Add emscripten_idb_clear API (#20182)

This patch adds missing `clear` IndexedDB API (both sync and async
versions).

site/source/docs/api_reference/emscripten.h.rst

@@ -865,6 +865,21 @@ Asynchronous IndexedDB API
 
     - *(void*)* : Equal to ``arg`` (user defined data).
 
+.. c:function:: void emscripten_idb_async_clear(const char *db_name, void* arg, em_arg_callback_func onclear, em_arg_callback_func onerror)
+
+  Clears all data from local IndexedDB storage asynchronously.
+
+  When the storage has been cleared then the ``onclear`` callback will be called. If any error occurred ``onerror`` will be called.
+
+  :param db_name: The IndexedDB database.
+  :param void* arg: User-defined data that is passed to the callbacks, untouched by the API itself. This may be used by a callback to identify the associated call.
+  :param em_arg_callback_func onclear: Callback on successful clear. The callback function parameter is:
+
+    - *(void*)* : Equal to ``arg`` (user defined data).
+
+  :param em_arg_callback_func onerror: Callback in the event of failure. The callback function parameter is:
+
+    - *(void*)* : Equal to ``arg`` (user defined data).
 
 
 .. c:function:: int emscripten_run_preload_plugins(const char* file, em_str_callback_func onload, em_str_callback_func onerror)
@@ -1362,6 +1377,13 @@ IndexedDB
   :param pexists: An out parameter that will be filled with a non-zero value if the file exists in that database.
   :param perror: An out parameter that will be filled with a non-zero value if an error occurred.
 
+.. c:function:: void emscripten_idb_clear(const char *db_name, int *perror);
+
+  Synchronously clears all data from IndexedDB.
+
+  :param db_name: The name of the database to clear
+  :param perror: An out parameter that will be filled with a non-zero value if an error occurred.
+
 
 Upstream Asyncify functions
 ===========================

src/IDBStore.js

@@ -102,4 +102,12 @@ var IDBStore = {
       req.onerror = (error) => callback(error);
     });
   },
+  clearStore(dbName, callback) {
+    IDBStore.getStore(dbName, 'readwrite', (err, store) => {
+      if (err) return callback(err);
+      var req = store.clear();
+      req.onsuccess = (event) => callback();
+      req.onerror = (error) => callback(error);
+    });
+  },
 };

src/library_idbstore.js

@@ -76,6 +76,20 @@ var LibraryIDBStore = {
       });
     });
   },
+  emscripten_idb_async_clear__deps: ['$UTF8ToString', '$callUserCallback'],
+  emscripten_idb_async_clear: (db, arg, onclear, onerror) => {
+    {{{ runtimeKeepalivePush() }}};
+    IDBStore.clearStore(UTF8ToString(db), (error) => {
+      {{{ runtimeKeepalivePop() }}}
+      callUserCallback(() => {
+        if (error) {
+          if (onerror) {{{ makeDynCall('vp', 'onerror') }}}(arg);
+          return;
+        }
+        if (onclear) {{{ makeDynCall('vp', 'onclear') }}}(arg);
+      });
+    });
+  },
 
 #if ASYNCIFY
   emscripten_idb_load__async: true,
@@ -125,6 +139,15 @@ var LibraryIDBStore = {
       });
     });
   },
+  emscripten_idb_clear__async: true,
+  emscripten_idb_clear: (db, perror) => {
+    return Asyncify.handleSleep((wakeUp) => {
+      IDBStore.clearStore(UTF8ToString(db), (error) => {
+        {{{ makeSetValue('perror', 0, '!!error', 'i32') }}};
+        wakeUp();
+      });
+    });
+  },
   // extra worker methods - proxied
   emscripten_idb_load_blob__async: true,
   emscripten_idb_load_blob: (db, id, pblob, perror) => {
@@ -195,6 +218,9 @@ var LibraryIDBStore = {
   emscripten_idb_exists: (db, id, pexists, perror) => {
     throw 'Please compile your program with async support in order to use synchronous operations like emscripten_idb_exists, etc.';
   },
+  emscripten_idb_clear: (db, perror) => {
+    throw 'Please compile your program with async support in order to use synchronous operations like emscripten_idb_clear, etc.';
+  },
 #endif // ASYNCIFY
 };
 

src/library_sigs.js

@@ -650,10 +650,12 @@ sigs = {
   emscripten_has_threading_support__sig: 'i',
   emscripten_hide_mouse__sig: 'v',
   emscripten_html5_remove_all_event_listeners__sig: 'v',
+  emscripten_idb_async_clear__sig: 'vpppp',
   emscripten_idb_async_delete__sig: 'vppppp',
   emscripten_idb_async_exists__sig: 'vppppp',
   emscripten_idb_async_load__sig: 'vppppp',
   emscripten_idb_async_store__sig: 'vpppippp',
+  emscripten_idb_clear__sig: 'vpp',
   emscripten_idb_delete__sig: 'vppp',
   emscripten_idb_exists__sig: 'vpppp',
   emscripten_idb_load__sig: 'vppppp',

