Introduce an intermediary InvalidType error.

InvalidType is used where the column/parameter index is not known.

src/error.rs

@@ -53,6 +53,10 @@ pub enum Error {
     /// that column cannot be converted to the requested Rust type.
     InvalidColumnType(i32, Type),
 
+    /// Error when an SQLite value is requested, but the type of the result cannot be converted to the
+    /// requested Rust type.
+    InvalidType(Type),
+
     /// Error when a query that was expected to insert one row did not insert any or insert many.
     StatementChangedRows(c_int),
 
@@ -63,7 +67,7 @@ pub enum Error {
     /// Error returned by `functions::Context::get` when the function argument cannot be converted
     /// to the requested type.
     #[cfg(feature = "functions")]
-    InvalidFunctionParameterType(i32, Type),
+    InvalidFunctionParameterType(usize, Type),
 
     /// An error case available for implementors of custom user functions (e.g.,
     /// `create_scalar_function`).
@@ -107,6 +111,9 @@ impl fmt::Display for Error {
             Error::InvalidColumnType(i, ref t) => {
                 write!(f, "Invalid column type {} at index: {}", t, i)
             }
+            Error::InvalidType(ref t) => {
+                write!(f, "Invalid type {}", t)
+            }
             Error::StatementChangedRows(i) => write!(f, "Query changed {} rows", i),
             Error::StatementFailedToInsertRow => write!(f, "Statement failed to insert new row"),
 
@@ -140,6 +147,7 @@ impl error::Error for Error {
             Error::InvalidColumnIndex(_) => "invalid column index",
             Error::InvalidColumnName(_) => "invalid column name",
             Error::InvalidColumnType(_, _) => "invalid column type",
+            Error::InvalidType(_) => "invalid type",
             Error::StatementChangedRows(_) => "query inserted zero or more than one row",
             Error::StatementFailedToInsertRow => "statement failed to insert new row",
 
@@ -165,6 +173,7 @@ impl error::Error for Error {
             Error::InvalidColumnIndex(_) |
             Error::InvalidColumnName(_) |
             Error::InvalidColumnType(_, _) |
+            Error::InvalidType(_) |
             Error::InvalidPath(_) |
             Error::StatementChangedRows(_) |
             Error::StatementFailedToInsertRow => None,

src/functions.rs

@@ -217,8 +217,8 @@ impl<'a> Context<'a> {
     pub fn get<T: FromSql>(&self, idx: usize) -> Result<T> {
         let arg = self.args[idx];
         let value = unsafe { ValueRef::from_value(arg) };
-        FromSql::column_result(value, idx as i32).map_err(|err| match err {
-            Error::InvalidColumnType(i, t) => Error::InvalidFunctionParameterType(i, t),
+        FromSql::column_result(value).map_err(|err| match err {
+            Error::InvalidType(t) => Error::InvalidFunctionParameterType(idx, t),
             _ => err,
         })
     }

src/lib.rs

@@ -1066,7 +1066,10 @@ impl<'a, 'stmt> Row<'a, 'stmt> {
     pub fn get_checked<I: RowIndex, T: FromSql>(&self, idx: I) -> Result<T> {
         let idx = try!(idx.idx(self.stmt));
         let value = unsafe { ValueRef::new(&self.stmt.stmt, idx) };
-        FromSql::column_result(value, idx)
+        FromSql::column_result(value).map_err(|err| match err {
+            Error::InvalidType(t) => Error::InvalidColumnType(idx, t),
+            _ => err,
+        })
     }
 
     /// Return the number of columns in the current row.

src/types/chrono.rs

@@ -21,8 +21,8 @@ impl ToSql for NaiveDate {
 
 /// "YYYY-MM-DD" => ISO 8601 calendar date without timezone.
 impl FromSql for NaiveDate {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_str(idx).and_then(|s| match NaiveDate::parse_from_str(s, "%Y-%m-%d") {
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_str().and_then(|s| match NaiveDate::parse_from_str(s, "%Y-%m-%d") {
             Ok(dt) => Ok(dt),
             Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
         })
@@ -39,8 +39,8 @@ impl ToSql for NaiveTime {
 
