TODO(ongaro): docs. More...

#include <SimpleFileLog.h>

Inheritance diagram for LogCabin::Storage::SimpleFileLog:

Classes
class	Sync
Public Types
typedef Protocol::Raft::Entry	Entry
	The type of a log entry (the same format that's used in AppendEntries).
Public Member Functions
	SimpleFileLog (const Storage::FilesystemUtil::File &parentDir)
	~SimpleFileLog ()
std::pair< uint64_t, uint64_t >	append (const std::vector< const Entry * > &entries)
	Start to append new entries to the log.
std::string	getName () const
	Return the name of the log implementation as it would be specified in the config file.
std::unique_ptr< Log::Sync >	takeSync ()
	Get and remove the Log's Sync object in order to wait on it.
void	truncatePrefix (uint64_t firstEntryId)
	Delete the log entries before the given index.
void	truncateSuffix (uint64_t lastEntryId)
	Delete the log entries past the given index.
const Entry &	getEntry (uint64_t) const
	Look up an entry by its log index.
uint64_t	getLogStartIndex () const
	Get the index of the first entry in the log (whether or not this entry exists).
uint64_t	getLastLogIndex () const
	Get the index of the most recent entry in the log.
uint64_t	getSizeBytes () const
	Get the size of the entire log in bytes.
void	updateMetadata ()
	Call this after changing metadata.
Protected Member Functions
Storage::FilesystemUtil::File	updateMetadataCallerSync ()
std::string	readMetadata (const std::string &filename, SimpleFileLogMetadata::Metadata &metadata) const
std::vector< uint64_t >	getEntryIds () const
Entry	read (const std::string &entryPath) const
Protected Attributes
MemoryLog	memoryLog
SimpleFileLogMetadata::Metadata	metadata
	Opaque metadata that the log keeps track of.
Storage::FilesystemUtil::File	dir
Storage::FilesystemUtil::File	lostAndFound
std::unique_ptr< Sync >	currentSync

Detailed Description

TODO(ongaro): docs.

Definition at line 37 of file SimpleFileLog.h.

Member Typedef Documentation

typedef Protocol::Raft::Entry LogCabin::Storage::SimpleFileLog::Entry

The type of a log entry (the same format that's used in AppendEntries).

Reimplemented from LogCabin::Storage::Log.

Definition at line 50 of file SimpleFileLog.h.

Constructor & Destructor Documentation

LogCabin::Storage::SimpleFileLog::SimpleFileLog ( const Storage::FilesystemUtil::File & parentDir ) [explicit]

Definition at line 146 of file SimpleFileLog.cc.

LogCabin::Storage::SimpleFileLog::~SimpleFileLog ( )

Definition at line 219 of file SimpleFileLog.cc.

Member Function Documentation

std::pair< uint64_t, uint64_t > LogCabin::Storage::SimpleFileLog::append ( const std::vector< const Entry * > & entries ) [virtual]

Start to append new entries to the log.

The entries may not be on disk yet when this returns; see Sync.

Parameters:

entries Entries to place at the end of the log.

Returns:: Range of indexes of the new entries in the log, inclusive.

Implements LogCabin::Storage::Log.

Definition at line 226 of file SimpleFileLog.cc.

std::string LogCabin::Storage::SimpleFileLog::getName ( ) const [virtual]

Return the name of the log implementation as it would be specified in the config file.

Implements LogCabin::Storage::Log.

Definition at line 243 of file SimpleFileLog.cc.

std::unique_ptr< Log::Sync > LogCabin::Storage::SimpleFileLog::takeSync ( ) [virtual]

Get and remove the Log's Sync object in order to wait on it.

This Sync object must later be returned to the Log with syncComplete().

While takeSync() and syncComplete() may not be done concurrently with other Log operations, Sync::wait() may be done concurrently with all operations except truncateSuffix().

Implements LogCabin::Storage::Log.

Definition at line 249 of file SimpleFileLog.cc.

void LogCabin::Storage::SimpleFileLog::truncatePrefix ( uint64_t firstIndex ) [virtual]

Delete the log entries before the given index.

Once you truncate a prefix from the log, there's no way to undo this. The entries may still be on disk when this returns and file descriptors and other resources may remain open; see Sync.

Parameters:

firstIndex After this call, the log will contain no entries indexed less than firstIndex. This can be any log index, including 0 and those past the end of the log.

Implements LogCabin::Storage::Log.

Definition at line 257 of file SimpleFileLog.cc.

void LogCabin::Storage::SimpleFileLog::truncateSuffix ( uint64_t lastIndex ) [virtual]

Delete the log entries past the given index.

This will not affect the log start index.

Parameters:

lastIndex After this call, the log will contain no entries indexed greater than lastIndex. This can be any log index, including 0 and those past the end of the log.

Warning:: Callers should wait() on all Sync object prior to calling truncateSuffix(). This never happens on leaders, so it's not a real limitation, but things may go wonky otherwise.

Implements LogCabin::Storage::Log.

Definition at line 269 of file SimpleFileLog.cc.

const SimpleFileLog::Entry & LogCabin::Storage::SimpleFileLog::getEntry ( uint64_t index ) const [virtual]

Look up an entry by its log index.

Parameters:

index Must be in the range [getLogStartIndex(), getLastLogIndex()]. Otherwise, this will crash the server.

Returns:: The entry corresponding to that index. This reference is only guaranteed to be valid until the next time the log is modified.

Implements LogCabin::Storage::Log.

Definition at line 281 of file SimpleFileLog.cc.

uint64_t LogCabin::Storage::SimpleFileLog::getLogStartIndex ( ) const [virtual]

Get the index of the first entry in the log (whether or not this entry exists).

Returns:: 1 for logs that have never had truncatePrefix called, otherwise the largest index passed to truncatePrefix.

Implements LogCabin::Storage::Log.

Definition at line 287 of file SimpleFileLog.cc.

uint64_t LogCabin::Storage::SimpleFileLog::getLastLogIndex ( ) const [virtual]

Get the index of the most recent entry in the log.

Returns:: The index of the most recent entry in the log, or getLogStartIndex() - 1 if the log is empty.

Implements LogCabin::Storage::Log.

Definition at line 293 of file SimpleFileLog.cc.

uint64_t LogCabin::Storage::SimpleFileLog::getSizeBytes ( ) const [virtual]

Get the size of the entire log in bytes.

Implements LogCabin::Storage::Log.

Definition at line 299 of file SimpleFileLog.cc.

void LogCabin::Storage::SimpleFileLog::updateMetadata ( ) [virtual]

Call this after changing metadata.

Implements LogCabin::Storage::Log.

Definition at line 305 of file SimpleFileLog.cc.

FilesystemUtil::File LogCabin::Storage::SimpleFileLog::updateMetadataCallerSync ( ) [protected]

Definition at line 314 of file SimpleFileLog.cc.

std::string LogCabin::Storage::SimpleFileLog::readMetadata	(	const std::string &	filename,
		SimpleFileLogMetadata::Metadata &	metadata
	)		const `[protected]`