Download protoc in ci

ci/build_dnnlibrary.sh

@@ -5,6 +5,6 @@ echo "y" | $ANDROID_HOME/tools/bin/sdkmanager --install 'ndk-bundle'
 nproc=$(ci/get_cores.sh)
 
 mkdir build_dnnlibrary && pushd build_dnnlibrary
-cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_HOME/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_PLATFORM=android-27 -DANDROID_ABI=x86_64 -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_BUILD_TYPE=Release -DDNN_READ_ONNX=ON ..
+cmake -DCMAKE_TOOLCHAIN_FILE=$ANDROID_HOME/ndk-bundle/build/cmake/android.toolchain.cmake -DANDROID_PLATFORM=android-27 -DANDROID_ABI=x86_64 -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_BUILD_TYPE=Release -DDNN_READ_ONNX=ON -DDNN_CUSTOM_PROTOC_EXECUTABLE=protoc/bin/protoc ..
 cmake --build . -- -j$nproc
 popd

ci/dnnlibrary_build_and_test.yml

@@ -29,6 +29,8 @@ steps:
   submodules: true
 - bash: brew install watch gnu-sed
   displayName: Install watch and gnu-sed
+- bash: ci/download_protoc.sh
+  displayName: Download protoc
 - bash: ci/build_dnnlibrary.sh
   displayName: Build
 - bash: ci/start_android_emulator.sh

ci/download_protoc.sh

@@ -0,0 +1,5 @@
+#! /usr/bin/env bash
+set -e
+
+wget https://github.com/protocolbuffers/protobuf/releases/download/v3.7.1/protoc-3.7.1-osx-x86_64.zip -O protoc.zip
+unzip protoc.zip -d protoc

cmake/onnx.cmake

@@ -20,6 +20,10 @@ macro(configure_onnx)
     endif()
     set(ONNX_BUILD_MAIN_LIB ON)
     set(ONNX_NAMESPACE ${DAQ_ONNX_NAMESPACE} CACHE STRING "onnx namespace")
+    if (NOT EXISTS ${DNN_CUSTOM_PROTOC_EXECUTABLE})
+        message(FATAL ERROR "DNN_CUSTOM_PROTOC_EXECUTABLE is not set or wrong.")
+    endif()
+    set(ONNX_CUSTOM_PROTOC_EXECUTABLE ${DNN_CUSTOM_PROTOC_EXECUTABLE})
     add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/onnx)
     target_compile_definitions(onnx_proto PRIVATE ONNX_BUILD_MAIN_LIB)
     # Since https://github.com/onnx/onnx/pull/1318 is merged, we don't need to set it manually