Add optional serde serialization support

- Update ci to run serde tests
- Add serialization support for Enums except the enum `arrayfire::Scalar`
- Structs with serde support added
    - [x] Array
    - [x] Dim4
    - [x] Seq
    - [x] RandomEngine
- Structs without serde support
    - Features - currently not possible as `af_features` can't be recreated
      from individual `af_arrays` with current upstream API
    - Indexer - not possible with current API. Also, any subarray when fetched
      to host for serialization results in separate owned copy this making serde
      support for this unnecessary.
    - Callback
    - Event
    - Window

Author: 9prady9

.github/workflows/ci.yml

@@ -48,8 +48,8 @@ jobs:
                   export AF_PATH=${GITHUB_WORKSPACE}/afbin
                   export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${AF_PATH}/lib64
                   echo "Using cargo version: $(cargo --version)"
-                  cargo build --all
-                  cargo test --no-fail-fast
+                  cargo build --all --all-features
+                  cargo test --no-fail-fast --all-features
 
     format:
         name: Format Check

Cargo.toml

@@ -46,15 +46,19 @@ statistics = []
 vision = []
 default = ["algorithm", "arithmetic", "blas", "data", "indexing", "graphics", "image", "lapack",
 "ml", "macros", "random", "signal", "sparse", "statistics", "vision"]
+afserde = ["serde"]
 
 [dependencies]
 libc = "0.2"
 num  = "0.2"
 lazy_static = "1.0"
 half = "1.5.0"
+serde = { version = "1.0", features = ["derive"], optional = true }
 
 [dev-dependencies]
 half = "1.5.0"
+serde_json = "1.0"
+bincode = "1.3"
 
 [build-dependencies]
 serde_json = "1.0"

README.md

@@ -16,7 +16,7 @@ Only, Major(M) & Minor(m) version numbers need to match. *p1* and *p2* are patch
 
 ## Supported platforms
 
-Linux, Windows and OSX. Rust 1.15.1 or higher is required.
+Linux, Windows and OSX. Rust 1.31 or newer is required.
 
 ## Use from Crates.io [![][6]][7] [![][8]][9]
 

src/core/array.rs

@@ -851,6 +851,73 @@ pub fn is_eval_manual() -> bool {
     }
 }
 
+#[cfg(feature = "afserde")]
+mod afserde {
+    // Reimport required from super scope
+    use super::{Array, DType, Dim4, HasAfEnum};
+
+    use serde::de::{Deserializer, Error, Unexpected};
+    use serde::ser::Serializer;
+    use serde::{Deserialize, Serialize};
+
+    #[derive(Debug, Serialize, Deserialize)]
+    struct ArrayOnHost<T: HasAfEnum + std::fmt::Debug> {
+        dtype: DType,
+        shape: Dim4,
+        data: Vec<T>,
+    }
+
+    /// Serialize Implementation of Array
+    impl<T> Serialize for Array<T>
+    where
+        T: std::default::Default + std::clone::Clone + Serialize + HasAfEnum + std::fmt::Debug,
+    {
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+        {
+            let mut vec = vec![T::default(); self.elements()];
+            self.host(&mut vec);
+            let arr_on_host = ArrayOnHost {
+                dtype: self.get_type(),
+                shape: self.dims().clone(),
+                data: vec,
+            };
+            arr_on_host.serialize(serializer)
+        }
+    }
+
+    /// Deserialize Implementation of Array
+    impl<'de, T> Deserialize<'de> for Array<T>
+    where
+        T: Deserialize<'de> + HasAfEnum + std::fmt::Debug,
+    {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            match ArrayOnHost::<T>::deserialize(deserializer) {
+                Ok(arr_on_host) => {
+                    let read_dtype = arr_on_host.dtype;
+                    let expected_dtype = T::get_af_dtype();
+                    if expected_dtype != read_dtype {
+                        let error_msg = format!(
+                            "data type is {:?}, deserialized type is {:?}",
+                            expected_dtype, read_dtype
+                        );
+                        return Err(Error::invalid_value(Unexpected::Enum, &error_msg.as_str()));
+                    }
+                    Ok(Array::<T>::new(
+                        &arr_on_host.data,
+                        arr_on_host.shape.clone(),
+                    ))
+                }
+                Err(err) => Err(err),
+            }
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::super::array::print;
@@ -1082,4 +1149,37 @@ mod tests {
         //    8.0000     8.0000     8.0000
         // ANCHOR_END: accum_using_channel
     }
+
+    #[cfg(feature = "afserde")]
+    mod serde_tests {
+        use super::super::Array;
+        use crate::algorithm::sum_all;
+        use crate::randu;
+
+        #[test]
+        fn array_serde_json() {
+            let input = randu!(u8; 2, 2);
+            let serd = match serde_json::to_string(&input) {
+                Ok(serialized_str) => serialized_str,
+                Err(e) => e.to_string(),
+            };
+
+            let deserd: Array<u8> = serde_json::from_str(&serd).unwrap();
+
+            assert_eq!(sum_all(&(input - deserd)), (0u32, 0u32));
+        }
+
+        #[test]
+        fn array_serde_bincode() {
+            let input = randu!(u8; 2, 2);
+            let encoded = match bincode::serialize(&input) {
+                Ok(encoded) => encoded,
+                Err(_) => vec![],
+            };
+
+            let decoded: Array<u8> = bincode::deserialize(&encoded).unwrap();
+
+            assert_eq!(sum_all(&(input - decoded)), (0u32, 0u32));
+        }
+    }
 }