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'use strict';
const MONGODB_ERROR_CODES = require('../error_codes').MONGODB_ERROR_CODES;
const Aspect = require('./operation').Aspect;
const defineAspects = require('./operation').defineAspects;
const CommandOperationV2 = require('./command_v2');
const maxWireVersion = require('../core/utils').maxWireVersion;
const CountDocumentsOperation = require('./count_documents');
class EstimatedDocumentCountOperation extends CommandOperationV2 {
constructor(collection, options) {
super(collection, options);
this.collection = collection;
this.collectionName = collection.s.namespace.collection;
}
execute(server, callback) {
if (maxWireVersion(server) < 12) {
return this.executeLegacy(server, callback);
}
// if the user specifies a filter, use a CountDocumentsOperation instead
if (this.options.query) {
const op = new CountDocumentsOperation(this.collection, this.options.query, this.options);
return op.execute(server, callback);
}
const pipeline = [{ $collStats: { count: {} } }, { $group: { _id: 1, n: { $sum: '$count' } } }];
const cmd = { aggregate: this.collectionName, pipeline, cursor: {} };
if (typeof this.options.maxTimeMS === 'number') {
cmd.maxTimeMS = this.options.maxTimeMS;
}
super.executeCommand(server, cmd, (err, response) => {
if (err && err.code !== MONGODB_ERROR_CODES.NamespaceNotFound) {
callback(err);
return;
}
callback(
undefined,
(response &&
response.cursor &&
response.cursor.firstBatch &&
response.cursor.firstBatch[0].n) ||
0
);
});
}
executeLegacy(server, callback) {
const cmd = { count: this.collectionName };
const options = this.options;
if (options.query) {
cmd.query = options.query;
}
if (options.hint) {
cmd.hint = options.hint;
}
if (typeof options.maxTimeMS === 'number') {
cmd.maxTimeMS = options.maxTimeMS;
}
if (typeof options.skip === 'number') {
cmd.skip = options.skip;
}
if (typeof options.limit === 'number') {
cmd.limit = options.limit;
}
super.executeCommand(server, cmd, (err, response) => {
if (err) {
callback(err);
return;
}
callback(null, response.n);
});
}
}
defineAspects(EstimatedDocumentCountOperation, [
Aspect.READ_OPERATION,
Aspect.RETRYABLE,
Aspect.EXECUTE_WITH_SELECTION
]);
module.exports = EstimatedDocumentCountOperation;