/// <summary>
/// Check whether the provided <paramref name="filePath"/> points to a valid file. If the specified file exists,
/// while OverwriteExisting and AppendExisting are both false, an exception will be thrown.
/// </summary>
/// <param name="filePath">The path of the specified file for writing</param>
/// <param name="settings">The OverwriteExisting and AppendExisting properties will be used for checking the file specified</param>
protected static void CheckFilePath(String filePath, CsvWriterSettings settings)
{
settings = settings ?? new CsvWriterSettings();
if (String.IsNullOrEmpty(filePath))
{
throw new ArgumentException("Parameter is not valid", "filePath");
}
if (File.Exists(filePath) && !settings.OverwriteExisting && !settings.AppendExisting)
{
throw new Exception(String.Format("The specified file {0} already exists", filePath));
}
if (settings.OverwriteExisting && settings.AppendExisting)
{
throw new ArgumentException("Overwrite and Append cannot both be true.");
}
var parentFolder = Path.GetDirectoryName(filePath);
if (!Directory.Exists(parentFolder))
{
throw new FileNotFoundException("Cannot find specified folder", filePath);
}
}
/// <summary>
/// Initialize the current CsvWriter instance with provided information
/// </summary>
/// <param name="stream">A writable stream to which current writer will write data</param>
/// <param name="settings">Configurable options customizing current CsvWriter instance</param>
/// <param name="dataResolver">A customer data resolver converting objects to raw CSV values</param>
protected CsvWriter(Stream stream, CsvWriterSettings settings, IDataResolver <T> dataResolver)
{
this.mDataResolver = dataResolver;
this.mCsvSettings = settings = settings ?? new CsvWriterSettings();
EnsureParameters(stream, settings, dataResolver);
settings.BufferSize = Math.Min(BUFFER_SZMAX, Math.Max(settings.BufferSize, BUFFER_SZMIN));
mNeedQuoteChars = new Char[] { '\r', '\n', '\"', settings.Seperator };
this.mWriter = new StreamWriter(stream, settings.Encoding, settings.BufferSize);
if (stream.CanSeek)
{
if (settings.AppendExisting)
{
stream.Seek(0, SeekOrigin.End);
}
if (settings.OverwriteExisting)
{
stream.SetLength(0);
}
}
}
private static void EnsureParameters(Stream stream, CsvWriterSettings settings, IDataResolver <T> dataResolver)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
if (!stream.CanWrite)
{
throw new ArgumentException("stream is not writable", "stream");
}
if (settings.Encoding == null)
{
throw new ArgumentNullException("settings.Encoding");
}
if (dataResolver == null)
{
throw new ArgumentNullException("dataResolver");
}
}
/// <summary>
/// Create an instance of CsvWriter with a specified writable stream, a CsvWriterSettings object and a custom data resolver.
/// </summary>
/// <param name="stream">A writable strem to be written into.</param>
/// <param name="settings">Specify the options to control behavior of CsvWriter.</param>
/// <param name="dataResolver">A custom data resolver used to serialize and deserialize data.</param>
/// <returns>A CsvWriter instance.</returns>
public static CsvWriter <T> Create(Stream stream, CsvWriterSettings settings, IDataResolver <T> dataResolver)
{
return(new CsvWriter <T>(stream, settings, dataResolver));
}
/// <summary>
/// Create an instance of CsvWriter with a specified file path, a CsvWriterSettings object and a custom data resolver.
/// If the path already exists and AppendExisting and OverwriteExisting of settings are both false, an exception will be thrown.
/// </summary>
/// <param name="filePath">The path of the CSV file to be written.</param>
/// <param name="settings">Specify the options to control behavior of CsvWriter.</param>
/// <param name="dataResolver">A custom data resolver used to serialize and deserialize data.</param>
/// <returns>A CsvWriter instance.</returns>
public static CsvWriter <T> Create(String filePath, CsvWriterSettings settings, IDataResolver <T> dataResolver)
{
CheckFilePath(filePath, settings);
return(Create(File.OpenWrite(filePath), settings, dataResolver));
}
