public string ReadLine([CanBeNull] StringPool pool = null, bool advance = true)
{
if (_index == _s.Length)
{
return(null);
}
var startIndex = _index;
var endIndex = _s.IndexOf('\n', startIndex);
if (endIndex == -1)
{
return(ReadToEnd(advance));
}
if (advance)
{
_index = endIndex + 1;
}
return(pool != null
? pool.Intern(_s, startIndex, endIndex - startIndex)
: _s.Substring(startIndex, endIndex - startIndex));
}
private async Task ExecuteAsync(
GitModule module,
IReadOnlyList <IGitRef> refs,
IObserver <GitRevision> subject,
RefFilterOptions refFilterOptions,
string branchFilter,
string revisionFilter,
string pathFilter,
[CanBeNull] Func <GitRevision, bool> revisionPredicate)
{
await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
var token = _cancellationTokenSequence.Next();
var revisionCount = 0;
await TaskScheduler.Default;
token.ThrowIfCancellationRequested();
var branchName = module.IsValidGitWorkingDir()
? module.GetSelectedBranch()
: "";
token.ThrowIfCancellationRequested();
UpdateSelectedRef(module, refs, branchName);
var refsByObjectId = refs.ToLookup(head => head.ObjectId);
token.ThrowIfCancellationRequested();
var arguments = BuildArguments(refFilterOptions, branchFilter, revisionFilter, pathFilter);
#if TRACE
var sw = Stopwatch.StartNew();
#endif
// This property is relatively expensive to call for every revision, so
// cache it for the duration of the loop.
var logOutputEncoding = module.LogOutputEncoding;
using (var process = module.GitCommandRunner.RunDetached(arguments, redirectOutput: true, outputEncoding: GitModule.LosslessEncoding))
{
token.ThrowIfCancellationRequested();
// Pool string values likely to form a small set: encoding, authorname, authoremail, committername, committeremail
var stringPool = new StringPool();
var buffer = new byte[4096];
foreach (var chunk in process.StandardOutput.BaseStream.ReadNullTerminatedChunks(ref buffer))
{
token.ThrowIfCancellationRequested();
if (TryParseRevision(module, chunk, stringPool, logOutputEncoding, out var revision))
{
if (revisionPredicate == null || revisionPredicate(revision))
{
// The full commit message body is used initially in InMemFilter, after which it isn't
// strictly needed and can be re-populated asynchronously.
//
// We keep full multiline message bodies within the last six months.
// Commits earlier than that have their properties set to null and the
// memory will be GCd.
if (DateTime.Now - revision.AuthorDate > TimeSpan.FromDays(30 * 6))
{
revision.Body = null;
}
// Look up any refs associated with this revision
revision.Refs = refsByObjectId[revision.ObjectId].AsReadOnlyList();
revisionCount++;
subject.OnNext(revision);
}
}
}
#if TRACE
Trace.WriteLine($"**** [{nameof(RevisionReader)}] Emitted {revisionCount} revisions in {sw.Elapsed.TotalMilliseconds:#,##0.#} ms. bufferSize={buffer.Length} poolCount={stringPool.Count}");
#endif
}
if (!token.IsCancellationRequested)
{
subject.OnCompleted();
}
}
private static bool TryParseRevision(GitModule module, ArraySegment <byte> chunk, StringPool stringPool, Encoding logOutputEncoding, out GitRevision revision)
{
// The 'chunk' of data contains a complete git log item, encoded.
// This method decodes that chunk and produces a revision object.
// All values which can be read directly from the byte array are arranged
// at the beginning of the chunk. The latter part of the chunk will require
// decoding as a string.
if (chunk.Count == 0)
{
// "git log -z --name-only" returns multiple consecutive null bytes when logging
// the history of a single file. Haven't worked out why, but it's safe to skip
// such chunks.
