ReadFileHandle.cpp

#include "ReadFileHandle.h"
 
#include "FileManager.h"
#include "Exceptions/FileDoesNotExistException.h"
 
using namespace std;
 
namespace file_manager
{
    ReadFileHandle::ReadOnlyBuffer::ReadOnlyBuffer(string_view view)
    {
        char* data = const_cast<char*>(view.data());
 
        setg(data, data, data + view.size());
    }
 
    ReadFileHandle::ReadFileHandle(const filesystem::path& filePath, ios_base::openmode mode) :
        FileHandle(filePath, mode | ios_base::in)
    {
        Cache& cache = FileManager::getInstance().getCache();
 
        if (cache.contains(filePath))
        {
            buffer = make_unique<ReadOnlyBuffer>(cache.getCacheData(filePath));
 
            static_cast<iostream&>(file).rdbuf(buffer.get());
        }
    }
 
    const string& ReadFileHandle::readAllData()
    {
        Cache& cache = FileManager::getInstance().getCache();
 
        switch (cache.addCache(filePath, mode))
        {
        case Cache::CacheResultCodes::noError:
            return cache.getCacheData(filePath);
 
        case Cache::CacheResultCodes::fileDoesNotExist:
            throw exceptions::FileDoesNotExistException(filePath);
 
        case Cache::CacheResultCodes::notEnoughCacheSize:
            data = (ostringstream() << file.rdbuf()).str();
        }
 
        return data;
    }
 
    streamsize ReadFileHandle::readSome(string& outData, streamsize count, bool shrinkOutData, bool resizeOutData)
    {
        if (resizeOutData && outData.size() != count)
        {
            outData.resize(count);
        }
 
        streamsize result = file.read(outData.data(), count).gcount();
 
        if (shrinkOutData && outData.size() != result)
        {
            outData.resize(result);
        }
 
        return result;
    }
 
    istream& ReadFileHandle::getStream()
    {
        return file.read(nullptr, 0);
    }
 
    ReadFileHandle::~ReadFileHandle()
    {
        if (isNotifyOnDestruction)
        {
            FileManager::getInstance().decreaseReadRequests(filePath);
        }
    }
}