esphome::api::APIOverflowBuffer Class Reference

TCP send backlog, only used when the socket send buffer is full. More...

#include <api_overflow_buffer.h>

Public Member Functions
bool	empty () const
	True when no backlogged data is waiting.
ssize_t	try_drain (socket::Socket *socket)
	Drain queued messages to the socket.
bool	enqueue_iov (const struct iovec *iov, int iovcnt, size_t total_len, size_t skip)
	Queue iov data from byte offset skip as one message.
void	release ()
	Free the retained storage, now if empty, otherwise once it has drained.

Static Protected Member Functions
static constexpr size_t	reserve_for (size_t want)

Protected Attributes
APIBuffer	buf_
uint16_t	head_ {0}
uint8_t	count_ {0}
bool	draining_: 1 {false}
bool	release_when_drained_: 1 {false}

Static Protected Attributes
static constexpr size_t	LEN_PREFIX = 2
static constexpr size_t	BYTES_PER_SLOT = 2048
static constexpr size_t	GROW_QUANTUM = 256
static constexpr size_t	MAX_LONE_BYTES = APIBuffer::MAX_SIZE & ~(GROW_QUANTUM - 1)
static constexpr size_t	MAX_BYTES = std::min(API_MAX_SEND_QUEUE * BYTES_PER_SLOT, MAX_LONE_BYTES)

Detailed Description

TCP send backlog, only used when the socket send buffer is full.

One contiguous buffer per connection, allocated on the first stall and kept at its high-water mark so a lossy link does not churn the heap. Messages are stored as a 2 byte length prefix plus payload. API_MAX_SEND_QUEUE bounds queued messages and, at 2 KB per slot, queued bytes; exceeding either fails the connection.

Definition at line 22 of file api_overflow_buffer.h.

Member Function Documentation

empty()

bool esphome::api::APIOverflowBuffer::empty ( ) const

inline

True when no backlogged data is waiting.

Definition at line 25 of file api_overflow_buffer.h.

enqueue_iov()

bool esphome::api::APIOverflowBuffer::enqueue_iov	(	const struct iovec *	iov,
		int	iovcnt,
		size_t	total_len,
		size_t	skip )

Queue iov data from byte offset skip as one message.

Returns false when a limit is hit, allocation fails, or storage would move during a drain; the caller should fail the connection.

Definition at line 48 of file api_overflow_buffer.cpp.

release()

void esphome::api::APIOverflowBuffer::release ( )

inline

Free the retained storage, now if empty, otherwise once it has drained.

Definition at line 38 of file api_overflow_buffer.h.

reserve_for()

static constexpr size_t esphome::api::APIOverflowBuffer::reserve_for ( size_t want )

inlinestaticconstexprprotected

Definition at line 54 of file api_overflow_buffer.h.

try_drain()

ssize_t esphome::api::APIOverflowBuffer::try_drain

(

socket::Socket *

socket

)

Drain queued messages to the socket.

Returns bytes written, 0 for a re-entrant call, -1 on error (check errno for EWOULDBLOCK); callers only need to act on -1.

Definition at line 7 of file api_overflow_buffer.cpp.

Field Documentation

buf_

APIBuffer esphome::api::APIOverflowBuffer::buf_

protected

Definition at line 56 of file api_overflow_buffer.h.

BYTES_PER_SLOT

size_t esphome::api::APIOverflowBuffer::BYTES_PER_SLOT = 2048

staticconstexprprotected

Definition at line 48 of file api_overflow_buffer.h.

count_

uint8_t esphome::api::APIOverflowBuffer::count_ {0}

protected

Definition at line 58 of file api_overflow_buffer.h.

draining_

bool esphome::api::APIOverflowBuffer::draining_

protected

Definition at line 61 of file api_overflow_buffer.h.

GROW_QUANTUM

size_t esphome::api::APIOverflowBuffer::GROW_QUANTUM = 256

staticconstexprprotected

Definition at line 50 of file api_overflow_buffer.h.

head_

uint16_t esphome::api::APIOverflowBuffer::head_ {0}

protected

Definition at line 57 of file api_overflow_buffer.h.

LEN_PREFIX

size_t esphome::api::APIOverflowBuffer::LEN_PREFIX = 2

staticconstexprprotected

Definition at line 47 of file api_overflow_buffer.h.

MAX_BYTES

size_t esphome::api::APIOverflowBuffer::MAX_BYTES = std::min(API_MAX_SEND_QUEUE * BYTES_PER_SLOT, MAX_LONE_BYTES)

staticconstexprprotected

Definition at line 53 of file api_overflow_buffer.h.

MAX_LONE_BYTES

size_t esphome::api::APIOverflowBuffer::MAX_LONE_BYTES = APIBuffer::MAX_SIZE & ~(GROW_QUANTUM - 1)

staticconstexprprotected

Definition at line 52 of file api_overflow_buffer.h.

release_when_drained_

bool esphome::api::APIOverflowBuffer::release_when_drained_

protected

Definition at line 62 of file api_overflow_buffer.h.

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

• esphome/components/api/api_overflow_buffer.h
• esphome/components/api/api_overflow_buffer.cpp