@nozbe/lokijs - npm Package Compare versions

Comparing version 1.5.11-wmelon-idb-fix to 1.5.11-wmelon-idb-fix2

package.json

 {
   "name": "@nozbe/lokijs",
-  "version": "1.5.11-wmelon-idb-fix",
+  "version": "1.5.11-wmelon-idb-fix2",
   "description": "Nozbe's temporary fork of LokiJS - used for WatermelonDB purposes to work around NPM issues",
@@ -5,0 +5,0 @@ "homepage": "https://techfort.github.io/LokiJS/",

src/incremental-indexeddb-adapter.js

@@ -40,2 +40,5 @@ (function(root, factory) {
      *     Use this as an opportunity to execute code concurrently while IDB does work on a separate thread
+     * @param {function} options.onDidOverwrite Called when this adapter is forced to overwrite contents
+     *     of IndexedDB. This happens if there's another open tab of the same app that's making changes.
+     *     You might use it as an opportunity to alert user to the potential loss of data
      * @param {function} options.serializeChunk Called with a chunk (array of Loki documents) before
@@ -165,65 +168,89 @@ *     it's saved to IndexedDB. You can use it to manually compress on-disk representation
 
-      var updatePrevVersionIds = function () {
-        console.error('Unexpected successful tx - cannot update previous version ids');
-      };
+      // try..catch is required, e.g.:
+      // InvalidStateError: Failed to execute 'transaction' on 'IDBDatabase': The database connection is closing.
+      // (this may happen if another tab has called deleteDatabase)
+      try {
+        var updatePrevVersionIds = function () {
+          console.error('Unexpected successful tx - cannot update previous version ids');
+        };
+        var didOverwrite = false;
 
-      DEBUG && console.log("save tx: begin");
-      var tx = this.idb.transaction(['LokiIncrementalData'], "readwrite");
-      tx.oncomplete = function() {
-        updatePrevVersionIds();
-        DEBUG && console.log("save tx: complete");
-        return finish();
-      };
+        var tx = this.idb.transaction(['LokiIncrementalData'], "readwrite");
+        tx.oncomplete = function() {
+          updatePrevVersionIds();
+          finish();
+          if (didOverwrite && that.options.onDidOverwrite) {
+            that.options.onDidOverwrite();
+          }
+        };
 
-      tx.onerror = function(e) {
-        DEBUG && console.log("save tx: error");
-        return finish(e);
-      };
+        tx.onerror = function(e) {
+          finish(e);
+        };
 
-      tx.onabort = function(e) {
-        DEBUG && console.log("save tx: abort");
-        return finish(e);
-      };
+        tx.onabort = function(e) {
+          finish(e);
+        };
 
-      var store = tx.objectStore('LokiIncrementalData');
+        var store = tx.objectStore('LokiIncrementalData');
 
-      function performSave(maxChunkIds) {
-        var incremental = !maxChunkIds;
-        var chunkInfo = that._putInChunks(store, getLokiCopy(), incremental, maxChunkIds);
-        updatePrevVersionIds = function() {
-          that._prevLokiVersionId = chunkInfo.lokiVersionId;
-          chunkInfo.collectionVersionIds.forEach(function (collectionInfo) {
-            that._prevCollectionVersionIds[collectionInfo.name] = collectionInfo.versionId;
+        var performSave = function (maxChunkIds) {
+          try {
+            var incremental = !maxChunkIds;
+            var chunkInfo = that._putInChunks(store, getLokiCopy(), incremental, maxChunkIds);
+            // Update last seen version IDs, but only after the transaction is successful
+            updatePrevVersionIds = function() {
+              that._prevLokiVersionId = chunkInfo.lokiVersionId;
+              chunkInfo.collectionVersionIds.forEach(function (collectionInfo) {
+                that._prevCollectionVersionIds[collectionInfo.name] = collectionInfo.versionId;
+              });
+            };
+            tx.commit && tx.commit();
+          } catch (error) {
+            console.error('idb performSave failed: ', error);
+            tx.abort();
+          }
+        };
+
+        // Incrementally saving changed chunks breaks down if there is more than one writer to IDB
+        // (multiple tabs of the same web app), leading to data corruption. To fix that, we save all
+        // metadata chunks (loki + collections) with a unique ID on each save and remember it. Before
+        // the subsequent save, we read loki from IDB to check if its version ID changed. If not, we're
+        // guaranteed that persisted DB is consistent with our diff. Otherwise, we fall back to the slow
+        // path and overwrite *all* database chunks with our version. Both reading and writing must
+        // happen in the same IDB transaction for this to work.
+        // TODO: We can optimize the slow path by fetching collection metadata chunks and comparing their
+        // version IDs with those last seen by us. Since any change in collection data requires a metadata
+        // chunk save, we're guaranteed that if the IDs match, we don't need to overwrite chukns of this collection
+        var getAllKeysThenSave = function() {
+          // NOTE: We must fetch all keys to protect against a case where another tab has wrote more
+          // chunks whan we did -- if so, we must delete them.
+          idbReq(store.getAllKeys(), function(e) {
+            var maxChunkIds = getMaxChunkIds(e.target.result);
+            performSave(maxChunkIds);
+          }, function(e) {
+            console.error('Getting all keys failed: ', e);
+            tx.abort();
           });
         };
-        DEBUG && console.log('chunks saved');
-        tx.commit && tx.commit();
-      }
 
