Refactoring

Introduce VTab::destroy.
Let implementation specify the iVersion.
Rename simple_module into read_only_module.

src/vtab/array.rs

@@ -36,7 +36,7 @@ pub fn load_module(conn: &Connection) -> Result<()> {
 }
 
 lazy_static! {
-    static ref ARRAY_MODULE: Module<ArrayTab> = eponymous_only_module::<ArrayTab>();
+    static ref ARRAY_MODULE: Module<ArrayTab> = eponymous_only_module::<ArrayTab>(1);
 }
 
 // Column numbers

src/vtab/csvtab.rs

@@ -11,8 +11,8 @@ use std::str;
 use ffi;
 use types::Null;
 use vtab::{
-    dequote, escape_double_quote, parse_boolean, simple_module, Context, IndexInfo, Module, VTab,
-    VTabConnection, VTabCursor, Values,
+    dequote, escape_double_quote, parse_boolean, read_only_module, Context, IndexInfo, Module,
+    VTab, VTabConnection, VTabCursor, Values,
 };
 use {Connection, Error, Result};
 
@@ -33,7 +33,7 @@ pub fn load_module(conn: &Connection) -> Result<()> {
 }
 
 lazy_static! {
-    static ref CSV_MODULE: Module<CSVTab> = simple_module::<CSVTab>();
+    static ref CSV_MODULE: Module<CSVTab> = read_only_module::<CSVTab>(1);
 }
 
 /// An instance of the CSV virtual table

src/vtab/mod.rs

@@ -70,16 +70,16 @@ unsafe impl<T: VTab> Sync for Module<T> {}
 /// Create a read-only virtual table implementation.
 ///
 /// Step 2 of [Creating New Virtual Table Implementations](https://sqlite.org/vtab.html#creating_new_virtual_table_implementations).
-pub fn simple_module<T: VTab>() -> Module<T> {
+pub fn read_only_module<T: VTab>(version: c_int) -> Module<T> {
     // The xConnect and xCreate methods do the same thing, but they must be
     // different so that the virtual table is not an eponymous virtual table.
     let ffi_module = ffi::sqlite3_module {
-        iVersion: 1,
+        iVersion: version,
         xCreate: Some(rust_create::<T>),
         xConnect: Some(rust_connect::<T>),
         xBestIndex: Some(rust_best_index::<T>),
         xDisconnect: Some(rust_disconnect::<T>),
-        xDestroy: Some(rust_disconnect::<T>), // TODO Validate: no rust_destroy
+        xDestroy: Some(rust_destroy::<T>),
         xOpen: Some(rust_open::<T>),
         xClose: Some(rust_close::<T::Cursor>),
         xFilter: Some(rust_filter::<T::Cursor>),
@@ -107,11 +107,11 @@ pub fn simple_module<T: VTab>() -> Module<T> {
 /// Create an eponymous only virtual table implementation.
 ///
 /// Step 2 of [Creating New Virtual Table Implementations](https://sqlite.org/vtab.html#creating_new_virtual_table_implementations).
-pub fn eponymous_only_module<T: VTab>() -> Module<T> {
+pub fn eponymous_only_module<T: VTab>(version: c_int) -> Module<T> {
     // A virtual table is eponymous if its xCreate method is the exact same function as the xConnect method
     // For eponymous-only virtual tables, the xCreate method is NULL
     let ffi_module = ffi::sqlite3_module {
-        iVersion: 1,
+        iVersion: version,
         xCreate: None,
         xConnect: Some(rust_connect::<T>),
         xBestIndex: Some(rust_best_index::<T>),
@@ -177,6 +177,8 @@ pub trait VTab: Sized {
     /// Create a new instance of a virtual table in response to a CREATE VIRTUAL TABLE statement.
     /// The `db` parameter is a pointer to the SQLite database connection that is executing
     /// the CREATE VIRTUAL TABLE statement.
+    ///
+    /// Unused by eponymous virtual table. Call `connect` by default.
     /// (See [SQLite doc](https://sqlite.org/vtab.html#the_xcreate_method))
     fn create(
         db: &mut VTabConnection,
@@ -186,10 +188,17 @@ pub trait VTab: Sized {
         Self::connect(db, aux, args)
     }
 
-    // TODO Validate: no destroy
+    /// Destroy the underlying table implementation. This method undoes the work of `create`.
+    ///
+    /// Unused by eponymous virtual table. Do nothing by default.
+    /// (See [SQLite doc](https://sqlite.org/vtab.html#the_xdestroy_method))
+    fn destroy(&self) -> Result<()> {
+        Ok(())
+    }
 
     /// Similar to `create`. The difference is that `connect` is called to establish a new connection
     /// to an _existing_ virtual table whereas `create` is called to create a new virtual table from scratch.
+    ///
     /// (See [SQLite doc](https://sqlite.org/vtab.html#the_xconnect_method))
     fn connect(
         db: &mut VTabConnection,
@@ -717,11 +726,41 @@ unsafe extern "C" fn rust_disconnect<T>(vtab: *mut ffi::sqlite3_vtab) -> c_int
 where
     T: VTab,
 {
+    if vtab.is_null() {
+        return ffi::SQLITE_OK;
+    }
     let vtab = vtab as *mut T;
     let _: Box<T> = Box::from_raw(vtab);
     ffi::SQLITE_OK
 }
 
+unsafe extern "C" fn rust_destroy<T>(vtab: *mut ffi::sqlite3_vtab) -> c_int
+where
+    T: VTab,
+{
+    use std::error::Error as StdError;
+    if vtab.is_null() {
+        return ffi::SQLITE_OK;
+    }
+    let vt = vtab as *mut T;
+    match (*vt).destroy() {
+        Ok(_) => {
+            let _: Box<T> = Box::from_raw(vt);
+            ffi::SQLITE_OK
+        }
+        Err(Error::SqliteFailure(err, s)) => {
+            if let Some(err_msg) = s {
+                set_err_msg(vtab, &err_msg);
+            }
+            err.extended_code
+        }
+        Err(err) => {
+            set_err_msg(vtab, err.description());
+            ffi::SQLITE_ERROR
+        }
+    }
+}
+
 unsafe extern "C" fn rust_open<T>(
     vtab: *mut ffi::sqlite3_vtab,
     pp_cursor: *mut *mut ffi::sqlite3_vtab_cursor,

src/vtab/series.rs

@@ -19,7 +19,7 @@ pub fn load_module(conn: &Connection) -> Result<()> {
 }
 
 lazy_static! {
-    static ref SERIES_MODULE: Module<SeriesTab> = eponymous_only_module::<SeriesTab>();
+    static ref SERIES_MODULE: Module<SeriesTab> = eponymous_only_module::<SeriesTab>(1);
 }
 
 // Column numbers

tests/vtab.rs

@@ -7,12 +7,13 @@ extern crate rusqlite;
 #[test]
 fn test_dummy_module() {
     use rusqlite::vtab::{
-        eponymous_only_module, sqlite3_vtab, sqlite3_vtab_cursor, Context, IndexInfo, VTab, VTabConnection, VTabCursor, Values,
+        eponymous_only_module, sqlite3_vtab, sqlite3_vtab_cursor, Context, IndexInfo, VTab,
+        VTabConnection, VTabCursor, Values,
     };
     use rusqlite::{version_number, Connection, Result};
     use std::os::raw::c_int;
 
-    let module = eponymous_only_module::<DummyTab>();
+    let module = eponymous_only_module::<DummyTab>(1);
 
     #[repr(C)]
     struct DummyTab {