This is an in-memory, hierarchical key-value store. More...

#include <Tree.h>

Public Member Functions
	Tree ()
	Constructor.
void	dumpSnapshot (Core::ProtoBuf::OutputStream &stream) const
	Write the tree to the given stream.
void	loadSnapshot (Core::ProtoBuf::InputStream &stream)
	Load the tree from the given stream.
Result	checkCondition (const std::string &path, const std::string &contents) const
	Verify that the file at path has the given contents.
Result	makeDirectory (const std::string &path)
	Make sure a directory exists at the given path.
Result	listDirectory (const std::string &path, std::vector< std::string > &children) const
	List the contents of a directory.
Result	removeDirectory (const std::string &path)
	Make sure a directory does not exist.
Result	write (const std::string &path, const std::string &contents)
	Set the value of a file.
Result	read (const std::string &path, std::string &contents) const
	Get the value of a file.
Result	removeFile (const std::string &path)
	Make sure a file does not exist.
void	updateServerStats (Protocol::ServerStats_Tree &tstats) const
	Add metrics about the tree to the given structure.
Private Member Functions
Result	normalLookup (const Internal::Path &path, Internal::Directory **parent)
	Resolve the final next-to-last component of the given path (the target's parent).
Result	normalLookup (const Internal::Path &path, const Internal::Directory **parent) const
	Resolve the final next-to-last component of the given path (the target's parent) -- const version.
Result	mkdirLookup (const Internal::Path &path, Internal::Directory **parent)
	Like normalLookup but creates parent directories as necessary.
Private Attributes
Internal::Directory	superRoot
	This directory contains the root directory.
uint64_t	numConditionsChecked
uint64_t	numConditionsFailed
uint64_t	numMakeDirectoryAttempted
uint64_t	numMakeDirectorySuccess
uint64_t	numListDirectoryAttempted
uint64_t	numListDirectorySuccess
uint64_t	numRemoveDirectoryAttempted
uint64_t	numRemoveDirectoryParentNotFound
uint64_t	numRemoveDirectoryTargetNotFound
uint64_t	numRemoveDirectoryDone
uint64_t	numRemoveDirectorySuccess
uint64_t	numWriteAttempted
uint64_t	numWriteSuccess
uint64_t	numReadAttempted
uint64_t	numReadSuccess
uint64_t	numRemoveFileAttempted
uint64_t	numRemoveFileParentNotFound
uint64_t	numRemoveFileTargetNotFound
uint64_t	numRemoveFileDone
uint64_t	numRemoveFileSuccess

Detailed Description

This is an in-memory, hierarchical key-value store.

TODO(ongaro): Document how this fits into the rest of the system.

Definition at line 287 of file Tree.h.

Constructor & Destructor Documentation

LogCabin::Tree::Tree::Tree ( )

Constructor.

Definition at line 280 of file Tree.cc.

Member Function Documentation

void LogCabin::Tree::Tree::dumpSnapshot ( Core::ProtoBuf::OutputStream & stream ) const

Write the tree to the given stream.

Definition at line 365 of file Tree.cc.

void LogCabin::Tree::Tree::loadSnapshot ( Core::ProtoBuf::InputStream & stream )

Load the tree from the given stream.

Warning:: This will blow away any existing files and directories.

Definition at line 374 of file Tree.cc.

Result LogCabin::Tree::Tree::checkCondition	(	const std::string &	path,
		const std::string &	contents
	)		const

Verify that the file at path has the given contents.

Parameters:

path	The path to the file that must have the contents specified in 'contents'.
contents	The contents that the file specified by 'path' should have for an OK response. An OK response is also returned if 'contents' is the empty string and the file specified by 'path' does not exist.

Returns:

Status and error message. Possible errors are:

CONDITION_NOT_MET upon any error.

Definition at line 382 of file Tree.cc.

Result LogCabin::Tree::Tree::makeDirectory ( const std::string & path )

Make sure a directory exists at the given path.

Create parent directories listed in path as necessary.

Parameters:

path	The path where there should be a directory after this call.

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path exists but is a file.

Definition at line 415 of file Tree.cc.

Result LogCabin::Tree::Tree::listDirectory	(	const std::string &	path,
		std::vector< std::string > &	children
	)		const

List the contents of a directory.

Parameters:

	path	The directory whose direct children to list.
[out]	children	This will be replaced by a listing of the names of the directories and files that the directory at 'path' immediately contains. The names of directories in this listing will have a trailing slash. The order is first directories (sorted lexicographically), then files (sorted lexicographically).

