Expose commit hook

Author: davidisaaclee

src/libadapters.js

@@ -1,6 +1,6 @@
 // Method names for these signatures must be in src/asyncify_imports.json.
 const SIGNATURES = [
-  'ipp', // xProgress
+  'ipp', // xProgress, xCommitHook
   'ippp', // xClose, xSectorSize, xDeviceCharacteristics
   'vppp', // xShmBarrier, xFinal
   'ipppj', // xTruncate

src/libhook.c

@@ -10,6 +10,11 @@
     SIGNATURE##_async(KEY, __VA_ARGS__) : \
     SIGNATURE(KEY, __VA_ARGS__))
 
+static int libhook_xCommitHook(void* pApp) {
+  const int asyncFlags = pApp ? *(int *)pApp : 0;
+  return CALL_JS(ipp, pApp, pApp);
+}
+
 static void libhook_xUpdateHook(
   void* pApp,
   int iUpdateType,
@@ -22,6 +27,10 @@ static void libhook_xUpdateHook(
   CALL_JS(vppippii, pApp, pApp, iUpdateType, dbName, tblName, lo32, hi32);
 }
 
+void EMSCRIPTEN_KEEPALIVE libhook_commit_hook(sqlite3* db, int xCommitHook, void* pApp) {
+  sqlite3_commit_hook(db, xCommitHook ? &libhook_xCommitHook : NULL, pApp);
+}
+
 void EMSCRIPTEN_KEEPALIVE libhook_update_hook(sqlite3* db, int xUpdateHook, void* pApp) {
   sqlite3_update_hook(db, xUpdateHook ? &libhook_xUpdateHook : NULL, pApp);
 }

src/libhook.js

@@ -26,4 +26,26 @@
       });
     }
   };
-})();
+
+  Module['commit_hook'] = function(db, xCommitHook) {
+    if (pAsyncFlags) {
+      Module['deleteCallback'](pAsyncFlags);
+      Module['_sqlite3_free'](pAsyncFlags);
+      pAsyncFlags = 0;
+    }
+
+    pAsyncFlags = Module['_sqlite3_malloc'](4);
+    setValue(pAsyncFlags, xCommitHook instanceof AsyncFunction ? 1 : 0, 'i32');
+
+    ccall(
+      'libhook_commit_hook',
+      'void',
+      ['number', 'number', 'number'],
+      [db, xCommitHook ? 1 : 0, pAsyncFlags]);
+    if (xCommitHook) {
+      Module['setCallback'](pAsyncFlags, (_) => {
+        return xCommitHook();
+      });
+    }
+  };
+})();

src/sqlite-api.js

@@ -735,6 +735,11 @@ export function Factory(Module) {
     };
   })();
 
+  sqlite3.commit_hook = function(db, xCommitHook) {
+    verifyDatabase(db);
+    Module.commit_hook(db, xCommitHook);
+  };
+
   sqlite3.update_hook = function(db, xUpdateHook) {
     verifyDatabase(db);
 

test/callbacks.test.js

@@ -422,4 +422,133 @@ for (const [key, factory] of FACTORIES) {
       expect(calls).toEqual([[23, "main", "t", 1n]]);
     });
   });
+
+  describe(`${key} commit_hook`, function() {
+    let db;
+    beforeEach(async function() {
+      db = await sqlite3.open_v2(':memory:');
+    });
+  
+    afterEach(async function() {
+      await sqlite3.close(db);
+    });
+
+    it('should call commit hook', async function() {
+      let rc;
+
+      let callsCount = 0;
+      const resetCallsCount = () => callsCount = 0;
+
+      sqlite3.commit_hook(db, () => {
+        callsCount++;
+        return 0;
+      });
+      expect(callsCount).toEqual(0);
+      resetCallsCount();
+
+      rc = await sqlite3.exec(db, `
+        CREATE TABLE t(i integer primary key, x);
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+      expect(callsCount).toEqual(1);
+      resetCallsCount();
+
+      rc = await sqlite3.exec(db, `
+        SELECT * FROM t;
+      `);
+      expect(callsCount).toEqual(0);
+      resetCallsCount();
+
+      rc = await sqlite3.exec(db, `
+        BEGIN TRANSACTION;
+        INSERT INTO t VALUES (1, 'foo');
+        ROLLBACK;
+      `);
+      expect(callsCount).toEqual(0);
+      resetCallsCount();
+
+      rc = await sqlite3.exec(db, `
+        BEGIN TRANSACTION;
+        INSERT INTO t VALUES (1, 'foo');
+        INSERT INTO t VALUES (2, 'bar');
+        COMMIT;
+      `);
+      expect(callsCount).toEqual(1);
+      resetCallsCount();
+    });
+
+    it('can change commit hook', async function() {
+      let rc;
+      rc = await sqlite3.exec(db, `
+        CREATE TABLE t(i integer primary key, x);
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+
+      let a = 0;
+      let b = 0;
+
+      // set hook to increment `a` on commit
+      sqlite3.commit_hook(db, () => {
+        a++;
+        return 0;
+      });
+      rc = await sqlite3.exec(db, `
+        INSERT INTO t VALUES (1, 'foo');
+      `);
+      expect(a).toEqual(1);
+      expect(b).toEqual(0);
+
+      // switch to increment `b`
+      sqlite3.commit_hook(db, () => {
+        b++;
+        return 0;
+      });
+
+      rc = await sqlite3.exec(db, `
+        INSERT INTO t VALUES (2, 'bar');
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+      expect(a).toEqual(1);
+      expect(b).toEqual(1);
+
+      // disable hook by passing null
+      sqlite3.commit_hook(db, null);
+
+      rc = await sqlite3.exec(db, `
+        INSERT INTO t VALUES (3, 'qux');
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+      expect(a).toEqual(1);
+      expect(b).toEqual(1);
+    });
+
+    it('can rollback based on return value', async function() {
+      let rc;
+      rc = await sqlite3.exec(db, `
+        CREATE TABLE t(i integer primary key, x);
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+
+      // accept commit by returning 0
+      sqlite3.commit_hook(db, () => 0);
+      rc = await sqlite3.exec(db, `
+        INSERT INTO t VALUES (1, 'foo');
+      `);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+
+      // reject commit by returning 1, causing rollback
+      sqlite3.commit_hook(db, () => 1);
+      await expectAsync(
+        sqlite3.exec(db, `INSERT INTO t VALUES (2, 'bar');`)
+      ).toBeRejected();
+
+      // double-check that the insert was rolled back
+      let hasRow = false;
+      rc = await sqlite3.exec(db, `
+        SELECT * FROM t WHERE i = 2;
+      `, () => hasRow = true);
+      expect(rc).toEqual(SQLite.SQLITE_OK);
+      expect(hasRow).toBeFalse();
+    });
+  });
 }