public string Message => _message ?? string.Empty; // May be null due to default ctor
#endregion
#region De/Constructors
public Commit(IReadOnlyList <CommitId> parents, TreeId?treeId, Audit author, Audit committer, string message)
{
TreeId = treeId;
Author = author;
Committer = committer;
_message = message;
// We choose to coerce empty & null, so de/serialization round-trips with fidelity
if (parents == null)
{
_parents = Array.Empty <CommitId>();
return;
}
// Optimize for common cases 0, 1, 2, N
switch (parents.Count)
{
case 0:
_parents = Array.Empty <CommitId>();
return;
case 1:
_parents = new CommitId[1] {
parents[0]
};
return;
case 2:
{
var cmp = CommitIdComparer.Default.Compare(parents[0], parents[1]);
switch (cmp)
{
// Silently de-duplicate
case 0: _parents = new CommitId[1] {
parents[0]
}; return;
// Sort forward
case -1: _parents = new CommitId[2] {
parents[0], parents[1]
}; return;
// Sort reverse
default: _parents = new CommitId[2] {
parents[1], parents[0]
}; return;
}
}
default:
{
// Copy
var array = new CommitId[parents.Count];
for (var i = 0; i < parents.Count; i++)
{
array[i] = parents[i];
}
// Sort: Delegate dispatch faster than interface (https://github.com/dotnet/coreclr/pull/8504)
Array.Sort(array, CommitIdComparer.Default.Compare);
// Distinct
var j = 1;
for (var i = 1; i < array.Length; i++)
{
// If it's a duplicate, silently skip
if (CommitIdComparer.Default.Equals(array[i - 1], array[i]))
{
continue;
}
array[j++] = array[i]; // Increment target index iff distinct
}
if (j < array.Length)
{
Array.Resize(ref array, j);
}
// Assign
_parents = array;
}
return;
}
}
public Commit(CommitId?parent, TreeId?treeId, Audit author, Audit committer, string message)
: this(parent.HasValue ? new[] { parent.Value } : Array.Empty <CommitId>(), treeId, author, committer, message)
{
}
public void Deconstruct(out IReadOnlyList <CommitId> parents, out TreeId?treeId, out Audit author, out Audit committer, out string message)
{
parents = Parents;
treeId = TreeId;
author = Author;
committer = Committer;
message = Message;
}
public Commit(CommitId parent, TreeId treeId, Audit author, Audit committer, string message)
: this(new[] { parent }, treeId, author, committer, message)
{
}