shared_file.cpp

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/*****************************************************************************
** Cross Platform Functionality
*****************************************************************************/
// Only because there is only ofile_pos support so far.

#include <ecl/config/ecl.hpp>

/*****************************************************************************
** Includes
*****************************************************************************/

#include <iostream>
#include <map>
#include <string>
#include <ecl/errors/handlers.hpp>
#include <ecl/exceptions/standard_exception.hpp>
#include <ecl/exceptions/macros.hpp>
#include "../../include/ecl/devices/shared_file.hpp"

/*****************************************************************************
** Namespaces
*****************************************************************************/

namespace ecl {
namespace devices {

/****************************************************************************
** Using
*****************************************************************************/

using std::string;
using ecl::WriteMode;
using ecl::CloseError;
using ecl::StandardException;
using ecl::Mutex;

/*****************************************************************************
** Implementation [SharedFileCommon]
*****************************************************************************/

SharedFileCommon::SharedFileCommon(const std::string &name, ecl::WriteMode mode) :
        count(1),
        error_handler(NoError)
{
        ecl_try {
                if ( !file.open(name,mode) ) {
                        error_handler = file.error();
                }
        } ecl_catch( StandardException &e ) {
                error_handler = file.error();
                ecl_throw(StandardException(LOC,e));
        }
}

/*****************************************************************************
** Static Variable Initialisation [SharedFileManager]
*****************************************************************************/

Mutex SharedFileManager::mutex;
std::map<string,SharedFileCommon*> SharedFileManager::opened_files;

/*****************************************************************************
** Implementation [SharedFileManager]
*****************************************************************************/

SharedFileCommon* SharedFileManager::RegisterSharedFile(const std::string& name, ecl::WriteMode mode) {

        mutex.lock();
        std::map<std::string,SharedFileCommon*>::iterator iter = opened_files.find(name);
        SharedFileCommon* shared_instance;
        if ( iter != opened_files.end() ) {
        /******************************************
        ** File exists - do not open
        *******************************************/
        iter->second->count += 1;
        shared_instance = iter->second;
    } else {
        /******************************************
        ** File does not exist - open it
        *******************************************/
        ecl_try {
                shared_instance = new SharedFileCommon(name,mode);
                opened_files.insert(std::pair<string,SharedFileCommon*>(name,shared_instance));
        } ecl_catch ( StandardException &e ) {
                shared_instance = NULL;
                ecl_throw(StandardException(LOC,e));
        }
    }
    mutex.unlock();
    return shared_instance;
}
bool SharedFileManager::DeRegisterSharedFile(const std::string& name) {

        mutex.lock();
        std::map<std::string,SharedFileCommon*>::iterator iter = opened_files.find(name);

        if ( iter == opened_files.end() ) {
                ecl_throw(StandardException(LOC,CloseError,"The specified shared object file could not be closed - was not found."));
                return false;
        }
    if ( iter->second->count == 1 ) {
        delete iter->second;
        opened_files.erase(iter);
    } else {
        iter->second->count -= 1;
    }
    mutex.unlock();
    return true;
}

}; // namespace Interfaces

/*****************************************************************************
** Using
*****************************************************************************/

using std::string;

/*****************************************************************************
** Implementation [SharedFile]
*****************************************************************************/

SharedFile::SharedFile(const std::string &name, WriteMode mode) :
        shared_instance(NULL)
{
        ecl_try {
                open(name,mode);
        } ecl_catch( StandardException &e ) {
                ecl_throw(StandardException(LOC,e));
        }
}

SharedFile::~SharedFile() {
        ecl_try {
                devices::SharedFileManager::DeRegisterSharedFile( shared_instance->file.filename() );
        } ecl_catch( StandardException &e ) {
                // Never throw from a destructor!
                // use some other mechanism!!!
                // throw StandardException(LOC,e);
        }
}

bool SharedFile::open(const std::string &name, WriteMode mode) {
        ecl_try {
                shared_instance = devices::SharedFileManager::RegisterSharedFile(name,mode);
                if ( shared_instance == NULL ) {
                        shared_instance->error_handler = OpenError;
                        return false;
                } else {
                        shared_instance->error_handler = NoError;
                        return true;
                }
        } ecl_catch ( StandardException &e ) {
                shared_instance->error_handler = OpenError;
                ecl_throw(StandardException(LOC,e));
        }
}

long SharedFile::write(const char &c) {
        long n = buffer.append(c);
        if ( buffer.full() ) {
                if ( !flush() ) {
                        return -1;
                }
        }
        return n;
}

long SharedFile::write(const char* s, unsigned long n) {
        unsigned int no_written = 0;
        while ( no_written < n ) {
                no_written += buffer.append(s+no_written,n-no_written);
                if ( buffer.full() ) {
                        if ( !flush() ) {
                                return -1;
                        }
                }
        }
        return n;
}

bool SharedFile::flush() {
        long written;
        ecl_debug_try {
                written = shared_instance->file.write(buffer.c_ptr(), buffer.size() );
        } ecl_debug_catch(const StandardException &e) {
                shared_instance->error_handler = shared_instance->file.error();
                ecl_debug_throw(StandardException(LOC,e));
        }
        buffer.clear();
        // fallback for no exceptions
        shared_instance->error_handler = shared_instance->file.error();
        if ( written > 0 ) {
                return true;
        } else {
                return false;
        }
}


}; // namespace ecl