sqlite: initial work in connection

sqlx-core/Cargo.toml

@@ -17,14 +17,14 @@ default = [ "runtime-async-std" ]
 unstable = []
 postgres = [ "md-5", "sha2", "base64", "sha-1", "rand", "hmac" ]
 mysql = [ "sha-1", "sha2", "generic-array", "num-bigint", "base64", "digest", "rand" ]
-sqlite = [ ]
+sqlite = [ "libc", "libsqlite3-sys" ]
 tls = [ "async-native-tls" ]
 runtime-async-std = [ "async-native-tls/runtime-async-std", "async-std" ]
 runtime-tokio = [ "async-native-tls/runtime-tokio", "tokio" ]
 
 [dependencies]
 async-native-tls = { version = "0.3.2", default-features = false, optional = true }
-async-std = { version = "1.5.0", optional = true }
+async-std = { version = "1.5.0", features = [ "unstable" ], optional = true }
 async-stream = { version = "0.2.1", default-features = false }
 base64 = { version = "0.11.0", default-features = false, optional = true, features = [ "std" ] }
 bitflags = { version = "1.2.1", default-features = false }
@@ -50,6 +50,14 @@ sha2 = { version = "0.8.1", default-features = false, optional = true }
 tokio = { version = "0.2.13", default-features = false, features = [ "dns", "fs", "time", "tcp" ], optional = true }
 url = { version = "2.1.1", default-features = false }
 uuid = { version = "0.8.1", default-features = false, optional = true, features = [ "std" ] }
+libc = { version = "0.2", optional = true }
+
+# <https://github.com/jgallagher/rusqlite/tree/master/libsqlite3-sys>
+[dependencies.libsqlite3-sys]
+version = "0.17.1"
+optional = true
+default-features = false
+features = [ "pkg-config", "vcpkg", "bundled" ]
 
 [dev-dependencies]
 matches = "0.1.8"

sqlx-core/src/runtime.rs

@@ -6,7 +6,7 @@ pub use async_std::{
     io::{Read as AsyncRead, Write as AsyncWrite},
     net::TcpStream,
     task::sleep,
-    task::spawn,
+    task::{spawn, spawn_blocking},
     task::yield_now,
 };
 
@@ -15,7 +15,7 @@ pub use tokio::{
     fs,
     io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt},
     net::TcpStream,
-    task::spawn,
+    task::{spawn, spawn_blocking},
     task::yield_now,
     time::delay_for as sleep,
     time::timeout,

sqlx-core/src/sqlite/arguments.rs

@@ -2,23 +2,11 @@ use crate::arguments::Arguments;
 use crate::encode::Encode;
 use crate::sqlite::Sqlite;
 use crate::types::Type;
-
-#[derive(Debug, Clone)]
-pub enum SqliteValue {
-    // TODO: Take by reference to remove the allocation
-    Text(String),
-
-    // TODO: Take by reference to remove the allocation
-    Blob(Vec<u8>),
-
-    Double(f64),
-
-    Int(i64),
-}
+use crate::sqlite::value::SqliteArgumentValue;
 
 #[derive(Default)]
 pub struct SqliteArguments {
-    values: Vec<SqliteValue>,
+    values: Vec<SqliteArgumentValue>,
 }
 
 impl Arguments for SqliteArguments {

sqlx-core/src/sqlite/connection.rs

@@ -1,11 +1,70 @@
+use core::ptr::{NonNull, null, null_mut};
+
 use std::convert::TryInto;
+use std::ffi::CString;
+use std::fmt::{self, Debug};
 
 use futures_core::future::BoxFuture;
+use libsqlite3_sys::{
+    sqlite3, sqlite3_open_v2, SQLITE_OK, SQLITE_OPEN_CREATE, SQLITE_OPEN_NOMUTEX,
+    SQLITE_OPEN_READWRITE, SQLITE_OPEN_SHAREDCACHE,
+};
 
+use crate::runtime::spawn_blocking;
 use crate::connection::{Connect, Connection};
 use crate::url::Url;
+use futures_util::future;
+use crate::sqlite::SqliteError;
 
