knowrob::mongo::ChangeStream Class Reference

#include <ChangeStream.h>

Collaboration diagram for knowrob::mongo::ChangeStream:

Public Member Functions
	ChangeStream (const std::shared_ptr< Collection > &collection, const bson_t *query, ChangeStreamCallback callback)
	ChangeStream (const ChangeStream &)=delete
	~ChangeStream ()
bool	next ()
	ChangeStream (const std::shared_ptr< Collection > &collection, const bson_t *query, ChangeStreamCallback callback)
	ChangeStream (const ChangeStream &)=delete
	~ChangeStream ()
bool	next ()

Protected Attributes
std::shared_ptr< Collection >	collection_
ChangeStreamCallback	callback_
mongoc_change_stream_t *	stream_
bson_wrapper_ptr	next_ptr_

Detailed Description

A stream of query results that invokes a callback whenever a new result is found.

Definition at line 27 of file ChangeStream.h.

Constructor & Destructor Documentation

ChangeStream() [1/4]

ChangeStream::ChangeStream	(	const std::shared_ptr< Collection > &	collection,
		const bson_t *	query,
		ChangeStreamCallback	callback
	)

Definition at line 11 of file ChangeStream.cpp.

        : collection_(collection),
          callback_(std::move(callback)),
          stream_(nullptr),
          next_ptr_() {
    // connect and append session ID to options
    bson_t *opts = BCON_NEW(
            "maxAwaitTimeMS", BCON_INT32(1),            // the watcher should be non-blocking
            "fullDocument", BCON_UTF8("updateLookup")   // always fetch full document
    );
    collection_->appendSession(opts);
    bson_destroy(opts);
    // create the stream object
    stream_ = mongoc_collection_watch(collection_->coll(), query, opts);
}

ChangeStream() [2/4]

knowrob::mongo::ChangeStream::ChangeStream ( const ChangeStream &  )

delete

~ChangeStream() [1/2]

ChangeStream::~ChangeStream

(

)

Definition at line 30 of file ChangeStream.cpp.

                            {
    if (stream_ != nullptr) {
        mongoc_change_stream_destroy(stream_);
        stream_ = nullptr;
    }
}

ChangeStream() [3/4]

knowrob::mongo::ChangeStream::ChangeStream	(	const std::shared_ptr< Collection > &	collection,
		const bson_t *	query,
		ChangeStreamCallback	callback
	)

ChangeStream() [4/4]

knowrob::mongo::ChangeStream::ChangeStream ( const ChangeStream &  )

delete

~ChangeStream() [2/2]

knowrob::mongo::ChangeStream::~ChangeStream

(

)

Member Function Documentation

next() [1/2]

bool ChangeStream::next

(

)

Definition at line 37 of file ChangeStream.cpp.

                        {
    if (stream_ == nullptr) {
        // stream had an error before
        return false;
    }
 
    // try retrieving next document
    const bson_t *doc;
    if (mongoc_change_stream_next(stream_, &doc)) {
        next_ptr_.bson = doc;
        callback_(next_ptr_);
        return true;
    }
 
    // check if stream has an error
    const bson_t *err_doc;
    bson_error_t error;
    if (mongoc_change_stream_error_document(stream_, &error, &err_doc)) {
        mongoc_change_stream_destroy(stream_);
        stream_ = nullptr;
        throw MongoException("watch_error", error);
    }
 
    return false;
}

next() [2/2]

bool knowrob::mongo::ChangeStream::next

(

)

Member Data Documentation

callback_

ChangeStreamCallback knowrob::mongo::ChangeStream::callback_

protected

Definition at line 42 of file ChangeStream.h.

collection_

std::shared_ptr< Collection > knowrob::mongo::ChangeStream::collection_

protected

Definition at line 41 of file ChangeStream.h.

next_ptr_

bson_wrapper_ptr knowrob::mongo::ChangeStream::next_ptr_

protected

Definition at line 44 of file ChangeStream.h.

stream_

mongoc_change_stream_t * knowrob::mongo::ChangeStream::stream_

protected

Definition at line 43 of file ChangeStream.h.

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The documentation for this class was generated from the following files:

• build/_CPack_Packages/Linux/DEB/knowrob-2.1.0-Linux/usr/include/knowrob/storage/mongo/ChangeStream.h
• src/storage/mongo/ChangeStream.cpp