From efc6c8937022c910d314a8885001880b936da301 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Mon, 23 May 2016 21:46:51 -0400
Subject: [PATCH 01/11] Add RawStatement::column_type.

---
 src/raw_statement.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/raw_statement.rs b/src/raw_statement.rs
index 9676d94..adb5396 100644
--- a/src/raw_statement.rs
+++ b/src/raw_statement.rs
@@ -20,6 +20,10 @@ impl RawStatement {
         unsafe { ffi::sqlite3_column_count(self.0) }
     }
 
+    pub fn column_type(&self, idx: c_int) -> c_int {
+        unsafe { ffi::sqlite3_column_type(self.0, idx) }
+    }
+
     pub fn column_name(&self, idx: c_int) -> &CStr {
         unsafe { CStr::from_ptr(ffi::sqlite3_column_name(self.0, idx)) }
     }

From c90cd37c00e12e673441f6b0e1e9160b222a053f Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Mon, 23 May 2016 21:48:56 -0400
Subject: [PATCH 02/11] Add types::BorrowedValue.

---
 src/types/borrowed_value.rs | 51 +++++++++++++++++++++++++++++++++++++
 src/types/mod.rs            |  2 ++
 2 files changed, 53 insertions(+)
 create mode 100644 src/types/borrowed_value.rs

diff --git a/src/types/borrowed_value.rs b/src/types/borrowed_value.rs
new file mode 100644
index 0000000..8b97a33
--- /dev/null
+++ b/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),
+        }
+    }
+}
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 6110d25..f8c8fba 100644
--- a/src/types/mod.rs
+++ b/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;

From 5b0cdbaa5674becd1c04d25b21dc0b89b67a4fd9 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Mon, 23 May 2016 21:49:54 -0400
Subject: [PATCH 03/11] Redo FromSql to make implementing it not `unsafe`.

Pass implementers a BorrowedValue instead of relying on them to use
the FFI interface. We take the responsibility of converting the raw
statement and column index into a BorrowedValue.
---
 src/lib.rs              |  47 +++++++++++----
 src/types/chrono.rs     | 116 ++++++++++++++++++-------------------
 src/types/from_sql.rs   | 123 +++++++++++-----------------------------
 src/types/serde_json.rs |  21 ++-----
 src/types/time.rs       |  13 ++---
 5 files changed, 133 insertions(+), 187 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index e3894cd..909ba1f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -75,7 +75,7 @@ use std::result;
 use std::str;
 use libc::{c_int, c_char};
 
-use types::{ToSql, FromSql};
+use types::{ToSql, FromSql, BorrowedValue};
 use error::{error_from_sqlite_code, error_from_handle};
 use raw_statement::RawStatement;
 use cache::StatementCache;
@@ -1064,15 +1064,9 @@ impl<'a, 'stmt> Row<'a, 'stmt> {
     /// Returns an `Error::InvalidColumnName` if `idx` is not a valid column name
     /// for this row.
     pub fn get_checked<I: RowIndex, T: FromSql>(&self, idx: I) -> Result<T> {
-        unsafe {
-            let idx = try!(idx.idx(self.stmt));
-
-            if T::column_has_valid_sqlite_type(self.stmt.stmt.ptr(), idx) {
-                FromSql::column_result(self.stmt.stmt.ptr(), idx)
-            } else {
-                Err(Error::InvalidColumnType)
-            }
-        }
+        let idx = try!(idx.idx(self.stmt));
+        let value = unsafe { BorrowedValue::new(&self.stmt.stmt, idx) };
+        FromSql::column_result(value)
     }
 
     /// Return the number of columns in the current row.
@@ -1106,6 +1100,39 @@ impl<'a> RowIndex for &'a str {
     }
 }
 
+impl<'a> BorrowedValue<'a> {
+    unsafe fn new(stmt: &RawStatement, col: c_int) -> BorrowedValue {
+        use std::slice::from_raw_parts;
+
+        let raw = stmt.ptr();
+
+        match stmt.column_type(col) {
+            ffi::SQLITE_NULL => BorrowedValue::Null,
+            ffi::SQLITE_INTEGER => BorrowedValue::Integer(ffi::sqlite3_column_int64(raw, col)),
+            ffi::SQLITE_FLOAT => BorrowedValue::Real(ffi::sqlite3_column_double(raw, col)),
+            ffi::SQLITE_TEXT => {
+                let text = ffi::sqlite3_column_text(raw, col);
+                assert!(!text.is_null(), "unexpected SQLITE_TEXT column type with NULL data");
+                let s = CStr::from_ptr(text as *const c_char);
+
+                // sqlite3_column_text returns UTF8 data, so our unwrap here should be fine.
+                let s = s.to_str().expect("sqlite3_column_text returned invalid UTF-8");
+                BorrowedValue::Text(s)
+            }
+            ffi::SQLITE_BLOB => {
+                let blob = ffi::sqlite3_column_blob(raw, col);
+                assert!(!blob.is_null(), "unexpected SQLITE_BLOB column type with NULL data");
+
+                let len = ffi::sqlite3_column_bytes(raw, col);
+                assert!(len >= 0, "unexpected negative return from sqlite3_column_bytes");
+
+                BorrowedValue::Blob(from_raw_parts(blob as *const u8, len as usize))
+            }
+            _ => unreachable!("sqlite3_column_type returned invalid value")
+        }
+    }
+}
+
 #[cfg(test)]
 mod test {
     extern crate tempdir;
diff --git a/src/types/chrono.rs b/src/types/chrono.rs
index a9e0bea..7ecb28f 100644
--- a/src/types/chrono.rs
+++ b/src/types/chrono.rs
@@ -1,11 +1,13 @@
 //! Convert most of the [Time Strings](http://sqlite.org/lang_datefunc.html) to chrono types.
 extern crate chrono;
 
+use std::borrow::Cow;
+
 use self::chrono::{NaiveDate, NaiveTime, NaiveDateTime, DateTime, TimeZone, UTC, Local};
 use libc::c_int;
 
 use {Error, Result};
-use types::{FromSql, ToSql};
+use types::{FromSql, ToSql, BorrowedValue};
 
 use ffi::sqlite3_stmt;
 
