mkvmuxer: Add Init method to Cluster and Segment.

Remove asserts on the MkvWriter pointer in each constructor,
and assign the pointer in each Init method. Update Segment::Init
usage site in sample_muxer.

Change-Id: Id940f76b50dc15603742e76afc04cdffe0ec4990

mkvmuxer.cpp

@@ -986,7 +986,7 @@ bool Tracks::Write(IMkvWriter* writer) const {
 //
 // Cluster Class
 
-Cluster::Cluster(uint64 timecode, IMkvWriter* writer, int64 cues_pos)
+Cluster::Cluster(uint64 timecode, int64 cues_pos)
     : blocks_added_(0),
       finalized_(false),
       header_written_(false),
@@ -994,13 +994,20 @@ Cluster::Cluster(uint64 timecode, IMkvWriter* writer, int64 cues_pos)
       position_for_cues_(cues_pos),
       size_position_(-1),
       timecode_(timecode),
-      writer_(writer) {
-  assert(writer_);
+      writer_(NULL) {
 }
 
 Cluster::~Cluster() {
 }
 
+bool Cluster::Init(IMkvWriter* ptr_writer) {
+  if (!ptr_writer) {
+    return false;
+  }
+  writer_ = ptr_writer;
+  return true;
+}
+
 bool Cluster::AddFrame(const uint8* frame,
                        uint64 length,
                        uint64 track_number,
@@ -1352,7 +1359,7 @@ void SegmentInfo::set_writing_app(const char* app) {
 //
 // Segment Class
 
-Segment::Segment(IMkvWriter* writer)
+Segment::Segment()
     : chunk_count_(0),
       chunk_name_(NULL),
       chunk_writer_cluster_(NULL),
@@ -1378,13 +1385,9 @@ Segment::Segment(IMkvWriter* writer)
       output_cues_(true),
       payload_pos_(0),
       size_position_(0),
-      writer_cluster_(writer),
-      writer_cues_(writer),
-      writer_header_(writer) {
-  assert(writer_cluster_);
-
-  // TODO(fgalligan): Create an Init function for Segment.
-  segment_info_.Init();
+      writer_cluster_(NULL),
+      writer_cues_(NULL),
+      writer_header_(NULL) {
 }
 
 Segment::~Segment() {
@@ -1421,6 +1424,16 @@ Segment::~Segment() {
   }
 }
 
+bool Segment::Init(IMkvWriter* ptr_writer) {
+  if (!ptr_writer) {
+    return false;
+  }
+  writer_cluster_ = ptr_writer;
+  writer_cues_ = ptr_writer;
+  writer_header_ = ptr_writer;
+  return segment_info_.Init();
+}
+
 bool Segment::Finalize() {
   if (!WriteFramesAll())
     return false;
@@ -1650,11 +1663,17 @@ bool Segment::AddFrame(const uint8* frame,
     // are valid.
 
     cluster_list_[cluster_list_size_] =
-        new (std::nothrow) Cluster(timecode,
-                                   writer_cluster_,
-                                   MaxOffset());
+        new (std::nothrow) Cluster(timecode, MaxOffset());
+
     if (!cluster_list_[cluster_list_size_])
       return false;
+
+    const bool cluster_init_ok =
+        cluster_list_[cluster_list_size_]->Init(writer_cluster_);
+
+    if (!cluster_init_ok)
+      return false;
+
     cluster_list_size_ = new_size;
     new_cluster_ = false;
   }

mkvmuxer.hpp

@@ -436,13 +436,18 @@ class Tracks {
 
 ///////////////////////////////////////////////////////////////
 // Cluster element
+//
+// Notes:
+//  |Init| must be called before any other method in this class.
 class Cluster {
  public:
+  Cluster(uint64 timecode, int64 cues_pos);
+  ~Cluster();
+
   // |timecode| is the absolute timecode of the cluster. |cues_pos| is the
   // position for the cluster within the segment that should be written in
   // the cues element.
-  Cluster(uint64 timecode, IMkvWriter* writer, int64 cues_pos);
-  ~Cluster();
+  bool Init(IMkvWriter* ptr_writer);
 
   // Adds a frame to be output in the file. The frame is written out through
   // |writer_| if successful. Returns true on success.
@@ -491,7 +496,7 @@ class Cluster {
   uint64 payload_size_;
 
   // The file position used for cue points.
-  int64 position_for_cues_;
+  const int64 position_for_cues_;
 
   // The file position of the cluster's size element.
   int64 size_position_;
@@ -591,6 +596,9 @@ class SegmentInfo {
 ///////////////////////////////////////////////////////////////
 // This class represents the main segment in a WebM file. Currently only
 // supports one Segment element.
+//
+// Notes:
+//  |Init| must be called before any other method in this class.
 class Segment {
  public:
   enum Mode {
@@ -600,9 +608,13 @@ class Segment {
 
   const static uint64 kDefaultMaxClusterDuration = 30000000000ULL;
 
-  explicit Segment(IMkvWriter* writer);
+  Segment();
   virtual ~Segment();
 
+  // Initializes |SegmentInfo| and returns result. Always returns false when
+  // |ptr_writer| is NULL.
+  bool Init(IMkvWriter* ptr_writer);
+
   // Adds an audio track to the segment. Returns the number of the track on
   // success, 0 on error.
   uint64 AddAudioTrack(int32 sample_rate, int32 channels);

sample_muxer/sample_muxer.cpp

@@ -171,7 +171,13 @@ int main(int argc, char* argv[]) {
   }
 
   // Set Segment element attributes
-  mkvmuxer::Segment muxer_segment(&writer);
+  mkvmuxer::Segment muxer_segment;
+
+  if (!muxer_segment.Init(&writer)) {
+    printf("\n Could not initialize muxer segment!\n");
+    return -1;
+  }
+
   if (live_mode)
     muxer_segment.set_mode(mkvmuxer::Segment::kLive);
   else