Allow nul bytes in strings w/ SQLite

Unlike PG, SQLite actually allows all valid UTF-8 strings in its data
type which is documented to be UTF-8. I find this especially ironic,
since PG does not interface over C, but basically follows C semantics,
while SQLite which we *only* access via C, does not.

diesel/src/connection/sqlite/sqlite_value.rs

@@ -1,7 +1,6 @@
 extern crate libsqlite3_sys as ffi;
 extern crate libc;
 
-use std::ffi::CStr;
 use std::{slice, str};
 
 use backend::Sqlite;
@@ -25,10 +24,12 @@ impl SqliteValue {
         }
     }
 
-    pub fn read_text(&self) -> Result<&str, str::Utf8Error> {
+    pub fn read_text(&self) -> &str {
         unsafe {
             let ptr = ffi::sqlite3_column_text(self.inner_statement, self.col_index);
-            CStr::from_ptr(ptr as *const libc::c_char).to_str()
+            let len = ffi::sqlite3_column_bytes(self.inner_statement, self.col_index);
+            let bytes = slice::from_raw_parts(ptr as *const u8, len as usize);
+            str::from_utf8_unchecked(bytes)
         }
     }
 

diesel/src/types/impls/sqlite.rs

@@ -7,7 +7,7 @@ use types::{self, FromSql};
 
 impl FromSql<types::VarChar, Sqlite> for String {
     fn from_sql(value: Option<&SqliteValue>) -> Result<Self, Box<Error>> {
-        let text = try!(not_none!(value).read_text());
+        let text = not_none!(value).read_text();
         Ok(text.into())
     }
 }