XrdSysPlugin Class Reference

#include <XrdSysPlugin.hh>

Collaboration diagram for XrdSysPlugin:
Collaboration graph
[legend]

List of all members.

Classes

struct  PLlist

Public Member Functions

void * getPlugin (const char *pname, int optional=0)
void * getPlugin (const char *pname, int optional, bool global)
void * Persist ()
 XrdSysPlugin (XrdSysError *erp, const char *path)
 XrdSysPlugin (XrdSysError *erp, const char *path, const char *lname, XrdVersionInfo *vinf=0, int msgNum=-1)
 XrdSysPlugin (char *ebuff, int eblen, const char *path, const char *lname, XrdVersionInfo *vinf=0, int msgNum=-1)
 ~XrdSysPlugin ()
 Destructor.

Static Public Member Functions

static bool Preload (const char *path, char *ebuff=0, int eblen=0)
static bool VerCmp (XrdVersionInfo &vInf1, XrdVersionInfo &vInf2, bool noMsg=false)

Private Types

enum  cvResult {
  cvBad = 0, cvNone, cvMissing, cvClean,
  cvDirty
}

Private Member Functions

cvResult badVersion (XrdVersionInfo &urInfo, char mmv, int majv, int minv)
cvResult chkVersion (XrdVersionInfo &urInfo, const char *pname, void *lh)
void Inform (const char *txt1, const char *txt2=0, const char *txt3=0, const char *txt4=0, const char *txt5=0, int noHush=0)
cvResult libMsg (const char *txt1, const char *txt2, const char *mSym=0)
const char * msgSuffix (const char *Word, char *buff, int bsz)

Static Private Member Functions

static int DLflags ()
static void * Find (const char *libname)

Private Attributes

XrdSysErroreDest
const char * libName
char * libPath
void * libHandle
XrdVersionInfo * myInfo
char * eBuff
int eBLen
int msgCnt

Static Private Attributes

static PLlistplList

Detailed Description

Handy class to load run-time plugins and optionally check if the version is compatible with the caller's version number. Version numbers are defined as "aaa.bb.cc" where aaa is a decimnal major version, bb is a decimal minor version, and cc is the decimal patch version number. Only the major and, optionally, minor version numbers are checked. The checking rules are defined in XrdVersion.hh and are rather liberal in nature. In order to check versions, the plugin versioning rule must be defined in XrdVersion.hh and constructor #2 or #3 must be used. The symbolic name of the plugin's version information is the plugin symbol being looked up appended with "Version" and must be defined as an XrdVersionInfo structure.


Member Enumeration Documentation

enum XrdSysPlugin::cvResult [private]
Enumerator:
cvBad 
cvNone 
cvMissing 
cvClean 
cvDirty 

Constructor & Destructor Documentation

XrdSysPlugin::XrdSysPlugin ( XrdSysError erp,
const char *  path 
) [inline]

Constructor #1 (version number checking is not to be performed)

Parameters:
erp -> error message object to display error messages.
path -> path to the shared library containing a plug-in. If NULL the the executable image is searched for the plug-in. Storage must persist while this object is alive.
XrdSysPlugin::XrdSysPlugin ( XrdSysError erp,
const char *  path,
const char *  lname,
XrdVersionInfo *  vinf = 0,
int  msgNum = -1 
) [inline]

Constructor #2 (version number checking may be performed)

Parameters:
erp -> error message object to display error messages.
path -> path to the shared library containing a plug-in. If NULL the the executable image is searched for the plug-in. Storage must persist while this object is alive.
lname -> logical name of the plugin library (e.g. osslib) to be used in any error messages. Storage must persist while this object is alive.
vinf -> permanent version information of the plug-in loader. If zero, then no version checking is performed.
msgNum -> Number of times getPlugin() is to produce a version message for a loaded plugin. The default is always.
XrdSysPlugin::XrdSysPlugin ( char *  ebuff,
int  eblen,
const char *  path,
const char *  lname,
XrdVersionInfo *  vinf = 0,
int  msgNum = -1 
) [inline]

Constructor #3 (version number checking may be performed and any error is returned in a supplied buffer)

Parameters:
ebuff -> buffer where eror message is to be placed. The mesage will always end with a null byte.
eblen -> length of the supplied buffer, eBuff.
path -> path to the shared library containing a plug-in. If NULL the the executable image is searched for the plug-in. Storage must persist while this object is alive.
lname -> logical name of the plugin library (e.g. osslib) to be used in any error messages. Storage must persist while this object is alive.
vinf -> permanent version information of the plug-in loader. If Zero, then no version checking is performed.
msgNum -> Number of times getPlugin() is to produce a version message for a loaded plugin. The default is always.
XrdSysPlugin::~XrdSysPlugin (  ) 

Destructor.


