/// <summary>
///
/// </summary>
/// <param name="OldVHD"></param>
/// <param name="NewVHD"></param>
/// <param name="Output">Filename to the output file. Method will fail if this already exists unless Force is passed as 'true'.</param>
/// <param name="OutputType">A <see cref="VMProvisioningAgent.DiffVHD.DiskType"/> which specifies the output file format.</param>
/// <param name="Force">If true, will overwrite the Output file if it already exists. Defaults to 'false'.</param>
/// <param name="Partition">An int tuple which declares a specific pair of partitions to compare. The first value in the tuple will be the 0-indexed partition number from OldVHD to compare against. The second value of the tuple will be the 0-indexed parition from NewVHD to compare with.</param>
/// <param name="Style"></param>
/// <returns></returns>
internal static void CreateDiff(string OldVHD, string NewVHD, string Output, DiskType OutputType = DiskType.VHD, bool Force = false, Tuple <int, int> Partition = null, ComparisonStyle Style = ComparisonStyle.DateTimeOnly)
{
if (File.Exists(Output) && !Force)
{
throw new ArgumentException("Output file already exists.", "Output");
}
if (!File.Exists(OldVHD))
{
throw new ArgumentException("Input file does not exist.", "OldVHD");
}
if (!File.Exists(NewVHD))
{
throw new ArgumentException("Input file does not exist.", "NewVHD");
}
// byte[] CopyBuffer = new byte[1024*1024];
VirtualDisk Old, New, Out;
Old = VirtualDisk.OpenDisk(OldVHD, FileAccess.Read);
New = VirtualDisk.OpenDisk(NewVHD, FileAccess.Read);
using (Old)
using (New)
using (var OutFS = new FileStream(Output, Force ? FileMode.Create : FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None))
{
// Check type of filesystems being compared
if (!Old.IsPartitioned)
{
throw new ArgumentException("Input disk is not partitioned.", "OldVHD");
}
if (!New.IsPartitioned)
{
throw new ArgumentException("Input disk is not partitioned.", "NewVHD");
}
long CapacityBuffer = 64 * Math.Max(Old.Geometry.BytesPerSector, New.Geometry.BytesPerSector); // starting with 64 sectors as a buffer for partition information in the output file
long[] OutputCapacities = new long[Partition != null ? 1 : Old.Partitions.Count];
if (Partition != null)
{
var PartA = Old.Partitions[Partition.Item1];
var PartB = New.Partitions[Partition.Item2];
if (PartA.BiosType != PartB.BiosType)
{
throw new InvalidFileSystemException(
String.Format(
"Filesystem of partition {0} in '{1}' does not match filesystem type of partition {2} in '{3}'.",
Partition.Item2, NewVHD, Partition.Item1, OldVHD));
}
OutputCapacities[0] += Math.Max(PartA.SectorCount * Old.Geometry.BytesPerSector, PartB.SectorCount * New.Geometry.BytesPerSector);
}
else
{
if (Old.Partitions.Count != New.Partitions.Count)
{
throw new ArgumentException(
"Input disks do not have the same number of partitions. To compare specific partitions on mismatched disks, provide the 'Partition' parameter.");
}
for (int i = 0; i < Old.Partitions.Count; i++)
{
if (Old.Partitions[i].BiosType != New.Partitions[i].BiosType)
{
throw new InvalidFileSystemException(String.Format("Filesystem of partition {0} in '{1}' does not match filesystem type of partition {0} in '{2}'.", i, NewVHD, OldVHD));
}
else
{
OutputCapacities[i] = Math.Max(Old.Partitions[i].SectorCount * Old.Geometry.BytesPerSector, New.Partitions[i].SectorCount * New.Geometry.BytesPerSector);
}
}
}
long OutputCapacity = CapacityBuffer + OutputCapacities.Sum();
switch (OutputType)
{
case DiskType.VHD:
Out = DiscUtils.Vhd.Disk.InitializeDynamic(OutFS, Ownership.None, OutputCapacity, Math.Max(New.BlockSize, 512 * 1024)); // the Max() is present only because there's currently a bug with blocksize < (8*sectorSize) in DiscUtils
break;
case DiskType.VHDX:
Out = DiscUtils.Vhdx.Disk.InitializeDynamic(OutFS, Ownership.None, OutputCapacity, Math.Max(New.BlockSize, 512 * 1024));
break;
default:
throw new NotSupportedException("The selected disk type is not supported at this time.",
new ArgumentException(
"Selected DiskType not currently supported.", "OutputType"));
}
using (Out)
{
// set up the output location
if (Out is DiscUtils.Vhd.Disk)
{
((DiscUtils.Vhd.Disk)Out).AutoCommitFooter = false;
}
var OutParts = BiosPartitionTable.Initialize(Out);
if (Partition != null)
{
OutParts.Create(GetPartitionType(Old.Partitions[Partition.Item1]), false); // there is no need (ever) for a VHD diff to have bootable partitions
var OutFileSystem = Out.FormatPartition(0);
DiffPart(DetectFileSystem(Old.Partitions[Partition.Item1]),
DetectFileSystem(New.Partitions[Partition.Item2]),
OutFileSystem, // As we made the partition spen the entire drive, it should be the only partition
Style);
}
else // Partition == null
{
for (int i = 0; i < Old.Partitions.Count; i++)
{
var partIndex = OutParts.Create(Math.Max(Old.Partitions[i].SectorCount * Old.Parameters.BiosGeometry.BytesPerSector,
New.Partitions[i].SectorCount * New.Parameters.BiosGeometry.BytesPerSector),
GetPartitionType(Old.Partitions[i]), false);
var OutFileSystem = Out.FormatPartition(partIndex);
DiffPart(DetectFileSystem(Old.Partitions[i]),
DetectFileSystem(New.Partitions[i]),
OutFileSystem,
Style);
}
}
} // using (Out)
}// using (Old, New, and OutFS)
}
