/// <summary>
/// Parses <paramref name="format"/> into a <see cref="FileContentInfo"/> object.
///
/// The value must correspond to the format defined by the <see cref="Render"/> method
/// or <see cref="ContractException"/> is thrown.
/// </summary>
public static FileContentInfo Parse(string format)
{
Contract.Requires(format != null);
string[] splits = format.Split(new[] { RenderSeparator }, StringSplitOptions.None);
if (splits.Length != 2)
{
throw Contract.AssertFailure(I($"Invalid format: expected '{RenderSeparator}' to divide '{format}' into exactly 2 parts."));
}
ContentHash hash;
if (!ContentHash.TryParse(splits[0], out hash))
{
throw Contract.AssertFailure(I($"Invalid ContentHash format: '{splits[0]}'"));
}
long lengthAndExistence;
if (!long.TryParse(splits[1], out lengthAndExistence))
{
throw Contract.AssertFailure(I($"Invalid file length format: '{splits[1]}'"));
}
return(new FileContentInfo(hash, LengthAndExistence.Deserialize(lengthAndExistence)));
}
/// <summary>
/// Creates a <see cref="FileContentInfo"/> with real USN version information.
/// </summary>
public FileContentInfo(ContentHash hash, long length)
{
Contract.Requires(length >= 0);
m_lengthAndExistence = new LengthAndExistence(
length,
// if the length is valid, assign the existence value
IsValidLength(length, hash)
? PathExistence.ExistsAsFile
: (PathExistence?)null);
Hash = hash;
}
/// <summary>
/// Creates a <see cref="FileContentInfo"/> using a combined existence/length value.
/// </summary>
/// <remarks>
/// Mainly used for deserialization and files with unknown length.
/// </remarks>
public FileContentInfo(ContentHash hash, LengthAndExistence lengthAndExistence)
{
m_lengthAndExistence = lengthAndExistence;
Hash = hash;
}
