[gRPC] Fix out-of-sync in gRPC supportsubmit/tizen/20201201.060822accepted/tizen/unified/20201201.124754

This patch fixes out-of-sync in flatbuffer's gRPC support.
The inferface between gRPC and flatbuf has been broken since gRPC 1.17.

This problem comes from that gRPC decided to hide its internal byte buffer.
(e.g., gRPC::ByteBuffer contains grpc_byte_buffer, but not exposed)

As the version of gRPC is already 1.20.1 in tizen upstream,
I want to directly fix the glue header in flatbuffers by applying
this workaround patch.

Related issues:
- https://github.com/google/flatbuffers/issues/5836
- https://github.com/google/flatbuffers/issues/5096
- https://github.com/grpc/grpc/issues/20594

Change-Id: Ia4149826cc74c690fbc48d07c3141d2221c718f6
Signed-off-by: Dongju Chae <dongju.chae@samsung.com>

8 files changed, 97 insertions, 2 deletions

diff --git a/debian/changelog b/debian/changelog
index f7befddd..b3e22e6d 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+flatbuffers (1.12.0-4) unstable; urgency=medium
+
+  * Apply the patch file to fix out-of-sync with gRPC
+
+ -- Dongju Chae <dongju.chae@samsung.com>  Fri, 27 Nov 2020 16:37:00 +0900
+
 flatbuffers (1.12.0-3) unstable; urgency=medium
 
   * Include flatbuffers.pc to the dev-kit package
diff --git a/debian/control b/debian/control
index 8ad479b4..b9564a0f 100644
--- a/debian/control
+++ b/debian/control
@@ -1,7 +1,7 @@
 Source: flatbuffers
 Section: libdevel
 Priority: optional
-Build-Depends: debhelper (>=9), cmake,
+Build-Depends: debhelper (>=9), cmake, quilt,
  gcc-9 | gcc-8 | gcc-7 | gcc-6 | gcc-5 (>>5.4)
 Maintainer: Wook Song <wook16.song@samsung.com>
 Standards-Version: 3.6.1
diff --git a/debian/format b/debian/format
new file mode 100644
index 00000000..89ae9db8
--- /dev/null
+++ b/debian/format
@@ -0,0 +1 @@
+3.0 (native)
diff --git a/debian/patches/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch b/debian/patches/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
new file mode 100644
index 00000000..daf0eebc
--- /dev/null
+++ b/debian/patches/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
@@ -0,0 +1,41 @@
+--- a/include/flatbuffers/grpc.h
++++ b/include/flatbuffers/grpc.h
+@@ -268,6 +268,21 @@ class MessageBuilder : private detail::S
+ }  // namespace grpc
+ }  // namespace flatbuffers
+ 
++// This is a horrible hack to get internal grpc_byte_buffer. Remove later.
++namespace grpc {
++namespace internal {
++  class GrpcByteBufferPeer {
++    public:
++      static void setBuffer(grpc::ByteBuffer* dest, grpc_byte_buffer* p) {
++        dest->set_buffer(p);
++      }
++      static grpc_byte_buffer** getBufferPtr(grpc::ByteBuffer* buf) {
++        return buf->c_buffer_ptr();
++      }
++  };
++}  // namespace internal
++}  // namespace grpc
++
+ namespace grpc {
+ 
+ template<class T> class SerializationTraits<flatbuffers::grpc::Message<T>> {
+@@ -323,6 +338,16 @@ template<class T> class SerializationTra
+     }
+ #endif
+   }
++
++  // A workaround to sync the interface between flatbuffers and gRPC
++  static grpc::Status Deserialize(ByteBuffer *buffer,
++                                  flatbuffers::grpc::Message<T> *msg) {
++    return Deserialize(*(grpc::internal::GrpcByteBufferPeer::getBufferPtr(buffer)), msg);
++  }
++  static grpc::Status Deserialize(ByteBuffer::ByteBufferPointer p,
++                                  flatbuffers::grpc::Message<T> *msg) {
++    return Deserialize((grpc_byte_buffer*)(p), msg);
++  }
+ };
+ 
+ }  // namespace grpc
diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644
index 00000000..9ce32910
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1 @@
+0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
diff --git a/debian/rules b/debian/rules
index fa699795..624c1833 100755
--- a/debian/rules
+++ b/debian/rules
@@ -18,7 +18,7 @@ export DEB_CMAKE_EXTRA_FLAGS +=  -DFLATBUFFERS_INSTALL=ON \
 	-DCMAKE_BUILD_TYPE=Release
 
