Merge pull request #671 from serde-rs/fields

Stop generating visit_usize and visit_bytes for FieldVisitor

serde_codegen/src/de.rs

@@ -1,5 +1,5 @@
 use syn::{self, aster};
-use quote::{self, Tokens};
+use quote::Tokens;
 
 use bound;
 use internals::ast::{Body, Field, Item, Style, Variant};
@@ -642,7 +642,7 @@ fn deserialize_field_visitor(
     is_variant: bool,
 ) -> Tokens {
     // Create the field names for the fields.
-    let field_idents: Vec<_> = (0 .. field_names.len())
+    let ref field_idents: Vec<_> = (0 .. field_names.len())
         .map(|i| aster::id(format!("__field{}", i)))
         .collect();
 
@@ -652,90 +652,18 @@ fn deserialize_field_visitor(
         Some(quote!(__ignore,))
     };
 
-    let index_field_arms: Vec<_> = field_idents.iter()
+    let fallthrough_arm = if is_variant {
-        .enumerate()
-        .map(|(field_index, field_ident)| {
         quote! {
-                #field_index => { Ok(__Field::#field_ident) }
+            Err(_serde::de::Error::unknown_variant(value))
+        }
+    } else if item_attrs.deny_unknown_fields() {
+        quote! {
+            Err(_serde::de::Error::unknown_field(value))
         }
-        })
-        .collect();
-
-    let (index_error_msg, unknown_ident) = if is_variant {
-        ("expected a variant", aster::id("unknown_variant"))
     } else {
-        ("expected a field", aster::id("unknown_field"))
-    };
-
-    let fallthrough_index_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
         quote! {
             Ok(__Field::__ignore)
         }
-    } else {
-        quote! {
-            Err(_serde::de::Error::invalid_value(#index_error_msg))
-        }
-    };
-
-    let index_body = quote! {
-        match value {
-            #(#index_field_arms)*
-            _ => #fallthrough_index_arm_expr
-        }
-    };
-
-    // Match arms to extract a field from a string
-    let str_field_arms: Vec<_> = field_idents.iter().zip(field_names.iter())
-        .map(|(field_ident, field_name)| {
-            quote! {
-                #field_name => { Ok(__Field::#field_ident) }
-            }
-        })
-        .collect();
-
-    let fallthrough_str_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
-        quote! {
-            Ok(__Field::__ignore)
-        }
-    } else {
-        quote! {
-            Err(_serde::de::Error::#unknown_ident(value))
-        }
-    };
-
-    let str_body = quote! {
-        match value {
-            #(#str_field_arms)*
-            _ => #fallthrough_str_arm_expr
-        }
-    };
-
-    // Match arms to extract a field from a string
-    let bytes_field_arms: Vec<_> = field_idents.iter().zip(field_names.iter())
-        .map(|(field_ident, field_name)| {
-            let bytes_field_name = quote::ByteStr(field_name);
-            quote! {
-                #bytes_field_name => { Ok(__Field::#field_ident) }
-            }
-        })
-        .collect();
-
-    let fallthrough_bytes_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
-        quote! {
-            Ok(__Field::__ignore)
-        }
-    } else {
-        quote!({
-            let value = ::std::string::String::from_utf8_lossy(value);
-            Err(_serde::de::Error::#unknown_ident(&value))
-        })
-    };
-
-    let bytes_body = quote! {
-        match value {
-            #(#bytes_field_arms)*
-            _ => #fallthrough_bytes_arm_expr
-        }
     };
 
     quote! {
@@ -755,22 +683,15 @@ fn deserialize_field_visitor(
                 impl _serde::de::Visitor for __FieldVisitor {
                     type Value = __Field;
 
-                    fn visit_usize<__E>(&mut self, value: usize) -> ::std::result::Result<__Field, __E>
-                        where __E: _serde::de::Error
-                    {
-                        #index_body
-                    }
-
                     fn visit_str<__E>(&mut self, value: &str) -> ::std::result::Result<__Field, __E>
                         where __E: _serde::de::Error
                     {
-                        #str_body
+                        match value {
+                            #(
+                                #field_names => Ok(__Field::#field_idents),
+                            )*
+                            _ => #fallthrough_arm
                         }
-
-                    fn visit_bytes<__E>(&mut self, value: &[u8]) -> ::std::result::Result<__Field, __E>
-                        where __E: _serde::de::Error
-                    {
-                        #bytes_body
                     }
                 }
 

testing/tests/test_de.rs

@@ -3,7 +3,7 @@ use std::net;
 use std::path::PathBuf;
 use std::time::Duration;
 
-use serde::Deserialize;
+use serde::de::{Deserialize, Type};
 
 extern crate fnv;
 use self::fnv::FnvHasher;
@@ -723,20 +723,6 @@ declare_tests! {
             Token::EnumMapEnd,
         ],
     }
-    test_enum_unit_usize {
-        Enum::Unit => &[
-            Token::EnumStart("Enum"),
-            Token::Usize(0),
-            Token::Unit,
-        ],
-    }
-    test_enum_unit_bytes {
-        Enum::Unit => &[
-            Token::EnumStart("Enum"),
-            Token::Bytes(b"Unit"),
-            Token::Unit,
-        ],
-    }
     test_box {
         Box::new(0i32) => &[Token::I32(0)],
     }
@@ -847,4 +833,20 @@ declare_error_tests! {
         ],
         Error::DuplicateField("a"),
     }
+    test_enum_unit_usize<Enum> {
+        &[
+            Token::EnumStart("Enum"),
+            Token::Usize(0),
+            Token::Unit,
+        ],
+        Error::InvalidType(Type::U64),
+    }
+    test_enum_unit_bytes<Enum> {
+        &[
+            Token::EnumStart("Enum"),
+            Token::Bytes(b"Unit"),
+            Token::Unit,
+        ],
+        Error::InvalidType(Type::Bytes),
+    }
 }