Breaking Change: Mark final ZeroCopyInputStream, ZeroCopyOutputStream…

…, and DefaultFieldComparator classes.

PiperOrigin-RevId: 503297575

src/google/protobuf/io/gzip_stream.h

@@ -56,8 +56,7 @@ namespace protobuf {
 namespace io {
 
 // A ZeroCopyInputStream that reads compressed data through zlib
-class PROTOBUF_EXPORT GzipInputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyInputStream {
+class PROTOBUF_EXPORT GzipInputStream final : public ZeroCopyInputStream {
  public:
   // Format key for constructor
   enum Format {
@@ -105,8 +104,7 @@ class PROTOBUF_EXPORT GzipInputStream PROTOBUF_FUTURE_FINAL
   void DoNextOutput(const void** data, int* size);
 };
 
-class PROTOBUF_EXPORT GzipOutputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyOutputStream {
+class PROTOBUF_EXPORT GzipOutputStream final : public ZeroCopyOutputStream {
  public:
   // Format key for constructor
   enum Format {

src/google/protobuf/io/zero_copy_stream_impl.h

@@ -62,8 +62,7 @@ namespace io {
 // The latter will introduce an extra layer of buffering, harming performance.
 // Also, it's conceivable that FileInputStream could someday be enhanced
 // to use zero-copy file descriptors on OSs which support them.
-class PROTOBUF_EXPORT FileInputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyInputStream {
+class PROTOBUF_EXPORT FileInputStream final : public ZeroCopyInputStream {
  public:
   // Creates a stream that reads from the given Unix file descriptor.
   // If a block_size is given, it specifies the number of bytes that
@@ -98,7 +97,7 @@ class PROTOBUF_EXPORT FileInputStream PROTOBUF_FUTURE_FINAL
   int64_t ByteCount() const override;
 
  private:
-  class PROTOBUF_EXPORT CopyingFileInputStream PROTOBUF_FUTURE_FINAL
+  class PROTOBUF_EXPORT CopyingFileInputStream final
       : public CopyingInputStream {
    public:
     CopyingFileInputStream(int file_descriptor);
@@ -141,7 +140,7 @@ class PROTOBUF_EXPORT FileInputStream PROTOBUF_FUTURE_FINAL
 // harming performance.  Also, it's conceivable that FileOutputStream could
 // someday be enhanced to use zero-copy file descriptors on OSs which
 // support them.
-class PROTOBUF_EXPORT FileOutputStream PROTOBUF_FUTURE_FINAL
+class PROTOBUF_EXPORT FileOutputStream final
     : public CopyingOutputStreamAdaptor {
  public:
   // Creates a stream that writes to the given Unix file descriptor.
@@ -173,7 +172,7 @@ class PROTOBUF_EXPORT FileOutputStream PROTOBUF_FUTURE_FINAL
   int GetErrno() const { return copying_output_.GetErrno(); }
 
  private:
-  class PROTOBUF_EXPORT CopyingFileOutputStream PROTOBUF_FUTURE_FINAL
+  class PROTOBUF_EXPORT CopyingFileOutputStream final
       : public CopyingOutputStream {
    public:
     CopyingFileOutputStream(int file_descriptor);
@@ -207,8 +206,7 @@ class PROTOBUF_EXPORT FileOutputStream PROTOBUF_FUTURE_FINAL
 //
 // Note that for reading files (or anything represented by a file descriptor),
 // FileInputStream is more efficient.
-class PROTOBUF_EXPORT IstreamInputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyInputStream {
+class PROTOBUF_EXPORT IstreamInputStream final : public ZeroCopyInputStream {
  public:
   // Creates a stream that reads from the given C++ istream.
   // If a block_size is given, it specifies the number of bytes that
@@ -225,7 +223,7 @@ class PROTOBUF_EXPORT IstreamInputStream PROTOBUF_FUTURE_FINAL
   int64_t ByteCount() const override;
 
  private:
-  class PROTOBUF_EXPORT CopyingIstreamInputStream PROTOBUF_FUTURE_FINAL
+  class PROTOBUF_EXPORT CopyingIstreamInputStream final
       : public CopyingInputStream {
    public:
     CopyingIstreamInputStream(std::istream* input);
@@ -253,8 +251,7 @@ class PROTOBUF_EXPORT IstreamInputStream PROTOBUF_FUTURE_FINAL
 //
 // Note that for writing files (or anything represented by a file descriptor),
 // FileOutputStream is more efficient.
-class PROTOBUF_EXPORT OstreamOutputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyOutputStream {
+class PROTOBUF_EXPORT OstreamOutputStream final : public ZeroCopyOutputStream {
  public:
   // Creates a stream that writes to the given C++ ostream.
   // If a block_size is given, it specifies the size of the buffers
@@ -271,7 +268,7 @@ class PROTOBUF_EXPORT OstreamOutputStream PROTOBUF_FUTURE_FINAL
   int64_t ByteCount() const override;
 
  private:
-  class PROTOBUF_EXPORT CopyingOstreamOutputStream PROTOBUF_FUTURE_FINAL
+  class PROTOBUF_EXPORT CopyingOstreamOutputStream final
       : public CopyingOutputStream {
    public:
     CopyingOstreamOutputStream(std::ostream* output);
@@ -301,7 +298,7 @@ class PROTOBUF_EXPORT OstreamOutputStream PROTOBUF_FUTURE_FINAL
 // ConcatenatingInputStream may do odd things.  It is suggested that you do
 // not use ConcatenatingInputStream on streams that might produce read errors
 // other than end-of-stream.
-class PROTOBUF_EXPORT ConcatenatingInputStream PROTOBUF_FUTURE_FINAL
+class PROTOBUF_EXPORT ConcatenatingInputStream final
     : public ZeroCopyInputStream {
  public:
   // All streams passed in as well as the array itself must remain valid

src/google/protobuf/io/zero_copy_stream_impl_lite.h

@@ -68,8 +68,7 @@ namespace io {
 // ===================================================================
 