 /// "HH:MM"/"HH:MM:SS"/"HH:MM:SS.SSS" => ISO 8601 time without timezone.
 impl FromSql for NaiveTime {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_str(idx).and_then(|s| {
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_str().and_then(|s| {
             let fmt = match s.len() {
                 5 => "%H:%M",
                 8 => "%H:%M:%S",
@@ -65,8 +65,8 @@ impl ToSql for NaiveDateTime {
 /// "YYYY-MM-DD HH:MM:SS"/"YYYY-MM-DD HH:MM:SS.SSS" => ISO 8601 combined date and time
 /// without timezone. ("YYYY-MM-DDTHH:MM:SS"/"YYYY-MM-DDTHH:MM:SS.SSS" also supported)
 impl FromSql for NaiveDateTime {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_str(idx).and_then(|s| {
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_str().and_then(|s| {
             let fmt = if s.len() >= 11 && s.as_bytes()[10] == b'T' {
                 "%Y-%m-%dT%H:%M:%S%.f"
             } else {
@@ -91,10 +91,10 @@ impl<Tz: TimeZone> ToSql for DateTime<Tz> {
 
 /// RFC3339 ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM") into DateTime<UTC>.
 impl FromSql for DateTime<UTC> {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         {
             // Try to parse value as rfc3339 first.
-            let s = try!(value.as_str(idx));
+            let s = try!(value.as_str());
 
             // If timestamp looks space-separated, make a copy and replace it with 'T'.
             let s = if s.len() >= 11 && s.as_bytes()[10] == b' ' {
@@ -115,14 +115,14 @@ impl FromSql for DateTime<UTC> {
         }
 
         // Couldn't parse as rfc3339 - fall back to NaiveDateTime.
-        NaiveDateTime::column_result(value, idx).map(|dt| UTC.from_utc_datetime(&dt))
+        NaiveDateTime::column_result(value).map(|dt| UTC.from_utc_datetime(&dt))
     }
 }
 
 /// RFC3339 ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM") into DateTime<Local>.
 impl FromSql for DateTime<Local> {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        let utc_dt = try!(DateTime::<UTC>::column_result(value, idx));
+    fn column_result(value: ValueRef) -> Result<Self> {
+        let utc_dt = try!(DateTime::<UTC>::column_result(value));
         Ok(utc_dt.with_timezone(&Local))
     }
 }

src/types/from_sql.rs

@@ -4,34 +4,34 @@ use ::error::Error;
 
 /// A trait for types that can be created from a SQLite value.
 pub trait FromSql: Sized {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self>;
+    fn column_result(value: ValueRef) -> Result<Self>;
 }
 
 impl FromSql for i32 {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        i64::column_result(value, idx).map(|i| i as i32)
+    fn column_result(value: ValueRef) -> Result<Self> {
+        i64::column_result(value).map(|i| i as i32)
     }
 }
 
 impl FromSql for i64 {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_i64(idx)
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_i64()
     }
 }
 
 impl FromSql for f64 {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
             ValueRef::Integer(i) => Ok(i as f64),
             ValueRef::Real(f) => Ok(f),
-            _ => Err(Error::InvalidColumnType(idx, value.data_type())),
+            _ => Err(Error::InvalidType(value.data_type())),
         }
     }
 }
 
 impl FromSql for bool {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        i64::column_result(value, idx).map(|i| match i {
+    fn column_result(value: ValueRef) -> Result<Self> {
+        i64::column_result(value).map(|i| match i {
             0 => false,
             _ => true,
         })
@@ -39,28 +39,28 @@ impl FromSql for bool {
 }
 
 impl FromSql for String {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_str(idx).map(|s| s.to_string())
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_str().map(|s| s.to_string())
     }
 }
 
