1 files changed, 138 insertions, 0 deletions
diff --git a/Jellyfin.Api/Helpers/HlsHelpers.cs b/Jellyfin.Api/Helpers/HlsHelpers.cs
new file mode 100644
index 000000000..456762147
--- /dev/null
+++ b/Jellyfin.Api/Helpers/HlsHelpers.cs
@@ -0,0 +1,138 @@
+using System;
+using System.Globalization;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Api.Models.StreamingDtos;
+using MediaBrowser.Controller.MediaEncoding;
+using MediaBrowser.Model.IO;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Api.Helpers
+{
+    /// <summary>
+    /// The hls helpers.
+    /// </summary>
+    public static class HlsHelpers
+    {
+        /// <summary>
+        /// Waits for a minimum number of segments to be available.
+        /// </summary>
+        /// <param name="playlist">The playlist string.</param>
+        /// <param name="segmentCount">The segment count.</param>
+        /// <param name="logger">Instance of the <see cref="ILogger"/> interface.</param>
+        /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
+        /// <returns>A <see cref="Task"/> indicating the waiting process.</returns>
+        public static async Task WaitForMinimumSegmentCount(string playlist, int? segmentCount, ILogger logger, CancellationToken cancellationToken)
+        {
+            logger.LogDebug("Waiting for {0} segments in {1}", segmentCount, playlist);
+
+            while (!cancellationToken.IsCancellationRequested)
+            {
+                try
+                {
+                    // Need to use FileShare.ReadWrite because we're reading the file at the same time it's being written
+                    var fileStream = new FileStream(
+                        playlist,
+                        FileMode.Open,
+                        FileAccess.Read,
+                        FileShare.ReadWrite,
+                        IODefaults.FileStreamBufferSize,
+                        FileOptions.Asynchronous | FileOptions.SequentialScan);
+                    await using (fileStream.ConfigureAwait(false))
+                    {
+                        using var reader = new StreamReader(fileStream);
+                        var count = 0;
+
+                        while (!reader.EndOfStream)
+                        {
+                            var line = await reader.ReadLineAsync().ConfigureAwait(false);
+                            if (line == null)
+                            {
+                                // Nothing currently in buffer.
+                                break;
+                            }
+
+                            if (line.IndexOf("#EXTINF:", StringComparison.OrdinalIgnoreCase) != -1)
+                            {
+                                count++;
+                                if (count >= segmentCount)
+                                {
+                                    logger.LogDebug("Finished waiting for {0} segments in {1}", segmentCount, playlist);
+                                    return;
+                                }
+                            }
+                        }
+                    }
+
+                    await Task.Delay(100, cancellationToken).ConfigureAwait(false);
+                }
+                catch (IOException)
+                {
+                    // May get an error if the file is locked
+                }
+
+                await Task.Delay(50, cancellationToken).ConfigureAwait(false);
+            }
+        }
+
+        /// <summary>
+        /// Gets the #EXT-X-MAP string.
+        /// </summary>
+        /// <param name="outputPath">The output path of the file.</param>
+        /// <param name="state">The <see cref="StreamState"/>.</param>
+        /// <param name="isOsDepends">Get a normal string or depends on OS.</param>
+        /// <returns>The string text of #EXT-X-MAP.</returns>
+        public static string GetFmp4InitFileName(string outputPath, StreamState state, bool isOsDepends)
+        {
+            var directory = Path.GetDirectoryName(outputPath) ?? throw new ArgumentException($"Provided path ({outputPath}) is not valid.", nameof(outputPath));
+            var outputFileNameWithoutExtension = Path.GetFileNameWithoutExtension(outputPath);
+            var outputPrefix = Path.Combine(directory, outputFileNameWithoutExtension);
+            var outputExtension = EncodingHelper.GetSegmentFileExtension(state.Request.SegmentContainer);
+
+            // on Linux/Unix
+            // #EXT-X-MAP:URI="prefix-1.mp4"
+            var fmp4InitFileName = outputFileNameWithoutExtension + "-1" + outputExtension;
+            if (!isOsDepends)
+            {
+                return fmp4InitFileName;
+            }
+
+            if (OperatingSystem.IsWindows())
+            {
+                // on Windows
+                // #EXT-X-MAP:URI="X:\transcodes\prefix-1.mp4"
+                fmp4InitFileName = outputPrefix + "-1" + outputExtension;
+            }
+
+            return fmp4InitFileName;
+        }
+
+        /// <summary>
+        /// Gets the hls playlist text.
+        /// </summary>
+        /// <param name="path">The path to the playlist file.</param>
+        /// <param name="state">The <see cref="StreamState"/>.</param>
+        /// <returns>The playlist text as a string.</returns>
+        public static string GetLivePlaylistText(string path, StreamState state)
+        {
+            var text = File.ReadAllText(path);
+
+            var segmentFormat = EncodingHelper.GetSegmentFileExtension(state.Request.SegmentContainer).TrimStart('.');
+            if (string.Equals(segmentFormat, "mp4", StringComparison.OrdinalIgnoreCase))
+            {
+                var fmp4InitFileName = GetFmp4InitFileName(path, state, true);
+                var baseUrlParam = string.Format(
+                    CultureInfo.InvariantCulture,
+                    "hls/{0}/",
+                    Path.GetFileNameWithoutExtension(path));
+                var newFmp4InitFileName = baseUrlParam + GetFmp4InitFileName(path, state, false);
+
+                // Replace fMP4 init file URI.
+                text = text.Replace(fmp4InitFileName, newFmp4InitFileName, StringComparison.InvariantCulture);
+            }
+
+            return text;
+        }
+    }
+}