From fae72200e592b03886bbc7407bf626838b931dd7 Mon Sep 17 00:00:00 2001
From: Peter Maatman <blackwolf12333@gmail.com>
Date: Sat, 8 Aug 2020 12:23:07 +0200
Subject: [PATCH] sqlite: Add basic json implementation

Fixes #608
---
 sqlx-core/src/sqlite/types/json.rs | 44 ++++++++++++++++++++++++++++++
 sqlx-core/src/sqlite/types/mod.rs  |  2 ++
 tests/sqlite/types.rs              | 40 +++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 sqlx-core/src/sqlite/types/json.rs

diff --git a/sqlx-core/src/sqlite/types/json.rs b/sqlx-core/src/sqlite/types/json.rs
new file mode 100644
index 00000000..8f6bf6dc
--- /dev/null
+++ b/sqlx-core/src/sqlite/types/json.rs
@@ -0,0 +1,44 @@
+use serde::{Deserialize, Serialize};
+
+use crate::decode::Decode;
+use crate::encode::{Encode, IsNull};
+use crate::error::BoxDynError;
+use crate::sqlite::{
+    type_info::DataType, Sqlite, SqliteArgumentValue, SqliteTypeInfo, SqliteValueRef,
+};
+use crate::types::{Json, Type};
+
+impl<T> Type<Sqlite> for Json<T> {
+    fn type_info() -> SqliteTypeInfo {
+        SqliteTypeInfo(DataType::Text)
+    }
+
+    fn compatible(ty: &SqliteTypeInfo) -> bool {
+        <&str as Type<Sqlite>>::compatible(ty)
+    }
+}
+
+impl<T> Encode<'_, Sqlite> for Json<T>
+where
+    T: Serialize,
+{
+    fn encode_by_ref(&self, buf: &mut Vec<SqliteArgumentValue<'_>>) -> IsNull {
+        let json_string_value =
+            serde_json::to_string(&self.0).expect("serde_json failed to convert to string");
+
+        Encode::<Sqlite>::encode(json_string_value, buf)
+    }
+}
+
+impl<'r, T> Decode<'r, Sqlite> for Json<T>
+where
+    T: 'r + Deserialize<'r>,
+{
+    fn decode(value: SqliteValueRef<'r>) -> Result<Self, BoxDynError> {
+        let string_value = <&str as Decode<Sqlite>>::decode(value)?;
+
+        serde_json::from_str(&string_value)
+            .map(Json)
+            .map_err(Into::into)
+    }
+}
diff --git a/sqlx-core/src/sqlite/types/mod.rs b/sqlx-core/src/sqlite/types/mod.rs
index 9553d5a2..84ca6154 100644
--- a/sqlx-core/src/sqlite/types/mod.rs
+++ b/sqlx-core/src/sqlite/types/mod.rs
@@ -35,4 +35,6 @@ mod bytes;
 mod chrono;
 mod float;
 mod int;
+#[cfg(feature = "json")]
+mod json;
 mod str;
diff --git a/tests/sqlite/types.rs b/tests/sqlite/types.rs
index a64572ea..340ce9b9 100644
--- a/tests/sqlite/types.rs
+++ b/tests/sqlite/types.rs
@@ -32,6 +32,46 @@ test_type!(bytes<Vec<u8>>(Sqlite,
         == vec![0_u8, 0, 0, 0, 0x52]
 ));
 
+#[cfg(feature = "json")]
+mod json_tests {
+    use super::*;
+    use serde_json::{json, Value as JsonValue};
+    use sqlx::types::Json;
+    use sqlx_test::test_type;
+
+    test_type!(json<JsonValue>(
+        Sqlite,
+        "'\"Hello, World\"'" == json!("Hello, World"),
+        "'\"😎\"'" == json!("😎"),
+        "'\"🙋‍♀️\"'" == json!("🙋‍♀️"),
+        "'[\"Hello\",\"World!\"]'" == json!(["Hello", "World!"])
+    ));
+
+    #[derive(serde::Deserialize, serde::Serialize, Debug, PartialEq)]
+    struct Friend {
+        name: String,
+        age: u32,
+    }
+
+    test_type!(json_struct<Json<Friend>>(
+        Sqlite,
+        "\'{\"name\":\"Joe\",\"age\":33}\'" == Json(Friend { name: "Joe".to_string(), age: 33 })
+    ));
+
+    // NOTE: This is testing recursive (and transparent) usage of the `Json` wrapper. You don't
+    //       need to wrap the Vec in Json<_> to make the example work.
+
+    #[derive(Debug, PartialEq, serde::Serialize, serde::Deserialize)]
+    struct Customer {
+        json_column: Json<Vec<i64>>,
+    }
+
+    test_type!(json_struct_json_column<Json<Customer>>(
+        Sqlite,
+        "\'{\"json_column\":[1,2]}\'" == Json(Customer { json_column: Json(vec![1, 2]) })
+    ));
+}
+
 #[cfg(feature = "chrono")]
 mod chrono {
     use super::*;