 impl FromSql for Vec<u8> {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_blob(idx).map(|b| b.to_vec())
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_blob().map(|b| b.to_vec())
     }
 }
 
 impl<T: FromSql> FromSql for Option<T> {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
             ValueRef::Null => Ok(None),
-            _ => FromSql::column_result(value, idx).map(Some),
+            _ => FromSql::column_result(value).map(Some),
         }
     }
 }
 
 impl FromSql for Value {
-    fn column_result(value: ValueRef, _: i32) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         Ok(value.into())
     }
 }

src/types/serde_json.rs

@@ -19,11 +19,11 @@ impl ToSql for Value {
 
 /// Deserialize text/blob to JSON `Value`.
 impl FromSql for Value {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
                 ValueRef::Text(ref s) => serde_json::from_str(s),
                 ValueRef::Blob(ref b) => serde_json::from_slice(b),
-                _ => return Err(Error::InvalidColumnType(idx, value.data_type())),
+                _ => return Err(Error::InvalidType(value.data_type())),
             }
             .map_err(|err| Error::FromSqlConversionFailure(Box::new(err)))
     }

src/types/time.rs

@@ -16,8 +16,8 @@ impl ToSql for time::Timespec {
 }
 
 impl FromSql for time::Timespec {
-    fn column_result(value: ValueRef, idx: i32) -> Result<Self> {
-        value.as_str(idx).and_then(|s| match time::strptime(s, SQLITE_DATETIME_FMT) {
+    fn column_result(value: ValueRef) -> Result<Self> {
+        value.as_str().and_then(|s| match time::strptime(s, SQLITE_DATETIME_FMT) {
             Ok(tm) => Ok(tm.to_timespec()),
             Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
         })

src/types/value_ref.rs

@@ -35,37 +35,37 @@ impl<'a> ValueRef<'a> {
 impl<'a> ValueRef<'a> {
     /// If `self` is case `Integer`, returns the integral value. Otherwise, returns
     /// `Err(Error::InvalidColumnType)`.
-    pub fn as_i64(&self, idx: i32) -> Result<i64> {
+    pub fn as_i64(&self) -> Result<i64> {
         match *self {
             ValueRef::Integer(i) => Ok(i),
-            _ => Err(Error::InvalidColumnType(idx, self.data_type())),
+            _ => Err(Error::InvalidType(self.data_type())),
         }
     }
 
     /// If `self` is case `Real`, returns the floating point value. Otherwise, returns
     /// `Err(Error::InvalidColumnType)`.
-    pub fn as_f64(&self, idx: i32) -> Result<f64> {
+    pub fn as_f64(&self) -> Result<f64> {
         match *self {
             ValueRef::Real(f) => Ok(f),
-            _ => Err(Error::InvalidColumnType(idx, self.data_type())),
+            _ => Err(Error::InvalidType(self.data_type())),
         }
     }
 
     /// If `self` is case `Text`, returns the string value. Otherwise, returns
     /// `Err(Error::InvalidColumnType)`.
-    pub fn as_str(&self, idx: i32) -> Result<&str> {
+    pub fn as_str(&self) -> Result<&str> {
         match *self {
             ValueRef::Text(ref t) => Ok(t),
-            _ => Err(Error::InvalidColumnType(idx, self.data_type())),
+            _ => Err(Error::InvalidType(self.data_type())),
         }
     }
 
     /// If `self` is case `Blob`, returns the byte slice. Otherwise, returns
     /// `Err(Error::InvalidColumnType)`.
-    pub fn as_blob(&self, idx: i32) -> Result<&[u8]> {
+    pub fn as_blob(&self) -> Result<&[u8]> {
         match *self {
             ValueRef::Blob(ref b) => Ok(b),
-            _ => Err(Error::InvalidColumnType(idx, self.data_type())),
+            _ => Err(Error::InvalidType(self.data_type())),
         }
     }
 }