Wrappers for low-level POSIX I/O routines. More...

#include <config.h>
#include "io_utils.h"
#include "posixy_wrapper.h"
#include "safeunistd.h"
#include <cerrno>
#include <cstring>
#include <string>
#include <xapian/error.h>
#include "noreturn.h"
#include "omassert.h"
#include "str.h"

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Functions
bool	io_unlink (const std::string &filename)
	Delete a file. More...

int	io_open_block_wr (const char *fname, bool anew)
	Open a block-based file for writing. More...

size_t	io_read (int fd, char *p, size_t n, size_t min)
	Read n bytes (or until EOF) into block pointed to by p from file descriptor fd. More...

void	io_write (int fd, const char *p, size_t n)
	Write n bytes from block pointed to by p to file descriptor fd. More...

static void	throw_block_error (const char *s, off_t b, int e=0)

void	io_read_block (int fd, char *p, size_t n, off_t b, off_t o)
	Read block b size n bytes into buffer p from file descriptor fd, offset o. More...

void	io_write_block (int fd, const char *p, size_t n, off_t b, off_t o)
	Write block b size n bytes from buffer p to file descriptor fd, offset o. More...

bool	io_tmp_rename (const std::string &tmp_file, const std::string &real_file)
	Rename a temporary file to its final position. More...

Variables
const int	MIN_WRITE_FD = 3

Detailed Description

Wrappers for low-level POSIX I/O routines.

Definition in file io_utils.cc.

Function Documentation

◆ io_open_block_wr()

int io_open_block_wr	(	const char *	fname,
		bool	anew
	)

Open a block-based file for writing.

Parameters

fname	The path of the file to open.
anew	If true, open the file anew (create or truncate it).

Definition at line 67 of file io_utils.cc.

References Assert, close(), MIN_WRITE_FD, O_BINARY, O_CLOEXEC, and Xapian::InMemory::open().

Referenced by GlassTable::do_open_to_write(), ChertTable::do_open_to_write(), io_open_block_rd(), io_open_block_wr(), and test_ioblock1().

◆ io_read()

size_t io_read	(	int	fd,
		char *	p,
		size_t	n,
		size_t	min = `0`
	)

Read n bytes (or until EOF) into block pointed to by p from file descriptor fd.

If a read error occurs, throws DatabaseError.

If min is specified and EOF is reached after less than min bytes, throws DatabaseCorruptError.

Returns the number of bytes actually read.

Definition at line 123 of file io_utils.cc.

Referenced by ChertTableCheck::check(), GlassChanges::check(), GlassDatabase::get_changeset_revisions(), ChertDatabase::get_changeset_revisions(), io_full_sync(), ChertTable_base::read(), GlassVersion::read(), ChertVersion::read_and_check(), and test_if_single_file_db().

◆ io_read_block()

void io_read_block	(	int	fd,
		char *	p,
		size_t	n,
		off_t	b,
		off_t	o
	)

Read block b size n bytes into buffer p from file descriptor fd, offset o.

Definition at line 180 of file io_utils.cc.

References rare, throw_block_error(), and usual.

Referenced by io_readahead_block(), ChertTable::read_block(), GlassTable::read_block(), and test_ioblock1().

◆ io_tmp_rename()

bool io_tmp_rename	(	const std::string &	tmp_file,
		const std::string &	real_file
	)

Rename a temporary file to its final position.

Attempts to deal with NFS infelicities. If the rename fails, the temporary file is removed.

Returns: true if the rename succeeded; false if it failed (and errno will be set appropriately).

Definition at line 271 of file io_utils.cc.

References posixy_rename.

Referenced by GlassChanges::commit(), ChertTable::commit(), Xapian::Database::compact_(), io_write_block(), ChertDatabaseReplicator::process_changeset_chunk_base(), GlassDatabaseReplicator::process_changeset_chunk_version(), GlassVersion::sync(), and Xapian::DatabaseReplica::Internal::update_stub_database().

◆ io_unlink()

bool io_unlink ( const std::string & filename )

Delete a file.

Parameters

filename The file to delete.

Exceptions

Xapian::DatabaseError is thrown if filename existed but couldn't be unlinked.

Returns: true if filename was successfully removed; false if it didn't exist. If the file is on NFS, false may be returned even if the file was removed (if the server fails after removing the file but before telling the client, and the client then retries).

Definition at line 52 of file io_utils.cc.

References posixy_unlink.

Referenced by GlassChanges::commit(), ChertTable::create_and_open(), GlassTable::create_and_open(), ChertTable::erase(), io_write_block(), ChertDatabase::set_revision_number(), test_ioblock1(), ChertTable::write_block(), and GlassChanges::~GlassChanges().