Initial commit

core/lib.rs

@@ -0,0 +1,62 @@
+mod pager;
+mod sqlite3_ondisk;
+mod vdbe;
+
+use anyhow::Result;
+use fallible_iterator::FallibleIterator;
+use pager::Pager;
+use sqlite3_parser::{ast::Cmd, lexer::sql::Parser};
+use std::sync::Arc;
+
+pub struct Database {
+    pager: Arc<Pager>,
+}
+
+impl Database {
+    pub fn open(io: Arc<dyn IO>, path: &str) -> Result<Database> {
+        let pager = Arc::new(Pager::open(io.clone(), path)?);
+        Ok(Database { pager })
+    }
+
+    pub fn connect(&self) -> Connection {
+        Connection {
+            pager: self.pager.clone(),
+        }
+    }
+}
+
+pub struct Connection {
+    pager: Arc<Pager>,
+}
+
+impl Connection {
+    pub fn execute(&self, sql: impl Into<String>) -> Result<()> {
+        let sql = sql.into();
+        let mut parser = Parser::new(sql.as_bytes());
+        let cmd = parser.next()?;
+        if let Some(cmd) = cmd {
+            match cmd {
+                Cmd::Explain(stmt) => {
+                    let program = vdbe::translate(stmt)?;
+                    program.explain();
+                }
+                Cmd::ExplainQueryPlan(_stmt) => todo!(),
+                Cmd::Stmt(stmt) => {
+                    let mut program = vdbe::translate(stmt)?;
+                    program.step(self.pager.clone())?;
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+pub type DatabaseRef = usize;
+
+pub trait IO {
+    /// Open a database file.
+    fn open(&self, path: &str) -> Result<DatabaseRef>;
+
+    /// Get a page from the database file.
+    fn get(&self, database_ref: DatabaseRef, page_idx: usize, buf: &mut [u8]) -> Result<()>;
+}