#include <XrdSsiShMat.hh>

Inheritance diagram for XrdSsiShMat:

Classes
struct	CRZParms

struct	NewParms

Public Member Functions
virtual bool	AddItem (void newdata, void olddata, const char *key, int hash=0, bool replace=false)=0

virtual bool	Attach (int tout, bool isrw=false)=0

virtual bool	Create (CRZParms &parms)=0

virtual bool	Export ()=0

virtual bool	DelItem (void data, const char key, int hash=0)=0

virtual void	Detach ()=0
	Detach the map from the shared memory.

virtual bool	Enumerate (void &jar, char &key, void *&val)=0

virtual bool	Enumerate (void *&jar)=0

virtual int	Info (const char vname, char buff=0, int blen=0)=0

virtual bool	GetItem (void data, const char key, int hash=0)=0

virtual bool	Resize (CRZParms &parms)=0

virtual bool	Sync ()=0

virtual bool	Sync (bool dosync, bool syncdo=false)=0

virtual bool	Sync (int synqsz)=0

	XrdSsiShMat (NewParms &parms)
	Constructor (arguments the same as for New())

virtual	~XrdSsiShMat ()
	Destructor. Warning, your destructor should call your own Detach()!

Static Public Member Functions
static XrdSsiShMat *	New (NewParms &parms)

Protected Attributes
char *	shmImpl

char *	shmPath

char *	shmType

int	shmTypeSz

int	shmHash

Detailed Description

This class defines an abstract interface to a generic shared memory table that stores key-value pairs. Since this class a pure abstract any number of implementations may be supplied. The default one is named "XrdSsiShMam".

Constructor & Destructor Documentation

◆ XrdSsiShMat()

XrdSsiShMat::XrdSsiShMat ( NewParms & parms )

inline

Constructor (arguments the same as for New())

◆ ~XrdSsiShMat()

virtual XrdSsiShMat::~XrdSsiShMat ( )

inlinevirtual

Destructor. Warning, your destructor should call your own Detach()!

References shmImpl, shmPath, and shmType.

Member Function Documentation

◆ AddItem()

virtual bool XrdSsiShMat::AddItem	(	void *	newdata,
		void *	olddata,
		const char *	key,
		int	hash = `0`,
		bool	replace = `false`
	)

pure virtual

Add an item to the shared memory table.

Parameters

newdata	Pointer to the data to be added.
olddata	Pointer to the area where the replaced data, if any, is to be placed.
key	The key associated with the data that is to be added.
hash	The hash of the key that is to be used to lookup the key. If the value is zero, an internal hash is computed.
replace	When true, if the key exists, the data associated with the key is replaced. When false, if the key exists, the addition fails with errno set to EEXIST.

Returns: true The addition/replacement succeeded. If the key was actually replaced errno is set to EEXIST else it is set to 0.; false The addition/replacement failed; errno indicates reason.

Implemented in XrdSsiShMam.

◆ Attach()

virtual bool XrdSsiShMat::Attach	(	int	tout,
		bool	isrw = `false`
	)

pure virtual

Attach this object to the shared memory associated with this object at creation time (see New() method). The attach operation waits until the shared memory file is available. At that time, the file is memory mapped.

Parameters

tout	The maximum number of seconds to wait for the shared memory file to become available. If tout is zero, then the file must be immediately available. If the value is negative then the attach waits as long as needed. When tout is reached the attach fails with errno set to ETIMEDOUT.
isrw	When true the file is mapped to writable memory and allows updates to the table. If false, the shared memory is made read/only and may be significantly faster to access.

Returns: true - The shared memory was attached, the table can be used.; false - The shared memory could not be attached, errno holds reason.

Implemented in XrdSsiShMam.

◆ Create()

virtual bool XrdSsiShMat::Create ( CRZParms & parms )

pure virtual

Implemented in XrdSsiShMam.

◆ DelItem()

virtual bool XrdSsiShMat::DelItem	(	void *	data,
		const char *	key,
		int	hash = `0`
	)

pure virtual

Delete an item from the table.

Parameters

data	Pointer to the area to receive the value of the deleted key. If the pointer is nil, then the key value is not returned.
key	Pointer to the key of length <= MaxKLen.
hash	The hash of the key that is to be used to lookup the key. If the value is zero, an internal hash is computed.

Returns: true - The key and data have been deleted. This is always returned when data is nil.; false - The key and data either not deleted or the key does not exist and data was not nil. The errno value decribes why. Typical reason: the key was not found (errno == ENOENT).

Implemented in XrdSsiShMam.

◆ Detach()

virtual void XrdSsiShMat::Detach ( )

pure virtual

Detach the map from the shared memory.

Implemented in XrdSsiShMam.

◆ Enumerate() [1/2]

virtual bool XrdSsiShMat::Enumerate ( void *& jar )

pure virtual

Terminate an active enumeration. An active enumeration is any enumeration where the previous form of Enumerate() did not return false. Terminating an active enumeration releases all of the enumeration resources allocated.

Parameters

jar	The opaque cookie initialized by a previous call to Enumerate() requesting the next key-value pair.

Returns: true The enumeration has been terminated and the jar was deleted and the jar pointer is set to zero. Keys are returned in arbitrary order and not all keys may be returned if the map is being actively updated.; false The jar pointer was zero; no enumeration was active.

Implemented in XrdSsiShMam.

◆ Enumerate() [2/2]

virtual bool XrdSsiShMat::Enumerate	(	void *&	jar,
		char *&	key,
		void *&	val
	)

pure virtual

Enumerate the keys and assocaited values.

