Cross compiling fixes and improvements (#59)

* CMake: Expose CMake options to includes

This change shuffles the order of several CMake steps to expose CMake
options to included files.

By defining options before inclusion, included files are able to access
the input provided by the build system.

* CMake: Exclude test dependencies when building tests

* CMake: Allow build system to provide protobuf compiler

When building without Hunter, it is desirable to pass the path to protoc and
the protobuf include directory from the build system. Allow these variables
to be overridden.

Fixes the error:

| CMake Error at cmake/functions.cmake:52 (message):
|   Protobuf_PROTOC_EXECUTABLE is empty
| Call Stack (most recent call first):
|   cmake/functions.cmake:96 (compile_proto_to_cpp)
|   src/crypto/protobuf/CMakeLists.txt:6 (add_proto_library)

* Fix build error due to missing include

Error was:

| literals.cpp: In function 'libp2p::common::Hash256 libp2p::common::operator""_hash256(const char*, size_t)':
| literals.cpp:17:36: error: no matching function for call to 'min(size_t&, long unsigned int)'
|    17 |     std::copy_n(c, std::min(s, 32ul), hash.rbegin());
|       |                                    ^

* Fix build error due to mismatched types

Error was:

| literals.cpp: In function 'libp2p::common::Hash256 libp2p::common::operator""_hash256(const char*, size_t)':
| literals.cpp:19:36: error: no matching function for call to 'min(size_t&, long unsigned int)'
|    19 |     std::copy_n(c, std::min(s, 32ul), hash.rbegin());
|       |                                    ^

* Fix compiler warning due to sign comparison

When compiling with -Werror, this causes the build to fail.

Warning was:

| yamux_frame.cpp:103:28: error: comparison of integers of different signs: 'gsl::span::index_type' (aka 'int') and 'const uint32_t' (aka 'const unsigned int') [-Werror,-Wsign-compare]
|     if (frame_bytes.size() < YamuxFrame::kHeaderLength) {
|         ~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~

Author: eigendude

CMakeLists.txt

@@ -17,18 +17,6 @@ include("cmake/Hunter/init.cmake")
 cmake_policy(SET CMP0048 NEW)
 project(libp2p VERSION 0.0.1 LANGUAGES C CXX)
 
-include(cmake/print.cmake)
-print("C flags: ${CMAKE_C_FLAGS}")
-print("CXX flags: ${CMAKE_CXX_FLAGS}")
-print("Using CMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}")
-
-include(CheckCXXCompilerFlag)
-include(cmake/install.cmake)
-include(cmake/libp2p_add_library.cmake)
-include(cmake/dependencies.cmake)
-include(cmake/functions.cmake)
-include(cmake/san.cmake)
-
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 option(TESTING "Build tests" ON)
@@ -44,6 +32,18 @@ option(TSAN "Enable thread sanitizer" OFF)
 option(UBSAN "Enable UB sanitizer" OFF)
 option(EXPOSE_MOCKS "Make mocks header files visible for child projects" OFF)
 
+include(cmake/print.cmake)
+print("C flags: ${CMAKE_C_FLAGS}")
+print("CXX flags: ${CMAKE_CXX_FLAGS}")
+print("Using CMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}")
+
+include(CheckCXXCompilerFlag)
+include(cmake/install.cmake)
+include(cmake/libp2p_add_library.cmake)
+include(cmake/dependencies.cmake)
+include(cmake/functions.cmake)
+include(cmake/san.cmake)
+
 
 ## setup compilation flags
 if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "^(AppleClang|Clang|GNU)$")

cmake/dependencies.cmake

@@ -1,7 +1,14 @@
-# https://docs.hunter.sh/en/latest/packages/pkg/GTest.html
-hunter_add_package(GTest)
-find_package(GTest CONFIG REQUIRED)
-find_package(GMock CONFIG REQUIRED)
+#
+# Copyright Soramitsu Co., Ltd. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+
+if (TESTING)
+  # https://docs.hunter.sh/en/latest/packages/pkg/GTest.html
+  hunter_add_package(GTest)
+  find_package(GTest CONFIG REQUIRED)
+  find_package(GMock CONFIG REQUIRED)
+endif()
 
 # https://docs.hunter.sh/en/latest/packages/pkg/Boost.html
 hunter_add_package(Boost COMPONENTS random filesystem program_options)

cmake/functions.cmake

@@ -45,8 +45,13 @@ function(add_flag flag)
 endfunction()
 
 function(compile_proto_to_cpp PROTO_LIBRARY_NAME PB_H PB_CC PROTO)
-  get_target_property(Protobuf_INCLUDE_DIR protobuf::libprotobuf INTERFACE_INCLUDE_DIRECTORIES)
-  get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc IMPORTED_LOCATION_RELEASE)
+  if (NOT Protobuf_INCLUDE_DIR)
+    get_target_property(Protobuf_INCLUDE_DIR protobuf::libprotobuf INTERFACE_INCLUDE_DIRECTORIES)
+  endif()
+  if (NOT Protobuf_PROTOC_EXECUTABLE)
+    get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc IMPORTED_LOCATION_RELEASE)
+    set(PROTOBUF_DEPENDS protobuf::protoc)
+  endif()
 
   if (NOT Protobuf_PROTOC_EXECUTABLE)
     message(FATAL_ERROR "Protobuf_PROTOC_EXECUTABLE is empty")
@@ -78,7 +83,7 @@ function(compile_proto_to_cpp PROTO_LIBRARY_NAME PB_H PB_CC PROTO)
       COMMAND ${GEN_COMMAND}
       ARGS -I${PROJECT_SOURCE_DIR}/src -I${GEN_ARGS} --cpp_out=${SCHEMA_OUT_DIR} ${PROTO_ABS}
       WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
-      DEPENDS protobuf::protoc
+      DEPENDS ${PROTOBUF_DEPENDS}
       VERBATIM
   )
 

src/common/literals.cpp

@@ -11,16 +11,18 @@
 #include <libp2p/multi/multihash.hpp>
 #include <libp2p/peer/peer_id.hpp>
 
+#include <algorithm>
+
 namespace libp2p::common {
   libp2p::common::Hash256 operator""_hash256(const char *c, size_t s) {
     libp2p::common::Hash256 hash{};
-    std::copy_n(c, std::min(s, 32ul), hash.rbegin());
+    std::copy_n(c, std::min(s, static_cast<size_t>(32u)), hash.rbegin());
     return hash;
   }
 
   libp2p::common::Hash512 operator""_hash512(const char *c, size_t s) {
     libp2p::common::Hash512 hash{};
-    std::copy_n(c, std::min(s, 64ul), hash.rbegin());
+    std::copy_n(c, std::min(s, static_cast<size_t>(64u)), hash.rbegin());
     return hash;
   }
 

src/muxer/yamux/yamux_frame.cpp

@@ -100,7 +100,7 @@ namespace libp2p::connection {
   }
 
   boost::optional<YamuxFrame> parseFrame(gsl::span<const uint8_t> frame_bytes) {
-    if (frame_bytes.size() < YamuxFrame::kHeaderLength) {
+    if (frame_bytes.size() < static_cast<int>(YamuxFrame::kHeaderLength)) {
       return {};
     }