source: trunk/FACT++/src/DimDescriptionService.cc@ 10492

// **************************************************************************
/** @class DimDescriptionService

@brief A DimService which broadcasts descriptions for services and commands

The DimDescriptionService creates a service with the name of the server like
SERVER/SERVICE_DESC. This is meant in addition to the SERVICE_LIST service
of each node to contain a description of the service and its arguments.

Assume you have created a service (or command) with the format I:2;F:1
a valid description string would look like

   Description|int[addr]:Address range (from - to)|val[byte]:Value to be set

Description is a general description of the command or service itself,
int and val are the names of the arguments (e.g. names of FITS columns),
addr and byte have the meaning of a unit (e.g. unit of FITS column)
and the text after the colon is a description of the arguments
(e.g. comment of a FITS column). The description must not contain a
line-break character \n.

You can omit either the name, the unit or the comment or any combination of them.
The descriptions of the individual format strings are separated by a vertical line.

The description should contain as many descriptions as format chunks, e.g.

I:1          should contain one description chunks
I:1;F:1      should contain two description chunks
I:2;F:1      should contain two description chunks
I:2;I:1;F:1  should contain three description chunks

*/
// **************************************************************************
#include "DimDescriptionService.h"

#include <stdexcept>

#include "dis.hxx"

using namespace std;

DimService *DimDescriptionService::fService = 0;
int         DimDescriptionService::fCount   = 0;
std::string DimDescriptionService::fData    = "";

// --------------------------------------------------------------------------
//
//! When the constructor is first called, a service with the name
//! SERVER/SERVICE_DESC is created. The server name SERVER is retrieved
//! from DimServer::itsName. If DimServer::itsName is empty, the
//! server name is extracted from the given name as the part before the
//! first '/'. A string "name=format\n" is added to fData and stored
//! in fDescription.
//!
//! A counter fCount for the number of instantiations is increased.
//!
//! @param name
//!     The name of the service or command to be described, e.g. SERVER/COMMAND
//!
//! @param desc
//!     A description string. For details see class reference
//!
//! @throws
//!     If a server name couldn't be reliably determined a logic_error
//!     exception is thrown; if the given description contains a '\n'
//!     also a logic_error is thrown.
//
DimDescriptionService::DimDescriptionService(const std::string &name, const std::string &desc)
{
    string server = DimServer::itsName;
    if (server.empty())
    {
        const size_t p = name.find_first_of('/');
        if (p==string::npos)
            throw logic_error("Could not determine server name");

        server = name.substr(0, p);
    }

    if (desc.find_first_of('\n')!=string::npos)
            throw logic_error("Description for "+name+" contains '\\n'");

    if (!fService)
    {
        fService = new DimService((server+"/SERVICE_DESC").c_str(), const_cast<char*>(""));
        fData =
            server + "/SERVICE_DESC"
            "=This service holds a descriptions for services or command "
            "and there arguments|Description[string]:For a detailed "
            "explanation of the descriptive string see the class reference "
            "of DimDescriptionService.\n" +
            server + "/CLIENT_LIST"
            "=This is a native Dim service. It contains a list "
            "of all clients currently connected.\n" +
            server + "/VERSION_NUMBER"
            "=This is a native Dim service. It contains the version number "
            "of Dim in use and can be used to check if a client is connected."
            "|DimVer[int]:Version*100+Release (e.g. V19r17 = 1917)\n" +
            server + "/EXIT"
            "=This is a native Dim service. It allows to exit the program "
            "remotely. FACT++ programs use the given number as return code."
            "|Rc[int]:Return code (42 will call exit() directly, 0x4242 will call abort() directly.\n" +
            server + "/SERVICE_LIST"
            "=This is a native Dim service. It provides a list of all "
            "commands and services together with their formats currently "
            "provided by the server."
            "|ServiceList[string]:For details see the Dim manual.\n";
    }


    fCount++;

    fDescription = name + '=' + desc;

    if (fData.find(fDescription+'\n')!=std::string::npos)
        return;

    fData += fDescription + '\n';

    fService->setData(const_cast<char*>(fData.c_str()));
    fService->updateService();
}


// --------------------------------------------------------------------------
//
//! If fDescription is found in fData it is removed from fData.
//! The counter fCount is decreased and fService deleted if the counter
//! reached 0.
//
DimDescriptionService::~DimDescriptionService()
{
    const size_t pos = fData.find(fDescription+'\n');
    if (pos!=std::string::npos)
        fData.replace(pos, fDescription.size()+1, "");

    if (--fCount>0)
        return;

    delete fService;
    fService=0;
}