Parameters

jar	An opaque cookie that tracks progress. It should be initialized to zero and otherwise not touched. The same jar must be used for all successive calls. The jar is deleted when false is returned (also see the next Enumerate method).
key	The pointer variable where the location of the key is returned upon success.
val	The pointer variable where the location f the key values is to be returned upon success.

Returns: true A key and val pointers have been set. Keys are returned in arbitrary order and not all keys may be returned if the map is being actively updated.; false Key not returned; errno holds the reason. Typically, ENOENT there ae no more keys. Other errors may also be reflected. Whne false is returned the jar is deleted and the pointer to it set to zero.

Implemented in XrdSsiShMam.

◆ Export()

virtual bool XrdSsiShMat::Export ( )

pure virtual

Export a newly created table (i.e. see Create()).

Returns: true - The table has been exported and is now visible to others.; false - The export failed, the errno value describes the reason.

Implemented in XrdSsiShMam.

◆ GetItem()

virtual bool XrdSsiShMat::GetItem	(	void *	data,
		const char *	key,
		int	hash = `0`
	)

pure virtual

Get an item from the table.

Parameters

data	Pointer to an area to receive the value associated with key. If the pointer is nil, then the key value is not returned.
key	Pointer to the key of length <= MaxKLen.
hash	The hash of the key that is to be used to lookup the key. If the value is zero, an internal hash is computed.

Returns: true - The key was found and if data was not nil, contains the value associated key.; false - The key not found; errno holds the reason (typically is ENOENT but may be some other reason).

Implemented in XrdSsiShMam.

◆ Info()

virtual int XrdSsiShMat::Info	(	const char *	vname,
		char *	buff = `0`,
		int	blen = `0`
	)

pure virtual

Return information about the table.

Parameters

vname	Pointer to the variable name whose value is wanted. A particular implementation may not support all variable and may support variables not listed here. These are for the default implementation unless otherwise noted. They are: hash - name of hash being used. impl - The table implementation being used. indexsz - Number of index entries indexused - Number of index entries in use keys - Number of keys in the bale. keys/indexused is the hash table collision factor keysfree - Number of keys that can still be added maxkeylen - Longest allowed key multw - If table supports multiple writers, else 0 reuse - If table allows object reuse, else 0 type - Name of the data type in the table. typesz - The number of bytes in the table's data type
buff	- Pointer to the buffer to receive text values. Variables that return text are: hash, impl, and type. A buffer must be supplied in any of these variables are requested. If buff is nill or too small a -1 is returned with errno set to EMSGSIZE.
blen	The length of the buffer.

Returns: >=0 - The variable's value or the length of the text information.; < 0 - The variable's value could not be returned; errno has the error code describing the reason, typically ENOTSUP.

Implemented in XrdSsiShMam.

◆ New()

static XrdSsiShMat * XrdSsiShMat::New ( NewParms & parms )

static

◆ Resize()

virtual bool XrdSsiShMat::Resize ( CRZParms & parms )

pure virtual

Resize a shared memory segment and associated file specified at object instantiation (see New() method). Resizing is implementation specific but may involve creating a new table and exporting it.

Parameters

parms Resize parameters. See the CRZParms struct for details. For resize, zero values or unspecified flags use the existing table values.

Returns: true - The shared memory was resized, the table can be used.; false - The shared memory could not be resized, errno holds reason.

Implemented in XrdSsiShMam.

◆ Sync() [1/3]

virtual bool XrdSsiShMat::Sync ( )

pure virtual

Synchronize all modified pages to the associated backing file.

Returns: true - Operation completed successfully.; false - Operation failed; errno holds the error code explaining why.

Implemented in XrdSsiShMam.

◆ Sync() [2/3]

virtual bool XrdSsiShMat::Sync	(	bool	dosync,
		bool	syncdo = `false`
	)

pure virtual

Turn memry synchronization on or off.

Parameters

dosync	When true, modified table pages are written back to the backing file. The synchronous or async nature of the write is controlled by the second parameter. When false, memory-file synchronization is turned off (initial setting).
syncdo	When true, synchronization is done in the forground. That is, a call triggering a sync will not return until complete. When false, synchronization is done in the background.

Returns: true - Operation completed successfully.; false - Operation failed; errno holds the error code explaining why.

Implemented in XrdSsiShMam.

◆ Sync() [3/3]

virtual bool XrdSsiShMat::Sync ( int synqsz )

pure virtual

Set the sync defer queue size.

Parameters

synqsz The maximum number of modified pages before flushing.

Returns: true - Operation completed successfully.; false - Operation failed; errno holds the error code explaining why.

Implemented in XrdSsiShMam.

Member Data Documentation

◆ shmHash

int XrdSsiShMat::shmHash

protected

◆ shmImpl

char* XrdSsiShMat::shmImpl

protected

Referenced by ~XrdSsiShMat().

◆ shmPath

char* XrdSsiShMat::shmPath

protected

Referenced by ~XrdSsiShMat().

◆ shmType

char* XrdSsiShMat::shmType

protected

Referenced by ~XrdSsiShMat().

◆ shmTypeSz

int XrdSsiShMat::shmTypeSz

protected

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

XrdSsiShMat.hh

Classes

Public Member Functions

Static Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ XrdSsiShMat()

◆ ~XrdSsiShMat()

Member Function Documentation

◆ AddItem()

◆ Attach()

◆ Create()

◆ DelItem()

◆ Detach()

◆ Enumerate() [1/2]

◆ Enumerate() [2/2]

◆ Export()

◆ GetItem()

◆ Info()

◆ New()

◆ Resize()

◆ Sync() [1/3]

◆ Sync() [2/3]

◆ Sync() [3/3]

Member Data Documentation

◆ shmHash

◆ shmImpl

◆ shmPath

◆ shmType

◆ shmTypeSz