ripple::NodeStore::EncodedBlob Class Reference

Convert a NodeObject from in-memory to database format. More...

#include <EncodedBlob.h>

Collaboration diagram for ripple::NodeStore::EncodedBlob:

Public Member Functions
	EncodedBlob (std::shared_ptr< NodeObject > const &obj)
	~EncodedBlob ()
void const *	getKey () const noexcept
std::size_t	getSize () const noexcept
void const *	getData () const noexcept

Private Attributes
std::array< std::uint8_t, 32 >	key_
	The 32-byte key of the serialized object.
std::array< std::uint8_t, boost::alignment::align_up(9+1024, alignof(std::uint32_t))>	payload_
	A pre-allocated buffer for the serialized object.
std::uint32_t	size_
	The size of the serialized data.
std::uint8_t *const	ptr_
	A pointer to the serialized data.

Detailed Description

Convert a NodeObject from in-memory to database format.

The (suboptimal) database format consists of:

• 8 prefix bytes which will typically be 0, but don't assume that's the case; earlier versions of the code would use these bytes to store the ledger index either once or twice.
• A single byte denoting the type of the object.
• The payload.

Note

This class is typically instantiated on the stack, so the size of the object does not matter as much as it normally would since the allocation is, effectively, free.

We leverage that fact to preallocate enough memory to handle most payloads as part of this object, eliminating the need for dynamic allocation. As of this writing ~94% of objects require fewer than 1024 payload bytes.

Definition at line 36 of file EncodedBlob.h.

Constructor & Destructor Documentation

EncodedBlob()

ripple::NodeStore::EncodedBlob::EncodedBlob ( std::shared_ptr< NodeObject > const &  obj )

explicit

Definition at line 63 of file EncodedBlob.h.

~EncodedBlob()

ripple::NodeStore::EncodedBlob::~EncodedBlob

(

)

Definition at line 85 of file EncodedBlob.h.

Member Function Documentation

getKey()

void const * ripple::NodeStore::EncodedBlob::getKey ( ) const

noexcept

Definition at line 98 of file EncodedBlob.h.

getSize()

std::size_t ripple::NodeStore::EncodedBlob::getSize ( ) const

noexcept

Definition at line 104 of file EncodedBlob.h.

getData()

void const * ripple::NodeStore::EncodedBlob::getData ( ) const

noexcept

Definition at line 110 of file EncodedBlob.h.

Member Data Documentation

key_

std::array<std::uint8_t, 32> ripple::NodeStore::EncodedBlob::key_

private

The 32-byte key of the serialized object.

Definition at line 39 of file EncodedBlob.h.

payload_

std::array< std::uint8_t, boost::alignment::align_up(9 + 1024, alignof(std::uint32_t))> ripple::NodeStore::EncodedBlob::payload_

private

A pre-allocated buffer for the serialized object.

The buffer is large enough for the 9 byte prefix and at least 1024 more bytes. The precise size is calculated automatically at compile time so as to avoid wasting space on padding bytes.

Definition at line 50 of file EncodedBlob.h.

size_

std::uint32_t ripple::NodeStore::EncodedBlob::size_

private

The size of the serialized data.

Definition at line 53 of file EncodedBlob.h.

ptr_

std::uint8_t* const ripple::NodeStore::EncodedBlob::ptr_

private

A pointer to the serialized data.

This may point to the pre-allocated buffer (if it is sufficiently large) or to a dynamically allocated buffer.

Definition at line 60 of file EncodedBlob.h.