Merge #1908

1908: Implement TryFrom<Value<T>> for i32/u32/i64/u64/f32/f64 r=syrusakbary a=webmaster128 # Description After the migration from 0.17 to 1.0 users have to handle much more dynamic return values. This PR makes working with `Value<T>` more convenient by implementing `TryFrom<Value<T>>` for `i32`/`u32`/`i64`/`u64`/`f32`/`f64`. This PR is tested and demonstrated at CosmWasm/cosmwasm#658 # Review - [ ] Add a short description of the the change to the CHANGELOG.md file Co-authored-by: Simon Warta <[email protected]>
wasmerio · Dec 10, 2020 · df3a211 · df3a211
2 parents 39d6959 + 878da59
commit df3a211
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@
 
 * [#1867](https://github.com/wasmerio/wasmer/pull/1867) Added `Metering::get_remaining_points` and `Metering::set_remaining_points` 
 * [#1881](https://github.com/wasmerio/wasmer/pull/1881) Added `UnsupportedTarget` error to `CompileError`
+* [#1908](https://github.com/wasmerio/wasmer/pull/1908) Implemented `TryFrom<Value<T>>` for `i32`/`u32`/`i64`/`u64`/`f32`/`f64`
 
 ### Changed
 

diff --git a/lib/wasmer-types/src/lib.rs b/lib/wasmer-types/src/lib.rs
@@ -38,14 +38,14 @@ mod lib {
     #[cfg(feature = "core")]
     pub mod std {
         pub use alloc::{borrow, boxed, format, rc, slice, string, vec};
-        pub use core::{any, cell, fmt, hash, marker, ops, ptr, sync};
+        pub use core::{any, cell, convert, fmt, hash, marker, ops, ptr, sync};
     }
 
     #[cfg(feature = "std")]
     pub mod std {
         pub use std::{
-            any, borrow, boxed, cell, fmt, format, hash, marker, ops, ptr, rc, slice, string, sync,
-            vec,
+            any, borrow, boxed, cell, convert, fmt, format, hash, marker, ops, ptr, rc, slice,
+            string, sync, vec,
         };
     }
 }

diff --git a/lib/wasmer-types/src/values.rs b/lib/wasmer-types/src/values.rs
@@ -1,3 +1,4 @@
+use crate::lib::std::convert::TryFrom;
 use crate::lib::std::fmt;
 use crate::lib::std::ptr;
 use crate::lib::std::string::{String, ToString};
@@ -223,6 +224,59 @@ impl<T> From<ExternRef> for Value<T> {
 //     }
 // }
 
+const NOT_I32: &'static str = "Value is not of Wasm type i32";
+const NOT_I64: &'static str = "Value is not of Wasm type i64";
+const NOT_F32: &'static str = "Value is not of Wasm type f32";
+const NOT_F64: &'static str = "Value is not of Wasm type f64";
+
+impl<T> TryFrom<Value<T>> for i32 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.i32().ok_or(NOT_I32)
+    }
+}
+
+impl<T> TryFrom<Value<T>> for u32 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.i32().ok_or(NOT_I32).map(|int| int as Self)
+    }
+}
+
+impl<T> TryFrom<Value<T>> for i64 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.i64().ok_or(NOT_I64)
+    }
+}
+
+impl<T> TryFrom<Value<T>> for u64 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.i64().ok_or(NOT_I64).map(|int| int as Self)
+    }
+}
+
+impl<T> TryFrom<Value<T>> for f32 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.f32().ok_or(NOT_F32)
+    }
+}
+
+impl<T> TryFrom<Value<T>> for f64 {
+    type Error = &'static str;
+
+    fn try_from(value: Value<T>) -> Result<Self, Self::Error> {
+        value.f64().ok_or(NOT_F64)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -264,4 +318,94 @@ mod tests {
         let v = Value::<()>::from(u64::from_be_bytes(bytes.clone()));
         assert_eq!(v, Value::I64(i64::from_be_bytes(bytes.clone())));
     }
+
+    #[test]
+    fn convert_value_to_i32() {
+        let value = Value::<()>::I32(5678);
+        let result = i32::try_from(value);
+        assert_eq!(result.unwrap(), 5678);
+
+        let value = Value::<()>::from(u32::MAX);
+        let result = i32::try_from(value);
+        assert_eq!(result.unwrap(), -1);
+
+        let value = Value::<()>::V128(42);
+        let result = i32::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type i32");
+    }
+
+    #[test]
+    fn convert_value_to_u32() {
+        let value = Value::<()>::from(u32::MAX);
+        let result = u32::try_from(value);
+        assert_eq!(result.unwrap(), u32::MAX);
+
+        let value = Value::<()>::I32(-1);
+        let result = u32::try_from(value);
+        assert_eq!(result.unwrap(), u32::MAX);
+
+        let value = Value::<()>::V128(42);
+        let result = u32::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type i32");
+    }
+
+    #[test]
+    fn convert_value_to_i64() {
+        let value = Value::<()>::I64(5678);
+        let result = i64::try_from(value);
+        assert_eq!(result.unwrap(), 5678);
+
+        let value = Value::<()>::from(u64::MAX);
+        let result = i64::try_from(value);
+        assert_eq!(result.unwrap(), -1);
+
+        let value = Value::<()>::V128(42);
+        let result = i64::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type i64");
+    }
+
+    #[test]
+    fn convert_value_to_u64() {
+        let value = Value::<()>::from(u64::MAX);
+        let result = u64::try_from(value);
+        assert_eq!(result.unwrap(), u64::MAX);
+
+        let value = Value::<()>::I64(-1);
+        let result = u64::try_from(value);
+        assert_eq!(result.unwrap(), u64::MAX);
+
+        let value = Value::<()>::V128(42);
+        let result = u64::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type i64");
+    }
+
+    #[test]
+    fn convert_value_to_f32() {
+        let value = Value::<()>::F32(1.234);
+        let result = f32::try_from(value);
+        assert_eq!(result.unwrap(), 1.234);
+
+        let value = Value::<()>::V128(42);
+        let result = f32::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type f32");
+
+        let value = Value::<()>::F64(1.234);
+        let result = f32::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type f32");
+    }
+
+    #[test]
+    fn convert_value_to_f64() {
+        let value = Value::<()>::F64(1.234);
+        let result = f64::try_from(value);
+        assert_eq!(result.unwrap(), 1.234);
+
+        let value = Value::<()>::V128(42);
+        let result = f64::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type f64");
+
+        let value = Value::<()>::F32(1.234);
+        let result = f64::try_from(value);
+        assert_eq!(result.unwrap_err(), "Value is not of Wasm type f64");
+    }
 }