FileHistory Feature

LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj

@@ -57,6 +57,7 @@
     <Compile Include="CheckoutFixture.cs" />
     <Compile Include="CherryPickFixture.cs" />
     <Compile Include="DescribeFixture.cs" />
+    <Compile Include="FileHistoryFixture.cs" />
     <Compile Include="GlobalSettingsFixture.cs" />
     <Compile Include="PatchStatsFixture.cs" />
     <Compile Include="RefSpecFixture.cs" />
@@ -157,4 +158,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>

LibGit2Sharp/CommitLog.cs

@@ -80,6 +80,32 @@ public ICommitLog QueryBy(CommitFilter filter)
             return new CommitLog(repo, filter);
         }
 
+        /// <summary>
+        /// Returns the list of commits of the repository representing the history of a file beyond renames.
+        /// </summary>
+        /// <param name="path">The file's path.</param>
+        /// <returns>A list of file history entries, ready to be enumerated.</returns>
+        public IEnumerable<LogEntry> QueryBy(string path)
+        {
+            Ensure.ArgumentNotNull(path, "path");
+
+            return new FileHistory(repo, path);
+        }
+
+        /// <summary>
+        /// Returns the list of commits of the repository representing the history of a file beyond renames.
+        /// </summary>
+        /// <param name="path">The file's path.</param>
+        /// <param name="filter">The options used to control which commits will be returned.</param>
+        /// <returns>A list of file history entries, ready to be enumerated.</returns>
+        public IEnumerable<LogEntry> QueryBy(string path, FollowFilter filter)
+        {
+            Ensure.ArgumentNotNull(path, "path");
+            Ensure.ArgumentNotNull(filter, "filter");
+
+            return new FileHistory(repo, path, new CommitFilter {SortBy = filter.SortBy});
+        }
+
         /// <summary>
         /// Find the best possible merge base given two <see cref="Commit"/>s.
         /// </summary>
@@ -206,7 +232,6 @@ private void FirstParentOnly(bool firstParent)
                 }
             }
         }
-
     }
 
