public void can_look_up_paths_by_value_from_serialised_data()
{
// you can assign the same value to multiple paths
// this could be quite useful, but I'd like to be able to
// reverse the process -- see what paths an objects is bound
// to. Could be a simple set of scans (slow) or a restructuring
// of the internal data.
var source = new ReverseTrie <ByteString>();
source.Add("very different", "value0");
source.Add("my/path/1", "value1");
source.Add("my/path/2", "value2");
source.Add("b - very different", "value0");
source.Add("my/other/path", "value3");
source.Add("my/other/path/longer", "value4");
source.Add("another/path/for/3", "value3");
source.Add("z - very different", "value0");
var bytes = source.Freeze();
var reconstituted = new ReverseTrie <ByteString>();
bytes.Seek(0, SeekOrigin.Begin);
reconstituted.Defrost(bytes);
var result = string.Join(", ", reconstituted.GetPathsForEntry("value3"));
Assert.That(result, Is.EqualTo("my/other/path, another/path/for/3"));
}
/// <summary>
/// Remove a path binding if it exists. If the path is not bound, nothing happens.
/// Linked documents are not removed.
/// </summary>
public void UnbindPath(string exactPath)
{
_pathLookupCache = null;
lock (_fslock)
{
var pathLink = GetPathLookupLink();
var pathIndex = new ReverseTrie <SerialGuid>();
if (!pathLink.TryGetLink(0, out var pathPageId))
{
return;
}
pathIndex.Defrost(GetStream(pathPageId));
// Unbind the path
pathIndex.Delete(exactPath);
// Write back to new chain
var newPageId = WriteStream(pathIndex.Freeze());
// Update version link
pathLink.WriteNewLink(newPageId, out var expired);
SetPathLookupLink(pathLink);
ReleaseChain(expired);
Flush();
}
}
[NotNull] private ReverseTrie <SerialGuid> GetPathLookupIndex()
{
var pathIndex = _pathLookupCache;
if (pathIndex != null)
{
return(pathIndex);
}
lock (_fslock)
{
var pathLink = GetPathLookupLink();
pathIndex = new ReverseTrie <SerialGuid>();
if (pathLink.TryGetLink(0, out var pathPageId))
{
pathIndex.Defrost(GetStream(pathPageId));
}
_pathLookupCache = pathIndex;
}
return(pathIndex);
}
public void serialisation_and_restoring()
{
var subject = new ReverseTrie <ByteString>();
var rawLength = 0;
// Fill it up
for (int i = 0; i < 100; i++)
{
var key = $"Path number {i}";
var value = $"{i}";
rawLength += key.Length + value.Length;
subject.Add(key, ByteString.Wrap(value));
}
var frozen = subject.Freeze();
frozen.Seek(0, SeekOrigin.Begin);
Console.WriteLine($"Encoding 100 paths in {frozen.Length} bytes. Raw input was {rawLength} bytes");
Console.WriteLine(frozen.ToHexString());
subject = null;
var result = new ReverseTrie <ByteString>();
frozen.Seek(0, SeekOrigin.Begin);
result.Defrost(frozen);
// Check every result
for (int i = 0; i < 100; i++)
{
var key = $"Path number {i}";
var expected = $"{i}";
Assert.That(result.Get(key)?.ToString(), Is.EqualTo(expected), $"Lost data at path '{key}'");
}
}
/// <summary>
/// Bind an exact path to a document ID.
/// If an existing document was bound to the same path, its ID will be returned
/// </summary>
/// <param name="path">Exact path for document</param>
/// <param name="documentId">new document id</param>
/// <param name="previousDocId">old document id that has been replaced, if any.</param>
public void BindPath(string path, Guid documentId, out Guid?previousDocId)
{
previousDocId = null;
if (string.IsNullOrEmpty(path))
{
throw new Exception("Path must not be null or empty");
}
_pathLookupCache = null;
lock (_fslock)
{
// Read current path document (if it exists)
var pathLink = GetPathLookupLink();
var pathIndex = new ReverseTrie <SerialGuid>();
if (pathLink.TryGetLink(0, out var pathPageId))
{
pathIndex.Defrost(GetStream(pathPageId));
}
// Bind the path
var serialGuid = pathIndex.Add(path, documentId);
if (serialGuid != null)
{
previousDocId = serialGuid.Value;
}
// Write back to new chain
var newPageId = WriteStream(pathIndex.Freeze());
// Update version link
pathLink.WriteNewLink(newPageId, out var expired);
SetPathLookupLink(pathLink);
ReleaseChain(expired);
Flush();
}
}