Refactor Pipe implementation

* Remove Pipe classes
* Rename BasePipe to Pipe
* Hide Pipe class in anonymous namespace in pipe.cc
* Add CreatePipe static method
* Replace Payload(std::function<InputStream&()>) with Payload(std::unique_ptr<InputStream>)
* Find&Replace Pipe usages

PiperOrigin-RevId: 557276980

connections/swift/NearbyCoreAdapter/Sources/CPPInputStream.h

@@ -0,0 +1,45 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Note: File language is detected using heuristics. Many Objective-C++ headers
+// are incorrectly classified as C++ resulting in invalid linter errors. The use
+// of "NSArray" and other Foundation classes like "NSData", "NSDictionary" and
+// "NSUUID" are highly weighted for Objective-C and Objective-C++ scores. Oddly,
+// "#import <Foundation/Foundation.h>" does not contribute any points. This
+// comment alone should be enough to trick the IDE in to believing this is
+// actually some sort of Objective-C file. See:
+// cs/google3/devtools/search/lang/recognize_language_classifiers_data
+
+#import <Foundation/Foundation.h>
+
+#ifdef __cplusplus
+
+// TODO(b/239758418): Change this to the non-internal version when available.
+#include "internal/platform/input_stream.h"
+
+class CPPInputStream : public nearby::InputStream {
+ public:
+  explicit CPPInputStream(NSInputStream *iStream);
+
+  ~CPPInputStream() override;
+
+  nearby::ExceptionOr<nearby::ByteArray> Read(std::int64_t size) override;
+
+  nearby::Exception Close() override;
+
+ private:
+  NSInputStream *iStream_;
+};
+
+#endif