StatusWith<std::unique_ptr<ClusterClientCursor>> ClusterCursorManager::detachCursor_inlock(
const NamespaceString& nss, CursorId cursorId) {
CursorEntry* entry = getEntry_inlock(nss, cursorId);
if (!entry) {
return cursorNotFoundStatus(nss, cursorId);
}
std::unique_ptr<ClusterClientCursor> cursor = entry->releaseCursor();
if (!cursor) {
return cursorInUseStatus(nss, cursorId);
}
auto nsToContainerIt = _namespaceToContainerMap.find(nss);
invariant(nsToContainerIt != _namespaceToContainerMap.end());
CursorEntryMap& entryMap = nsToContainerIt->second.entryMap;
size_t eraseResult = entryMap.erase(cursorId);
invariant(1 == eraseResult);
if (entryMap.empty()) {
// This was the last cursor remaining in the given namespace. Erase all state associated
// with this namespace.
size_t numDeleted =
_cursorIdPrefixToNamespaceMap.erase(nsToContainerIt->second.containerPrefix);
invariant(numDeleted == 1);
_namespaceToContainerMap.erase(nsToContainerIt);
invariant(_namespaceToContainerMap.size() == _cursorIdPrefixToNamespaceMap.size());
}
return std::move(cursor);
}
StatusWith<ClusterCursorManager::PinnedCursor> ClusterCursorManager::checkOutCursor(
const NamespaceString& nss, CursorId cursorId) {
// Read the clock out of the lock.
const auto now = _clockSource->now();
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_inShutdown) {
return Status(ErrorCodes::ShutdownInProgress,
"Cannot check out cursor as we are in the process of shutting down");
}
CursorEntry* entry = getEntry_inlock(nss, cursorId);
if (!entry) {
return cursorNotFoundStatus(nss, cursorId);
}
if (entry->getKillPending()) {
return cursorNotFoundStatus(nss, cursorId);
}
std::unique_ptr<ClusterClientCursor> cursor = entry->releaseCursor();
if (!cursor) {
return cursorInUseStatus(nss, cursorId);
}
entry->setLastActive(now);
// Note that pinning a cursor transfers ownership of the underlying ClusterClientCursor object
// to the pin; the CursorEntry is left with a null ClusterClientCursor.
return PinnedCursor(this, std::move(cursor), nss, cursorId);
}
StatusWith<ClusterCursorManager::PinnedCursor> ClusterCursorManager::checkOutCursor(
const NamespaceString& nss, CursorId cursorId) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
CursorEntry* entry = getEntry_inlock(nss, cursorId);
if (!entry) {
return cursorNotFoundStatus(nss, cursorId);
}
if (entry->getKillPending()) {
return cursorNotFoundStatus(nss, cursorId);
}
std::unique_ptr<ClusterClientCursor> cursor = entry->releaseCursor();
if (!cursor) {
return cursorInUseStatus(nss, cursorId);
}
entry->setLastActive(_clockSource->now());
// Note that pinning a cursor transfers ownership of the underlying ClusterClientCursor object
// to the pin; the CursorEntry is left with a null ClusterClientCursor.
return PinnedCursor(this, std::move(cursor), nss, cursorId);
}