Remove functions::FromValue.

With the new definition of FromSql, we can reuse it since we can convert
a sqlite3_value into a BorrowedValue.

src/functions.rs

@@ -54,7 +54,6 @@ use std::ffi::CStr;
 use std::mem;
 use std::ptr;
 use std::slice;
-use std::str;
 use libc::{c_int, c_double, c_char, c_void};
 
 use ffi;
@@ -63,7 +62,7 @@ pub use ffi::sqlite3_value;
 pub use ffi::sqlite3_value_type;
 pub use ffi::sqlite3_value_numeric_type;
 
-use types::Null;
+use types::{Null, FromSql, BorrowedValue};
 
 use {Result, Error, Connection, str_to_cstring, InnerConnection};
 
@@ -157,107 +156,34 @@ impl ToResult for Null {
     }
 }
 
-/// A trait for types that can be created from a SQLite function parameter value.
+impl<'a> BorrowedValue<'a> {
-pub trait FromValue: Sized {
+    unsafe fn from_value(value: *mut sqlite3_value) -> BorrowedValue<'a> {
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<Self>;
-
-    /// FromValue types can implement this method and use sqlite3_value_type to check that
-    /// the type reported by SQLite matches a type suitable for Self. This method is used
-    /// by `Context::get` to confirm that the parameter contains a valid type before
-    /// attempting to retrieve the value.
-    unsafe fn parameter_has_valid_sqlite_type(_: *mut sqlite3_value) -> bool {
-        true
-    }
-}
-
-
-macro_rules! raw_from_impl(
-    ($t:ty, $f:ident, $c:expr) => (
-        impl FromValue for $t {
-            unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<$t> {
-                Ok(ffi::$f(v))
-            }
-
-            unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
-                sqlite3_value_numeric_type(v) == $c
-            }
-        }
-    )
-);
-
-raw_from_impl!(c_int, sqlite3_value_int, ffi::SQLITE_INTEGER);
-raw_from_impl!(i64, sqlite3_value_int64, ffi::SQLITE_INTEGER);
-
-impl FromValue for bool {
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<bool> {
-        match ffi::sqlite3_value_int(v) {
-            0 => Ok(false),
-            _ => Ok(true),
-        }
-    }
-
-    unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
-        sqlite3_value_numeric_type(v) == ffi::SQLITE_INTEGER
-    }
-}
-
-impl FromValue for c_double {
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<c_double> {
-        Ok(ffi::sqlite3_value_double(v))
-    }
-
-    unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
-        sqlite3_value_numeric_type(v) == ffi::SQLITE_FLOAT ||
-        sqlite3_value_numeric_type(v) == ffi::SQLITE_INTEGER
-    }
-}
-
-impl FromValue for String {
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<String> {
-        let c_text = ffi::sqlite3_value_text(v);
-        if c_text.is_null() {
-            Ok("".to_owned())
-        } else {
-            let c_slice = CStr::from_ptr(c_text as *const c_char).to_bytes();
-            let utf8_str = try!(str::from_utf8(c_slice));
-            Ok(utf8_str.into())
-        }
-    }
-
-    unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
-        sqlite3_value_type(v) == ffi::SQLITE_TEXT
-    }
-}
-
-impl FromValue for Vec<u8> {
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<Vec<u8>> {
         use std::slice::from_raw_parts;
-        let c_blob = ffi::sqlite3_value_blob(v);
-        let len = ffi::sqlite3_value_bytes(v);
 
-        assert!(len >= 0,
+        match ffi::sqlite3_value_type(value) {
-                "unexpected negative return from sqlite3_value_bytes");
+            ffi::SQLITE_NULL => BorrowedValue::Null,
-        let len = len as usize;
+            ffi::SQLITE_INTEGER => BorrowedValue::Integer(ffi::sqlite3_value_int64(value)),
+            ffi::SQLITE_FLOAT => BorrowedValue::Real(ffi::sqlite3_value_double(value)),
+            ffi::SQLITE_TEXT => {
+                let text = ffi::sqlite3_value_text(value);
+                assert!(!text.is_null(), "unexpected SQLITE_TEXT value type with NULL data");
+                let s = CStr::from_ptr(text as *const c_char);
 
-        Ok(from_raw_parts(mem::transmute(c_blob), len).to_vec())
+                // sqlite3_value_text returns UTF8 data, so our unwrap here should be fine.
+                let s = s.to_str().expect("sqlite3_value_text returned invalid UTF-8");
+                BorrowedValue::Text(s)
             }
+            ffi::SQLITE_BLOB => {
+                let blob = ffi::sqlite3_value_blob(value);
+                assert!(!blob.is_null(), "unexpected SQLITE_BLOB value type with NULL data");
 
-    unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
+                let len = ffi::sqlite3_value_bytes(value);
-        sqlite3_value_type(v) == ffi::SQLITE_BLOB
+                assert!(len >= 0, "unexpected negative return from sqlite3_value_bytes");
-    }
-}
 
-impl<T: FromValue> FromValue for Option<T> {
+                BorrowedValue::Blob(from_raw_parts(blob as *const u8, len as usize))
-    unsafe fn parameter_value(v: *mut sqlite3_value) -> Result<Option<T>> {
-        if sqlite3_value_type(v) == ffi::SQLITE_NULL {
-            Ok(None)
-        } else {
-            FromValue::parameter_value(v).map(Some)
             }
+            _ => unreachable!("sqlite3_value_type returned invalid value")
         }
-
-    unsafe fn parameter_has_valid_sqlite_type(v: *mut sqlite3_value) -> bool {
-        sqlite3_value_type(v) == ffi::SQLITE_NULL || T::parameter_has_valid_sqlite_type(v)
     }
 }
 
@@ -288,15 +214,13 @@ impl<'a> Context<'a> {
     /// Will panic if `idx` is greater than or equal to `self.len()`.
     ///
     /// Will return Err if the underlying SQLite type cannot be converted to a `T`.
-    pub fn get<T: FromValue>(&self, idx: usize) -> Result<T> {
+    pub fn get<T: FromSql>(&self, idx: usize) -> Result<T> {
         let arg = self.args[idx];
-        unsafe {
+        let value = unsafe { BorrowedValue::from_value(arg) };
-            if T::parameter_has_valid_sqlite_type(arg) {
+        FromSql::column_result(value).map_err(|err| match err {
-                T::parameter_value(arg)
+            Error::InvalidColumnType => Error::InvalidFunctionParameterType,
-            } else {
+            _ => err
-                Err(Error::InvalidFunctionParameterType)
+        })
-            }
-        }
     }
 
     /// Sets the auxilliary data associated with a particular parameter. See