Initial commit

node_modules/mongodb/lib/operations/map_reduce.js

@@ -0,0 +1,190 @@
+'use strict';
+
+const applyWriteConcern = require('../utils').applyWriteConcern;
+const Code = require('../core').BSON.Code;
+const decorateWithCollation = require('../utils').decorateWithCollation;
+const decorateWithReadConcern = require('../utils').decorateWithReadConcern;
+const executeCommand = require('./db_ops').executeCommand;
+const handleCallback = require('../utils').handleCallback;
+const isObject = require('../utils').isObject;
+const loadDb = require('../dynamic_loaders').loadDb;
+const OperationBase = require('./operation').OperationBase;
+const ReadPreference = require('../core').ReadPreference;
+const toError = require('../utils').toError;
+
+const exclusionList = [
+  'readPreference',
+  'session',
+  'bypassDocumentValidation',
+  'w',
+  'wtimeout',
+  'j',
+  'writeConcern'
+];
+
+/**
+ * Run Map Reduce across a collection. Be aware that the inline option for out will return an array of results not a collection.
+ *
+ * @class
+ * @property {Collection} a Collection instance.
+ * @property {(function|string)} map The mapping function.
+ * @property {(function|string)} reduce The reduce function.
+ * @property {object} [options] Optional settings. See Collection.prototype.mapReduce for a list of options.
+ */
+class MapReduceOperation extends OperationBase {
+  /**
+   * Constructs a MapReduce operation.
+   *
+   * @param {Collection} a Collection instance.
+   * @param {(function|string)} map The mapping function.
+   * @param {(function|string)} reduce The reduce function.
+   * @param {object} [options] Optional settings. See Collection.prototype.mapReduce for a list of options.
+   */
+  constructor(collection, map, reduce, options) {
+    super(options);
+
+    this.collection = collection;
+    this.map = map;
+    this.reduce = reduce;
+  }
+
+  /**
+   * Execute the operation.
+   *
+   * @param {Collection~resultCallback} [callback] The command result callback
+   */
+  execute(callback) {
+    const coll = this.collection;
+    const map = this.map;
+    const reduce = this.reduce;
+    let options = this.options;
+
+    const mapCommandHash = {
+      mapReduce: coll.collectionName,
+      map: map,
+      reduce: reduce
+    };
+
+    // Add any other options passed in
+    for (let n in options) {
+      if ('scope' === n) {
+        mapCommandHash[n] = processScope(options[n]);
+      } else {
+        // Only include if not in exclusion list
+        if (exclusionList.indexOf(n) === -1) {
+          mapCommandHash[n] = options[n];
+        }
+      }
+    }
+
+    options = Object.assign({}, options);
+
+    // Ensure we have the right read preference inheritance
+    options.readPreference = ReadPreference.resolve(coll, options);
+
+    // If we have a read preference and inline is not set as output fail hard
+    if (
+      options.readPreference !== false &&
+      options.readPreference !== 'primary' &&
+      options['out'] &&
+      options['out'].inline !== 1 &&
+      options['out'] !== 'inline'
+    ) {
+      // Force readPreference to primary
+      options.readPreference = 'primary';
+      // Decorate command with writeConcern if supported
+      applyWriteConcern(mapCommandHash, { db: coll.s.db, collection: coll }, options);
+    } else {
+      decorateWithReadConcern(mapCommandHash, coll, options);
+    }
+
+    // Is bypassDocumentValidation specified
+    if (options.bypassDocumentValidation === true) {
+      mapCommandHash.bypassDocumentValidation = options.bypassDocumentValidation;
+    }
+
+    // Have we specified collation
+    try {
+      decorateWithCollation(mapCommandHash, coll, options);
+    } catch (err) {
+      return callback(err, null);
+    }
+
+    // Execute command
+    executeCommand(coll.s.db, mapCommandHash, options, (err, result) => {
+      if (err) return handleCallback(callback, err);
+      // Check if we have an error
+      if (1 !== result.ok || result.err || result.errmsg) {
+        return handleCallback(callback, toError(result));
+      }
+
+      // Create statistics value
+      const stats = {};
+      if (result.timeMillis) stats['processtime'] = result.timeMillis;
+      if (result.counts) stats['counts'] = result.counts;
+      if (result.timing) stats['timing'] = result.timing;
+
+      // invoked with inline?
+      if (result.results) {
+        // If we wish for no verbosity
+        if (options['verbose'] == null || !options['verbose']) {
+          return handleCallback(callback, null, result.results);
+        }
+
+        return handleCallback(callback, null, { results: result.results, stats: stats });
+      }
+
+      // The returned collection
+      let collection = null;
+
+      // If we have an object it's a different db
+      if (result.result != null && typeof result.result === 'object') {
+        const doc = result.result;
+        // Return a collection from another db
+        let Db = loadDb();
+        collection = new Db(doc.db, coll.s.db.s.topology, coll.s.db.s.options).collection(
+          doc.collection
+        );
+      } else {
+        // Create a collection object that wraps the result collection
+        collection = coll.s.db.collection(result.result);
+      }
+
+      // If we wish for no verbosity
+      if (options['verbose'] == null || !options['verbose']) {
+        return handleCallback(callback, err, collection);
+      }
+
+      // Return stats as third set of values
+      handleCallback(callback, err, { collection: collection, stats: stats });
+    });
+  }
+}
+
+/**
+ * Functions that are passed as scope args must
+ * be converted to Code instances.
+ * @ignore
+ */
+function processScope(scope) {
+  if (!isObject(scope) || scope._bsontype === 'ObjectID') {
+    return scope;
+  }
+
+  const keys = Object.keys(scope);
+  let key;
+  const new_scope = {};
+
+  for (let i = keys.length - 1; i >= 0; i--) {
+    key = keys[i];
+    if ('function' === typeof scope[key]) {
+      new_scope[key] = new Code(String(scope[key]));
+    } else {
+      new_scope[key] = processScope(scope[key]);
+    }
+  }
+
+  return new_scope;
+}
+
+module.exports = MapReduceOperation;