MpdBuilder should be able to write to File instance

Change interface of MpdBuilder so that it can write to a File instance
directly.

Change-Id: I4007deed4d0246a7c75fbc7c5aca3ece374c1224

mpd/base/mpd_builder.cc

@@ -15,6 +15,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
+#include "media/file/file.h"
 #include "mpd/base/content_protection_element.h"
 #include "mpd/base/mpd_utils.h"
 #include "mpd/base/xml/xml_node.h"
@@ -156,6 +157,29 @@ int SearchTimedOutRepeatIndex(uint64 timeshift_limit,
   return (timeshift_limit - segment_info.start_time) / segment_info.duration;
 }
 
+// Overload this function to support different types of |output|.
+// Note that this could be done by call MpdBuilder::ToString() and use the
+// result to write to a file, it requires an extra copy.
+bool WriteXmlCharArrayToOutput(xmlChar* doc,
+                               int doc_size,
+                               std::string* output) {
+  DCHECK(doc);
+  DCHECK(output);
+  output->assign(doc, doc + doc_size);
+  return true;
+}
+
+bool WriteXmlCharArrayToOutput(xmlChar* doc,
+                               int doc_size,
+                               media::File* output) {
+  DCHECK(doc);
+  DCHECK(output);
+  if (output->Write(doc, doc_size) < doc_size)
+    return false;
+
+  return output->Flush();
+}
+
 }  // namespace
 
 MpdOptions::MpdOptions()
@@ -190,12 +214,20 @@ AdaptationSet* MpdBuilder::AddAdaptationSet() {
   return adaptation_set.release();
 }
 
-bool MpdBuilder::ToString(std::string* output) {
+bool MpdBuilder::WriteMpdToFile(media::File* output_file) {
   base::AutoLock scoped_lock(lock_);
-  return ToStringImpl(output);
+  DCHECK(output_file);
+  return WriteMpdToOutput(output_file);
 }
 
-bool MpdBuilder::ToStringImpl(std::string* output) {
+bool MpdBuilder::ToString(std::string* output) {
+  base::AutoLock scoped_lock(lock_);
+  DCHECK(output);
+  return WriteMpdToOutput(output);
+}
+
+template <typename OutputType>
+bool MpdBuilder::WriteMpdToOutput(OutputType* output) {
   xmlInitParser();
   xml::ScopedXmlPtr<xmlDoc>::type doc(GenerateMpd());
   if (!doc.get())
@@ -207,15 +239,13 @@ bool MpdBuilder::ToStringImpl(std::string* output) {
   xmlDocDumpFormatMemoryEnc(
       doc.get(), &doc_str, &doc_str_size, "UTF-8", kNiceFormat);
 
-  output->assign(doc_str, doc_str + doc_str_size);
+  bool result = WriteXmlCharArrayToOutput(doc_str, doc_str_size, output);
   xmlFree(doc_str);
 
-  DLOG(INFO) << *output;
-
   // Cleanup, free the doc then cleanup parser.
   doc.reset();
   xmlCleanupParser();
-  return true;
+  return result;
 }
 
 xmlDocPtr MpdBuilder::GenerateMpd() {

mpd/base/mpd_builder.h

@@ -25,6 +25,13 @@
 #include "mpd/base/segment_info.h"
 #include "mpd/base/xml/scoped_xml_ptr.h"
 
+namespace media {
+class File;
+}
+
+// TODO(rkuroiwa): For classes with |id_|, consider removing the field and let
+// the MPD (XML) generation functions take care of assigning an ID to each
+// element.
 namespace dash_packager {
 
 class AdaptationSet;
@@ -70,6 +77,12 @@ class MpdBuilder {
   /// @return The new adaptation set, which is owned by this instance.
   AdaptationSet* AddAdaptationSet();
 
+  /// Write the MPD to specified file.
+  /// @param[out] output_file is MPD destination. output_file will be
+  ///             flushed but not closed.
+  /// @return true on success, false otherwise.
+  bool WriteMpdToFile(media::File* output_file);
+
   /// Writes the MPD to the given string.
   /// @param[out] output is an output string where the MPD gets written.
   /// @return true on success, false otherwise.
@@ -85,6 +98,11 @@ class MpdBuilder {
 
   bool ToStringImpl(std::string* output);
 
+  // This is a helper method for writing out MPDs, called from WriteMpdToFile()
+  // and ToString().
+  template <typename OutputType>
+  bool WriteMpdToOutput(OutputType* output);
+
   // Returns the document pointer to the MPD. This must be freed by the caller
   // using appropriate xmlDocPtr freeing function.
   // On failure, this returns NULL.

mpd/base/mpd_builder_unittest.cc

@@ -11,6 +11,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
+#include "media/file/file.h"
 #include "mpd/base/mpd_builder.h"
 #include "mpd/base/mpd_utils.h"
 #include "mpd/test/mpd_builder_test_helper.h"
@@ -362,6 +363,31 @@ TEST_F(StaticMpdBuilderTest, MediaInfoMissingBandwidth) {
   ASSERT_FALSE(mpd_.ToString(&mpd_doc));
 }
 
+TEST_F(StaticMpdBuilderTest, WriteToFile) {
+  MediaInfo video_media_info = GetTestMediaInfo(kFileNameVideoMediaInfo1);
+  AdaptationSet* video_adaptation_set = mpd_.AddAdaptationSet();
+  ASSERT_TRUE(video_adaptation_set);
+
+  Representation* video_representation =
+      video_adaptation_set->AddRepresentation(video_media_info);
+  ASSERT_TRUE(video_representation);
+
+  base::FilePath file_path;
+  ASSERT_TRUE(base::CreateTemporaryFile(&file_path));
+  media::File* file = media::File::Open(file_path.value().data(), "w");
+  ASSERT_TRUE(file);
+  ASSERT_TRUE(mpd_.WriteMpdToFile(file));
+  ASSERT_TRUE(file->Close());
+
+  std::string file_content;
+  ASSERT_TRUE(base::ReadFileToString(file_path, &file_content));
+  ASSERT_NO_FATAL_FAILURE(ExpectMpdToEqualExpectedOutputFile(
+      file_content, kFileNameExpectedMpdOutputVideo1));
+
+  const bool kNonRecursive = false;
+  EXPECT_TRUE(DeleteFile(file_path, kNonRecursive));
+}
+
 // Check whether the attributes are set correctly for dynamic <MPD> element.
 TEST_F(DynamicMpdBuilderTest, CheckMpdAttributes) {
   static const char kExpectedOutput[] =

mpd/mpd.gyp

@@ -51,6 +51,7 @@
       ],
       'dependencies': [
         '../base/base.gyp:base',
+        '../media/file/file.gyp:file',
         '../third_party/libxml/libxml.gyp:libxml',
         'media_info_proto',
       ],