feat: added live query listener

Author: Wojtach

ios/CblReactnative.mm

@@ -236,6 +236,19 @@ @interface RCT_EXTERN_MODULE(CblReactnative, RCTEventEmitter)
 
 // MARK: - SQL++ Query Functions
 
+RCT_EXTERN_METHOD(query_AddChangeListener:
+  (NSString *)changeListenerToken
+  withQuery:(NSString *)query
+  withParameters:(NSDictionary *)parameters
+  fromDatabaseWithName:(NSString *)name
+  withResolver:(RCTPromiseResolveBlock)resolve
+  withRejecter:(RCTPromiseRejectBlock)reject)
+
+RCT_EXTERN_METHOD(query_RemoveChangeListener:
+  (NSString *)changeListenerToken
+  withResolver:(RCTPromiseResolveBlock)resolve
+  withRejecter:(RCTPromiseRejectBlock)reject)
+
 RCT_EXTERN_METHOD(query_Execute:
   (NSString *)query
   withParameters: (NSDictionary *)parameters

ios/CblReactnative.swift

@@ -1041,6 +1041,87 @@ class CblReactnative: RCTEventEmitter {
   }
 
   // MARK: - SQL++ Query Functions
+  @objc(query_AddChangeListener:withQuery:withParameters:fromDatabaseWithName:withResolver:withRejecter:)
+  func query_AddChangeListener(
+    changeListenerToken: NSString,
+    query: NSString,
+    parameters: NSDictionary,
+    name: NSString,
+    resolve: @escaping RCTPromiseResolveBlock,
+    reject: @escaping RCTPromiseRejectBlock
+  ) -> Void {
+    let (isError, databaseName) = DataAdapter.shared.adaptDatabaseName(name: name, reject: reject)
+    let (isTokenError, token) = DataAdapter.shared.adaptNonEmptyString(value: changeListenerToken, propertyName: "changeListenerToken", reject: reject)
+    let (isQueryError, queryString) = DataAdapter.shared.adaptNonEmptyString(value: query, propertyName: "query", reject: reject)
+  
+    if isError || isTokenError || isQueryError {
+      return
+    }
+    
+    backgroundQueue.async {
+      do {
+        guard let database = DatabaseManager.shared.getDatabase(databaseName) else {
+          reject("DATABASE_ERROR", "Could not find database with name \(databaseName)", nil)
+          return
+        }
+    
+        let query = try database.createQuery(queryString)
+      
+        if parameters.count > 0 {
+          let params = try QueryHelper.getParamatersFromJson(parameters as? [String: Any] ?? [:])
+          query.parameters = params
+        }
+      
+        let listener = query.addChangeListener(withQueue: self.backgroundQueue) { [weak self] (change) in
+          guard let self = self else { return }
+        
+          let resultData = NSMutableDictionary()
+          resultData.setValue(token, forKey: "token")
+        
+          if let results = change.results {
+            // Convert results to JSON format
+            let resultJSONs = results.map { $0.toJSON() }
+            let jsonArray = "[" + resultJSONs.joined(separator: ",") + "]"
+            resultData.setValue(jsonArray, forKey: "data")
+          }
+        
+          if let error = change.error {
+            resultData.setValue(error.localizedDescription, forKey: "error")
+          }
+        
+          self.sendEvent(withName: self.kQueryChange, body: resultData)
+        }
+      
+        self.queryChangeListeners[token] = listener
+        resolve(nil)
+      } catch let error as NSError {
+        reject("DATABASE_ERROR", error.localizedDescription, nil)
+      } catch {
+        reject("DATABASE_ERROR", error.localizedDescription, nil)
+      }
+    }
+  }
+
+  @objc(query_RemoveChangeListener:withResolver:withRejecter:)
+  func query_RemoveChangeListener(
+    changeListenerToken: NSString,
+    resolve: @escaping RCTPromiseResolveBlock,
+    reject: @escaping RCTPromiseRejectBlock
+  ) -> Void {
+    let token = String(changeListenerToken)
+  
+    backgroundQueue.async {
+      if let listener = self.queryChangeListeners[token] as? ListenerToken {
+        listener.remove()
+        self.queryChangeListeners.removeValue(forKey: token)
+        resolve(nil)
+        return
+      }
+    
+      reject("DATABASE_ERROR", "No query listener found for token \(token)", nil)
+    }
+  }
+
   @objc(query_Execute:
           withParameters:
           fromDatabaseWithName:

src/CblReactNativeEngine.tsx

@@ -79,6 +79,7 @@ export class CblReactNativeEngine implements ICoreEngine {
   private _isReplicatorDocumentChangeEventSetup: boolean = false;
 
   private _collectionChangeListeners: Map<string, ListenerCallback> = new Map();
+  private _queryChangeListeners: Map<string, ListenerCallback> = new Map();
 
   private static readonly LINKING_ERROR =
     `The package 'cbl-reactnative' doesn't seem to be linked. Make sure: \n\n` +
@@ -993,12 +994,49 @@ export class CblReactNativeEngine implements ICoreEngine {
   }
 
   query_AddChangeListener(
-    // eslint-disable-next-line
     args: QueryChangeListenerArgs,
-    // eslint-disable-next-line
     lcb: ListenerCallback
   ): Promise<void> {
-    return Promise.resolve(undefined);
+    return new Promise((resolve, reject) => {
+      const token = args.changeListenerToken;
+
+      if (this._queryChangeListeners.has(token)) {
+        reject(new Error('Query change listener token already exists'));
+        return;
+      }
+
+      const subscription = this.startListeningEvents(
+        this._eventQueryChange,
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (results: any) => {
+          if (results.token === token) {
+            this.debugLog(
+              `::DEBUG:: Received query change event for token: ${token}`
+            );
+            lcb(results);
+          }
+        }
+      );
+
+      this._emitterSubscriptions.set(token, subscription);
+      this._queryChangeListeners.set(token, lcb);
+
+      this.CblReactNative.query_AddChangeListener(
+        token,
+        args.query,
+        args.parameters,
+        args.name
+      ).then(
+        () => resolve(),
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (error: any) => {
+          this._emitterSubscriptions.delete(token);
+          this._queryChangeListeners.delete(token);
+          subscription.remove();
+          reject(error);
+        }
+      );
+    });
   }
 
   query_Execute(args: QueryExecuteArgs): Promise<Result> {
@@ -1038,10 +1076,37 @@ export class CblReactNativeEngine implements ICoreEngine {
   }
 
   query_RemoveChangeListener(
-    // eslint-disable-next-line
     args: QueryRemoveChangeListenerArgs
   ): Promise<void> {
-    return Promise.resolve(undefined);
+    return new Promise((resolve, reject) => {
+      const token = args.changeListenerToken;
+
+      if (this._emitterSubscriptions.has(token)) {
+        this._emitterSubscriptions.get(token)?.remove();
+        this._emitterSubscriptions.delete(token);
+      }
+
+      if (this._queryChangeListeners.has(token)) {
+        this._queryChangeListeners.delete(token);
+      } else {
+        reject(new Error(`No query listener found with token: ${token}`));
+        return;
+      }
+
+      this.CblReactNative.query_RemoveChangeListener(token).then(
+        () => {
+          this.debugLog(
+            `::DEBUG:: query_RemoveChangeListener completed for token: ${token}`
+          );
+          resolve();
+        },
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        (error: any) => {
+          this.debugLog(`::DEBUG:: query_RemoveChangeListener Error: ${error}`);
+          reject(error);
+        }
+      );
+    });
   }
 
   replicator_AddChangeListener(