@@ -19,16 +21,11 @@ impl ToSql for NaiveDate {
 
 /// "YYYY-MM-DD" => ISO 8601 calendar date without timezone.
 impl FromSql for NaiveDate {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveDate> {
-        let s = try!(String::column_result(stmt, col));
-        match NaiveDate::parse_from_str(&s, "%Y-%m-%d") {
+    fn column_result(value: BorrowedValue) -> 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))),
-        }
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        String::column_has_valid_sqlite_type(stmt, col)
+        })
     }
 }
 
@@ -42,21 +39,18 @@ impl ToSql for NaiveTime {
 
 /// "HH:MM"/"HH:MM:SS"/"HH:MM:SS.SSS" => ISO 8601 time without timezone.
 impl FromSql for NaiveTime {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveTime> {
-        let s = try!(String::column_result(stmt, col));
-        let fmt = match s.len() {
-            5 => "%H:%M",
-            8 => "%H:%M:%S",
-            _ => "%H:%M:%S%.f",
-        };
-        match NaiveTime::parse_from_str(&s, fmt) {
-            Ok(dt) => Ok(dt),
-            Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
-        }
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        String::column_has_valid_sqlite_type(stmt, col)
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        value.as_str().and_then(|s| {
+            let fmt = match s.len() {
+                5 => "%H:%M",
+                8 => "%H:%M:%S",
+                _ => "%H:%M:%S%.f",
+            };
+            match NaiveTime::parse_from_str(s, fmt) {
+                Ok(dt) => Ok(dt),
+                Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
+            }
+        })
     }
 }
 
@@ -71,23 +65,19 @@ 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 {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<NaiveDateTime> {
-        let s = try!(String::column_result(stmt, col));
+    fn column_result(value: BorrowedValue) -> 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 {
+                "%Y-%m-%d %H:%M:%S%.f"
+            };
 
-        let fmt = if s.len() >= 11 && s.as_bytes()[10] == b'T' {
-            "%Y-%m-%dT%H:%M:%S%.f"
-        } else {
-            "%Y-%m-%d %H:%M:%S%.f"
-        };
-
-        match NaiveDateTime::parse_from_str(&s, fmt) {
-            Ok(dt) => Ok(dt),
-            Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
-        }
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        String::column_has_valid_sqlite_type(stmt, col)
+            match NaiveDateTime::parse_from_str(s, fmt) {
+                Ok(dt) => Ok(dt),
+                Err(err) => Err(Error::FromSqlConversionFailure(Box::new(err))),
+            }
+        })
     }
 }
 
@@ -101,38 +91,40 @@ impl<Tz: TimeZone> ToSql for DateTime<Tz> {
 
 /// RFC3339 ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM") into DateTime<UTC>.
 impl FromSql for DateTime<UTC> {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<DateTime<UTC>> {
-        let s = {
-            let mut s = try!(String::column_result(stmt, col));
-            if s.len() >= 11 {
-                let sbytes = s.as_mut_vec();
-                if sbytes[10] == b' ' {
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        {
+            // Try to parse value as rfc3339 first.
+            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' ' {
+                let mut s = s.to_string();
+                unsafe {
+                    let sbytes = s.as_mut_vec();
                     sbytes[10] = b'T';
                 }
-            }
-            s
-        };
-        match DateTime::parse_from_rfc3339(&s) {
-            Ok(dt) => Ok(dt.with_timezone(&UTC)),
-            Err(_) => NaiveDateTime::column_result(stmt, col).map(|dt| UTC.from_utc_datetime(&dt)),
-        }
-    }
+                Cow::Owned(s)
+            } else {
+                Cow::Borrowed(s)
+            };
 
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        String::column_has_valid_sqlite_type(stmt, col)
+            match DateTime::parse_from_rfc3339(&s) {
+                Ok(dt) => return Ok(dt.with_timezone(&UTC)),
+                Err(_) => (),
+            }
+        }
+
+        // Couldn't parse as rfc3339 - fall back to NaiveDateTime.
+        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> {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<DateTime<Local>> {
-        let utc_dt = try!(DateTime::<UTC>::column_result(stmt, col));
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        let utc_dt = try!(DateTime::<UTC>::column_result(value));
         Ok(utc_dt.with_timezone(&Local))
     }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        DateTime::<UTC>::column_has_valid_sqlite_type(stmt, col)
-    }
 }
 
 #[cfg(test)]
diff --git a/src/types/from_sql.rs b/src/types/from_sql.rs
index a9fc3f6..a996347 100644
--- a/src/types/from_sql.rs
+++ b/src/types/from_sql.rs
@@ -1,119 +1,60 @@
-use std::ffi::CStr;
-use std::mem;
-use std::str;
+use super::{BorrowedValue, Value};
+use ::Result;
 
-use libc::{c_char, c_double, c_int};
-
-use super::Value;
-use ffi::{sqlite3_stmt, sqlite3_column_type};
-use ::{ffi, Result};
-use ::error::Error;
-
-/// A trait for types that can be created from a SQLite value.
 pub trait FromSql: Sized {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Self>;
+    fn column_result(value: BorrowedValue) -> Result<Self>;
+}
 
-    /// FromSql types can implement this method and use sqlite3_column_type to check that
-    /// the type reported by SQLite matches a type suitable for Self. This method is used
-    /// by `Row::get_checked` to confirm that the column contains a valid type before
-    /// attempting to retrieve the value.
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true
+impl FromSql for i32 {
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        i64::column_result(value).map(|i| i as i32)
     }
 }
 
-macro_rules! raw_from_impl(
-    ($t:ty, $f:ident, $c:expr) => (
-        impl FromSql for $t {
-            unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<$t> {
-                Ok(ffi::$f(stmt, col))
-            }
+impl FromSql for i64 {
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        value.as_i64()
+    }
+}
 