revision = default;
return(false);
}
#region Object ID, Tree ID, Parent IDs
// The first 40 bytes are the revision ID and the tree ID back to back
if (!ObjectId.TryParseAsciiHexBytes(chunk, 0, out var objectId) ||
!ObjectId.TryParseAsciiHexBytes(chunk, ObjectId.Sha1CharCount, out var treeId))
{
revision = default;
return(false);
}
var array = chunk.Array;
var offset = chunk.Offset + (ObjectId.Sha1CharCount * 2);
var lastOffset = chunk.Offset + chunk.Count;
// Next we have zero or more parent IDs separated by ' ' and terminated by '\n'
var parentIds = new ObjectId[CountParents(offset)];
var parentIndex = 0;
int CountParents(int baseOffset)
{
if (array[baseOffset] == '\n')
{
return(0);
}
var count = 1;
while (true)
{
baseOffset += ObjectId.Sha1CharCount;
var c = array[baseOffset];
if (c != ' ')
{
break;
}
count++;
baseOffset++;
}
return(count);
}
while (true)
{
if (offset >= lastOffset - ObjectId.Sha1CharCount - 1)
{
revision = default;
return(false);
}
var b = array[offset];
if (b == '\n')
{
// There are no more parent IDs
offset++;
break;
}
if (b == ' ')
{
// We are starting a new parent ID
offset++;
}
if (!ObjectId.TryParseAsciiHexBytes(array, offset, out var parentId))
{
// TODO log this parse problem
revision = default;
return(false);
}
parentIds[parentIndex++] = parentId;
offset += ObjectId.Sha1CharCount;
}
#endregion
#region Timestamps
// Lines 2 and 3 are timestamps, as decimal ASCII seconds since the unix epoch, each terminated by `\n`
var authorDate = ParseUnixDateTime();
var commitDate = ParseUnixDateTime();
DateTime ParseUnixDateTime()
{
long unixTime = 0;
while (true)
{
var c = array[offset++];
if (c == '\n')
{
return(DateTimeUtils.UnixEpoch.AddTicks(unixTime * TimeSpan.TicksPerSecond).ToLocalTime());
}
unixTime = (unixTime * 10) + (c - '0');
}
}
#endregion
#region Encoding
// Line is the name of the encoding used by git, or an empty string, terminated by `\n`
string encodingName;
Encoding encoding;
var encodingNameEndOffset = Array.IndexOf(array, (byte)'\n', offset);
if (encodingNameEndOffset == -1)
{
// TODO log this error case
revision = default;
return(false);
}
if (offset == encodingNameEndOffset)
{
// No encoding specified
encoding = logOutputEncoding;
encodingName = null;
}
else
{
encodingName = logOutputEncoding.GetString(array, offset, encodingNameEndOffset - offset);
encoding = module.GetEncodingByGitName(encodingName);
}
offset = encodingNameEndOffset + 1;
#endregion
#region Encoded string values (names, emails, subject, body, name)
// Finally, decode the names, email, subject and body strings using the required text encoding
var s = encoding.GetString(array, offset, lastOffset - offset);
var reader = new StringLineReader(s);
var author = reader.ReadLine(stringPool);
var authorEmail = reader.ReadLine(stringPool);
var committer = reader.ReadLine(stringPool);
var committerEmail = reader.ReadLine(stringPool);
var subject = reader.ReadLine(advance: false);
if (author == null || authorEmail == null || committer == null || committerEmail == null || subject == null)
{
// TODO log this parse error
Debug.Fail("Unable to read an entry from the log -- this should not happen");
revision = default;
return(false);
}
// NOTE the convention is that the Subject string is duplicated at the start of the Body string
// Therefore we read the subject twice.
// If there are not enough characters remaining for a body, then just assign the subject string directly.
var body = reader.Remaining - subject.Length == 2 ? subject : reader.ReadToEnd();
if (body == null)
{
// TODO log this parse error
Debug.Fail("Unable to read body from the log -- this should not happen");
revision = default;
return(false);
}
var indexOfEndOfBody = body.LastIndexOf(EndOfBody, StringComparison.InvariantCulture);
string additionalData = null;
var bodyContainsAdditionalData = body.Length > indexOfEndOfBody + EndOfBody.Length;
if (bodyContainsAdditionalData)
{
additionalData = body.Substring(indexOfEndOfBody + EndOfBody.Length).TrimStart();
}
body = body.Substring(0, indexOfEndOfBody);
#endregion
revision = new GitRevision(objectId)
{
ParentIds = parentIds,
TreeGuid = treeId,
Author = author,
AuthorEmail = authorEmail,
AuthorDate = authorDate,
Committer = committer,
CommitterEmail = committerEmail,
CommitDate = commitDate,
MessageEncoding = encodingName,
Subject = subject,
Body = body,
Name = additionalData,
HasMultiLineMessage = !ReferenceEquals(subject, body),
HasNotes = false
};
return(true);
}
private async Task ExecuteAsync(
GitModule module,
IObserver <GitRevision> subject,
RefFilterOptions refFilterOptions,
string branchFilter,
string revisionFilter,
string pathFilter,
[CanBeNull] Func <GitRevision, bool> revisionPredicate)
{
ThreadHelper.ThrowIfNotOnUIThread();
var token = _cancellationTokenSequence.Next();
RevisionCount = 0;
await TaskScheduler.Default;
subject.OnNext(null);
token.ThrowIfCancellationRequested();
var branchName = module.IsValidGitWorkingDir()
? module.GetSelectedBranch()
: "";
token.ThrowIfCancellationRequested();
LatestRefs = module.GetRefs();
UpdateSelectedRef(module, LatestRefs, branchName);
var refsByObjectId = LatestRefs.ToLookup(head => head.Guid);
token.ThrowIfCancellationRequested();
const string fullFormat =
// These header entries can all be decoded from the bytes directly.
