Added TextSample

Added a text sample type that can be passed between media handlers.
This will allow text samples to safely be moved between media
handlers before converting to their final format.

Bug: 36138902
Change-Id: Ic4946f774a7d37c43066b9ea46596d5c5f3c05a8

packager/media/base/media_base.gyp

@@ -84,6 +84,8 @@
         'status.h',
         'stream_info.cc',
         'stream_info.h',
+        'text_sample.cc',
+        'text_sample.h',
         'text_stream_info.cc',
         'text_stream_info.h',
         'text_track.h',

packager/media/base/media_handler.h

@@ -14,6 +14,7 @@
 #include "packager/media/base/media_sample.h"
 #include "packager/media/base/status.h"
 #include "packager/media/base/stream_info.h"
+#include "packager/media/base/text_sample.h"
 
 namespace shaka {
 namespace media {
@@ -23,6 +24,7 @@ enum class StreamDataType {
   kPeriodInfo,
   kStreamInfo,
   kMediaSample,
+  kTextSample,
   kMediaEvent,
   kSegmentInfo,
 };
@@ -49,6 +51,7 @@ struct StreamData {
   std::shared_ptr<PeriodInfo> period_info;
   std::shared_ptr<StreamInfo> stream_info;
   std::shared_ptr<MediaSample> media_sample;
+  std::shared_ptr<TextSample> text_sample;
   std::shared_ptr<MediaEvent> media_event;
   std::shared_ptr<SegmentInfo> segment_info;
 };
@@ -140,6 +143,17 @@ class MediaHandler {
     return Dispatch(std::move(stream_data));
   }
 
+  /// Dispatch the text sample to downsream handlers.
+  // DispatchTextSample should only be override for testing.
+  Status DispatchTextSample(size_t stream_index,
+                            std::shared_ptr<TextSample> text_sample) {
+    std::unique_ptr<StreamData> stream_data(new StreamData);
+    stream_data->stream_index = stream_index;
+    stream_data->stream_data_type = StreamDataType::kTextSample;
+    stream_data->text_sample = std::move(text_sample);
+    return Dispatch(std::move(stream_data));
+  }
+
   /// Dispatch the media event to downstream handlers.
   Status DispatchMediaEvent(size_t stream_index,
                             std::shared_ptr<MediaEvent> media_event) {

packager/media/base/text_sample.cc

@@ -0,0 +1,32 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+#include "packager/media/base/text_sample.h"
+
+#include "packager/base/logging.h"
+
+namespace shaka {
+namespace media {
+
+uint64_t TextSample::EndTime() const {
+  return start_time_ + duration_;
+}
+
+void TextSample::SetTime(uint64_t start_time, uint64_t end_time) {
+  DCHECK_LT(start_time, end_time);
+  start_time_ = start_time;
+  duration_ = end_time - start_time;
+}
+
+void TextSample::AppendPayload(const std::string& payload) {
+  if (payload_.length()) {
+    payload_ += "\n";
+  }
+  payload_ += payload;
+}
+
+}  // namespace media
+}  // namespace shaka

packager/media/base/text_sample.h

@@ -0,0 +1,47 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+#ifndef PACKAGER_MEDIA_BASE_TEXT_SAMPLE_H_
+#define PACKAGER_MEDIA_BASE_TEXT_SAMPLE_H_
+
+#include <stdint.h>
+
+#include <string>
+
+namespace shaka {
+namespace media {
+
+class TextSample {
+ public:
+  TextSample() = default;
+
+  const std::string& id() const { return id_; }
+  uint64_t start_time() const { return start_time_; }
+  uint64_t duration() const { return duration_; }
+  const std::string& settings() const { return settings_; }
+  const std::string& payload() const { return payload_; }
+  uint64_t EndTime() const;
+
+  void set_id(const std::string& id) { id_ = id; }
+  void set_settings(const std::string& settings) { settings_ = settings; }
+  void SetTime(uint64_t start_time, uint64_t end_time);
+  void AppendPayload(const std::string& payload);
+
+ private:
+  TextSample(const TextSample&) = delete;
+  TextSample& operator=(const TextSample&) = delete;
+
+  std::string id_;
+  uint64_t start_time_ = 0;
+  uint64_t duration_ = 0;
+  std::string settings_;
+  std::string payload_;
+};
+
+}  // namespace media
+}  // namespace shaka
+
+#endif  // MEDIA_BASE_TEXT_SAMPLE_H_