-            unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-                sqlite3_column_type(stmt, col) == $c
-            }
-        }
-    )
-);
-
-raw_from_impl!(c_int, sqlite3_column_int, ffi::SQLITE_INTEGER); // i32
-raw_from_impl!(i64, sqlite3_column_int64, ffi::SQLITE_INTEGER);
-raw_from_impl!(c_double, sqlite3_column_double, ffi::SQLITE_FLOAT); // f64
+impl FromSql for f64 {
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        value.as_f64()
+    }
+}
 
 impl FromSql for bool {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<bool> {
-        match ffi::sqlite3_column_int(stmt, col) {
-            0 => Ok(false),
-            _ => Ok(true),
-        }
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        sqlite3_column_type(stmt, col) == ffi::SQLITE_INTEGER
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        i64::column_result(value).map(|i| match i {
+            0 => false,
+            _ => true,
+        })
     }
 }
 
 impl FromSql for String {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<String> {
-        let c_text = ffi::sqlite3_column_text(stmt, col);
-        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 column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        sqlite3_column_type(stmt, col) == ffi::SQLITE_TEXT
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        value.as_str().map(|s| s.to_string())
     }
 }
 
 impl FromSql for Vec<u8> {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Vec<u8>> {
-        use std::slice::from_raw_parts;
-        let c_blob = ffi::sqlite3_column_blob(stmt, col);
-        let len = ffi::sqlite3_column_bytes(stmt, col);
-
-        // The documentation for sqlite3_column_bytes indicates it is always non-negative,
-        // but we should assert here just to be sure.
-        assert!(len >= 0,
-                "unexpected negative return from sqlite3_column_bytes");
-        let len = len as usize;
-
-        Ok(from_raw_parts(mem::transmute(c_blob), len).to_vec())
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        sqlite3_column_type(stmt, col) == ffi::SQLITE_BLOB
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        value.as_blob().map(|b| b.to_vec())
     }
 }
 
 impl<T: FromSql> FromSql for Option<T> {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Option<T>> {
-        if sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL {
-            Ok(None)
-        } else {
-            FromSql::column_result(stmt, col).map(Some)
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        match value {
+            BorrowedValue::Null => Ok(None),
+            _ => FromSql::column_result(value).map(Some),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL ||
-        T::column_has_valid_sqlite_type(stmt, col)
-    }
 }
 
 impl FromSql for Value {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Value> {
-        match sqlite3_column_type(stmt, col) {
-            ffi::SQLITE_TEXT => FromSql::column_result(stmt, col).map(Value::Text),
-            ffi::SQLITE_INTEGER => Ok(Value::Integer(ffi::sqlite3_column_int64(stmt, col))),
-            ffi::SQLITE_FLOAT => Ok(Value::Real(ffi::sqlite3_column_double(stmt, col))),
-            ffi::SQLITE_NULL => Ok(Value::Null),
-            ffi::SQLITE_BLOB => FromSql::column_result(stmt, col).map(Value::Blob),
-            _ => Err(Error::InvalidColumnType),
-        }
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        Ok(value.to_value())
     }
 }
diff --git a/src/types/serde_json.rs b/src/types/serde_json.rs
index dc1eeff..a3da2fc 100644
--- a/src/types/serde_json.rs
+++ b/src/types/serde_json.rs
@@ -5,11 +5,9 @@ use libc::c_int;
 use self::serde_json::Value;
 
 use {Error, Result};
-use types::{FromSql, ToSql};
+use types::{FromSql, ToSql, BorrowedValue};
 
-use ffi;
 use ffi::sqlite3_stmt;
-use ffi::sqlite3_column_type;
 
 /// Serialize JSON `Value` to text.
 impl ToSql for Value {
@@ -21,19 +19,12 @@ impl ToSql for Value {
 
 /// Deserialize text/blob to JSON `Value`.
 impl FromSql for Value {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Value> {
-        let value_result = match sqlite3_column_type(stmt, col) {
-            ffi::SQLITE_TEXT => {
-                let s = try!(String::column_result(stmt, col));
-                serde_json::from_str(&s)
-            }
-            ffi::SQLITE_BLOB => {
-                let blob = try!(Vec::<u8>::column_result(stmt, col));
-                serde_json::from_slice(&blob)
-            }
+    fn column_result(value: BorrowedValue) -> Result<Self> {
+        match value {
+            BorrowedValue::Text(ref s) => serde_json::from_str(s),
+            BorrowedValue::Blob(ref b) => serde_json::from_slice(b),
             _ => return Err(Error::InvalidColumnType),
-        };
-        value_result.map_err(|err| Error::FromSqlConversionFailure(Box::new(err)))
+        }.map_err(|err| Error::FromSqlConversionFailure(Box::new(err)))
     }
 }
 
diff --git a/src/types/time.rs b/src/types/time.rs
index fe77956..ae524ec 100644
--- a/src/types/time.rs
+++ b/src/types/time.rs
@@ -2,7 +2,7 @@ extern crate time;
 
 use libc::c_int;
 use {Error, Result};
-use types::{FromSql, ToSql};
+use types::{FromSql, ToSql, BorrowedValue};
 
 use ffi::sqlite3_stmt;
 
@@ -16,16 +16,11 @@ impl ToSql for time::Timespec {
 }
 
 impl FromSql for time::Timespec {
-    unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<time::Timespec> {
-        let s = try!(String::column_result(stmt, col));
-        match time::strptime(&s, SQLITE_DATETIME_FMT) {
+    fn column_result(value: BorrowedValue) -> 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))),
-        }
-    }
-
-    unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
-        String::column_has_valid_sqlite_type(stmt, col)
+        })
     }
 }
 

From 734f18c9856637ac3e498ae242f2397496231cb4 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 19:36:38 -0400
Subject: [PATCH 04/11] Impl `From` for converting Value <-> BorrowedValue

---
 src/types/borrowed_value.rs | 34 ++++++++++++++++++++++++----------
 src/types/from_sql.rs       |  2 +-
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/src/types/borrowed_value.rs b/src/types/borrowed_value.rs
index 8b97a33..cbbb977 100644
--- a/src/types/borrowed_value.rs
+++ b/src/types/borrowed_value.rs
@@ -11,16 +11,6 @@ pub enum BorrowedValue<'a> {
 }
 
