path(ref path) => {
             return quote!(#path());

serde_codegen/src/ser.rs

@@ -30,7 +30,7 @@ pub fn expand_derive_serialize(item: &syn::MacroInput) -> Result<Tokens, String>
             extern crate serde as _serde;
             #[automatically_derived]
             impl #impl_generics _serde::Serialize for #ty #where_clause {
-                fn serialize<__S>(&self, _serializer: __S) -> ::std::result::Result<__S::Ok, __S::Error>
+                fn serialize<__S>(&self, _serializer: __S) -> _serde::export::Result<__S::Ok, __S::Error>
                     where __S: _serde::Serializer
                 {
                     #body
@@ -541,7 +541,7 @@ fn wrap_serialize_with(
         }
 
         impl #wrapper_generics _serde::Serialize for #wrapper_ty #where_clause {
-            fn serialize<__S>(&self, __s: __S) -> ::std::result::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&self, __s: __S) -> _serde::export::Result<__S::Ok, __S::Error>
                 where __S: _serde::Serializer
             {
                 #path(self.value, __s)

serde_derive/no-std-tests/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "serde_derive_tests_no_std"
+version = "0.9.0-rc2"
+publish = false
+
+[dependencies]
+serde = { path = "../../serde", default-features = false }
+serde_derive = { path = ".." }

serde_derive/no-std-tests/src/main.rs

@@ -0,0 +1,50 @@
+#![feature(lang_items, start, libc)]
+#![no_std]
+
+extern crate libc;
+
+#[start]
+fn start(_argc: isize, _argv: *const *const u8) -> isize {
+    0
+}
+
+#[lang = "eh_personality"]
+#[no_mangle]
+pub extern fn rust_eh_personality() {}
+
+#[lang = "eh_unwind_resume"]
+#[no_mangle]
+pub extern fn rust_eh_unwind_resume() {}
+
+#[lang = "panic_fmt"]
+#[no_mangle]
+pub extern fn rust_begin_panic(_msg: core::fmt::Arguments,
+                               _file: &'static str,
+                               _line: u32) -> ! {
+    loop {}
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize, Deserialize)]
+struct Unit;
+
+#[derive(Serialize, Deserialize)]
+struct Newtype(u8);
+
+#[derive(Serialize, Deserialize)]
+struct Tuple(u8, u8);
+
+#[derive(Serialize, Deserialize)]
+struct Struct { f: u8 }
+
+#[derive(Serialize, Deserialize)]
+enum Enum {
+    Unit,
+    Newtype(u8),
+    Tuple(u8, u8),
+    Struct { f: u8 },
+}