Prepare support for update hooks

Author: simolus3

crates/core/src/crud_vtab.rs

@@ -334,13 +334,15 @@ extern "C" fn begin(vtab: *mut sqlite::vtab) -> c_int {
 
 extern "C" fn commit(vtab: *mut sqlite::vtab) -> c_int {
     let tab = unsafe { &mut *(vtab.cast::<VirtualTable>()) };
+    tab.state.track_commit();
     tab.end_transaction();
     ResultCode::OK as c_int
 }
 
 extern "C" fn rollback(vtab: *mut sqlite::vtab) -> c_int {
     let tab = unsafe { &mut *(vtab.cast::<VirtualTable>()) };
     tab.end_transaction();
+    tab.state.track_rollback();
     // ps_tx will be rolled back automatically
     ResultCode::OK as c_int
 }

crates/core/src/lib.rs

@@ -1,9 +1,10 @@
 #![no_std]
-#![feature(vec_into_raw_parts)]
 #![allow(internal_features)]
+#![feature(btree_set_entry)]
 #![feature(core_intrinsics)]
 #![feature(assert_matches)]
 #![feature(strict_overflow_ops)]
+#![feature(vec_into_raw_parts)]
 
 extern crate alloc;
 

crates/core/src/state.rs

@@ -1,9 +1,14 @@
 use core::{
+    cell::RefCell,
     ffi::{c_int, c_void},
     sync::atomic::{AtomicBool, Ordering},
 };
 
-use alloc::sync::Arc;
+use alloc::{
+    collections::btree_set::BTreeSet,
+    string::{String, ToString},
+    sync::Arc,
+};
 use sqlite::{Connection, ResultCode};
 use sqlite_nostd::{self as sqlite, Context};
 
@@ -14,12 +19,16 @@ use sqlite_nostd::{self as sqlite, Context};
 /// functions/vtabs that need access to it.
 pub struct DatabaseState {
     pub is_in_sync_local: AtomicBool,
+    pending_updates: RefCell<BTreeSet<String>>,
+    commited_updates: RefCell<BTreeSet<String>>,
 }
 
 impl DatabaseState {
     pub fn new() -> Self {
         DatabaseState {
             is_in_sync_local: AtomicBool::new(false),
+            pending_updates: Default::default(),
+            commited_updates: Default::default(),
         }
     }
 
@@ -39,6 +48,25 @@ impl DatabaseState {
         ClearOnDrop(self)
     }
 
+    pub fn track_update(self, tbl: &str) {
+        let mut set = self.pending_updates.borrow_mut();
+        set.get_or_insert_with(tbl, str::to_string);
+    }
+
+    pub fn track_rollback(&self) {
+        self.pending_updates.borrow_mut().clear();
+    }
+
+    pub fn track_commit(&self) {
+        let mut commited = self.commited_updates.borrow_mut();
+        let mut pending = self.pending_updates.borrow_mut();
+        let pending = core::mem::replace(&mut *pending, Default::default());
+
+        for pending in pending.into_iter() {
+            commited.insert(pending);
+        }
+    }
+
     pub unsafe extern "C" fn destroy_arc(ptr: *mut c_void) {
         drop(unsafe { Arc::from_raw(ptr.cast::<DatabaseState>()) });
     }