Fix FromSql/ToSql for serde_json::Value

Fix #882 for valid JSON values

src/types/serde_json.rs

@@ -1,24 +1,62 @@
 //! [`ToSql`] and [`FromSql`] implementation for JSON `Value`.
 
-use serde_json::Value;
+use serde_json::{Number, Value};
 
 use crate::types::{FromSql, FromSqlError, FromSqlResult, ToSql, ToSqlOutput, ValueRef};
-use crate::Result;
+use crate::{Error, Result};
 
-/// Serialize JSON `Value` to text.
+/// Serialize JSON `Value` to text:
+///
+///
+/// | JSON   | SQLite    |
+/// |----------|---------|
+/// | Null     | NULL    |
+/// | Bool     | 'true' / 'false' |
+/// | Number   | INT or REAL except u64 |
+/// | _ | TEXT |
 impl ToSql for Value {
     #[inline]
     fn to_sql(&self) -> Result<ToSqlOutput<'_>> {
-        Ok(ToSqlOutput::from(serde_json::to_string(self).unwrap()))
+        match self {
+            Value::Null => Ok(ToSqlOutput::Borrowed(ValueRef::Null)),
+            Value::Number(n) if n.is_i64() => Ok(ToSqlOutput::from(n.as_i64().unwrap())),
+            Value::Number(n) if n.is_f64() => Ok(ToSqlOutput::from(n.as_f64().unwrap())),
+            _ => serde_json::to_string(self)
+                .map(ToSqlOutput::from)
+                .map_err(|err| Error::ToSqlConversionFailure(err.into())),
+        }
     }
 }
 
-/// Deserialize text/blob to JSON `Value`.
+/// Deserialize SQLite value to JSON `Value`:
+///
+/// | SQLite   | JSON    |
+/// |----------|---------|
+/// | NULL     | Null    |
+/// | 'null'   | Null    |
+/// | 'true'   | Bool    |
+/// | 1        | Number  |
+/// | 0.1      | Number  |
+/// | '"text"' | String  |
+/// | 'text'   | _Error_ |
+/// | '[0, 1]' | Array   |
+/// | '{"x": 1}' | Object  |
 impl FromSql for Value {
     #[inline]
     fn column_result(value: ValueRef<'_>) -> FromSqlResult<Self> {
-        let bytes = value.as_bytes()?;
-        serde_json::from_slice(bytes).map_err(|err| FromSqlError::Other(Box::new(err)))
+        match value {
+            ValueRef::Text(s) => serde_json::from_slice(s), // KO for b"text"
+            ValueRef::Blob(b) => serde_json::from_slice(b),
+            ValueRef::Integer(i) => Ok(Value::Number(Number::from(i))),
+            ValueRef::Real(f) => {
+                match Number::from_f64(f) {
+                    Some(n) => Ok(Value::Number(n)),
+                    _ => return Err(FromSqlError::InvalidType), // FIXME
+                }
+            }
+            ValueRef::Null => Ok(Value::Null),
+        }
+        .map_err(|err| FromSqlError::Other(Box::new(err)))
     }
 }
 
@@ -26,7 +64,7 @@ impl FromSql for Value {
 mod test {
     use crate::types::ToSql;
     use crate::{Connection, Result};
-    use serde_json::Value;
+    use serde_json::{Number, Value};
 
     fn checked_memory_handle() -> Result<Connection> {
         let db = Connection::open_in_memory()?;
@@ -51,4 +89,47 @@ mod test {
         assert_eq!(data, b);
         Ok(())
     }
+
+    #[test]
+    fn test_to_sql() -> Result<()> {
+        let db = Connection::open_in_memory()?;
+
+        let v: Option<String> = db.query_row("SELECT ?", [Value::Null], |r| r.get(0))?;
+        assert_eq!(None, v);
+        let v: String = db.query_row("SELECT ?", [Value::Bool(true)], |r| r.get(0))?;
+        assert_eq!("true", v);
+        let v: i64 = db.query_row("SELECT ?", [Value::Number(Number::from(1))], |r| r.get(0))?;
+        assert_eq!(1, v);
+        let v: f64 = db.query_row(
+            "SELECT ?",
+            [Value::Number(Number::from_f64(0.1).unwrap())],
+            |r| r.get(0),
+        )?;
+        assert_eq!(0.1, v);
+        let v: String =
+            db.query_row("SELECT ?", [Value::String("text".to_owned())], |r| r.get(0))?;
+        assert_eq!("\"text\"", v);
+        Ok(())
+    }
+
+    #[test]
+    fn test_from_sql() -> Result<()> {
+        let db = Connection::open_in_memory()?;
+
+        let v: Value = db.one_column("SELECT NULL")?;
+        assert_eq!(Value::Null, v);
+        let v: Value = db.one_column("SELECT 'null'")?;
+        assert_eq!(Value::Null, v);
+        let v: Value = db.one_column("SELECT 'true'")?;
+        assert_eq!(Value::Bool(true), v);
+        let v: Value = db.one_column("SELECT 1")?;
+        assert_eq!(Value::Number(Number::from(1)), v);
+        let v: Value = db.one_column("SELECT 0.1")?;
+        assert_eq!(Value::Number(Number::from_f64(0.1).unwrap()), v);
+        let v: Value = db.one_column("SELECT '\"text\"'")?;
+        assert_eq!(Value::String("text".to_owned()), v);
+        let v: Result<Value> = db.one_column("SELECT 'text'");
+        assert!(v.is_err());
+        Ok(())
+    }
 }