/// <summary>
/// Adds the existence state of the path if not present or returns the current cached existence state of the path
/// </summary>
/// <remarks>
/// If flags are provided, those are added to potentially existing flags
/// </remarks>
private PathExistence GetOrAddExistence(AbsolutePath path, FileSystemViewMode mode, PathExistence existence, out bool added, bool updateParents = true, FileSystemEntryFlags flags = FileSystemEntryFlags.None)
{
PathExistence result = existence;
var originalPath = path;
while (path.IsValid)
{
var getOrAddResult = PathExistenceCache.GetOrAdd(path, FileSystemEntry.Create(mode, existence).SetFlag(flags));
if (getOrAddResult.IsFound)
{
var currentExistence = getOrAddResult.Item.Value.GetExistence(mode);
var currentFlags = getOrAddResult.Item.Value.Flags;
if (currentExistence != null && currentFlags.HasFlag(flags))
{
if (originalPath != path)
{
// Parent entry with existence already exists, just return the result
added = true;
return(result);
}
else
{
// Entry with existence already exists, just return the value
added = false;
return(currentExistence.Value);
}
}
// found entry for the 'path', but it does not contain existence for the specified 'mode'
var updateResult = PathExistenceCache.AddOrUpdate(path, (mode, existence),
(key, data) => FileSystemEntry.Create(data.mode, data.existence).SetFlag(flags),
(key, data, oldValue) => oldValue.TryUpdate(data.mode, data.existence).SetFlag(flags));
// the same entry might be updated concurrently; check whether we lost the race, and if we did, stop further processing
currentExistence = updateResult.OldItem.Value.GetExistence(mode);
currentFlags = updateResult.OldItem.Value.Flags;
if (currentExistence != null && currentFlags.HasFlag(flags))
{
if (originalPath != path)
{
// Parent entry with existence already exists, just return the result
added = true;
return(result);
}
else
{
// Entry with existence already exists, just return the value
added = false;
return(currentExistence.Value);
}
}
}
// Only register parents as directories if path exists AND updateParents=true
if (existence == PathExistence.Nonexistent || !updateParents)
{
break;
}
// Set ancestor paths existence to directory existent for existent paths
existence = PathExistence.ExistsAsDirectory;
path = path.GetParent(PathTable);
}
added = true;
return(result);
}
/// <summary>
/// Adds the existence state of the path if not present or returns the current cached existence state of the path
/// </summary>
private PathExistence GetOrAddExistence(AbsolutePath path, FileSystemViewMode mode, PathExistence existence, bool updateParents = true, FileSystemEntryFlags flags = FileSystemEntryFlags.None)
{
return(GetOrAddExistence(path, mode, existence, out var added, updateParents, flags));
}
