[PDB] Partial resubmit of r296215, which improved PDB Stream Library.

This was reverted because it was breaking some builds, and
because of incorrect error code usage.  Since the CL was
large and contained many different things, I'm resubmitting
it in pieces.

This portion is NFC, and consists of:

1) Renaming classes to follow a consistent naming convention.
2) Fixing the const-ness of the interface methods.
3) Adding detailed doxygen comments.
4) Fixing a few instances of passing `const BinaryStream& X`.  These
   are now passed as `BinaryStreamRef X`.

llvm-svn: 296394
diff --git a/llvm/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp b/llvm/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
index 60687ac..f8d4432 100644
--- a/llvm/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
@@ -153,18 +153,18 @@
   uint32_t Size = calculateModiSubstreamSize();
   auto Data = Allocator.Allocate<uint8_t>(Size);
 
-  ModInfoBuffer = MutableByteStream(MutableArrayRef<uint8_t>(Data, Size));
+  ModInfoBuffer = MutableBinaryByteStream(MutableArrayRef<uint8_t>(Data, Size));
 
-  StreamWriter ModiWriter(ModInfoBuffer);
+  BinaryStreamWriter ModiWriter(ModInfoBuffer);
   for (const auto &M : ModuleInfoList) {
     ModuleInfoHeader Layout = {};
     Layout.ModDiStream = kInvalidStreamIndex;
     Layout.NumFiles = M->SourceFiles.size();
     if (auto EC = ModiWriter.writeObject(Layout))
       return EC;
-    if (auto EC = ModiWriter.writeZeroString(M->Mod))
+    if (auto EC = ModiWriter.writeCString(M->Mod))
       return EC;
-    if (auto EC = ModiWriter.writeZeroString(M->Obj))
+    if (auto EC = ModiWriter.writeCString(M->Obj))
       return EC;
   }
   if (ModiWriter.bytesRemaining() > sizeof(uint32_t))
@@ -179,11 +179,12 @@
   auto Data = Allocator.Allocate<uint8_t>(Size);
   uint32_t NamesOffset = Size - NameSize;
 
-  FileInfoBuffer = MutableByteStream(MutableArrayRef<uint8_t>(Data, Size));
+  FileInfoBuffer =
+      MutableBinaryByteStream(MutableArrayRef<uint8_t>(Data, Size));
 
-  WritableStreamRef MetadataBuffer =
-      WritableStreamRef(FileInfoBuffer).keep_front(NamesOffset);
-  StreamWriter MetadataWriter(MetadataBuffer);
+  WritableBinaryStreamRef MetadataBuffer =
+      WritableBinaryStreamRef(FileInfoBuffer).keep_front(NamesOffset);
+  BinaryStreamWriter MetadataWriter(MetadataBuffer);
 
   uint16_t ModiCount = std::min<uint32_t>(UINT16_MAX, ModuleInfos.size());
   uint16_t FileCount = std::min<uint32_t>(UINT16_MAX, SourceFileNames.size());
@@ -209,11 +210,11 @@
   // A side effect of this is that this will actually compute the various
   // file name offsets, so we can then go back and write the FileNameOffsets
   // array to the other substream.
-  NamesBuffer = WritableStreamRef(FileInfoBuffer).drop_front(NamesOffset);
-  StreamWriter NameBufferWriter(NamesBuffer);
+  NamesBuffer = WritableBinaryStreamRef(FileInfoBuffer).drop_front(NamesOffset);
+  BinaryStreamWriter NameBufferWriter(NamesBuffer);
   for (auto &Name : SourceFileNames) {
     Name.second = NameBufferWriter.getOffset();
-    if (auto EC = NameBufferWriter.writeZeroString(Name.getKey()))
+    if (auto EC = NameBufferWriter.writeCString(Name.getKey()))
       return EC;
   }
 
@@ -363,14 +364,14 @@
 }
 
 Error DbiStreamBuilder::commit(const msf::MSFLayout &Layout,
-                               const msf::WritableStream &Buffer) {
+                               WritableBinaryStreamRef Buffer) {
   if (auto EC = finalize())
     return EC;
 
   auto InfoS =
       WritableMappedBlockStream::createIndexedStream(Layout, Buffer, StreamDBI);
 
-  StreamWriter Writer(*InfoS);
+  BinaryStreamWriter Writer(*InfoS);
   if (auto EC = Writer.writeObject(*Header))
     return EC;
 
@@ -404,9 +405,9 @@
   for (auto &Stream : DbgStreams) {
     if (Stream.StreamNumber == kInvalidStreamIndex)
       continue;
-    auto WritableStream = WritableMappedBlockStream::createIndexedStream(
+    auto WritableBinaryStream = WritableMappedBlockStream::createIndexedStream(
         Layout, Buffer, Stream.StreamNumber);
-    StreamWriter DbgStreamWriter(*WritableStream);
+    BinaryStreamWriter DbgStreamWriter(*WritableBinaryStream);
     if (auto EC = DbgStreamWriter.writeArray(Stream.Data))
       return EC;
   }