// Each hash is 20 bytes long. There is always a
/* Object ID */ "%H" +
/* Tree ID */ "%T" +
/* Parent IDs */ "%P%n" +
/* Author date */ "%at%n" +
/* Commit date */ "%ct%n" +
/* Encoding */ "%e%n" +
// Items below here must be decoded as strings to support non-ASCII
/* Author name */ "%aN%n" +
/* Author email */ "%aE%n" +
/* Committer name */ "%cN%n" +
/* Committer email */ "%cE%n" +
/* Commit subject */ "%s%n%n" +
/* Commit body */ "%b";
// TODO add AppBuilderExtensions support for flags enums, starting with RefFilterOptions, then use it in the below construction
var arguments = BuildArguments();
var sw = Stopwatch.StartNew();
// This property is relatively expensive to call for every revision, so
// cache it for the duration of the loop.
var logOutputEncoding = module.LogOutputEncoding;
using (var process = module.RunGitCmdDetached(arguments.ToString(), GitModule.LosslessEncoding))
{
token.ThrowIfCancellationRequested();
// Pool string values likely to form a small set: encoding, authorname, authoremail, committername, committeremail
var stringPool = new StringPool();
var buffer = new byte[4096];
foreach (var chunk in process.StandardOutput.BaseStream.ReadNullTerminatedChunks(ref buffer))
{
token.ThrowIfCancellationRequested();
if (TryParseRevision(module, chunk, stringPool, logOutputEncoding, out var revision))
{
if (revisionPredicate == null || revisionPredicate(revision))
{
// Remove full commit message to reduce memory consumption (28% for a repo with 69K commits)
// Full commit message is used in InMemFilter but later it's not needed
revision.Body = null;
// Look up any refs associate with this revision
revision.Refs = refsByObjectId[revision.Guid].AsReadOnlyList();
RevisionCount++;
subject.OnNext(revision);
}
}
}
Trace.WriteLine($"**** [{nameof(RevisionReader)}] Emitted {RevisionCount} revisions in {sw.Elapsed.TotalMilliseconds:#,##0.#} ms. bufferSize={buffer.Length} poolCount={stringPool.Count}");
}
await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync(token);
if (!token.IsCancellationRequested)
{
subject.OnCompleted();
}
ArgumentBuilder BuildArguments()
{
return(new ArgumentBuilder
{
"log",
"-z",
$"--pretty=format:\"{fullFormat}\"",
{ AppSettings.OrderRevisionByDate, "--date-order", "--topo-order" },
{ AppSettings.ShowReflogReferences, "--reflog" },
{
refFilterOptions.HasFlag(RefFilterOptions.All),
"--all",
new ArgumentBuilder
{
{
refFilterOptions.HasFlag(RefFilterOptions.Branches) &&
!branchFilter.IsNullOrWhiteSpace() &&
branchFilter.IndexOfAny(new[] { '?', '*', '[' }) != -1,
"--branches=" + branchFilter
},
{ refFilterOptions.HasFlag(RefFilterOptions.Remotes), "--remotes" },
{ refFilterOptions.HasFlag(RefFilterOptions.Tags), "--tags" },
}.ToString()
},
{ refFilterOptions.HasFlag(RefFilterOptions.Boundary), "--boundary" },
{ refFilterOptions.HasFlag(RefFilterOptions.ShowGitNotes), "--not --glob=notes --not" },
{ refFilterOptions.HasFlag(RefFilterOptions.NoMerges), "--no-merges" },
{ refFilterOptions.HasFlag(RefFilterOptions.FirstParent), "--first-parent" },
{ refFilterOptions.HasFlag(RefFilterOptions.SimplifyByDecoration), "--simplify-by-decoration" },
revisionFilter,
"--",
pathFilter
});
}
}
private static bool TryParseRevision(GitModule module, ArraySegment <byte> chunk, StringPool stringPool, Encoding logOutputEncoding, out GitRevision revision)
{
// The 'chunk' of data contains a complete git log item, encoded.
