Merge pull request #837 from serde-rs/borrow

Derive for borrowed fields
serde-rs · Apr 4, 2017 · 7c27e10 · 7c27e10
2 parents 8c3e72f + 20ff9ba
commit 7c27e10
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Showing 15 changed files with 712 additions and 103 deletions.
diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs
@@ -328,9 +328,9 @@ impl<'a> Visitor<'a> for StrVisitor {
     }
 }
 
-impl<'a> Deserialize<'a> for &'a str {
+impl<'de: 'a, 'a> Deserialize<'de> for &'a str {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer<'a>
+        where D: Deserializer<'de>
     {
         deserializer.deserialize_str(StrVisitor)
     }
@@ -360,9 +360,9 @@ impl<'a> Visitor<'a> for BytesVisitor {
     }
 }
 
-impl<'a> Deserialize<'a> for &'a [u8] {
+impl<'de: 'a, 'a> Deserialize<'de> for &'a [u8] {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer<'a>
+        where D: Deserializer<'de>
     {
         deserializer.deserialize_bytes(BytesVisitor)
     }

diff --git a/serde/src/de/private.rs b/serde/src/de/private.rs
@@ -1,7 +1,24 @@
+#[cfg(any(feature = "std", feature = "collections"))]
+use core::{fmt, str};
+
 use core::marker::PhantomData;
 
+#[cfg(feature = "collections")]
+use collections::borrow::ToOwned;
+
+#[cfg(feature = "std")]
+use std::borrow::Cow;
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::borrow::Cow;
+
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::{String, Vec};
+
 use de::{Deserialize, Deserializer, Error, Visitor};
 
+#[cfg(any(feature = "std", feature = "collections"))]
+use de::Unexpected;
+
 #[cfg(any(feature = "std", feature = "collections"))]
 pub use de::content::{Content, ContentRefDeserializer, ContentDeserializer, TaggedContentVisitor,
                       TagOrContentField, TagOrContentFieldVisitor, InternallyTaggedUnitVisitor,
@@ -42,3 +59,118 @@ pub fn missing_field<'de, V, E>(field: &'static str) -> Result<V, E>
     let deserializer = MissingFieldDeserializer(field, PhantomData);
     Deserialize::deserialize(deserializer)
 }
+
+#[cfg(any(feature = "std", feature = "collections"))]
+pub fn borrow_cow_str<'de: 'a, 'a, D>(deserializer: D) -> Result<Cow<'a, str>, D::Error>
+    where D: Deserializer<'de>
+{
+    struct CowStrVisitor;
+
+    impl<'a> Visitor<'a> for CowStrVisitor {
+        type Value = Cow<'a, str>;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a string")
+        }
+
+        fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v.to_owned()))
+        }
+
+        fn visit_borrowed_str<E>(self, v: &'a str) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Borrowed(v))
+        }
+
+        fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v))
+        }
+
+        fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+            where E: Error
+        {
+            match str::from_utf8(v) {
+                Ok(s) => Ok(Cow::Owned(s.to_owned())),
+                Err(_) => Err(Error::invalid_value(Unexpected::Bytes(v), &self)),
+            }
+        }
+
+        fn visit_borrowed_bytes<E>(self, v: &'a [u8]) -> Result<Self::Value, E>
+            where E: Error
+        {
+            match str::from_utf8(v) {
+                Ok(s) => Ok(Cow::Borrowed(s)),
+                Err(_) => Err(Error::invalid_value(Unexpected::Bytes(v), &self)),
+            }
+        }
+
+        fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
+            where E: Error
+        {
+            match String::from_utf8(v) {
+                Ok(s) => Ok(Cow::Owned(s)),
+                Err(e) => Err(Error::invalid_value(Unexpected::Bytes(&e.into_bytes()), &self)),
+            }
+        }
+    }
+
+    deserializer.deserialize_str(CowStrVisitor)
+}
+
+#[cfg(any(feature = "std", feature = "collections"))]
+pub fn borrow_cow_bytes<'de: 'a, 'a, D>(deserializer: D) -> Result<Cow<'a, [u8]>, D::Error>
+    where D: Deserializer<'de>
+{
+    struct CowBytesVisitor;
+
+    impl<'a> Visitor<'a> for CowBytesVisitor {
+        type Value = Cow<'a, [u8]>;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a byte array")
+        }
+
+        fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v.as_bytes().to_vec()))
+        }
+
+        fn visit_borrowed_str<E>(self, v: &'a str) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Borrowed(v.as_bytes()))
+        }
+
+        fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v.into_bytes()))
+        }
+
+        fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v.to_vec()))
+        }
+
+        fn visit_borrowed_bytes<E>(self, v: &'a [u8]) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Borrowed(v))
+        }
+
+        fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
+            where E: Error
+        {
+            Ok(Cow::Owned(v))
+        }
+    }
+
+    deserializer.deserialize_str(CowBytesVisitor)
+}
diff --git a/serde_codegen_internals/Cargo.toml b/serde_codegen_internals/Cargo.toml
@@ -12,7 +12,8 @@ readme = "../README.md"
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 
 [dependencies]
-syn = { version = "0.11", default-features = false, features = ["parsing"] }
+syn = { version = "0.11.10", default-features = false, features = ["parsing"] }
+synom = "0.11"
 
 [badges]
 travis-ci = { repository = "serde-rs/serde" }