 // A ZeroCopyInputStream backed by an in-memory array of bytes.
-class PROTOBUF_EXPORT ArrayInputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyInputStream {
+class PROTOBUF_EXPORT ArrayInputStream final : public ZeroCopyInputStream {
  public:
   // Create an InputStream that returns the bytes pointed to by "data".
   // "data" remains the property of the caller but must remain valid until
@@ -105,8 +104,7 @@ class PROTOBUF_EXPORT ArrayInputStream PROTOBUF_FUTURE_FINAL
 // ===================================================================
 
 // A ZeroCopyOutputStream backed by an in-memory array of bytes.
-class PROTOBUF_EXPORT ArrayOutputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyOutputStream {
+class PROTOBUF_EXPORT ArrayOutputStream final : public ZeroCopyOutputStream {
  public:
   // Create an OutputStream that writes to the bytes pointed to by "data".
   // "data" remains the property of the caller but must remain valid until
@@ -140,8 +138,7 @@ class PROTOBUF_EXPORT ArrayOutputStream PROTOBUF_FUTURE_FINAL
 // ===================================================================
 
 // A ZeroCopyOutputStream which appends bytes to a string.
-class PROTOBUF_EXPORT StringOutputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyOutputStream {
+class PROTOBUF_EXPORT StringOutputStream final : public ZeroCopyOutputStream {
  public:
   // Create a StringOutputStream which appends bytes to the given string.
   // The string remains property of the caller, but it is mutated in arbitrary
@@ -364,8 +361,7 @@ class PROTOBUF_EXPORT CopyingOutputStreamAdaptor : public ZeroCopyOutputStream {
 
 // A ZeroCopyInputStream which wraps some other stream and limits it to
 // a particular byte count.
-class PROTOBUF_EXPORT LimitingInputStream PROTOBUF_FUTURE_FINAL
-    : public ZeroCopyInputStream {
+class PROTOBUF_EXPORT LimitingInputStream final : public ZeroCopyInputStream {
  public:
   LimitingInputStream(ZeroCopyInputStream* input, int64_t limit);
   ~LimitingInputStream() override;

src/google/protobuf/port_def.inc

@@ -208,11 +208,6 @@ static_assert(PROTOBUF_CPLUSPLUS_MIN(201402L), "Protobuf only supports C++14 and
 // Owner: mordberg@
 #define PROTOBUF_FUTURE_MAP_PAIR_UPGRADE 1
 
-// Used on classes that are historically not marked as final, but that may be
-// marked final in future (breaking) releases.
-// Owner: kfm@
-#define PROTOBUF_FUTURE_FINAL final
-
 // Used to remove the RTTI checks for `DefaultFieldComparator`.
 // Owner: kfm@
 #define PROTOBUF_FUTURE_REMOVE_DEFAULT_FIELD_COMPARATOR 1
@@ -221,8 +216,6 @@ static_assert(PROTOBUF_CPLUSPLUS_MIN(201402L), "Protobuf only supports C++14 and
 // Owner: mkruskal@
 #define PROTOBUF_FUTURE_REMOVE_CLEARED_API 1
 
-#else
-#define PROTOBUF_FUTURE_FINAL
 #endif
 
 #ifdef PROTOBUF_VERSION

src/google/protobuf/port_undef.inc

@@ -88,7 +88,6 @@
 #undef PROTOBUF_EXPORT_TEMPLATE_DEFINE
 #undef PROTOBUF_ALIGNAS
 #undef PROTOBUF_FINAL
-#undef PROTOBUF_FUTURE_FINAL
 #undef PROTOBUF_THREAD_LOCAL
 #undef PROTOBUF_LITTLE_ENDIAN
 #undef PROTOBUF_BIG_ENDIAN
@@ -123,8 +122,6 @@
 #undef PROTOBUF_FUTURE_REMOVE_CLEARED_API
 #endif
 
-#undef PROTOBUF_FUTURE_FINAL
-
 // Restore macros that may have been #undef'd in port_def.inc.
 
 #ifdef PROTOBUF_DID_UNDEF_PACKAGE

src/google/protobuf/util/field_comparator.h

@@ -258,7 +258,7 @@ class PROTOBUF_EXPORT SimpleFieldComparator : public FieldComparator {
 };
 
 // Default field comparison: use the basic implementation of FieldComparator.
-class PROTOBUF_EXPORT DefaultFieldComparator PROTOBUF_FUTURE_FINAL
+class PROTOBUF_EXPORT DefaultFieldComparator final
     : public SimpleFieldComparator {
  public:
   ComparisonResult Compare(const Message& message_1, const Message& message_2,