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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/messagebus/trace.h>
namespace storage {
class MemoryBoundedTrace {
public:
MemoryBoundedTrace(size_t softMemoryUpperBound);
/**
* Attempt to append the given trace node to the internal trace tree.
* If the amount of memory currently being used exceeds that of the upper
* bound used when constructing `this`, the node will not be added to
* the tree. Note that this only takes place on the granularity of full
* trees; either the entire trace tree given by `node` is added or nothing
* at all. This means it's possible to exceed the upper bound if the node
* is sufficiently large when added before memory has hit the limit; only
* subsequent adds will fail.
*
* Returns true if `node` was added to internal trace state, false
* otherwise.
*/
bool add(const mbus::TraceNode& node);
bool add(mbus::Trace && trace);
/**
* Append current trace tree to the output trace node and clear internal
* tree in the process. In the case that at least 1 node has been
* omitted due to memory bounds being exceeded, the trace will contain a
* node at its end detailing the number of traces and bytes that have been
* omitted from the output.
*
* If current trace is empty, no nodes are added to `out`.
*/
void moveTraceTo(mbus::Trace& out);
size_t getApproxMemoryUsed() const noexcept {
return _currentMemoryUsed;
}
private:
mbus::Trace _trace;
size_t _currentMemoryUsed;
size_t _omittedNodes;
size_t _omittedBytes;
size_t _softMemoryUpperBound;
};
} // storage
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