-pub struct SqliteConnection {}
+#[derive(Debug)]
+pub struct SqliteConnection {
+    pub(super) handle: NonNull<sqlite3>,
+}
+
+// SAFE: A sqlite3 handle is safe to access from multiple threads provided
+//       that only one thread access it at a time. Or in other words,
+//       the same guarantees that [Sync] requires. This is upheld as long
+//       [SQLITE_CONFIG_MULTITHREAD] is enabled and [SQLITE_THREADSAFE] was
+//       enabled when sqlite was compiled. We refuse to work if these conditions are
+//       not upheld, see [SqliteConnection::establish].
+//
+// <https://www.sqlite.org/c3ref/threadsafe.html>
+// <https://www.sqlite.org/c3ref/c_config_covering_index_scan.html#sqliteconfigmultithread>
+#[allow(unsafe_code)]
+unsafe impl Send for SqliteConnection {}
+#[allow(unsafe_code)]
+unsafe impl Sync for SqliteConnection {}
+
+fn establish(url: crate::Result<Url>) -> crate::Result<SqliteConnection> {
+    let url = url?;
+    let url = url.as_str().trim_start_matches("sqlite://");
+
+    // By default, we connect to an in-memory database.
+    // TODO: Handle the error when there are internal NULs in the database URL
+    let filename = CString::new(url).unwrap();
+    let mut handle = null_mut();
+
+    // [SQLITE_OPEN_NOMUTEX] will instruct [sqlite3_open_v2] to return an error if it
+    // cannot satisfy our wish for a thread-safe, lock-free connection object
+    let flags = SQLITE_OPEN_READWRITE
+        | SQLITE_OPEN_CREATE
+        | SQLITE_OPEN_NOMUTEX
+        | SQLITE_OPEN_SHAREDCACHE;
+
+    // <https://www.sqlite.org/c3ref/open.html>
+    #[allow(unsafe_code)]
+    let status = unsafe {
+        sqlite3_open_v2(filename.as_ptr(), &mut handle, flags, null())
+    };
+
+    if status != SQLITE_OK {
+        return Err(SqliteError::new(status).into());
+    }
+
+    Ok(SqliteConnection {
+        handle: NonNull::new(handle).unwrap(),
+    })
+}
 
 impl Connect for SqliteConnection {
     fn connect<T>(url: T) -> BoxFuture<'static, crate::Result<SqliteConnection>>
@@ -13,8 +72,8 @@ impl Connect for SqliteConnection {
         T: TryInto<Url, Error = crate::Error>,
         Self: Sized,
     {
-        // Box::pin(SqliteConnection::new(url.try_into()))
-        todo!()
+        let url = url.try_into();
+        Box::pin(spawn_blocking(move || establish(url)))
     }
 }
 
@@ -25,7 +84,7 @@ impl Connection for SqliteConnection {
     }
 
     fn ping(&mut self) -> BoxFuture<crate::Result<()>> {
-        //Box::pin(Executor::execute(self, "SELECT 1").map_ok(|_| ()))
-        todo!()
+        // For SQLite connections, PING does effectively nothing
+        Box::pin(future::ok(()))
     }
 }

sqlx-core/src/sqlite/database.rs

@@ -1,5 +1,5 @@
 use crate::database::{Database, HasCursor, HasRawValue, HasRow};
-use crate::sqlite::arguments::SqliteValue;
+use crate::sqlite::value::{SqliteResultValue, SqliteArgumentValue};
 
 /// **Sqlite** database driver.
 pub struct Sqlite;
@@ -14,13 +14,13 @@ impl Database for Sqlite {
     // TODO?
     type TableId = u32;
 
-    type RawBuffer = Vec<SqliteValue>;
+    type RawBuffer = Vec<SqliteArgumentValue>;
 }
 
-impl<'a> HasRow<'a> for Sqlite {
+impl<'c> HasRow<'c> for Sqlite {
     type Database = Sqlite;
 
-    type Row = super::SqliteRow<'a>;
+    type Row = super::SqliteRow<'c>;
 }
 
 impl<'s, 'q> HasCursor<'s, 'q> for Sqlite {
@@ -29,7 +29,6 @@ impl<'s, 'q> HasCursor<'s, 'q> for Sqlite {
     type Cursor = super::SqliteCursor<'s, 'q>;
 }
 
-impl<'a> HasRawValue<'a> for Sqlite {
-    // TODO
-    type RawValue = Option<()>;
+impl<'c> HasRawValue<'c> for Sqlite {
+    type RawValue = SqliteResultValue<'c>;
 }

sqlx-core/src/sqlite/error.rs

@@ -1,10 +1,28 @@
 use crate::error::DatabaseError;
+use libc::c_int;
+use std::ffi::CStr;
+use libsqlite3_sys::{sqlite3, sqlite3_errstr};
 
