1 files changed, 69 insertions, 43 deletions

diff --git a/llvm/include/llvm/DebugInfo/Msf/StreamRef.h b/llvm/include/llvm/DebugInfo/Msf/StreamRef.h
index e87d298a834..87e53ce4fa4 100644
--- a/llvm/include/llvm/DebugInfo/Msf/StreamRef.h
+++ b/llvm/include/llvm/DebugInfo/Msf/StreamRef.h
@@ -15,17 +15,63 @@
 
 namespace llvm {
 namespace msf {
-
-class StreamRef {
+template <class StreamType, class RefType> class StreamRefBase {
 public:
-  StreamRef() : Stream(nullptr), ViewOffset(0), Length(0) {}
-  StreamRef(const StreamInterface &Stream)
-      : Stream(&Stream), ViewOffset(0), Length(Stream.getLength()) {}
-  StreamRef(const StreamInterface &Stream, uint32_t Offset, uint32_t Length)
+  StreamRefBase() : Stream(nullptr), Length(0), ViewOffset(0) {}
+  StreamRefBase(const StreamType &Stream, uint32_t Offset, uint32_t Length)
       : Stream(&Stream), ViewOffset(Offset), Length(Length) {}
 
+  uint32_t getLength() const { return Length; }
+  const StreamType *getStream() const { return Stream; }
+
+  RefType drop_front(uint32_t N) const {
+    if (!Stream)
+      return RefType();
+
+    N = std::min(N, Length);
+    return RefType(*Stream, ViewOffset + N, Length - N);
+  }
+
+  RefType keep_front(uint32_t N) const {
+    if (!Stream)
+      return RefType();
+    N = std::min(N, Length);
+    return RefType(*Stream, ViewOffset, N);
+  }
+
+  RefType slice(uint32_t Offset, uint32_t Len) const {
+    return drop_front(Offset).keep_front(Len);
+  }
+
+  bool operator==(const RefType &Other) const {
+    if (Stream != Other.Stream)
+      return false;
+    if (ViewOffset != Other.ViewOffset)
+      return false;
+    if (Length != Other.Length)
+      return false;
+    return true;
+  }
+
+protected:
+  const StreamType *Stream;
+  uint32_t ViewOffset;
+  uint32_t Length;
+};
+
+class ReadableStreamRef
+    : public StreamRefBase<ReadableStream, ReadableStreamRef> {
+public:
+  ReadableStreamRef() : StreamRefBase() {}
+  ReadableStreamRef(const ReadableStream &Stream)
+      : StreamRefBase(Stream, 0, Stream.getLength()) {}
+  ReadableStreamRef(const ReadableStream &Stream, uint32_t Offset,
+                    uint32_t Length)
+      : StreamRefBase(Stream, Offset, Length) {}
+
   // Use StreamRef.slice() instead.
-  StreamRef(const StreamRef &S, uint32_t Offset, uint32_t Length) = delete;
+  ReadableStreamRef(const ReadableStreamRef &S, uint32_t Offset,
+                    uint32_t Length) = delete;
 
   Error readBytes(uint32_t Offset, uint32_t Size,
                   ArrayRef<uint8_t> &Buffer) const {
@@ -53,6 +99,21 @@ public:
       Buffer = Buffer.slice(0, MaxLength);
     return Error::success();
   }
+};
+
+class WritableStreamRef
+    : public StreamRefBase<WritableStream, WritableStreamRef> {
+public:
+  WritableStreamRef() : StreamRefBase() {}
+  WritableStreamRef(const WritableStream &Stream)
+      : StreamRefBase(Stream, 0, Stream.getLength()) {}
+  WritableStreamRef(const WritableStream &Stream, uint32_t Offset,
+                    uint32_t Length)
+      : StreamRefBase(Stream, Offset, Length) {}
+
+  // Use StreamRef.slice() instead.
+  WritableStreamRef(const WritableStreamRef &S, uint32_t Offset,
+                    uint32_t Length) = delete;
 
   Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> Data) const {
     if (Data.size() + Offset > Length)
@@ -60,44 +121,9 @@ public:
     return Stream->writeBytes(ViewOffset + Offset, Data);
   }
 
-  uint32_t getLength() const { return Length; }
-
   Error commit() const { return Stream->commit(); }
-
-  StreamRef drop_front(uint32_t N) const {
-    if (!Stream)
-      return StreamRef();
-
-    N = std::min(N, Length);
-    return StreamRef(*Stream, ViewOffset + N, Length - N);
-  }
-
-  StreamRef keep_front(uint32_t N) const {
-    if (!Stream)
-      return StreamRef();
-    N = std::min(N, Length);
-    return StreamRef(*Stream, ViewOffset, N);
-  }
-
-  StreamRef slice(uint32_t Offset, uint32_t Len) const {
-    return drop_front(Offset).keep_front(Len);
-  }
-
-  bool operator==(const StreamRef &Other) const {
-    if (Stream != Other.Stream)
-      return false;
-    if (ViewOffset != Other.ViewOffset)
-      return false;
-    if (Length != Other.Length)
-      return false;
-    return true;
-  }
-
-private:
-  const StreamInterface *Stream;
-  uint32_t ViewOffset;
-  uint32_t Length;
 };
+
 } // namespace msf
 } // namespace llvm