 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),
@@ -49,3 +39,27 @@ impl<'a> BorrowedValue<'a> {
         }
     }
 }
+
+impl<'a> From<BorrowedValue<'a>> for Value {
+    fn from(borrowed: BorrowedValue) -> Value {
+        match borrowed {
+            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()),
+        }
+    }
+}
+
+impl<'a> From<&'a Value> for BorrowedValue<'a> {
+    fn from(value: &'a Value) -> BorrowedValue<'a> {
+        match *value {
+            Value::Null => BorrowedValue::Null,
+            Value::Integer(i) => BorrowedValue::Integer(i),
+            Value::Real(r) => BorrowedValue::Real(r),
+            Value::Text(ref s) => BorrowedValue::Text(s),
+            Value::Blob(ref b) => BorrowedValue::Blob(b),
+        }
+    }
+}
diff --git a/src/types/from_sql.rs b/src/types/from_sql.rs
index a996347..c733f07 100644
--- a/src/types/from_sql.rs
+++ b/src/types/from_sql.rs
@@ -55,6 +55,6 @@ impl<T: FromSql> FromSql for Option<T> {
 
 impl FromSql for Value {
     fn column_result(value: BorrowedValue) -> Result<Self> {
-        Ok(value.to_value())
+        Ok(value.into())
     }
 }

From 9d47d5109aeaad1c5d3c3fb940c48f0a90c66feb Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 19:48:26 -0400
Subject: [PATCH 05/11] Add doc comments for BorrowedValue and friends.

---
 src/types/borrowed_value.rs | 18 ++++++++++++++++++
 src/types/from_sql.rs       |  1 +
 src/types/mod.rs            | 20 +++++++++++---------
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/types/borrowed_value.rs b/src/types/borrowed_value.rs
index cbbb977..f8e5068 100644
--- a/src/types/borrowed_value.rs
+++ b/src/types/borrowed_value.rs
@@ -2,15 +2,27 @@ use ::Result;
 use ::error::Error;
 use super::Value;
 
+/// A non-owning [dynamic type value](http://sqlite.org/datatype3.html). Typically the
+/// memory backing this value is owned by SQLite.
+///
+/// See [`Value`](enum.Value.html) for an owning dynamic type value.
+#[derive(Copy,Clone,Debug,PartialEq)]
 pub enum BorrowedValue<'a> {
+    /// The value is a `NULL` value.
     Null,
+    /// The value is a signed integer.
     Integer(i64),
+    /// The value is a floating point number.
     Real(f64),
+    /// The value is a text string.
     Text(&'a str),
+    /// The value is a blob of data
     Blob(&'a [u8]),
 }
 
 impl<'a> BorrowedValue<'a> {
+    /// If `self` is case `Integer`, returns the integral value. Otherwise, returns
+    /// `Err(Error::InvalidColumnType)`.
     pub fn as_i64(&self) -> Result<i64> {
         match *self {
             BorrowedValue::Integer(i) => Ok(i),
@@ -18,6 +30,8 @@ impl<'a> BorrowedValue<'a> {
         }
     }
 
+    /// If `self` is case `Real`, returns the floating point value. Otherwise, returns
+    /// `Err(Error::InvalidColumnType)`.
     pub fn as_f64(&self) -> Result<f64> {
         match *self {
             BorrowedValue::Real(f) => Ok(f),
@@ -25,6 +39,8 @@ impl<'a> BorrowedValue<'a> {
         }
     }
 
+    /// If `self` is case `Text`, returns the string value. Otherwise, returns
+    /// `Err(Error::InvalidColumnType)`.
     pub fn as_str(&self) -> Result<&str> {
         match *self {
             BorrowedValue::Text(ref t) => Ok(t),
@@ -32,6 +48,8 @@ impl<'a> BorrowedValue<'a> {
         }
     }
 
+    /// If `self` is case `Blob`, returns the byte slice. Otherwise, returns
+    /// `Err(Error::InvalidColumnType)`.
     pub fn as_blob(&self) -> Result<&[u8]> {
         match *self {
             BorrowedValue::Blob(ref b) => Ok(b),
diff --git a/src/types/from_sql.rs b/src/types/from_sql.rs
index c733f07..cddf287 100644
--- a/src/types/from_sql.rs
+++ b/src/types/from_sql.rs
@@ -1,6 +1,7 @@
 use super::{BorrowedValue, Value};
 use ::Result;
 
+/// A trait for types that can be created from a SQLite value.
 pub trait FromSql: Sized {
     fn column_result(value: BorrowedValue) -> Result<Self>;
 }
diff --git a/src/types/mod.rs b/src/types/mod.rs
index f8c8fba..d00693e 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -4,7 +4,9 @@
 //! the `ToSql` and `FromSql` traits are provided for the basic types that SQLite provides methods
 //! for:
 //!
-//! * C integers and doubles (`c_int` and `c_double`)
+//! * Integers (`i32` and `i64`; SQLite uses `i64` internally, so getting an `i32` will truncate
+//!   if the value is too large or too small).
+//! * Reals (`f64`)
 //! * Strings (`String` and `&str`)
 //! * Blobs (`Vec<u8>` and `&[u8]`)
 //!
@@ -15,12 +17,6 @@
 //! truncates timespecs to the nearest second. If you want different storage for timespecs, you can
 //! use a newtype. For example, to store timespecs as doubles:
 //!
-//! `ToSql` and `FromSql` are also implemented for `Option<T>` where `T` implements `ToSql` or
-//! `FromSql` for the cases where you want to know if a value was NULL (which gets translated to
-//! `None`). If you get a value that was NULL in SQLite but you store it into a non-`Option` value
-//! in Rust, you will get a "sensible" zero value - 0 for numeric types (including timespecs), an
-//! empty string, or an empty vector of bytes.
-//!
 //! ```rust,ignore
 //! extern crate rusqlite;
 //! extern crate libc;
@@ -51,6 +47,10 @@
 //!     }
 //! }
 //! ```
+//!
+//! `ToSql` and `FromSql` are also implemented for `Option<T>` where `T` implements `ToSql` or
+//! `FromSql` for the cases where you want to know if a value was NULL (which gets translated to
+//! `None`).
 
 pub use ffi::sqlite3_stmt;
 pub use ffi::sqlite3_column_type;
@@ -88,8 +88,10 @@ mod serde_json;
 #[derive(Copy,Clone)]
 pub struct Null;
 
-/// Dynamic type value (http://sqlite.org/datatype3.html)
-/// Value's type is dictated by SQLite (not by the caller).
+/// Owning [dynamic type value](http://sqlite.org/datatype3.html). Value's type is typically
+/// dictated by SQLite (not by the caller).
+///
+/// See [`BorrowedValue`](enum.BorrowedValue.html) for a non-owning dynamic type value.
 #[derive(Clone,Debug,PartialEq)]
 pub enum Value {
     /// The value is a `NULL` value.