-pub struct SqliteError;
+pub struct SqliteError {
+    #[allow(dead_code)]
+    code: c_int,
+    message: String,
+}
+
+impl SqliteError {
+    pub(crate) fn new(code: c_int) -> Self {
+        #[allow(unsafe_code)]
+        let message = unsafe {
+            CStr::from_ptr(sqlite3_errstr(code))
+        };
+
+        Self { code, message: message.to_string_lossy().into_owned() }
+    }
+}
 
 impl DatabaseError for SqliteError {
     fn message(&self) -> &str {
-        todo!()
+        &self.message
     }
 }
 

sqlx-core/src/sqlite/mod.rs

@@ -3,6 +3,7 @@ mod connection;
 mod cursor;
 mod database;
 mod error;
+mod value;
 mod executor;
 mod row;
 mod types;
@@ -14,3 +15,11 @@ pub use database::Sqlite;
 pub use error::SqliteError;
 pub use row::SqliteRow;
 pub use types::SqliteTypeInfo;
+
+/// An alias for [`Pool`][crate::Pool], specialized for **Sqlite**.
+pub type SqlitePool = crate::pool::Pool<SqliteConnection>;
+
+make_query_as!(SqliteQueryAs, Sqlite, SqliteRow);
+impl_map_row_for_row!(Sqlite, SqliteRow);
+impl_column_index_for_row!(Sqlite);
+impl_from_row_for_tuples!(Sqlite, SqliteRow);

sqlx-core/src/sqlite/row.rs

@@ -7,9 +7,11 @@ use std::sync::Arc;
 use crate::error::UnexpectedNullError;
 use crate::row::{ColumnIndex, Row};
 use crate::sqlite::Sqlite;
+use crate::sqlite::value::SqliteResultValue;
 
 pub struct SqliteRow<'c> {
     c: std::marker::PhantomData<&'c ()>,
+    pub(super) columns: Arc<HashMap<Box<str>, u16>>,
 }
 
 impl<'c> Row<'c> for SqliteRow<'c> {
@@ -19,7 +21,7 @@ impl<'c> Row<'c> for SqliteRow<'c> {
         todo!()
     }
 
-    fn try_get_raw<'r, I>(&'r self, index: I) -> crate::Result<Option<()>>
+    fn try_get_raw<'r, I>(&'r self, index: I) -> crate::Result<SqliteResultValue<'c>>
     where
         I: ColumnIndex<Self::Database>,
     {

sqlx-core/src/sqlite/types/int.rs

@@ -0,0 +1,25 @@
+use crate::types::Type;
+use crate::sqlite::{Sqlite, SqliteTypeInfo};
+use crate::encode::Encode;
+use crate::sqlite::value::{SqliteArgumentValue, SqliteResultValue};
+use crate::decode::Decode;
+
+impl Type<Sqlite> for i32 {
+    fn type_info() -> SqliteTypeInfo {
+        // SqliteTypeInfo::new(ValueKind::Int)
+        todo!()
+    }
+}
+
+impl Encode<Sqlite> for i32 {
+    fn encode(&self, values: &mut Vec<SqliteArgumentValue>) {
+        values.push(SqliteArgumentValue::Int((*self).into()));
+    }
+}
+
+impl<'a> Decode<'a, Sqlite> for i32 {
+    fn decode(value: SqliteResultValue<'a>) -> crate::Result<i32> {
+        // Ok(value.int())
+        todo!()
+    }
+}

sqlx-core/src/sqlite/types/mod.rs

@@ -2,6 +2,12 @@ use std::fmt::{self, Display};
 
 use crate::types::TypeInfo;
 
+// mod bool;
+// mod bytes;
+// mod float;
+mod int;
+// mod str;
+
 #[derive(Debug, Clone)]
 pub struct SqliteTypeInfo {}
 

sqlx-core/src/sqlite/value.rs

@@ -0,0 +1,17 @@
+#[derive(Debug, Clone)]
+pub enum SqliteArgumentValue {
+    // TODO: Take by reference to remove the allocation
+    Text(String),
+
+    // TODO: Take by reference to remove the allocation
+    Blob(Vec<u8>),
+
+    Double(f64),
+
+    Int(i64),
+}
+
+pub struct SqliteResultValue<'c> {
+    // statement: SqliteStatement<'c>,
+    statement: std::marker::PhantomData<&'c ()>,
+}

sqlx-core/src/url.rs

@@ -1,6 +1,7 @@
 use std::borrow::Cow;
 use std::convert::{TryFrom, TryInto};
 
+#[derive(Debug)]
 pub struct Url(url::Url);
 
 impl TryFrom<String> for Url {
@@ -28,6 +29,10 @@ impl<'s> TryFrom<&'s String> for Url {
 }
 
 impl Url {
+    pub(crate) fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+
     pub fn host(&self) -> &str {
         let host = self.0.host_str();