esphome::api::APIOverflowBuffer Class Reference

Circular queue of heap-allocated byte buffers used as a TCP send backlog. More...

#include <api_overflow_buffer.h>

Data Structures
struct	Entry
	A single heap-allocated send-backlog entry. More...

Public Member Functions
	~APIOverflowBuffer ()
bool	empty () const
	True when no backlogged data is waiting.
bool	full () const
	True when the queue has no room for another entry.
uint8_t	count () const
	Number of entries currently queued.
ssize_t	try_drain (socket::Socket *socket)
	Try to drain queued data to the socket.
bool	enqueue_iov (const struct iovec *iov, int iovcnt, uint16_t total_len, uint16_t skip)
	Enqueue unsent IOV data into the backlog.

Protected Attributes
std::array< Entry *, API_MAX_SEND_QUEUE >	queue_ {}
uint8_t	head_ {0}
uint8_t	tail_ {0}
uint8_t	count_ {0}

Detailed Description

Circular queue of heap-allocated byte buffers used as a TCP send backlog.

Under normal operation this buffer is never used — data goes straight from the frame helper to the socket. It only fills when the LWIP TCP send buffer is full (slow client, congested network, heavy logging). The queue drains automatically on subsequent write/loop calls once the socket becomes writable again.

Capacity is compile-time-fixed via API_MAX_SEND_QUEUE (set from Python config). If the queue fills completely the connection is marked failed.

Definition at line 25 of file api_overflow_buffer.h.

Constructor & Destructor Documentation

~APIOverflowBuffer()

esphome::api::APIOverflowBuffer::~APIOverflowBuffer

(

)

Definition at line 7 of file api_overflow_buffer.cpp.

Member Function Documentation

count()

uint8_t esphome::api::APIOverflowBuffer::count ( ) const

inline

Number of entries currently queued.

Definition at line 53 of file api_overflow_buffer.h.

empty()

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

inline

True when no backlogged data is waiting.

Definition at line 47 of file api_overflow_buffer.h.

enqueue_iov()

bool esphome::api::APIOverflowBuffer::enqueue_iov	(	const struct iovec *	iov,
		int	iovcnt,
		uint16_t	total_len,
		uint16_t	skip )

Enqueue unsent IOV data into the backlog.

Copies iov data starting at byte offset skip into a new entry. Returns false if the queue is full (caller should fail the connection).

Definition at line 42 of file api_overflow_buffer.cpp.

full()

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

inline

True when the queue has no room for another entry.

Definition at line 50 of file api_overflow_buffer.h.

try_drain()

ssize_t esphome::api::APIOverflowBuffer::try_drain

(

socket::Socket *

socket

)

Try to drain queued data to the socket.

Returns bytes-written > 0 on success/partial, 0 if all drained or no progress, -1 on error (caller must check errno to distinguish EWOULDBLOCK from hard errors). Callers only need to act on -1; 0 and positive values both mean "no error". Frees entries as they are fully sent.

Definition at line 14 of file api_overflow_buffer.cpp.

Field Documentation

count_

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

protected

Definition at line 71 of file api_overflow_buffer.h.

head_

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

protected

Definition at line 69 of file api_overflow_buffer.h.

queue_

std::array<Entry *, API_MAX_SEND_QUEUE> esphome::api::APIOverflowBuffer::queue_ {}

protected

Definition at line 68 of file api_overflow_buffer.h.

tail_

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

protected

Definition at line 70 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