Member Function Documentation

cvResult XrdSysPlugin::badVersion ( XrdVersionInfo &  urInfo,
char  mmv,
int  majv,
int  minv 
) [private]
cvResult XrdSysPlugin::chkVersion ( XrdVersionInfo &  urInfo,
const char *  pname,
void *  lh 
) [private]
static int XrdSysPlugin::DLflags (  )  [static, private]
static void* XrdSysPlugin::Find ( const char *  libname  )  [static, private]
void* XrdSysPlugin::getPlugin ( const char *  pname,
int  optional,
bool  global 
)

Get the address of a plugin from a shared library, opening the plug-in shared library if not already open and optionally make the symbols global.

Parameters:
pname the plug-in extern "C" symbolic name
optional when 0 then issue error message when symbol isn't found. Otherwise, the mising symbol is treated as an error. When optional is greater than 1, the load message is suppressed.
global when !0 then the symbols defined in the plug-in shared library are made available for symbol resolution of subsequently loaded libraries.
Returns:
Success: the address of the symbol in the shared library/executable. The address becomes invalid when this object is deleted unless Persist() is called prior to deletion. Failure: Null
void* XrdSysPlugin::getPlugin ( const char *  pname,
int  optional = 0 
)

Get the address of a plugin from a shared library, opening the plug-in shared library if not already open. Symbols in the library are local.

Parameters:
pname the plug-in extern "C" symbolic name
optional when 0 then issue error message when symbol isn't found. Otherwise, the mising symbol is treated as an error.
Returns:
Success: the address of the symbol in the shared library/executable. The address becomes invalid when this object is deleted unless Persist() is called prior to deletion. Failure: Null
void XrdSysPlugin::Inform ( const char *  txt1,
const char *  txt2 = 0,
const char *  txt3 = 0,
const char *  txt4 = 0,
const char *  txt5 = 0,
int  noHush = 0 
) [private]
cvResult XrdSysPlugin::libMsg ( const char *  txt1,
const char *  txt2,
const char *  mSym = 0 
) [private]
const char* XrdSysPlugin::msgSuffix ( const char *  Word,
char *  buff,
int  bsz 
) [private]
void* XrdSysPlugin::Persist (  )  [inline]

Make library persistent even when the plugin object is deleted. Note that if getPlugin() is called afterwards, the library will be re-opened!

Returns:
pointer to the opened shared library.

References libHandle.

static bool XrdSysPlugin::Preload ( const char *  path,
char *  ebuff = 0,
int  eblen = 0 
) [static]

Preload a shared library. This method is meant for those threading models that require libraries to be opened in the main thread (e.g. MacOS). This method is meant to be called before therads start and is not thread-safe.

Parameters:
path -> to the library path, typically this should just be the library filename so that LD_LIBRARY_PATH is used to discover the directory path. This allows getPlugin() to properly match preloaded libraries.
ebuff -> buffer where eror message is to be placed. The mesage will always end with a null byte. If no error buffer is supplied, any error messages are discarded.
eblen -> length of the supplied buffer, eBuff.
Returns:
True The library was preloaded. False The library could not be preloaded, ebuff, if supplied, contains the error message text.
static bool XrdSysPlugin::VerCmp ( XrdVersionInfo &  vInf1,
XrdVersionInfo &  vInf2,
bool  noMsg = false 
) [static]

Compare two versions for compatability, optionally printing a warning.

Parameters:
vInf1 -> Version information for source.
vInf2 -> Version information for target.
noMsg -> If true, no error messages are written to stderr.
Returns:
True if versions are compatible (i.e. major and minor versions are identical as required for locally linked code); false otherwise.

Member Data Documentation

int XrdSysPlugin::eBLen [private]
char* XrdSysPlugin::eBuff [private]
void* XrdSysPlugin::libHandle [private]

Referenced by Persist().

const char* XrdSysPlugin::libName [private]
char* XrdSysPlugin::libPath [private]
int XrdSysPlugin::msgCnt [private]
XrdVersionInfo* XrdSysPlugin::myInfo [private]
PLlist* XrdSysPlugin::plList [static, private]

The documentation for this class was generated from the following file:
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Generated on 22 Feb 2019 for xrootd by  doxygen 1.6.1