 %:
-	dh $@ --parallel --buildsystem=cmake
+	dh $@ --with quilt --parallel --buildsystem=cmake
 
 override_dh_auto_configure:
 	dh_auto_configure -- $(DEB_CMAKE_EXTRA_FLAGS)
diff --git a/packaging/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch b/packaging/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
new file mode 100644
index 00000000..daf0eebc
--- /dev/null
+++ b/packaging/0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
@@ -0,0 +1,41 @@
+--- a/include/flatbuffers/grpc.h
++++ b/include/flatbuffers/grpc.h
+@@ -268,6 +268,21 @@ class MessageBuilder : private detail::S
+ }  // namespace grpc
+ }  // namespace flatbuffers
+ 
++// This is a horrible hack to get internal grpc_byte_buffer. Remove later.
++namespace grpc {
++namespace internal {
++  class GrpcByteBufferPeer {
++    public:
++      static void setBuffer(grpc::ByteBuffer* dest, grpc_byte_buffer* p) {
++        dest->set_buffer(p);
++      }
++      static grpc_byte_buffer** getBufferPtr(grpc::ByteBuffer* buf) {
++        return buf->c_buffer_ptr();
++      }
++  };
++}  // namespace internal
++}  // namespace grpc
++
+ namespace grpc {
+ 
+ template<class T> class SerializationTraits<flatbuffers::grpc::Message<T>> {
+@@ -323,6 +338,16 @@ template<class T> class SerializationTra
+     }
+ #endif
+   }
++
++  // A workaround to sync the interface between flatbuffers and gRPC
++  static grpc::Status Deserialize(ByteBuffer *buffer,
++                                  flatbuffers::grpc::Message<T> *msg) {
++    return Deserialize(*(grpc::internal::GrpcByteBufferPeer::getBufferPtr(buffer)), msg);
++  }
++  static grpc::Status Deserialize(ByteBuffer::ByteBufferPointer p,
++                                  flatbuffers::grpc::Message<T> *msg) {
++    return Deserialize((grpc_byte_buffer*)(p), msg);
++  }
+ };
+ 
+ }  // namespace grpc
diff --git a/packaging/flatbuffers.spec b/packaging/flatbuffers.spec
index 1e6eed6f..8ba227d8 100644
--- a/packaging/flatbuffers.spec
+++ b/packaging/flatbuffers.spec
@@ -7,6 +7,7 @@ Packager:	Parichay Kapoor <pk.kapoor@samsung.com>
 License:	Apache-2.0
 Source0:	%{name}-%{version}.tar.gz
 Source1:	%{name}.manifest
+Source2:	0001-gRPC-Fix-out-of-sync-in-gRPC-support.patch
 
 BuildRequires:	cmake
 BuildRequires:	gcc-c++
@@ -28,6 +29,7 @@ This package provides headers and other miscellaneous files required to use flat
 %prep
 %setup -q
 cp %{SOURCE1} .
+%{__patch} -p1 < %{SOURCE2}
 
 %build
 export CFLAGS+=" -fno-lto"
@@ -77,6 +79,9 @@ sed -i 's#@includedir@#%{_includedir}#g' %{buildroot}%{_libdir}/pkgconfig/%{name
 %{_libdir}/pkgconfig/flatbuffers.pc
 
 %changelog
+* Fri Nov 27 2020 Dongju Chae <wook16.song@samsung.com>
+- Apply the patch file to fix out-of-sync with gRPC
+
 * Tue Sep 15 2020 Wook Song <wook16.song@samsung.com>
 - Add the pkg-config file to the dev-kit package