     /// <summary>

LibGit2Sharp/Core/FileHistory.cs

@@ -0,0 +1,172 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace LibGit2Sharp.Core
+{
+    /// <summary>
+    /// Represents a file-related log of commits beyond renames.
+    /// </summary>
+    internal class FileHistory : IEnumerable<LogEntry>
+    {
+        #region Fields
+
+        /// <summary>
+        /// The allowed commit sort strategies.
+        /// </summary>
+        private static readonly List<CommitSortStrategies> AllowedSortStrategies = new List<CommitSortStrategies>
+        {
+            CommitSortStrategies.Topological,
+            CommitSortStrategies.Time,
+            CommitSortStrategies.Topological | CommitSortStrategies.Time
+        };
+
+        /// <summary>
+        /// The repository.
+        /// </summary>
+        private readonly Repository _repo;
+
+        /// <summary>
+        /// The file's path relative to the repository's root.
+        /// </summary>
+        private readonly string _path;
+
+        /// <summary>
+        /// The filter to be used in querying the commit log.
+        /// </summary>
+        private readonly CommitFilter _queryFilter;
+
+        #endregion
+
+        #region Constructors
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FileHistory"/> class.
+        /// The commits will be enumerated in reverse chronological order.
+        /// </summary>
+        /// <param name="repo">The repository.</param>
+        /// <param name="path">The file's path relative to the repository's root.</param>
+        /// <exception cref="ArgumentNullException">If any of the parameters is null.</exception>
+        internal FileHistory(Repository repo, string path)
+            : this(repo, path, new CommitFilter())
+        { }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FileHistory"/> class.
+        /// The given <see cref="CommitFilter"/> instance specifies the commit
+        /// sort strategies and range of commits to be considered.
+        /// Only the time (corresponding to <code>--date-order</code>) and topological
+        /// (coresponding to <code>--topo-order</code>) sort strategies are supported.
+        /// </summary>
+        /// <param name="repo">The repository.</param>
+        /// <param name="path">The file's path relative to the repository's root.</param>
+        /// <param name="queryFilter">The filter to be used in querying the commit log.</param>
+        /// <exception cref="ArgumentNullException">If any of the parameters is null.</exception>
+        /// <exception cref="ArgumentException">When an unsupported commit sort strategy is specified.</exception>
+        internal FileHistory(Repository repo, string path, CommitFilter queryFilter)
+        {
+            Ensure.ArgumentNotNull(repo, "repo");
+            Ensure.ArgumentNotNull(path, "path");
+            Ensure.ArgumentNotNull(queryFilter, "queryFilter");
+
+            // Ensure the commit sort strategy makes sense.
+            if (!AllowedSortStrategies.Contains(queryFilter.SortBy))
+                throw new ArgumentException(
+                    "Unsupported sort strategy. Only 'Topological', 'Time', or 'Topological | Time' are allowed.",
+                    "queryFilter");
+
+            _repo = repo;
+            _path = path;
+            _queryFilter = queryFilter;
+        }
+
+        #endregion
+
+        #region IEnumerable<LogEntry> Members
+
+        /// <summary>
+        /// Gets the <see cref="IEnumerator{LogEntry}"/> that enumerates the
+        /// <see cref="LogEntry"/> instances representing the file's history,
+        /// including renames (as in <code>git log --follow</code>).
+        /// </summary>
+        /// <returns>A <see cref="IEnumerator{LogEntry}"/>.</returns>
+        public IEnumerator<LogEntry> GetEnumerator()
+        {
+            return FullHistory(_repo, _path, _queryFilter).GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        #endregion
+
+        /// <summary>
+        /// Gets the relevant commits in which the given file was created, changed, or renamed.
+        /// </summary>
+        /// <param name="repo">The repository.</param>
+        /// <param name="path">The file's path relative to the repository's root.</param>
+        /// <param name="filter">The filter to be used in querying the commits log.</param>
+        /// <returns>A collection of <see cref="LogEntry"/> instances.</returns>
+        private static IEnumerable<LogEntry> FullHistory(IRepository repo, string path, CommitFilter filter)
+        {
+            var map = new Dictionary<Commit, string>();
+
+            foreach (var currentCommit in repo.Commits.QueryBy(filter))
+            {
+                var currentPath = map.Keys.Count > 0 ? map[currentCommit] : path;
+                var currentTreeEntry = currentCommit.Tree[currentPath];
+
+                if (currentTreeEntry == null)
+                {
+                    yield break;
+                }
+
+                var parentCount = currentCommit.Parents.Count();
+                if (parentCount == 0)
+                {
+                    yield return new LogEntry { Path = currentPath, Commit = currentCommit };
+                }
+                else
+                {
+                    DetermineParentPaths(repo, currentCommit, currentPath, map);
+
+                    if (parentCount != 1)
+                    {
+                        continue;
+                    }
+
+                    var parentCommit = currentCommit.Parents.Single();
+                    var parentPath = map[parentCommit];
+                    var parentTreeEntry = parentCommit.Tree[parentPath];
+
+                    if (parentTreeEntry == null ||
+                        parentTreeEntry.Target.Id != currentTreeEntry.Target.Id ||
+                        parentPath != currentPath)
+                    {
+                        yield return new LogEntry { Path = currentPath, Commit = currentCommit };
+                    }
+                }
+            }
+        }
+
+        private static void DetermineParentPaths(IRepository repo, Commit currentCommit, string currentPath, IDictionary<Commit, string> map)
+        {
+            foreach (var parentCommit in currentCommit.Parents.Where(parentCommit => !map.ContainsKey(parentCommit)))
+            {
+                map.Add(parentCommit, ParentPath(repo, currentCommit, currentPath, parentCommit));
+            }
+        }
+
+        private static string ParentPath(IRepository repo, Commit currentCommit, string currentPath, Commit parentCommit)
+        {
+            var treeChanges = repo.Diff.Compare<TreeChanges>(parentCommit.Tree, currentCommit.Tree);
+            var treeEntryChanges = treeChanges.FirstOrDefault(c => c.Path == currentPath);
+            return treeEntryChanges != null && treeEntryChanges.Status == ChangeKind.Renamed
+                ? treeEntryChanges.OldPath
+                : currentPath;
+        }
+    }
+}