From 4662b9b93278c612ca905bd0d108a75cf9b97987 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 20:05:32 -0400
Subject: [PATCH 06/11] Allow FromSql::<f64> to work on SQLite integer values.

---
 src/types/from_sql.rs | 7 ++++++-
 src/types/mod.rs      | 3 +--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/types/from_sql.rs b/src/types/from_sql.rs
index cddf287..ba35b73 100644
--- a/src/types/from_sql.rs
+++ b/src/types/from_sql.rs
@@ -1,5 +1,6 @@
 use super::{BorrowedValue, Value};
 use ::Result;
+use ::error::Error;
 
 /// A trait for types that can be created from a SQLite value.
 pub trait FromSql: Sized {
@@ -20,7 +21,11 @@ impl FromSql for i64 {
 
 impl FromSql for f64 {
     fn column_result(value: BorrowedValue) -> Result<Self> {
-        value.as_f64()
+        match value {
+            BorrowedValue::Integer(i) => Ok(i as f64),
+            BorrowedValue::Real(f) => Ok(f),
+            _ => Err(Error::InvalidColumnType),
+        }
     }
 }
 
diff --git a/src/types/mod.rs b/src/types/mod.rs
index d00693e..cfb8280 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -223,10 +223,9 @@ mod test {
         assert!(is_invalid_column_type(row.get_checked::<i32, Option<c_int>>(1).err().unwrap()));
 
         // 2 is actually an integer
-        assert!(is_invalid_column_type(row.get_checked::<i32, c_double>(2).err().unwrap()));
         assert!(is_invalid_column_type(row.get_checked::<i32, String>(2).err().unwrap()));
         assert!(is_invalid_column_type(row.get_checked::<i32, Vec<u8>>(2).err().unwrap()));
-        assert!(is_invalid_column_type(row.get_checked::<i32, Option<c_double>>(2).err().unwrap()));
+        assert!(is_invalid_column_type(row.get_checked::<i32, Option<String>>(2).err().unwrap()));
 
         // 3 is actually a float (c_double)
         assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(3).err().unwrap()));

From 0fbfad24525f4cbc11d3eb3154a11906d63ccd41 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 20:08:12 -0400
Subject: [PATCH 07/11] 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 | 134 ++++++++++-------------------------------------
 1 file changed, 29 insertions(+), 105 deletions(-)

diff --git a/src/functions.rs b/src/functions.rs
index 8c8723e..b261fce 100644
--- a/src/functions.rs
+++ b/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};
 
@@ -157,108 +156,35 @@ impl ToResult for Null {
     }
 }
 
-/// A trait for types that can be created from a SQLite function parameter value.
-pub trait FromValue: Sized {
-    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>> {
+impl<'a> BorrowedValue<'a> {
+    unsafe fn from_value(value: *mut sqlite3_value) -> BorrowedValue<'a> {
         use std::slice::from_raw_parts;
-        let c_blob = ffi::sqlite3_value_blob(v);
-        let len = ffi::sqlite3_value_bytes(v);
 
-        assert!(len >= 0,
-                "unexpected negative return from sqlite3_value_bytes");
-        let len = len as usize;
+        match ffi::sqlite3_value_type(value) {
+            ffi::SQLITE_NULL => BorrowedValue::Null,
+            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 {
-        sqlite3_value_type(v) == ffi::SQLITE_BLOB
-    }
-}
+                let len = ffi::sqlite3_value_bytes(value);
+                assert!(len >= 0, "unexpected negative return from sqlite3_value_bytes");
 
-impl<T: FromValue> FromValue for Option<T> {
-    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)
+                BorrowedValue::Blob(from_raw_parts(blob as *const u8, len as usize))
+            }
+            _ => 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)
-    }
 }
 
 unsafe extern "C" fn free_boxed_value<T>(p: *mut c_void) {
@@ -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 {
-            if T::parameter_has_valid_sqlite_type(arg) {
-                T::parameter_value(arg)
-            } else {
-                Err(Error::InvalidFunctionParameterType)
-            }
-        }
+        let value = unsafe { BorrowedValue::from_value(arg) };
+        FromSql::column_result(value).map_err(|err| match err {
+            Error::InvalidColumnType => Error::InvalidFunctionParameterType,
+            _ => err
+        })
     }
 
     /// Sets the auxilliary data associated with a particular parameter. See

From d9df23ca90064a474d40be61992c62a93327a9e0 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 20:12:29 -0400
Subject: [PATCH 08/11] Fix doc comment example of FromSql implementation.

---
 src/types/mod.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/types/mod.rs b/src/types/mod.rs
index cfb8280..03bb75a 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -15,7 +15,7 @@
 //! `"%Y-%m-%d %H:%M:%S"`, as SQLite's builtin
 //! [datetime](https://www.sqlite.org/lang_datefunc.html) function.  Note that this storage
 //! truncates timespecs to the nearest second. If you want different storage for timespecs, you can
-//! use a newtype. For example, to store timespecs as doubles:
+//! use a newtype. For example, to store timespecs as `f64`s:
 //!
 //! ```rust,ignore
 //! extern crate rusqlite;
@@ -29,10 +29,8 @@
 //! pub struct TimespecSql(pub time::Timespec);
 //!
 //! impl FromSql for TimespecSql {
-//!     unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int)
-//!             -> Result<TimespecSql> {
-//!         let as_f64_result = FromSql::column_result(stmt, col);
-//!         as_f64_result.map(|as_f64: f64| {
+//!     fn column_result(value: BorrowedValue) -> Result<Self> {
+//!         f64::column_result(value).map(|as_f64| {
 //!             TimespecSql(time::Timespec{ sec: as_f64.trunc() as i64,
 //!                                         nsec: (as_f64.fract() * 1.0e9) as i32 })
 //!         })

From 308789495c1497397e2b6cf6469cbbb6daa69a9a Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 20:16:13 -0400
Subject: [PATCH 09/11] Add FromSql breaking change note to Changelog.

