/// <summary>
/// Aggregates all the supplied FILES into THE FIRST file (marking it as a PERMA file) using the supplied combineF
/// action to merge all the individual files into 1 combined output file.
/// </summary>
/// <remarks>
/// The first file is renamed to the resultFileNameTemplate, marked as a PERMA file and updated in place on the
/// file system. This is more efficient because we do not make a copy of the first file, we rename the first file and
/// UPDATE IT IN PLACE. This results in less file IO, which improves performance for large files.
/// </remarks>
/// <param name="files">The sequence of files to combine into 1 file.</param>
/// <param name="resultFileNameTemplate">The template string to use for the name of the combined file.</param>
/// <param name="combineF">
/// Action to combine 2 files into 1.
/// combineF :: (accumulator: TempFile, inputFile: TempFile) -> unit.
/// </param>
/// <returns>A TempFile instance for the new combined file.</returns>
public TempFile AggregateFilesIntoFirstAsPerma(IEnumerable <TempFile> files, string resultFileNameTemplate, Action <TempFile, TempFile> combineF)
{
if (files.IsEmpty())
{
TempFile accumulatorFile = NewPermaFile(resultFileNameTemplate);
accumulatorFile.CreateIfNotExists();
return(accumulatorFile);
}
if (files.Count() == 1)
{
TempFile accumulatorFile = files.Single();
accumulatorFile.Rename(resultFileNameTemplate);
accumulatorFile.MakePermanent();
return(accumulatorFile);
}
{
TempFile accumulatorFile = files.First();
accumulatorFile.Rename(resultFileNameTemplate);
accumulatorFile.MakePermanent();
files.Skip(1).Each(file => combineF(accumulatorFile, file));
return(accumulatorFile);
}
}
/// <summary>
/// Creates a new TempFile object, relative to this TempDir, using the supplied fileNameTemplate. Files created
/// with this method will NOT be deleted when calling the ClearTempFiles() method.
///
/// NOTE: This does NOT actually create the file on the file system.
/// </summary>
/// <param name="fileNameTemplate">
/// A template string that is used to determine the name of the new TempFile.
/// It can have 1 of 3 possible values:
/// (1.) Empty - a fully random name will be generated that is unique within the TempDir.
/// (2.) "temp_file_{0}.tmp" - a semi random name will be generated, replacing the {0} placeholder with some random, unique value.
/// (3.) "my_temp_file" - an exact, non-random name that will always be the same.
/// </param>
public TempFile NewPermaFile(string fileNameTemplate = "")
{
string fileName = TempUtils.GenerateFsEntryName(DirPath, fileNameTemplate);
var permaFile = new TempFile(this, fileName);
permaFile.MakePermanent();
// keep track of temp files so that we can selectively clean them up later
_files.Add(permaFile);
return(permaFile);
}