LibGit2Sharp/FollowFilter.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+
+namespace LibGit2Sharp
+{
+    /// <summary>
+    /// Criteria used to order the commits of the repository when querying its history.
+    /// <para>
+    /// The commits will be enumerated from the current HEAD of the repository.
+    /// </para>
+    /// </summary>
+    public sealed class FollowFilter
+    {
+        private static readonly List<CommitSortStrategies> AllowedSortStrategies = new List<CommitSortStrategies>
+        {
+            CommitSortStrategies.Topological,
+            CommitSortStrategies.Time,
+            CommitSortStrategies.Topological | CommitSortStrategies.Time
+        };
+
+        private CommitSortStrategies _sortBy;
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="FollowFilter" />.
+        /// </summary>
+        public FollowFilter()
+        {
+            SortBy = CommitSortStrategies.Time;
+        }
+
+        /// <summary>
+        /// The ordering strategy to use.
+        /// <para>
+        /// By default, the commits are shown in reverse chronological order.
+        /// </para>
+        /// <para>
+        /// Only 'Topological', 'Time', or 'Topological | Time' are allowed.
+        /// </para>
+        /// </summary>
+        public CommitSortStrategies SortBy
+        {
+            get { return _sortBy; }
+
+            set
+            {
+                if (!AllowedSortStrategies.Contains(value))
+                {
+                    throw new ArgumentException(
+                        "Unsupported sort strategy. Only 'Topological', 'Time', or 'Topological | Time' are allowed.",
+                        "value");
+                }
+
+                _sortBy = value;
+            }
+        }
+    }
+}

LibGit2Sharp/IQueryableCommitLog.cs

@@ -15,6 +15,21 @@ public interface IQueryableCommitLog : ICommitLog
         /// <returns>A list of commits, ready to be enumerated.</returns>
         ICommitLog QueryBy(CommitFilter filter);
 
+        /// <summary>
+        /// Returns the list of commits of the repository representing the history of a file beyond renames.
+        /// </summary>
+        /// <param name="path">The file's path.</param>
+        /// <returns>A list of file history entries, ready to be enumerated.</returns>
+        IEnumerable<LogEntry> QueryBy(string path);
+
+        /// <summary>
+        /// Returns the list of commits of the repository representing the history of a file beyond renames.
+        /// </summary>
+        /// <param name="path">The file's path.</param>
+        /// <param name="filter">The options used to control which commits will be returned.</param>
+        /// <returns>A list of file history entries, ready to be enumerated.</returns>
+        IEnumerable<LogEntry> QueryBy(string path, FollowFilter filter);
+
         /// <summary>
         /// Find the best possible merge base given two <see cref="Commit"/>s.
         /// </summary>

LibGit2Sharp/LibGit2Sharp.csproj

@@ -68,6 +68,7 @@
     <Compile Include="CommitOptions.cs" />
     <Compile Include="CommitSortStrategies.cs" />
     <Compile Include="CompareOptions.cs" />
+    <Compile Include="Core\FileHistory.cs" />
     <Compile Include="Core\Platform.cs" />
     <Compile Include="Core\Handles\ConflictIteratorSafeHandle.cs" />
     <Compile Include="DescribeOptions.cs" />
@@ -80,6 +81,8 @@
     <Compile Include="Core\Handles\IndexReucEntrySafeHandle.cs" />
     <Compile Include="EntryExistsException.cs" />
     <Compile Include="FetchOptionsBase.cs" />
+    <Compile Include="LogEntry.cs" />
+    <Compile Include="FollowFilter.cs" />
     <Compile Include="IBelongToARepository.cs" />
     <Compile Include="Identity.cs" />
     <Compile Include="IndexNameEntryCollection.cs" />

LibGit2Sharp/LogEntry.cs

@@ -0,0 +1,18 @@
+namespace LibGit2Sharp
+{
+    /// <summary>
+    /// An entry in a file's commit history.
+    /// </summary>
+    public sealed class LogEntry
+    {
+        /// <summary>
+        /// The file's path relative to the repository's root.
+        /// </summary>
+        public string Path { get; internal set; }
+
+        /// <summary>
+        /// The commit in which the file was created or changed.
+        /// </summary>
+        public Commit Commit { get; internal set; }
+    }
+}