---
 Changelog.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index 358d93f..233a58b 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,9 @@
+# Version UPCOMING (...)
+
+* BREAKING CHANGE: The `FromSql` trait has been redesigned. It now requires a single, safe
+  method instead of the previous definition which required implementing one or two unsafe
+  methods.
+
 # Version 0.7.2 (2016-05-19)
 
 * BREAKING CHANGE: `Rows` no longer implements `Iterator`. It still has a `next()` method, but

From 2f4990dafd18816fc99182f37768683471e32dcd Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Tue, 24 May 2016 21:34:18 -0400
Subject: [PATCH 10/11] Rename BorrowedValue -> ValueRef.

---
 src/functions.rs                              | 18 ++++-----
 src/lib.rs                                    | 18 ++++-----
 src/types/chrono.rs                           | 12 +++---
 src/types/from_sql.rs                         | 26 ++++++------
 src/types/mod.rs                              |  8 ++--
 src/types/serde_json.rs                       |  8 ++--
 src/types/time.rs                             |  4 +-
 src/types/{borrowed_value.rs => value_ref.rs} | 40 +++++++++----------
 8 files changed, 67 insertions(+), 67 deletions(-)
 rename src/types/{borrowed_value.rs => value_ref.rs} (62%)

diff --git a/src/functions.rs b/src/functions.rs
index b261fce..32e4d1e 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -62,7 +62,7 @@ pub use ffi::sqlite3_value;
 pub use ffi::sqlite3_value_type;
 pub use ffi::sqlite3_value_numeric_type;
 
-use types::{Null, FromSql, BorrowedValue};
+use types::{Null, FromSql, ValueRef};
 
 use {Result, Error, Connection, str_to_cstring, InnerConnection};
 
@@ -156,14 +156,14 @@ impl ToResult for Null {
     }
 }
 
-impl<'a> BorrowedValue<'a> {
-    unsafe fn from_value(value: *mut sqlite3_value) -> BorrowedValue<'a> {
+impl<'a> ValueRef<'a> {
+    unsafe fn from_value(value: *mut sqlite3_value) -> ValueRef<'a> {
         use std::slice::from_raw_parts;
 
         match ffi::sqlite3_value_type(value) {
-            ffi::SQLITE_NULL => BorrowedValue::Null,
-            ffi::SQLITE_INTEGER => BorrowedValue::Integer(ffi::sqlite3_value_int64(value)),
-            ffi::SQLITE_FLOAT => BorrowedValue::Real(ffi::sqlite3_value_double(value)),
+            ffi::SQLITE_NULL => ValueRef::Null,
+            ffi::SQLITE_INTEGER => ValueRef::Integer(ffi::sqlite3_value_int64(value)),
+            ffi::SQLITE_FLOAT => ValueRef::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");
@@ -171,7 +171,7 @@ impl<'a> BorrowedValue<'a> {
 
                 // 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)
+                ValueRef::Text(s)
             }
             ffi::SQLITE_BLOB => {
                 let blob = ffi::sqlite3_value_blob(value);
@@ -180,7 +180,7 @@ impl<'a> BorrowedValue<'a> {
                 let len = ffi::sqlite3_value_bytes(value);
                 assert!(len >= 0, "unexpected negative return from sqlite3_value_bytes");
 
-                BorrowedValue::Blob(from_raw_parts(blob as *const u8, len as usize))
+                ValueRef::Blob(from_raw_parts(blob as *const u8, len as usize))
             }
             _ => unreachable!("sqlite3_value_type returned invalid value")
         }
@@ -216,7 +216,7 @@ impl<'a> Context<'a> {
     /// Will return Err if the underlying SQLite type cannot be converted to a `T`.
     pub fn get<T: FromSql>(&self, idx: usize) -> Result<T> {
         let arg = self.args[idx];
-        let value = unsafe { BorrowedValue::from_value(arg) };
+        let value = unsafe { ValueRef::from_value(arg) };
         FromSql::column_result(value).map_err(|err| match err {
             Error::InvalidColumnType => Error::InvalidFunctionParameterType,
             _ => err
diff --git a/src/lib.rs b/src/lib.rs
index 909ba1f..8d84890 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -75,7 +75,7 @@ use std::result;
 use std::str;
 use libc::{c_int, c_char};
 
-use types::{ToSql, FromSql, BorrowedValue};
+use types::{ToSql, FromSql, ValueRef};
 use error::{error_from_sqlite_code, error_from_handle};
 use raw_statement::RawStatement;
 use cache::StatementCache;
@@ -1065,7 +1065,7 @@ impl<'a, 'stmt> Row<'a, 'stmt> {
     /// for this row.
     pub fn get_checked<I: RowIndex, T: FromSql>(&self, idx: I) -> Result<T> {
         let idx = try!(idx.idx(self.stmt));
-        let value = unsafe { BorrowedValue::new(&self.stmt.stmt, idx) };
+        let value = unsafe { ValueRef::new(&self.stmt.stmt, idx) };
         FromSql::column_result(value)
     }
 
@@ -1100,16 +1100,16 @@ impl<'a> RowIndex for &'a str {
     }
 }
 
-impl<'a> BorrowedValue<'a> {
-    unsafe fn new(stmt: &RawStatement, col: c_int) -> BorrowedValue {
+impl<'a> ValueRef<'a> {
+    unsafe fn new(stmt: &RawStatement, col: c_int) -> ValueRef {
         use std::slice::from_raw_parts;
 
         let raw = stmt.ptr();
 
         match stmt.column_type(col) {
-            ffi::SQLITE_NULL => BorrowedValue::Null,
-            ffi::SQLITE_INTEGER => BorrowedValue::Integer(ffi::sqlite3_column_int64(raw, col)),
-            ffi::SQLITE_FLOAT => BorrowedValue::Real(ffi::sqlite3_column_double(raw, col)),
+            ffi::SQLITE_NULL => ValueRef::Null,
+            ffi::SQLITE_INTEGER => ValueRef::Integer(ffi::sqlite3_column_int64(raw, col)),
+            ffi::SQLITE_FLOAT => ValueRef::Real(ffi::sqlite3_column_double(raw, col)),
             ffi::SQLITE_TEXT => {
                 let text = ffi::sqlite3_column_text(raw, col);
                 assert!(!text.is_null(), "unexpected SQLITE_TEXT column type with NULL data");
@@ -1117,7 +1117,7 @@ impl<'a> BorrowedValue<'a> {
 
