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Storage Engine API
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Storage Engine API
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Public Member Functions | |
| boost::optional< Record > | next () final |
| Moves forward and returns the new data or boost::none if there is no more data. More... | |
| boost::optional< Record > | seekExact (const RecordId &id) final |
| Seeks to a Record with the provided id. More... | |
| void | save () final |
| Prepares for state changes in underlying data in a way that allows the cursor's current position to be restored. More... | |
| bool | restore () final |
| Recovers from potential state changes in underlying data. More... | |
| void | detachFromOperationContext () final |
| Detaches from the OperationContext and releases any storage-engine state. More... | |
| void | reattachToOperationContext (OperationContext *opCtx) final |
| Reattaches to the OperationContext and reacquires any storage-engine state. More... | |
 Public Member Functions inherited from mongo::SeekableRecordCursor | |
| virtual void | saveUnpositioned () |
| Prepares for state changes in underlying data without necessarily saving the current state. More... | |
| virtual std::unique_ptr< RecordFetcher > | fetcherForId (const RecordId &id) const |
| Returns a RecordFetcher if needed to fetch the provided Record or none if unneeded. More... | |
| Public Member Functions inherited from mongo::RecordCursor | |
| virtual | ~RecordCursor ()=default |
| virtual void | invalidate (OperationContext *opCtx, const RecordId &id) |
| Inform the cursor that this id is being invalidated. More... | |
| virtual std::unique_ptr< RecordFetcher > | fetcherForNext () const |
| Returns a RecordFetcher if needed for a call to next() or none if unneeded. More... | |
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inlinefinalvirtual |
Detaches from the OperationContext and releases any storage-engine state.
It is only legal to call this when in a "saved" state. While in the "detached" state, it is only legal to call reattachToOperationContext or the destructor. It is not legal to call detachFromOperationContext() while already in the detached state.
Implements mongo::RecordCursor.
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inlinefinalvirtual |
Moves forward and returns the new data or boost::none if there is no more data.
Continues returning boost::none once it reaches EOF.
Implements mongo::RecordCursor.
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inlinefinalvirtual |
Reattaches to the OperationContext and reacquires any storage-engine state.
It is only legal to call this in the "detached" state. On return, the cursor is left in a "saved" state, so callers must still call restoreState to use this object.
Implements mongo::RecordCursor.
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inlinefinalvirtual |
Recovers from potential state changes in underlying data.
Returns false if it is invalid to continue using this iterator. This usually means that capped deletes have caught up to the position of this iterator and continuing could result in missed data.
If the former position no longer exists, but it is safe to continue iterating, the following call to next() will return the next closest position in the direction of the scan, if any.
This handles restoring after either save() or SeekableRecordCursor::saveUnpositioned().
Implements mongo::RecordCursor.
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inlinefinalvirtual |
Prepares for state changes in underlying data in a way that allows the cursor's current position to be restored.
It is safe to call save multiple times in a row. No other method (excluding destructor) may be called until successfully restored.
Implements mongo::RecordCursor.
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inlinefinalvirtual |
Seeks to a Record with the provided id.
If an exact match can't be found, boost::none will be returned and the resulting position of the cursor is unspecified.
Implements mongo::SeekableRecordCursor.
1.8.13