Implement prepared statements

src/database.rs

@@ -3,25 +3,25 @@ use raw;
 use std::marker::PhantomData;
 use std::path::Path;
 
-use Result;
+use {Result, Statement};
 
 /// A database.
-pub struct Database<'d> {
-    db: *mut raw::sqlite3,
-    _phantom: PhantomData<&'d raw::sqlite3>,
+pub struct Database<'l> {
+    raw: *mut raw::sqlite3,
+    _phantom: PhantomData<&'l raw::sqlite3>,
 }
 
 /// A callback executed for each row of the result of an SQL query.
-pub type ExecuteCallback<'c> = FnMut(Vec<(String, String)>) -> bool + 'c;
+pub type ExecuteCallback<'l> = FnMut(Vec<(String, String)>) -> bool + 'l;
 
-impl<'d> Database<'d> {
+impl<'l> Database<'l> {
     /// Open a database.
-    pub fn open(path: &Path) -> Result<Database<'d>> {
-        let mut db = 0 as *mut _;
+    pub fn open(path: &Path) -> Result<Database> {
+        let mut raw = 0 as *mut _;
         unsafe {
-            success!(raw::sqlite3_open(path_to_c_str!(path), &mut db));
+            success!(raw::sqlite3_open(path_to_c_str!(path), &mut raw));
         }
-        Ok(Database { db: db, _phantom: PhantomData })
+        Ok(Database { raw: raw, _phantom: PhantomData })
     }
 
     /// Execute an SQL statement.
@@ -32,24 +32,35 @@ impl<'d> Database<'d> {
             match callback {
                 Some(callback) => {
                     let mut callback = Box::new(callback);
-                    success!(raw::sqlite3_exec(self.db, str_to_c_str!(sql), Some(execute_callback),
+                    success!(raw::sqlite3_exec(self.raw, str_to_c_str!(sql),
+                                               Some(execute_callback),
                                                &mut callback as *mut _ as *mut _, 0 as *mut _));
                 },
                 None => {
-                    success!(raw::sqlite3_exec(self.db, str_to_c_str!(sql), None,
-                                               0 as *mut _, 0 as *mut _));
+                    success!(raw::sqlite3_exec(self.raw, str_to_c_str!(sql), None, 0 as *mut _,
+                                               0 as *mut _));
                 },
             }
         }
 
         Ok(())
     }
+
+    /// Create a prepared statement.
+    pub fn statement(&mut self, sql: &str) -> Result<Statement<'l>> {
+        let mut raw = 0 as *mut _;
+        unsafe {
+            success!(raw::sqlite3_prepare(self.raw, str_to_c_str!(sql), -1, &mut raw,
+                                          0 as *mut _));
+        }
+        Ok(::statement::from_raw(raw))
+    }
 }
 
-impl<'d> Drop for Database<'d> {
+impl<'l> Drop for Database<'l> {
     #[inline]
     fn drop(&mut self) {
-        unsafe { ::raw::sqlite3_close(self.db) };
+        unsafe { ::raw::sqlite3_close(self.raw) };
     }
 }
 

src/lib.rs

@@ -3,6 +3,7 @@
 extern crate libc;
 extern crate sqlite3_sys as raw;
 
+use libc::c_int;
 use std::path::Path;
 
 /// A result.
@@ -11,13 +12,13 @@ pub type Result<T> = std::result::Result<T, Error>;
 /// An error.
 #[derive(Debug)]
 pub struct Error {
-    pub code: ErrorCode,
+    pub code: ResultCode,
     pub message: Option<String>,
 }
 
-/// An error code.
-#[derive(Clone, Copy, Debug)]
-pub enum ErrorCode {
+/// A result code.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum ResultCode {
     Abort = raw::SQLITE_ABORT as isize,
     Authorization = raw::SQLITE_AUTH as isize,
     Busy = raw::SQLITE_BUSY as isize,
@@ -51,9 +52,16 @@ pub enum ErrorCode {
     Warning = raw::SQLITE_WARNING as isize,
 }
 
