Update cvedb.py

Author: RADXIshan

cve_bin_tool/cvedb.py

@@ -766,27 +766,47 @@ def update_vendors(self, cve_data):
         return updated_severity, updated_affected
 
     def db_open_and_get_cursor(self) -> sqlite3.Cursor:
-    """Opens connection to SQLite database with retry logic to handle 'database is locked' errors."""
+    """Opens connection to SQLite database with retry logic and cursor existence check."""
+
+    # If we already have a valid connection, try to use it
+    if self.connection:
+        try:
+            cursor = self.connection.cursor()
+            if cursor is None:
+                LOGGER.error("Database cursor does not exist")
+                raise CVEDBError("Cursor creation failed.")
+            return cursor
+        except sqlite3.Error as e:
+            LOGGER.warning(f"Existing DB connection failed, retrying from scratch. Error: {e}")
+            self.connection = None  # Reset and retry below
 
     retries = 0
     while retries < MAX_RETRIES:
         try:
-            self.connection = sqlite3.connect(self.dbpath, timeout=10)  # Extend timeout for better handling
-            return self.connection.cursor()
+            self.connection = sqlite3.connect(self.dbpath, timeout=10)
+            cursor = self.connection.cursor()
+            if cursor is None:
+                LOGGER.error("Database cursor does not exist")
+                raise CVEDBError("Cursor creation failed.")
+            return cursor
         except sqlite3.OperationalError as e:
             if "database is locked" in str(e):
                 retries += 1
-                wait_time = RETRY_DELAY * (2 ** retries)  # Exponential backoff
+                wait_time = RETRY_DELAY * (2 ** retries)
                 LOGGER.warning(f"Database locked, retrying in {wait_time:.2f} seconds...")
                 time.sleep(wait_time)
             else:
                 LOGGER.error(f"Database operation failed: {e}")
-                raise CVEDBError(f"Database operation failed: {e}")  # Ensuring consistent error handling
+                raise CVEDBError(f"Database operation failed: {e}")
+        except sqlite3.Error as e:
+            LOGGER.error(f"Unexpected database error: {e}")
+            raise CVEDBError(f"Unexpected database error: {e}")
 
     LOGGER.error("Max retries reached. Could not obtain database connection.")
     raise CVEDBError("Failed to open database connection after multiple attempts")
 
 
+
     def db_close(self) -> None:
         """Closes connection to sqlite database."""
         if self.connection: