Add types::BorrowedValue.

src/types/borrowed_value.rs

@@ -0,0 +1,51 @@
+use ::Result;
+use ::error::Error;
+use super::Value;
+
+pub enum BorrowedValue<'a> {
+    Null,
+    Integer(i64),
+    Real(f64),
+    Text(&'a str),
+    Blob(&'a [u8]),
+}
+
+impl<'a> BorrowedValue<'a> {
+    pub fn to_value(&self) -> Value {
+        match *self {
+            BorrowedValue::Null => Value::Null,
+            BorrowedValue::Integer(i) => Value::Integer(i),
+            BorrowedValue::Real(r) => Value::Real(r),
+            BorrowedValue::Text(s) => Value::Text(s.to_string()),
+            BorrowedValue::Blob(b) => Value::Blob(b.to_vec()),
+        }
+    }
+
+    pub fn as_i64(&self) -> Result<i64> {
+        match *self {
+            BorrowedValue::Integer(i) => Ok(i),
+            _ => Err(Error::InvalidColumnType),
+        }
+    }
+
+    pub fn as_f64(&self) -> Result<f64> {
+        match *self {
+            BorrowedValue::Real(f) => Ok(f),
+            _ => Err(Error::InvalidColumnType),
+        }
+    }
+
+    pub fn as_str(&self) -> Result<&str> {
+        match *self {
+            BorrowedValue::Text(ref t) => Ok(t),
+            _ => Err(Error::InvalidColumnType),
+        }
+    }
+
+    pub fn as_blob(&self) -> Result<&[u8]> {
+        match *self {
+            BorrowedValue::Blob(ref b) => Ok(b),
+            _ => Err(Error::InvalidColumnType),
+        }
+    }
+}

src/types/mod.rs

@@ -58,7 +58,9 @@ pub use ffi::{SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, SQLITE_NUL
 
 pub use self::from_sql::FromSql;
 pub use self::to_sql::ToSql;
+pub use self::borrowed_value::BorrowedValue;
 
+mod borrowed_value;
 mod from_sql;
 mod to_sql;
 mod time;