Node JS version

node_modules/cassandra-driver/lib/mapping/result-mapper.js

@@ -0,0 +1,112 @@
+/*
+ * Copyright DataStax, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const vm = require('vm');
+const utils = require('../utils');
+const types = require('../types');
+
+/**
+ * @ignore
+ */
+class ResultMapper {
+  /**
+   * Gets a generated function to adapt the row to a document.
+   * @param {ModelMappingInfo} info
+   * @param {ResultSet} rs
+   * @returns {Function}
+   */
+  static getSelectAdapter(info, rs) {
+    const columns = rs.columns;
+    if (!columns) {
+      throw new Error('Expected ROWS result obtained VOID');
+    }
+
+    let scriptText = '(function rowAdapter(row, info) {\n' +
+      '  const item = info.newInstance();\n';
+
+    for (const c of columns) {
+      scriptText += `  item['${info.getPropertyName(c.name)}'] = `;
+
+      if (!info.getToModelFn(c.name)) {
+        scriptText += `row['${c.name}'];\n`;
+      } else {
+        scriptText += `info.getToModelFn('${c.name}')(row['${c.name}']);\n`;
+      }
+    }
+
+    scriptText += '  return item;\n})';
+
+    const script = new vm.Script(scriptText, { filename: 'gen-result-mapper.js'});
+    return script.runInThisContext();
+  }
+
+  /**
+   * Gets a function used to adapt VOID results or conditional updates.
+   * @param {ResultSet} rs
+   * @returns {Function}
+   */
+  static getMutationAdapter(rs) {
+    if (rs.columns === null) {
+      // VOID result
+      return utils.noop;
+    }
+
+    if (
+      rs.columns.length === 1 && rs.columns[0].name === '[applied]' &&
+      rs.columns[0].type.code === types.dataTypes.boolean) {
+      return utils.noop;
+    }
+
+    return ResultMapper._getConditionalRowAdapter(rs);
+  }
+
+  static _getConditionalRowAdapter(rs) {
+    return (function conditionalRowAdapter(row, info) {
+      const item = info.newInstance();
+
+      // Skip the first column ("[applied]")
+      for (let i = 1; i < rs.columns.length; i++) {
+        const c = rs.columns[i];
+        item[info.getPropertyName(c.name)] = row[c.name];
+      }
+
+      return item;
+    });
+  }
+
+  /**
+   * @param {ModelMappingInfo} info
+   * @param {ResultSet} rs
+   * @returns {{canCache: Boolean, fn: Function}}
+   */
+  static getCustomQueryAdapter(info, rs) {
+    if (rs.columns === null || rs.columns.length === 0) {
+      // VOID result
+      return { canCache: true, fn: utils.noop };
+    }
+
+    if (rs.columns[0].name === '[applied]' && rs.columns[0].type.code === types.dataTypes.boolean) {
+      // Conditional update results adapter functions should not be cached
+      return { canCache: false, fn: ResultMapper._getConditionalRowAdapter(rs) };
+    }
+
+    return { canCache: true, fn: ResultMapper.getSelectAdapter(info, rs) };
+  }
+}
+
+module.exports = ResultMapper;