+impl ResultCode {
+    #[inline]
+    fn from_raw(code: c_int) -> ResultCode {
+        unsafe { std::mem::transmute(code as i8) }
+    }
+}
+
 macro_rules! raise(
     ($message:expr) => (
-        return Err(::Error { code: ::ErrorCode::Error, message: Some($message.to_string()) })
+        return Err(::Error { code: ::ResultCode::Error, message: Some($message.to_string()) })
     );
     ($code:expr, $message:expr) => (
         return Err(::Error { code: $code, message: $message })
@@ -64,7 +72,7 @@ macro_rules! success(
     ($result:expr) => (
         match $result {
             ::raw::SQLITE_OK => {},
-            code => raise!(unsafe { ::std::mem::transmute(code as i8) }, None),
+            code => raise!(::ResultCode::from_raw(code), None),
         }
     );
 );
@@ -91,8 +99,10 @@ macro_rules! str_to_c_str(
 );
 
 mod database;
+mod statement;
 
 pub use database::{Database, ExecuteCallback};
+pub use statement::{Statement, Binding};
 
 /// Open a database.
 #[inline]

src/statement.rs

@@ -0,0 +1,65 @@
+use libc::{c_double, c_int};
+use raw;
+use std::marker::PhantomData;
+
+use {Result, ResultCode};
+
+/// A prepared statement.
+pub struct Statement<'l> {
+    raw: *mut raw::sqlite3_stmt,
+    _phantom: PhantomData<&'l raw::sqlite3_stmt>,
+}
+
+/// A binding of a prepared statement.
+pub enum Binding<'l> {
+    Float(usize, f64),
+    Integer(usize, i64),
+    Text(usize, &'l str),
+}
+
+impl<'l> Statement<'l> {
+    /// Assign values to the placeholders.
+    pub fn bind(&mut self, bindings: &[Binding]) -> Result<()> {
+        for binding in bindings.iter() {
+            match *binding {
+                Binding::Float(i, value) => unsafe {
+                    success!(raw::sqlite3_bind_double(self.raw, i as c_int, value as c_double));
+                },
+                Binding::Integer(i, value) => unsafe {
+                    success!(raw::sqlite3_bind_int64(self.raw, i as c_int,
+                                                     value as raw::sqlite3_int64));
+                },
+                Binding::Text(i, value) => unsafe {
+                    success!(raw::sqlite3_bind_text(self.raw, i as c_int, str_to_c_str!(value),
+                                                    -1, None));
+                },
+            }
+        }
+        Ok(())
+    }
+
+    /// Take a step.
+    #[inline]
+    pub fn step(&mut self) -> ResultCode {
+        unsafe { ResultCode::from_raw(raw::sqlite3_step(self.raw)) }
+    }
+
+    /// Reset.
+    #[inline]
+    pub fn reset(&mut self) -> Result<()> {
+        unsafe { success!(raw::sqlite3_reset(self.raw)) };
+        Ok(())
+    }
+}
+
+impl<'l> Drop for Statement<'l> {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe { ::raw::sqlite3_finalize(self.raw) };
+    }
+}
+
+#[inline]
+pub fn from_raw<'l>(raw: *mut raw::sqlite3_stmt) -> Statement<'l> {
+    Statement { raw: raw, _phantom: PhantomData }
+}

tests/lib.rs

@@ -9,7 +9,10 @@ macro_rules! ok(
 );
 
 #[test]
-fn execute() {
+fn workflow() {
+    use sqlite::Binding::*;
+    use sqlite::ResultCode;
+
     macro_rules! pair(
         ($one:expr, $two:expr) => ((String::from($one), String::from($two)));
     );
@@ -20,8 +23,10 @@ fn execute() {
     let sql = r#"CREATE TABLE `users` (id INTEGER, name VARCHAR(255), age REAL);"#;
     ok!(database.execute(sql, None));
 
-    let sql = r#"INSERT INTO `users` (id, name, age) VALUES (1, "Alice", 20.99);"#;
-    ok!(database.execute(sql, None));
+    let sql = r#"INSERT INTO `users` (id, name, age) VALUES (?, ?, ?);"#;
+    let mut statement = ok!(database.statement(sql));
+    ok!(statement.bind(&[Integer(1, 1), Text(2, "Alice"), Float(3, 20.99)]));
+    assert!(statement.step() == ResultCode::Done);
 
     let mut done = false;
     let sql = r#"SELECT * FROM `users`;"#;