make try_convert module public so TryConvertOwned can be named

CHANGELOG.md

@@ -4,6 +4,8 @@
 ### Added
 
 ### Changed
+- `try_convert` module is now public so that `TryConvertOwned` can be
+  named/implemented.
 
 ### Deprecated
 

src/lib.rs

@@ -1860,7 +1860,7 @@ pub mod rb_sys;
 pub mod ruby_handle;
 pub mod scan_args;
 mod symbol;
-mod try_convert;
+pub mod try_convert;
 pub mod typed_data;
 pub mod value;
 

src/r_array.rs

@@ -802,12 +802,7 @@ impl RArray {
     where
         T: TryConvertOwned,
     {
-        unsafe {
-            self.as_slice()
-                .iter()
-                .map(|v| T::try_convert_owned(*v))
-                .collect()
-        }
+        unsafe { self.as_slice().iter().map(|v| T::try_convert(*v)).collect() }
     }
 
     /// Convert `self` to a Rust array of [`Value`]s, of length `N`.

src/try_convert.rs

@@ -1,3 +1,5 @@
+//! Traits for converting from Ruby [`Value`]s to Rust types.
+
 use std::path::PathBuf;
 
 use rb_sys::{rb_get_path, rb_num2dbl};
@@ -20,20 +22,16 @@ pub trait TryConvert: Sized {
     fn try_convert(val: Value) -> Result<Self, Error>;
 }
 
-/// Only implemented on Rust types. TryConvert may convert from a
-/// Value to another Ruby type. Use this when you need a Rust value that's
-/// divorced from the Ruby runtime, safe to put on the heap, etc.
-pub trait TryConvertOwned: TryConvert {
-    /// Convert `val` into `Self`.
-    fn try_convert_owned(val: Value) -> Result<Self, Error> {
-        Self::try_convert(val)
-    }
-}
-
-pub trait TryConvertForArg: Sized {
-    /// Convert `val` into `Self`.
-    fn try_convert_for_arg(val: Value) -> Result<Self, Error>;
-}
+/// Conversions from [`Value`] to Rust types that do not contain [`Value`].
+///
+/// This trait is used as a bound on some implementations of [`TryConvert`]
+/// (for example, for [`Vec`]) to prevent heap allocated datastructures
+/// containing `Value`, as it is not safe to store a `Value` on the heap.
+///
+/// # Safety
+///
+/// This trait must not be implemented for types that contain `Value`.
+pub unsafe trait TryConvertOwned: TryConvert {}
 
 impl<T> TryConvert for Option<T>
 where
@@ -44,100 +42,91 @@ where
     }
 }
 
-impl<T> TryConvertOwned for Option<T>
-where
-    T: TryConvertOwned,
-{
-    fn try_convert_owned(val: Value) -> Result<Self, Error> {
-        (!val.is_nil())
-            .then(|| T::try_convert_owned(val))
-            .transpose()
-    }
-}
+unsafe impl<T> TryConvertOwned for Option<T> where T: TryConvertOwned {}
 
 impl TryConvert for bool {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Ok(val.to_bool())
     }
 }
-impl TryConvertOwned for bool {}
+unsafe impl TryConvertOwned for bool {}
 
 impl TryConvert for i8 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_i8()
     }
 }
-impl TryConvertOwned for i8 {}
+unsafe impl TryConvertOwned for i8 {}
 
 impl TryConvert for i16 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_i16()
     }
 }
-impl TryConvertOwned for i16 {}
+unsafe impl TryConvertOwned for i16 {}
 
 impl TryConvert for i32 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_i32()
     }
 }
-impl TryConvertOwned for i32 {}
+unsafe impl TryConvertOwned for i32 {}
 
 impl TryConvert for i64 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_i64()
     }
 }
-impl TryConvertOwned for i64 {}
+unsafe impl TryConvertOwned for i64 {}
 
 impl TryConvert for isize {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_isize()
     }
 }
-impl TryConvertOwned for isize {}
+unsafe impl TryConvertOwned for isize {}
 
 impl TryConvert for u8 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_u8()
     }
 }
-impl TryConvertOwned for u8 {}
+unsafe impl TryConvertOwned for u8 {}
 
 impl TryConvert for u16 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_u16()
     }
 }
-impl TryConvertOwned for u16 {}
+unsafe impl TryConvertOwned for u16 {}
 
 impl TryConvert for u32 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_u32()
     }
 }
-impl TryConvertOwned for u32 {}
+unsafe impl TryConvertOwned for u32 {}
 
 impl TryConvert for u64 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_u64()
     }
 }
-impl TryConvertOwned for u64 {}
+unsafe impl TryConvertOwned for u64 {}
 
 impl TryConvert for usize {
     fn try_convert(val: Value) -> Result<Self, Error> {
         Integer::try_convert(val)?.to_usize()
     }
 }
-impl TryConvertOwned for usize {}
+unsafe impl TryConvertOwned for usize {}
 
 impl TryConvert for f32 {
     fn try_convert(val: Value) -> Result<Self, Error> {
         f64::try_convert(val).map(|f| f as f32)
     }
 }
-impl TryConvertOwned for f32 {}
+unsafe impl TryConvertOwned for f32 {}
 
 impl TryConvert for f64 {
     fn try_convert(val: Value) -> Result<Self, Error> {
@@ -157,15 +146,15 @@ impl TryConvert for f64 {
         Ok(res)
     }
 }
-impl TryConvertOwned for f64 {}
+unsafe impl TryConvertOwned for f64 {}
 
 impl TryConvert for String {
     fn try_convert(val: Value) -> Result<Self, Error> {
         debug_assert_value!(val);
         RString::try_convert(val)?.to_string()
     }
 }
-impl TryConvertOwned for String {}
+unsafe impl TryConvertOwned for String {}
 