system/include/emscripten/emscripten.h

@@ -95,13 +95,15 @@ void emscripten_idb_async_store(const char *db_name __attribute__((nonnull)), co
 void emscripten_idb_async_delete(const char *db_name __attribute__((nonnull)), const char *file_id __attribute__((nonnull)), void* arg, em_arg_callback_func ondelete, em_arg_callback_func onerror);
 typedef void (*em_idb_exists_func)(void*, int);
 void emscripten_idb_async_exists(const char *db_name __attribute__((nonnull)), const char *file_id __attribute__((nonnull)), void* arg, em_idb_exists_func oncheck, em_arg_callback_func onerror);
+void emscripten_idb_async_clear(const char *db_name __attribute__((nonnull)), void* arg, em_arg_callback_func onclear, em_arg_callback_func onerror);
 
 // IDB "sync"
 
 void emscripten_idb_load(const char *db_name, const char *file_id, void** pbuffer, int* pnum, int *perror);
 void emscripten_idb_store(const char *db_name, const char *file_id, void* buffer, int num, int *perror);
 void emscripten_idb_delete(const char *db_name, const char *file_id, int *perror);
 void emscripten_idb_exists(const char *db_name, const char *file_id, int* pexists, int *perror);
+void emscripten_idb_clear(const char *db_name, int *perror);
 
 void emscripten_idb_load_blob(const char *db_name, const char *file_id, int* pblob, int *perror);
 void emscripten_idb_store_blob(const char *db_name, const char *file_id, void* buffer, int num, int *perror);

test/browser/test_idbstore.c

@@ -77,6 +77,10 @@ int main() {
 #elif STAGE == 5
   expected = 77;
   emscripten_idb_async_exists(DB, "the_secret", (void*)expected, onchecknope, onerror);
+#elif STAGE == 6
+  expected = 88;
+  printf("clearing\n");
+  emscripten_idb_async_clear(DB, (void*)expected, ok, onerror);
 #else
   assert(0);
 #endif

test/browser/test_idbstore_sync.c

@@ -52,6 +52,16 @@ void test() {
   assert(error); // expected error!
   sum++;
 
+  printf("storing %s again\n", SECRET);
+  emscripten_idb_store(DB, "the_secret", SECRET, strlen(SECRET)+1, &error);
+  assert(!error);
+  sum++;
+
+  printf("clearing the store\n");
+  emscripten_idb_clear(DB, &error);
+  assert(!error);
+  sum++;
+
   printf("last checking\n");
   emscripten_idb_exists(DB, "the_secret", &exists, &error);
   assert(!error);

test/browser/test_idbstore_sync_worker.c

@@ -50,6 +50,16 @@ int main() {
   assert(error); // expected error!
   sum++;
 
+  printf("storing %s again\n", SECRET);
+  emscripten_idb_store(DB, "the_secret", SECRET, strlen(SECRET)+1, &error);
+  assert(!error);
+  sum++;
+
+  printf("clearing the store\n");
+  emscripten_idb_clear(DB, &error);
+  assert(!error);
+  sum++;
+
   printf("last checking\n");
   emscripten_idb_exists(DB, "the_secret", &exists, &error);
   assert(!error);
@@ -93,7 +103,7 @@ int main() {
 
   // finish up
 
-  assert(sum == 6);
+  assert(sum == 8);
   REPORT_RESULT(0);
   return 0;
 }

test/test_browser.py

@@ -1505,7 +1505,7 @@ def test_separate_metadata_later(self):
   @also_with_wasm64
   def test_idbstore(self):
     secret = str(time.time())
-    for stage in [0, 1, 2, 3, 0, 1, 2, 0, 0, 1, 4, 2, 5]:
+    for stage in [0, 1, 2, 3, 0, 1, 2, 0, 0, 1, 4, 2, 5, 0, 4, 6, 5]:
       print(stage)
       self.btest_exit('test_idbstore.c',
                       args=['-lidbstore.js', f'-DSTAGE={stage}', f'-DSECRET="{secret}"'],
@@ -1524,7 +1524,7 @@ def test_idbstore_sync(self, asyncify, wasm64):
     if asyncify == 2:
       self.require_jspi()
     secret = str(time.time())
-    self.btest('test_idbstore_sync.c', '6', args=['-lidbstore.js', f'-DSECRET="{secret}"', '-O3', '-g2', '-sASYNCIFY=' + str(asyncify)])
+    self.btest('test_idbstore_sync.c', '8', args=['-lidbstore.js', f'-DSECRET="{secret}"', '-O3', '-g2', '-sASYNCIFY=' + str(asyncify)])
 
   def test_idbstore_sync_worker(self):
     secret = str(time.time())