// This method decodes that chunk and produces a revision object.
// All values which can be read directly from the byte array are arranged
// at the beginning of the chunk. The latter part of the chunk will require
// decoding as a string.
#region Object ID, Tree ID, Parent IDs
// The first 40 bytes are the revision ID and the tree ID back to back
if (!ObjectId.TryParseAsciiHexBytes(chunk, 0, out var objectId) ||
!ObjectId.TryParseAsciiHexBytes(chunk, ObjectId.Sha1CharCount, out var treeId))
{
revision = default;
return(false);
}
var objectIdStr = objectId.ToString();
var array = chunk.Array;
var offset = chunk.Offset + (ObjectId.Sha1CharCount * 2);
var lastOffset = chunk.Offset + chunk.Count;
// Next we have zero or more parent IDs separated by ' ' and terminated by '\n'
var parentIds = new List <ObjectId>(capacity: 1);
while (true)
{
if (offset >= lastOffset - 21)
{
revision = default;
return(false);
}
var b = array[offset];
if (b == '\n')
{
// There are no more parent IDs
offset++;
break;
}
if (b == ' ')
{
// We are starting a new parent ID
offset++;
}
if (!ObjectId.TryParseAsciiHexBytes(array, offset, out var parentId))
{
// TODO log this parse problem
revision = default;
return(false);
}
parentIds.Add(parentId);
offset += ObjectId.Sha1CharCount;
}
#endregion
#region Timestamps
// Lines 2 and 3 are timestamps, as decimal ASCII seconds since the unix epoch, each terminated by `\n`
var authorDate = ParseUnixDateTime();
var commitDate = ParseUnixDateTime();
DateTime ParseUnixDateTime()
{
long unixTime = 0;
while (true)
{
var c = array[offset++];
if (c == '\n')
{
return(DateTimeUtils.UnixEpoch.AddTicks(unixTime * TimeSpan.TicksPerSecond).ToLocalTime());
}
unixTime = (unixTime * 10) + (c - '0');
}
}
#endregion
#region Encoding
// Line is the name of the encoding used by git, or an empty string, terminated by `\n`
string encodingName;
Encoding encoding;
var encodingNameEndOffset = Array.IndexOf(array, (byte)'\n', offset);
if (encodingNameEndOffset == -1)
{
// TODO log this error case
revision = default;
return(false);
}
if (offset == encodingNameEndOffset)
{
// No encoding specified
encoding = logOutputEncoding;
encodingName = null;
}
else
{
encodingName = logOutputEncoding.GetString(array, offset, encodingNameEndOffset - offset);
encoding = module.GetEncodingByGitName(encodingName);
}
offset = encodingNameEndOffset + 1;
#endregion
#region Encoded string valies (names, emails, subject, body)
// Finally, decode the names, email, subject and body strings using the required text encoding
var s = encoding.GetString(array, offset, lastOffset - offset);
var reader = new StringLineReader(s);
var author = reader.ReadLine(stringPool);
var authorEmail = reader.ReadLine(stringPool);
var committer = reader.ReadLine(stringPool);
var committerEmail = reader.ReadLine(stringPool);
// NOTE the convention is that the Body property contain a copy of Subject
// Therefore we read the subject twice
var subject = reader.ReadLine(advance: false);
var body = reader.ReadToEnd();
if (author == null || authorEmail == null || committer == null || committerEmail == null || subject == null || body == null)
{
// TODO log this parse error
Debug.Fail("Unable to read an entry from the log -- this should not happen");
revision = default;
return(false);
}
#endregion
revision = new GitRevision(null)
{
// TODO are we really sure we can't make Revision.Guid an ObjectId?
