XrdOucCache2 Class Reference

#include <XrdOucCache2.hh>

Inheritance diagram for XrdOucCache2:
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Collaboration diagram for XrdOucCache2:
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List of all members.

Public Types

enum  LFP_Reason { ForAccess = 0, ForInfo, ForPath }

Public Member Functions

virtual XrdOucCacheIO2Attach (XrdOucCacheIO2 *ioP, int opts=0)=0
virtual XrdOucCacheIOAttach (XrdOucCacheIO *ioP, int opts=0)
virtual XrdOucCacheCreate (Parms &Params, XrdOucCacheIO::aprParms *aprP=0)
virtual void EnvInfo (XrdOucEnv &theEnv)
virtual int LocalFilePath (const char *url, char *buff=0, int blen=0, LFP_Reason why=ForAccess)
virtual int Prepare (const char *url, int oflags, mode_t mode)
virtual int Stat (const char *url, struct stat &sbuff)
 XrdOucCache2 ()
virtual ~XrdOucCache2 ()

Detailed Description

The XrdOucCache2 class is used to define a version 2 cache. In version 2, there can be only one such instance. the cache is associated with one or more XrdOucCacheIO2 objects. Use the Attach() method in this class to create such associations.


Member Enumeration Documentation

Get the path to a file that is complete in the local cache. By default, the file must be complete in the cache (i.e. no blocks are missing). This can be overridden. Thes path can be used to access the file on the local node.

Parameters:
url - Pointer to the url of interest.
buff - Pointer to a buffer to receive the local path to the file. If nil, no path is returned.
blen - Length of the buffer, buff. If zero, no path is returned.
why - One of the LFP_Reason enums describing the call: ForAccess - the path will be used to access the file. If the file is complete, the system will delay purging the file for a configurable window, should a purge be imminent. A null path is returned for any non-zero return code. ForInfo - same as ForAccess except that purging will not be delayed if imminent. A path is always returned, if possible. Otherwise the first byte of any supplied buffer is set to 0. ForPath - Only the path is wanted and no checks need be performed. The only possible errors are -EINVAL and -ENAMETOOLONG.
Returns:
0 - the file is complete and the local path to the file is in the buffer, if it has been supllied.
<0 - the request could not be fulfilled. The return value is -errno describing why. If a buffer was supplied and a path could be generated it is returned only if "why" is ForInfo or ForPath. Otherwise, a null path is returned.

Common return codes are: -EINVAL an argument is invalid. -EISDIR target is a directory not a file. -ENAMETOOLONG buffer not big enough to hold path. -ENOENT file not in cache -ENOTSUP method not implemented -EREMOTE file is incomplete

Returns:
>0 - Reserved for future use.
Enumerator:
ForAccess 
ForInfo 
ForPath 

Constructor & Destructor Documentation

XrdOucCache2::XrdOucCache2 (  )  [inline]
virtual XrdOucCache2::~XrdOucCache2 (  )  [inline, virtual]

Member Function Documentation

virtual XrdOucCacheIO* XrdOucCache2::Attach ( XrdOucCacheIO ioP,
int  opts = 0 
) [inline, virtual]

Implements XrdOucCache.

virtual XrdOucCacheIO2* XrdOucCache2::Attach ( XrdOucCacheIO2 ioP,
int  opts = 0 
) [pure virtual]

Implemented in XrdFileCache::Cache, and XrdPosixCacheBC.

virtual XrdOucCache* XrdOucCache2::Create ( Parms Params,
XrdOucCacheIO::aprParms aprP = 0 
) [inline, virtual]

Creates an instance of a version 1 cache. This method is no longer used so we simply define a default for this method here for backward compatability.

Returns:
A pointer to an XrdOucCache object upon success or a nil pointer with errno set upon failure.

Implements XrdOucCache.

virtual void XrdOucCache2::EnvInfo ( XrdOucEnv theEnv  )  [inline, virtual]

Supply environmental information to the cache for optimization. This is only called server-side but is optional and might not be called. The environmental information should only be used for optimizations. When called, it is gauranteed to occur before any active use of the cache and is essentially serialized (i.e. the main start-up thread is used).

Parameters:
theEnv - Reference to environmental information.

Reimplemented in XrdFileCache::Cache.

virtual int XrdOucCache2::LocalFilePath ( const char *  url,
char *  buff = 0,
int  blen = 0,
LFP_Reason  why = ForAccess 
) [inline, virtual]

Reimplemented in XrdFileCache::Cache.

virtual int XrdOucCache2::Prepare ( const char *  url,
int  oflags,
mode_t  mode 
) [inline, virtual]

Prepare the cache for a file open request. This method is called prior to actually opening a file. This method is meant to allow defering an open request or implementing the full I/O stack in the cache layer.

Parameters:
url - Pointer to the url about to be opened.
oflags - Standard Unix open flags (see open(2)).
mode - Standard mode flags if file is being created.
Returns:
<0 Error has occurred, return value is -errno; fail open request. The error code -EUSERS may be returned to trigger overload recovery as specified by the xrootd.fsoverload directive. No other method should return this error code. =0 Continue with open() request. >0 Defer open but treat the file as actually being open. Use the XrdOucCacheIO2::Open() method to open the file at a later time.

Reimplemented in XrdFileCache::Cache.

virtual int XrdOucCache2::Stat ( const char *  url,
struct stat &  sbuff 
) [inline, virtual]

Perform a stat() operation (defaults to passthrough).

Parameters:
url pointer to the url whose stat information is wanted.
sbuff reference to the stat buffer to be filled in. Only fields st_size, st_blocks, st_mtime (st_atime and st_ctime may be set to st_mtime), st_ino, and st_mode need to be set. All other fields are preset and should not be changed.
Returns:
<0 - Stat failed, value is -errno. =0 - Stat succeeded, sbuff holds stat information. >0 - Stat could not be done, forward operation to next level.

Reimplemented in XrdFileCache::Cache.


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