 #[cfg(feature = "bytes-crate")]
 impl TryConvert for bytes::Bytes {
@@ -176,15 +165,15 @@ impl TryConvert for bytes::Bytes {
 }
 
 #[cfg(feature = "bytes-crate")]
-impl TryConvertOwned for bytes::Bytes {}
+unsafe impl TryConvertOwned for bytes::Bytes {}
 
 impl TryConvert for char {
     fn try_convert(val: Value) -> Result<Self, Error> {
         debug_assert_value!(val);
         RString::try_convert(val)?.to_char()
     }
 }
-impl TryConvertOwned for char {}
+unsafe impl TryConvertOwned for char {}
 
 impl<T> TryConvert for Vec<T>
 where
@@ -195,7 +184,7 @@ where
         RArray::try_convert(val)?.to_vec()
     }
 }
-impl<T> TryConvertOwned for Vec<T> where T: TryConvertOwned {}
+unsafe impl<T> TryConvertOwned for Vec<T> where T: TryConvertOwned {}
 
 impl<T, const N: usize> TryConvert for [T; N]
 where
@@ -206,7 +195,7 @@ where
         RArray::try_convert(val)?.to_array()
     }
 }
-impl<T, const N: usize> TryConvertOwned for [T; N] where T: TryConvert {}
+unsafe impl<T, const N: usize> TryConvertOwned for [T; N] where T: TryConvert {}
 
 impl<T0> TryConvert for (T0,)
 where
@@ -225,7 +214,7 @@ where
         Ok((slice[0].try_convert()?,))
     }
 }
-impl<T0> TryConvertOwned for (T0,) where T0: TryConvert {}
+unsafe impl<T0> TryConvertOwned for (T0,) where T0: TryConvert {}
 
 impl<T0, T1> TryConvert for (T0, T1)
 where
@@ -245,7 +234,7 @@ where
         Ok((slice[0].try_convert()?, slice[1].try_convert()?))
     }
 }
-impl<T0, T1> TryConvertOwned for (T0, T1)
+unsafe impl<T0, T1> TryConvertOwned for (T0, T1)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -275,7 +264,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2> TryConvertOwned for (T0, T1, T2)
+unsafe impl<T0, T1, T2> TryConvertOwned for (T0, T1, T2)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -308,7 +297,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3> TryConvertOwned for (T0, T1, T2, T3)
+unsafe impl<T0, T1, T2, T3> TryConvertOwned for (T0, T1, T2, T3)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -344,7 +333,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4> TryConvertOwned for (T0, T1, T2, T3, T4)
+unsafe impl<T0, T1, T2, T3, T4> TryConvertOwned for (T0, T1, T2, T3, T4)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -383,7 +372,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5> TryConvertOwned for (T0, T1, T2, T3, T4, T5)
+unsafe impl<T0, T1, T2, T3, T4, T5> TryConvertOwned for (T0, T1, T2, T3, T4, T5)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -425,7 +414,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6> TryConvertOwned for (T0, T1, T2, T3, T4, T5, T6)
+unsafe impl<T0, T1, T2, T3, T4, T5, T6> TryConvertOwned for (T0, T1, T2, T3, T4, T5, T6)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -470,7 +459,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6, T7> TryConvertOwned for (T0, T1, T2, T3, T4, T5, T6, T7)
+unsafe impl<T0, T1, T2, T3, T4, T5, T6, T7> TryConvertOwned for (T0, T1, T2, T3, T4, T5, T6, T7)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -518,7 +507,8 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6, T7, T8> TryConvertOwned for (T0, T1, T2, T3, T4, T5, T6, T7, T8)
+unsafe impl<T0, T1, T2, T3, T4, T5, T6, T7, T8> TryConvertOwned
+    for (T0, T1, T2, T3, T4, T5, T6, T7, T8)
 where
     T0: TryConvert,
     T1: TryConvert,
@@ -569,7 +559,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> TryConvertOwned
+unsafe impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> TryConvertOwned
     for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9)
 where
     T0: TryConvert,
@@ -625,7 +615,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> TryConvertOwned
+unsafe impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> TryConvertOwned
     for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10)
 where
     T0: TryConvert,
@@ -684,7 +674,7 @@ where
         ))
     }
 }
-impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> TryConvertOwned
+unsafe impl<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> TryConvertOwned
     for (T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11)
 where
     T0: TryConvert,
@@ -712,7 +702,7 @@ where
         RHash::try_convert(val)?.to_hash_map()
     }
 }
-impl<K, V> TryConvertOwned for std::collections::HashMap<K, V>
+unsafe impl<K, V> TryConvertOwned for std::collections::HashMap<K, V>
 where
     K: TryConvertOwned + Eq + std::hash::Hash,
     V: TryConvertOwned,
@@ -742,4 +732,4 @@ impl TryConvert for PathBuf {
     }
 }
 
-impl TryConvertOwned for PathBuf {}
+unsafe impl TryConvertOwned for PathBuf {}