Guid = objectIdStr,
// TODO take IReadOnlyList<ObjectId> instead
ParentGuids = parentIds.ToArray(p => p.ToString()),
TreeGuid = treeId,
Author = author,
AuthorEmail = authorEmail,
AuthorDate = authorDate,
Committer = committer,
CommitterEmail = committerEmail,
CommitDate = commitDate,
MessageEncoding = encodingName,
Subject = subject,
Body = body,
HasMultiLineMessage = !string.IsNullOrWhiteSpace(body)
};
return(true);
}
private async Task ExecuteAsync(
GitModule module,
IReadOnlyList <IGitRef> refs,
IObserver <GitRevision> subject,
RefFilterOptions refFilterOptions,
string branchFilter,
string revisionFilter,
string pathFilter,
[CanBeNull] Func <GitRevision, bool> revisionPredicate)
{
await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
var token = _cancellationTokenSequence.Next();
var revisionCount = 0;
await TaskScheduler.Default;
token.ThrowIfCancellationRequested();
var branchName = module.IsValidGitWorkingDir()
? module.GetSelectedBranch()
: "";
token.ThrowIfCancellationRequested();
UpdateSelectedRef(module, refs, branchName);
var refsByObjectId = refs.ToLookup(head => head.ObjectId);
token.ThrowIfCancellationRequested();
const string fullFormat =
// These header entries can all be decoded from the bytes directly.
// Each hash is 20 bytes long.
/* Object ID */ "%H" +
/* Tree ID */ "%T" +
/* Parent IDs */ "%P%n" +
/* Author date */ "%at%n" +
/* Commit date */ "%ct%n" +
/* Encoding */ "%e%n" +
// Items below here must be decoded as strings to support non-ASCII.
/* Author name */ "%aN%n" +
/* Author email */ "%aE%n" +
/* Committer name */ "%cN%n" +
/* Committer email */ "%cE%n" +
/* Commit subject */ "%s%n%n" +
/* Commit body */ "%b";
var arguments = BuildArguments();
var sw = Stopwatch.StartNew();
// This property is relatively expensive to call for every revision, so
// cache it for the duration of the loop.
var logOutputEncoding = module.LogOutputEncoding;
using (var process = module.RunGitCmdDetached(arguments, redirectOutput: true, outputEncoding: GitModule.LosslessEncoding))
{
token.ThrowIfCancellationRequested();
// Pool string values likely to form a small set: encoding, authorname, authoremail, committername, committeremail
var stringPool = new StringPool();
var buffer = new byte[4096];
foreach (var chunk in process.StandardOutput.BaseStream.ReadNullTerminatedChunks(ref buffer))
{
token.ThrowIfCancellationRequested();
if (TryParseRevision(module, chunk, stringPool, logOutputEncoding, out var revision))
{
if (revisionPredicate == null || revisionPredicate(revision))
{
// The full commit message body is used initially in InMemFilter, after which it isn't
// strictly needed and can be re-populated asynchronously.
//
// We keep full multiline message bodies within the last six months.
// Commits earlier than that have their properties set to null and the
// memory will be GCd.
if (DateTime.Now - revision.AuthorDate > TimeSpan.FromDays(30 * 6))
{
revision.Body = null;
}
// Look up any refs associated with this revision
revision.Refs = refsByObjectId[revision.ObjectId].AsReadOnlyList();
revisionCount++;
subject.OnNext(revision);
}
}
}
Trace.WriteLine($"**** [{nameof(RevisionReader)}] Emitted {revisionCount} revisions in {sw.Elapsed.TotalMilliseconds:#,##0.#} ms. bufferSize={buffer.Length} poolCount={stringPool.Count}");
}
if (!token.IsCancellationRequested)
{
subject.OnCompleted();
}
ArgumentBuilder BuildArguments()
{
return(new GitArgumentBuilder("log")
{
"-z",
$"--pretty=format:\"{fullFormat}\"",
{ AppSettings.ShowReflogReferences, "--reflog" },
{
refFilterOptions.HasFlag(RefFilterOptions.All),
"--all",
new ArgumentBuilder
{
{
refFilterOptions.HasFlag(RefFilterOptions.Branches) &&
!branchFilter.IsNullOrWhiteSpace() &&
branchFilter.IndexOfAny(new[] { '?', '*', '[' }) != -1,
"--branches=" + branchFilter
},
{ refFilterOptions.HasFlag(RefFilterOptions.Remotes), "--remotes" },
{ refFilterOptions.HasFlag(RefFilterOptions.Tags), "--tags" },
}.ToString()
},
{ refFilterOptions.HasFlag(RefFilterOptions.Boundary), "--boundary" },
{ refFilterOptions.HasFlag(RefFilterOptions.ShowGitNotes), "--not --glob=notes --not" },
{ refFilterOptions.HasFlag(RefFilterOptions.NoMerges), "--no-merges" },
{ refFilterOptions.HasFlag(RefFilterOptions.FirstParent), "--first-parent" },
{ refFilterOptions.HasFlag(RefFilterOptions.SimplifyByDecoration), "--simplify-by-decoration" },
revisionFilter,
"--",
pathFilter
});
}
}
