Move ChainHandlers to MediaHandler

Made ChainHandlers to MediaHandler::Chain so that it can be used in our
test code as well. After all it is a pretty helpful function.

Change-Id: I8d83ee184052cd9fa9b37f2741c96f3223d5ab48

packager/media/base/media_handler.cc

@@ -6,6 +6,8 @@
 
 #include "packager/media/base/media_handler.h"
 
+#include "packager/status_macros.h"
+
 namespace shaka {
 namespace media {
 
@@ -58,6 +60,26 @@ Status MediaHandler::Initialize() {
   return Status::OK;
 }
 
+Status MediaHandler::Chain(
+    std::initializer_list<std::shared_ptr<MediaHandler>> list) {
+  std::shared_ptr<MediaHandler> previous;
+
+  for (auto& next : list) {
+    // Skip null entries.
+    if (!next) {
+      continue;
+    }
+
+    if (previous) {
+      RETURN_IF_ERROR(previous->AddHandler(next));
+    }
+
+    previous = std::move(next);
+  }
+
+  return Status::OK;
+}
+
 Status MediaHandler::OnFlushRequest(size_t input_stream_index) {
   // The default implementation treats the output stream index to be identical
   // to the input stream index, which is true for most handlers.
@@ -98,6 +120,5 @@ Status MediaHandler::FlushAllDownstreams() {
   }
   return Status::OK;
 }
-
 }  // namespace media
 }  // namespace shaka

packager/media/base/media_handler.h

@@ -172,6 +172,9 @@ class MediaHandler {
   /// Validate if the handler is connected to its upstream handler.
   bool IsConnected() { return num_input_streams_ > 0; }
 
+  static Status Chain(
+      std::initializer_list<std::shared_ptr<MediaHandler>> list);
+
  protected:
   /// Internal implementation of initialize. Note that it should only initialize
   /// the MediaHandler itself. Downstream handlers are handled in Initialize().

packager/packager.cc

@@ -67,26 +67,6 @@ namespace {
 
 const char kMediaInfoSuffix[] = ".media_info";
 
-Status ChainHandlers(
-    std::initializer_list<std::shared_ptr<MediaHandler>> list) {
-  std::shared_ptr<MediaHandler> previous;
-
-  for (auto& next : list) {
-    // Skip null entries.
-    if (!next) {
-      continue;
-    }
-
-    if (previous) {
-      RETURN_IF_ERROR(previous->AddHandler(next));
-    }
-
-    previous = std::move(next);
-  }
-
-  return Status::OK;
-}
-
 MuxerOptions CreateMuxerOptions(const StreamDescriptor& stream,
                                 const PackagingParams& params) {
   MuxerOptions options;
@@ -497,7 +477,7 @@ Status CreateHlsTextJob(const StreamDescriptor& stream,
 
   job_manager->Add("Segmented Text Job", parser);
 
-  return ChainHandlers({std::move(parser), std::move(padder),
+  return MediaHandler::Chain({std::move(parser), std::move(padder),
                               std::move(cue_aligner), std::move(chunker),
                               std::move(output)});
 }
@@ -531,7 +511,7 @@ Status CreateWebVttToMp4TextJob(const StreamDescriptor& stream,
 
   *root = parser;
 
-  return ChainHandlers({std::move(parser), std::move(padder),
+  return MediaHandler::Chain({std::move(parser), std::move(padder),
                               std::move(cue_aligner), std::move(chunker),
                               std::move(text_to_mp4), std::move(muxer)});
 }
@@ -710,11 +690,11 @@ Status CreateAudioVideoJobs(
       // TODO(vaage) : Create a nicer way to connect handlers to demuxers.
       if (sync_points) {
         RETURN_IF_ERROR(
-            ChainHandlers({cue_aligner, chunker, encryptor, replicator}));
+            MediaHandler::Chain({cue_aligner, chunker, encryptor, replicator}));
         RETURN_IF_ERROR(
             demuxer->SetHandler(stream.stream_selector, cue_aligner));
       } else {
-        RETURN_IF_ERROR(ChainHandlers({chunker, encryptor, replicator}));
+        RETURN_IF_ERROR(MediaHandler::Chain({chunker, encryptor, replicator}));
         RETURN_IF_ERROR(demuxer->SetHandler(stream.stream_selector, chunker));
       }
     }
@@ -738,7 +718,7 @@ Status CreateAudioVideoJobs(
             ? std::make_shared<TrickPlayHandler>(stream.trick_play_factor)
             : nullptr;
 
-    RETURN_IF_ERROR(ChainHandlers({replicator, trick_play, muxer}));
+    RETURN_IF_ERROR(MediaHandler::Chain({replicator, trick_play, muxer}));
   }
 
   return Status::OK;