                 // sqlite3_column_text returns UTF8 data, so our unwrap here should be fine.
                 let s = s.to_str().expect("sqlite3_column_text returned invalid UTF-8");
-                BorrowedValue::Text(s)
+                ValueRef::Text(s)
             }
             ffi::SQLITE_BLOB => {
                 let blob = ffi::sqlite3_column_blob(raw, col);
@@ -1126,7 +1126,7 @@ impl<'a> BorrowedValue<'a> {
                 let len = ffi::sqlite3_column_bytes(raw, col);
                 assert!(len >= 0, "unexpected negative return from sqlite3_column_bytes");
 
-                BorrowedValue::Blob(from_raw_parts(blob as *const u8, len as usize))
+                ValueRef::Blob(from_raw_parts(blob as *const u8, len as usize))
             }
             _ => unreachable!("sqlite3_column_type returned invalid value")
         }
diff --git a/src/types/chrono.rs b/src/types/chrono.rs
index 7ecb28f..3d17dd6 100644
--- a/src/types/chrono.rs
+++ b/src/types/chrono.rs
@@ -7,7 +7,7 @@ use self::chrono::{NaiveDate, NaiveTime, NaiveDateTime, DateTime, TimeZone, UTC,
 use libc::c_int;
 
 use {Error, Result};
-use types::{FromSql, ToSql, BorrowedValue};
+use types::{FromSql, ToSql, ValueRef};
 
 use ffi::sqlite3_stmt;
 
@@ -21,7 +21,7 @@ impl ToSql for NaiveDate {
 
 /// "YYYY-MM-DD" => ISO 8601 calendar date without timezone.
 impl FromSql for NaiveDate {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    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))),
@@ -39,7 +39,7 @@ 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: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         value.as_str().and_then(|s| {
             let fmt = match s.len() {
                 5 => "%H:%M",
@@ -65,7 +65,7 @@ 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: BorrowedValue) -> Result<Self> {
+    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"
@@ -91,7 +91,7 @@ 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: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         {
             // Try to parse value as rfc3339 first.
             let s = try!(value.as_str());
@@ -121,7 +121,7 @@ impl FromSql for DateTime<UTC> {
 
 /// RFC3339 ("YYYY-MM-DDTHH:MM:SS.SSS[+-]HH:MM") into DateTime<Local>.
 impl FromSql for DateTime<Local> {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         let utc_dt = try!(DateTime::<UTC>::column_result(value));
         Ok(utc_dt.with_timezone(&Local))
     }
diff --git a/src/types/from_sql.rs b/src/types/from_sql.rs
index ba35b73..28df415 100644
--- a/src/types/from_sql.rs
+++ b/src/types/from_sql.rs
@@ -1,36 +1,36 @@
-use super::{BorrowedValue, Value};
+use super::{ValueRef, Value};
 use ::Result;
 use ::error::Error;
 
 /// A trait for types that can be created from a SQLite value.
 pub trait FromSql: Sized {
-    fn column_result(value: BorrowedValue) -> Result<Self>;
+    fn column_result(value: ValueRef) -> Result<Self>;
 }
 
 impl FromSql for i32 {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         i64::column_result(value).map(|i| i as i32)
     }
 }
 
 impl FromSql for i64 {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         value.as_i64()
     }
 }
 
 impl FromSql for f64 {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
-            BorrowedValue::Integer(i) => Ok(i as f64),
-            BorrowedValue::Real(f) => Ok(f),
+            ValueRef::Integer(i) => Ok(i as f64),
+            ValueRef::Real(f) => Ok(f),
             _ => Err(Error::InvalidColumnType),
         }
     }
 }
 
 impl FromSql for bool {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    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: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         value.as_str().map(|s| s.to_string())
     }
 }
 
 impl FromSql for Vec<u8> {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    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: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
-            BorrowedValue::Null => Ok(None),
+            ValueRef::Null => Ok(None),
             _ => FromSql::column_result(value).map(Some),
         }
     }
 }
 
 impl FromSql for Value {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         Ok(value.into())
     }
 }
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 03bb75a..7853291 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -29,7 +29,7 @@
 //! pub struct TimespecSql(pub time::Timespec);
 //!
 //! impl FromSql for TimespecSql {
-//!     fn column_result(value: BorrowedValue) -> Result<Self> {
+//!     fn column_result(value: ValueRef) -> Result<Self> {
 //!         f64::column_result(value).map(|as_f64| {
 //!             TimespecSql(time::Timespec{ sec: as_f64.trunc() as i64,
 //!                                         nsec: (as_f64.fract() * 1.0e9) as i32 })
@@ -56,9 +56,9 @@ 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;
+pub use self::value_ref::ValueRef;
 
-mod borrowed_value;
+mod value_ref;
 mod from_sql;
 mod to_sql;
 mod time;
@@ -89,7 +89,7 @@ pub struct Null;
 /// Owning [dynamic type value](http://sqlite.org/datatype3.html). Value's type is typically
 /// dictated by SQLite (not by the caller).
 ///
-/// See [`BorrowedValue`](enum.BorrowedValue.html) for a non-owning dynamic type value.
+/// See [`ValueRef`](enum.ValueRef.html) for a non-owning dynamic type value.
 #[derive(Clone,Debug,PartialEq)]
 pub enum Value {
     /// The value is a `NULL` value.
diff --git a/src/types/serde_json.rs b/src/types/serde_json.rs
index a3da2fc..937f914 100644
--- a/src/types/serde_json.rs
+++ b/src/types/serde_json.rs
@@ -5,7 +5,7 @@ use libc::c_int;
 use self::serde_json::Value;
 
 use {Error, Result};
-use types::{FromSql, ToSql, BorrowedValue};
+use types::{FromSql, ToSql, ValueRef};
 
 use ffi::sqlite3_stmt;
 
