/// <summary>
/// Checks the files provided in the given <see cref="VersionFileList"/> and compares them to the local files
/// to see what files need to be updated.
/// </summary>
/// <param name="vfl">The <see cref="VersionFileList"/> containing the files to be updated.</param>
/// <returns>The relative paths to the files that need to be updated.</returns>
IEnumerable <string> FindFilesToUpdate(VersionFileList vfl)
{
var ret = new List <string>();
// Loop through each file
foreach (var updateFileInfo in vfl.Files)
{
// Get the local file path
var localFilePath = PathHelper.CombineDifferentPaths(Settings.TargetPath, updateFileInfo.FilePath);
// If the file does not exist, add it
if (!File.Exists(localFilePath))
{
ret.Add(updateFileInfo.FilePath);
continue;
}
// Get the info for the local file
try
{
var localFileInfo = new FileInfo(localFilePath);
// If the size of the local file doesn't equal the size of the updated file, avoid
// checking the hash and just update it
if (localFileInfo.Length != updateFileInfo.Size)
{
if (log.IsDebugEnabled)
{
log.DebugFormat(
"Update check on file `{0}`: File needs update - size mismatch (current: {1}, expected: {2}).",
updateFileInfo.FilePath, localFileInfo.Length, updateFileInfo.Size);
}
ret.Add(updateFileInfo.FilePath);
continue;
}
// File exists and is of the correct size, so compare the hash of the local file to the expected hash
var localFileHash = Hasher.GetFileHash(localFilePath);
if (!StringComparer.Ordinal.Equals(localFileHash, updateFileInfo.Hash))
{
if (log.IsDebugEnabled)
{
log.DebugFormat(
"Update check on file `{0}`: File needs update - hash mismatch (current: {1}, expected: {2}).",
updateFileInfo.FilePath, localFileHash, updateFileInfo.Hash);
}
ret.Add(updateFileInfo.FilePath);
continue;
}
}
catch (IOException ex)
{
const string errmsg =
"Failed to analyze file `{0}` to see if it needs to be updated. Will assume update is required. Exception: {1}";
if (log.IsErrorEnabled)
{
log.ErrorFormat(errmsg, updateFileInfo.FilePath, ex);
}
Debug.Fail(string.Format(errmsg, updateFileInfo.FilePath, ex));
// On an IOException, assume the file needs to be updated
ret.Add(updateFileInfo.FilePath);
continue;
}
if (log.IsDebugEnabled)
{
log.DebugFormat("Update check on file `{0}`: file is up-to-date.", updateFileInfo.FilePath);
}
}
if (log.IsInfoEnabled)
{
log.InfoFormat("Found `{0}` files needing to be updated.", ret.Count);
}
return(ret);
}