signet::forge::WalWriter Class Reference

Append-only Write-Ahead Log writer with CRC-32 integrity per record. More...

#include <wal.hpp>

Public Types
using	Options = WalWriterOptions
	Alias for the options struct.

Public Member Functions
	WalWriter (const WalWriter &)=delete
WalWriter &	operator= (const WalWriter &)=delete
	WalWriter (WalWriter &&o) noexcept
WalWriter &	operator= (WalWriter &&)=delete
	~WalWriter ()
expected< int64_t >	append (const uint8_t *data, size_t size)
	Append a raw-byte record to the WAL.
expected< int64_t >	append (const std::vector< uint8_t > &data)
	Append a record from a byte vector.
expected< int64_t >	append (const char *data, size_t size)
	Append a record from a char pointer.
expected< int64_t >	append (std::string_view sv)
	Append a record from a string_view.
expected< void >	flush (bool do_fsync=false)
	Flush the stdio buffer to the OS page cache.
expected< void >	close ()
	Seal the WAL file: flush buffered data, fsync, and close the file handle.
bool	is_open () const noexcept
	True if the writer is open and accepting appends.
int64_t	next_seq () const noexcept
	The sequence number that will be assigned to the next appended record.
const std::string &	path () const noexcept
	Filesystem path of the WAL file.
int64_t	bytes_written () const noexcept
	Total bytes written to this WAL file (header + all records).
uint64_t	rejected_empty_count () const noexcept
	Number of empty records rejected (CWE-754).

Static Public Member Functions
static expected< WalWriter >	open (const std::string &path, Options opts={})
	Open or create a WAL file for appending.

Detailed Description

Append-only Write-Ahead Log writer with CRC-32 integrity per record.

Each record is written as: [magic(4)][seq(8)][ts_ns(8)][size(4)][data(N)][crc32(4)]. Thread-safe: all public methods acquire an internal mutex.

Non-copyable, move-constructible. Use WalWriter::open() to create.

See also

WalReader, WalManager, WalWriterOptions

Definition at line 236 of file wal.hpp.

Member Typedef Documentation

Options

using signet::forge::WalWriter::Options = WalWriterOptions

Alias for the options struct.

Definition at line 239 of file wal.hpp.

Constructor & Destructor Documentation

WalWriter() [1/2]

signet::forge::WalWriter::WalWriter ( const WalWriter &  )

delete

WalWriter() [2/2]

signet::forge::WalWriter::WalWriter ( WalWriter &&  o )

inlinenoexcept

Definition at line 244 of file wal.hpp.

~WalWriter()

signet::forge::WalWriter::~WalWriter ( )

inline

Definition at line 259 of file wal.hpp.

Member Function Documentation

append() [1/4]

expected< int64_t > signet::forge::WalWriter::append ( const char *  data, size_t  size  )

inline

Append a record from a char pointer.

Parameters

data	Record payload bytes (reinterpreted as uint8_t).
size	Number of bytes.

Returns

Sequence number assigned, or Error on failure.

Definition at line 477 of file wal.hpp.

append() [2/4]

expected< int64_t > signet::forge::WalWriter::append ( const std::vector< uint8_t > &  data )

inline

Append a record from a byte vector.

Parameters

data	Record payload bytes.

Returns

Sequence number assigned, or Error on failure.

Definition at line 469 of file wal.hpp.

append() [3/4]

expected< int64_t > signet::forge::WalWriter::append ( const uint8_t *  data, size_t  size  )

inline

Append a raw-byte record to the WAL.

Writes a complete record (header + payload + CRC-32) atomically under the internal mutex. If sync_on_append is enabled, fsyncs after each write.

Parameters

data	Pointer to the record payload bytes.
size	Number of payload bytes (must be > 0 and <= UINT32_MAX).

Returns

The sequence number assigned to this record, or Error on failure.

Definition at line 397 of file wal.hpp.

append() [4/4]

expected< int64_t > signet::forge::WalWriter::append ( std::string_view  sv )

inline

Append a record from a string_view.

Parameters

sv	Record payload.

Returns

Sequence number assigned, or Error on failure.

Definition at line 484 of file wal.hpp.

bytes_written()

int64_t signet::forge::WalWriter::bytes_written ( ) const

inlinenoexcept

Total bytes written to this WAL file (header + all records).

Definition at line 534 of file wal.hpp.

close()

expected< void > signet::forge::WalWriter::close ( )

inline

Seal the WAL file: flush buffered data, fsync, and close the file handle.

Returns

Error on I/O failure.

Definition at line 510 of file wal.hpp.

flush()

expected< void > signet::forge::WalWriter::flush ( bool  do_fsync = false )

inline

Flush the stdio buffer to the OS page cache.

If do_fsync is true (or sync_on_flush is enabled in Options), also performs a durable fsync to storage media.

Parameters

do_fsync

Force an fsync regardless of Options.

Returns

Error on I/O failure.

Definition at line 495 of file wal.hpp.

is_open()

bool signet::forge::WalWriter::is_open ( ) const

inlinenoexcept

True if the writer is open and accepting appends.

Definition at line 528 of file wal.hpp.

next_seq()

int64_t signet::forge::WalWriter::next_seq ( ) const

inlinenoexcept

The sequence number that will be assigned to the next appended record.

Definition at line 530 of file wal.hpp.

open()

static expected< WalWriter > signet::forge::WalWriter::open ( const std::string &  path, Options  opts = {}  )

inlinestatic

Open or create a WAL file for appending.

If the file already exists, it is scanned to determine the next sequence number so appends continue without gaps. The file header is written only when the file is first created (empty).

Parameters

path	Filesystem path to the WAL file.
opts	Writer options (sync policy, buffer size, start sequence).

Returns

WalWriter on success, Error on I/O failure.

Definition at line 270 of file wal.hpp.

operator=() [1/2]

WalWriter & signet::forge::WalWriter::operator= ( const WalWriter &  )

delete

operator=() [2/2]

WalWriter & signet::forge::WalWriter::operator= ( WalWriter &&  )

delete

path()

const std::string & signet::forge::WalWriter::path ( ) const

inlinenoexcept

Filesystem path of the WAL file.

Definition at line 532 of file wal.hpp.

rejected_empty_count()

uint64_t signet::forge::WalWriter::rejected_empty_count ( ) const

inlinenoexcept

Number of empty records rejected (CWE-754).

Definition at line 536 of file wal.hpp.

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

• include/signet/ai/wal.hpp