/// <summary>
/// Creates a new asset bundle patch.
/// </summary>
/// <param name="previousBundlePatches">List of previously created bundle patches.</param>
/// <param name="currentBundle">Up-to-date bundle with all assets.</param>
/// <param name="currentBundlePatch">Output bundle patch.</param>
/// <param name="baseBundleVersion">Version on the last bundle patch in the previousBundlePatches list.</param>
public static void CreatePatch(
List <AssetBundle> previousBundlePatches, AssetBundle currentBundle, AssetBundle currentBundlePatch,
int baseBundleVersion)
{
// Build up list of files inherited from the base bundle.
var inheritedFiles = new HashSet <string>();
foreach (var patch in previousBundlePatches)
{
foreach (var file in patch.EnumerateFiles())
{
inheritedFiles.Add(file);
}
var manifest = PackedAssetBundle.Manifest.Create(patch);
foreach (var deletedFile in manifest.DeletedAssets)
{
inheritedFiles.Remove(deletedFile);
}
}
// Import new or modified files.
var previousPatchesReversed = previousBundlePatches.ToList();
previousPatchesReversed.Reverse();
foreach (var file in currentBundle.EnumerateFiles())
{
if (!inheritedFiles.Contains(file))
{
// Import a new file.
ImportAsset(file, currentBundle, currentBundlePatch);
continue;
}
var fileModified = true;
foreach (var patch in previousPatchesReversed)
{
if (!patch.FileExists(file))
{
continue;
}
// Don't compare last write time because it can be different for the same files on different machines.
if (
currentBundle.GetAttributes(file) == patch.GetAttributes(file) &&
currentBundle.GetSourceExtension(file) == patch.GetSourceExtension(file) &&
AreByteArraysEqual(currentBundle.GetCookingRulesSHA1(file), patch.GetCookingRulesSHA1(file)) &&
AreFilesEqual(file, patch, currentBundle)
)
{
fileModified = false;
}
break;
}
if (fileModified)
{
ImportAsset(file, currentBundle, currentBundlePatch);
}
}
// Prepare the current bundle manifest.
var currentManifest = new PackedAssetBundle.Manifest();
// Build up deleted files list.
foreach (var file in inheritedFiles)
{
if (inheritedFiles.Contains(file) && !currentBundle.FileExists(file) && file != PackedAssetBundle.Manifest.FileName)
{
currentManifest.DeletedAssets.Add(file);
}
}
currentManifest.BaseBundleVersion = baseBundleVersion;
currentManifest.Write(currentBundlePatch);
}