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XrdSysPlugin Class Reference

#include <XrdSysPlugin.hh>

Collaboration diagram for XrdSysPlugin:
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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. More...
 

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 ( )
staticprivate
static void* XrdSysPlugin::Find ( const char *  libname)
staticprivate
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
pnamethe plug-in extern "C" symbolic name
optionalwhen 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::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
pnamethe plug-in extern "C" symbolic name
optionalwhen 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.
globalwhen !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::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
XrdSysError* XrdSysPlugin::eDest
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
staticprivate

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