-      function getAllKeysThenSave() {
-        idbReq(store.getAllKeys(), function(e) {
-          var maxChunkIds = getMaxChunkIds(e.target.result);
-          performSave(maxChunkIds);
-        }, function(e) {
-          console.error('Getting all keys failed: ', e);
-          tx.abort();
-        });
-      }
+        var getLokiThenSave = function() {
+          idbReq(store.get('loki'), function(e) {
+            if (lokiChunkVersionId(e.target.result) === that._prevLokiVersionId) {
+              performSave();
+            } else {
+              DEBUG && console.warn('Another writer changed Loki IDB, using slow path...');
+              didOverwrite = true;
+              getAllKeysThenSave();
+            }
+          }, function(e) {
+            console.error('Getting loki chunk failed: ', e);
+            tx.abort();
+          });
+        };
 
-      function getLokiThenSave() {
-        idbReq(store.get('loki'), function(e) {
-          if (lokiChunkVersionId(e.target.result) === that._prevLokiVersionId) {
-            performSave();
-          } else {
-            DEBUG && console.warn('--------> LOKI CHANGED!!! [slow path]');
-            // TODO: Get collection metadata chunks
-            getAllKeysThenSave();
-          }
-        }, function(e) {
-          console.error('Getting loki chunk failed: ', e);
-          tx.abort();
-        });
+        getLokiThenSave();
+      } catch (error) {
+        finish(error);
       }
-
-      getLokiThenSave();
     };
@@ -290,2 +317,3 @@
           savedSize += chunkData.length;
+          DEBUG && incremental && console.log('Saving: ' + collection.name + ".chunk." + chunkId);
           idbStore.put({
@@ -325,2 +353,3 @@ key: collection.name + ".chunk." + chunkId,
           savedSize += metadataChunk.length;
+          DEBUG && incremental && console.log('Saving: ' + collection.name + ".metadata");
           idbStore.put({
@@ -341,2 +370,3 @@ key: collection.name + ".metadata",
 
+      DEBUG && incremental && console.log('Saving: loki');
       idbStore.put({ key: "loki", value: serializedMetadata });
@@ -539,2 +569,7 @@
         db.onversionchange = function(versionChangeEvent) {
+          // Ignore if database was deleted and recreated in the meantime
+          if (that.idb !== db) {
+            return;
+          }
+
           DEBUG && console.log('IDB version change', versionChangeEvent);
@@ -547,3 +582,4 @@ // This function will be called if another connection changed DB version
           // to force logout
-          db.close();
+          that.idb.close();
+          that.idb = null;
           if (that.options.onversionchange) {
@@ -580,11 +616,8 @@ that.options.onversionchange(versionChangeEvent);
 
-      var request = tx.objectStore('LokiIncrementalData').getAll();
-      request.onsuccess = function(e) {
+      idbReq(tx.objectStore('LokiIncrementalData').getAll(), function(e) {
         var chunks = e.target.result;
         callback(chunks);
-      };
-
-      request.onerror = function(e) {
+      }, function(e) {
         callback(e);
-      };
+      });
 
@@ -682,3 +715,9 @@ if (this.options.onFetchStart) {
     function idbReq(request, onsuccess, onerror) {
-      request.onsuccess = onsuccess;
+      request.onsuccess = function (e) {
+        try {
+          return onsuccess(e);
+        } catch (error) {
+          onerror(error);
+        }
+      };
       request.onerror = onerror;
@@ -685,0 +724,0 @@ return request;

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

3068765

increased by0.09%

Lines of code

9919

increased by0.46%

No dependency changes