@@ -19,10 +19,10 @@ impl ToSql for Value {
 
 /// Deserialize text/blob to JSON `Value`.
 impl FromSql for Value {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    fn column_result(value: ValueRef) -> Result<Self> {
         match value {
-            BorrowedValue::Text(ref s) => serde_json::from_str(s),
-            BorrowedValue::Blob(ref b) => serde_json::from_slice(b),
+            ValueRef::Text(ref s) => serde_json::from_str(s),
+            ValueRef::Blob(ref b) => serde_json::from_slice(b),
             _ => return Err(Error::InvalidColumnType),
         }.map_err(|err| Error::FromSqlConversionFailure(Box::new(err)))
     }
diff --git a/src/types/time.rs b/src/types/time.rs
index ae524ec..1f1a818 100644
--- a/src/types/time.rs
+++ b/src/types/time.rs
@@ -2,7 +2,7 @@ extern crate time;
 
 use libc::c_int;
 use {Error, Result};
-use types::{FromSql, ToSql, BorrowedValue};
+use types::{FromSql, ToSql, ValueRef};
 
 use ffi::sqlite3_stmt;
 
@@ -16,7 +16,7 @@ impl ToSql for time::Timespec {
 }
 
 impl FromSql for time::Timespec {
-    fn column_result(value: BorrowedValue) -> Result<Self> {
+    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))),
diff --git a/src/types/borrowed_value.rs b/src/types/value_ref.rs
similarity index 62%
rename from src/types/borrowed_value.rs
rename to src/types/value_ref.rs
index f8e5068..aa2d3b8 100644
--- a/src/types/borrowed_value.rs
+++ b/src/types/value_ref.rs
@@ -7,7 +7,7 @@ use super::Value;
 ///
 /// See [`Value`](enum.Value.html) for an owning dynamic type value.
 #[derive(Copy,Clone,Debug,PartialEq)]
-pub enum BorrowedValue<'a> {
+pub enum ValueRef<'a> {
     /// The value is a `NULL` value.
     Null,
     /// The value is a signed integer.
@@ -20,12 +20,12 @@ pub enum BorrowedValue<'a> {
     Blob(&'a [u8]),
 }
 
-impl<'a> BorrowedValue<'a> {
+impl<'a> ValueRef<'a> {
     /// If `self` is case `Integer`, returns the integral value. Otherwise, returns
     /// `Err(Error::InvalidColumnType)`.
     pub fn as_i64(&self) -> Result<i64> {
         match *self {
-            BorrowedValue::Integer(i) => Ok(i),
+            ValueRef::Integer(i) => Ok(i),
             _ => Err(Error::InvalidColumnType),
         }
     }
@@ -34,7 +34,7 @@ impl<'a> BorrowedValue<'a> {
     /// `Err(Error::InvalidColumnType)`.
     pub fn as_f64(&self) -> Result<f64> {
         match *self {
-            BorrowedValue::Real(f) => Ok(f),
+            ValueRef::Real(f) => Ok(f),
             _ => Err(Error::InvalidColumnType),
         }
     }
@@ -43,7 +43,7 @@ impl<'a> BorrowedValue<'a> {
     /// `Err(Error::InvalidColumnType)`.
     pub fn as_str(&self) -> Result<&str> {
         match *self {
-            BorrowedValue::Text(ref t) => Ok(t),
+            ValueRef::Text(ref t) => Ok(t),
             _ => Err(Error::InvalidColumnType),
         }
     }
@@ -52,32 +52,32 @@ impl<'a> BorrowedValue<'a> {
     /// `Err(Error::InvalidColumnType)`.
     pub fn as_blob(&self) -> Result<&[u8]> {
         match *self {
-            BorrowedValue::Blob(ref b) => Ok(b),
+            ValueRef::Blob(ref b) => Ok(b),
             _ => Err(Error::InvalidColumnType),
         }
     }
 }
 
-impl<'a> From<BorrowedValue<'a>> for Value {
-    fn from(borrowed: BorrowedValue) -> Value {
+impl<'a> From<ValueRef<'a>> for Value {
+    fn from(borrowed: ValueRef) -> Value {
         match borrowed {
-            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()),
+            ValueRef::Null => Value::Null,
+            ValueRef::Integer(i) => Value::Integer(i),
+            ValueRef::Real(r) => Value::Real(r),
+            ValueRef::Text(s) => Value::Text(s.to_string()),
+            ValueRef::Blob(b) => Value::Blob(b.to_vec()),
         }
     }
 }
 
-impl<'a> From<&'a Value> for BorrowedValue<'a> {
-    fn from(value: &'a Value) -> BorrowedValue<'a> {
+impl<'a> From<&'a Value> for ValueRef<'a> {
+    fn from(value: &'a Value) -> ValueRef<'a> {
         match *value {
-            Value::Null => BorrowedValue::Null,
-            Value::Integer(i) => BorrowedValue::Integer(i),
-            Value::Real(r) => BorrowedValue::Real(r),
-            Value::Text(ref s) => BorrowedValue::Text(s),
-            Value::Blob(ref b) => BorrowedValue::Blob(b),
+            Value::Null => ValueRef::Null,
+            Value::Integer(i) => ValueRef::Integer(i),
+            Value::Real(r) => ValueRef::Real(r),
+            Value::Text(ref s) => ValueRef::Text(s),
+            Value::Blob(ref b) => ValueRef::Blob(b),
         }
     }
 }

From 8adb96131b6c2f81442066b3cbf1f855230c4082 Mon Sep 17 00:00:00 2001
From: John Gallagher <jgallagher@bignerdranch.com>
Date: Wed, 25 May 2016 19:53:18 -0400
Subject: [PATCH 11/11] Remove now-unnecessary FFI re-exports.

---
 src/types/mod.rs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/types/mod.rs b/src/types/mod.rs
index 7853291..758eb5d 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -51,8 +51,6 @@
 //! `None`).
 
 pub use ffi::sqlite3_stmt;
-pub use ffi::sqlite3_column_type;
-pub use ffi::{SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, SQLITE_NULL};
 
 pub use self::from_sql::FromSql;
 pub use self::to_sql::ToSql;