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
LOOKUP_ERROR if a parent of path does not exist.
LOOKUP_ERROR if path does not exist.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path exists but is a file.

Definition at line 436 of file Tree.cc.

Result LogCabin::Tree::Tree::removeDirectory ( const std::string & path )

Make sure a directory does not exist.

Also removes all direct and indirect children of the directory.

If called with the root directory, this will remove all descendants but not actually remove the root directory; it will still return status OK.

Parameters:

path	The path where there should not be a directory after this call.

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path exists but is a file.

Definition at line 467 of file Tree.cc.

Result LogCabin::Tree::Tree::write	(	const std::string &	path,
		const std::string &	contents
	)

Set the value of a file.

Parameters:

path	The path where there should be a file with the given contents after this call.
contents	The new value associated with the file.

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
INVALID_ARGUMENT if contents are too large to fit in a file.
LOOKUP_ERROR if a parent of path does not exist.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path exists but is a directory.

Definition at line 510 of file Tree.cc.

Result LogCabin::Tree::Tree::read	(	const std::string &	path,
		std::string &	contents
	)		const

Get the value of a file.

Parameters:

path	The path of the file whose contents to read.
contents	The current value associated with the file.

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
LOOKUP_ERROR if a parent of path does not exist.
LOOKUP_ERROR if path does not exist.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path is a directory.

Definition at line 533 of file Tree.cc.

Result LogCabin::Tree::Tree::removeFile ( const std::string & path )

Make sure a file does not exist.

Parameters:

path	The path where there should not be a file after this call.

Returns:

Status and error message. Possible errors are:

INVALID_ARGUMENT if path is malformed.
TYPE_ERROR if a parent of path is a file.
TYPE_ERROR if path exists but is a directory.

Definition at line 563 of file Tree.cc.

void LogCabin::Tree::Tree::updateServerStats ( Protocol::ServerStats_Tree & tstats ) const

Add metrics about the tree to the given structure.

Definition at line 594 of file Tree.cc.

Result LogCabin::Tree::Tree::normalLookup	(	const Internal::Path &	path,
		Internal::Directory **	parent
	)		`[private]`

Resolve the final next-to-last component of the given path (the target's parent).

Parameters:

[in]	path	The path whose parent directory to find.
[out]	parent	Upon successful return, points to the target's parent directory.

Returns:

Status and error message. Possible errors are:

LOOKUP_ERROR if a parent of path does not exist.
TYPE_ERROR if a parent of path is a file.

Definition at line 309 of file Tree.cc.

Result LogCabin::Tree::Tree::normalLookup	(	const Internal::Path &	path,
		const Internal::Directory **	parent
	)		const `[private]`

Resolve the final next-to-last component of the given path (the target's parent) -- const version.

Parameters:

[in]	path	The path whose parent directory to find.
[out]	parent	Upon successful return, points to the target's parent directory.

Returns:

Status and error message. Possible errors are:

LOOKUP_ERROR if a parent of path does not exist.
TYPE_ERROR if a parent of path is a file.

Definition at line 316 of file Tree.cc.

Result LogCabin::Tree::Tree::mkdirLookup	(	const Internal::Path &	path,
		Internal::Directory **	parent
	)		`[private]`

Like normalLookup but creates parent directories as necessary.

Parameters:

[in]	path	The path whose parent directory to find.
[out]	parent	Upon successful return, points to the target's parent directory.

Returns:

Status and error message. Possible errors are:

TYPE_ERROR if a parent of path is a file.

Definition at line 344 of file Tree.cc.

Member Data Documentation

Internal::Directory LogCabin::Tree::Tree::superRoot [private]

This directory contains the root directory.

The super root has a single child directory named "root", and the rest of the tree lies below "root". This is just an implementation detail; this class prepends "/root" to every path provided by the caller.

This removes a lot of special-case branches because every operation now has a name of a target within a parent directory -- even those operating on the root directory.

Definition at line 480 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numConditionsChecked [mutable, private]

Definition at line 485 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numConditionsFailed [mutable, private]

Definition at line 486 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numMakeDirectoryAttempted [private]

Definition at line 487 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numMakeDirectorySuccess [private]

Definition at line 488 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numListDirectoryAttempted [mutable, private]

Definition at line 489 of file Tree.h.

uint64_t LogCabin::Tree::Tree::numListDirectorySuccess [mutable, private]