Refactor CMake files and add Conan's support

- Add a finder for Gtest and use targets set by the finder
  (compatibility cmake >=3.5)
- Refactor unittests using function add_unittest() (cmake >=3.4)
- If conanbuildinfo.cmake is not found, fall back on googletest imported
  by git-submodule

CMakeLists.txt

@@ -1,10 +1,71 @@
-cmake_minimum_required (VERSION 3.0.2)
-project (utf8cpp VERSION 3.1 LANGUAGES CXX)
+cmake_minimum_required(VERSION 3.5)
+project (utf8cpp
+    DESCRIPTION "UTF-8 with C++ in a Portable Way"
+    VERSION 3.1
+    LANGUAGES CXX)
 
 option(UTF8_TESTS "Enable tests for UTF8-CPP" On)
 option(UTF8_INSTALL "Enable installation for UTF8-CPP" On)
 option(UTF8_SAMPLES "Enable building samples for UTF8-CPP" On)
 
+###############
+# Conan support
+###############
+
+if (UTF8_TESTS)
+    if (EXISTS "${CMAKE_BINARY_DIR}/conanbuildinfo.cmake")
+        include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
+        message(STATUS "conan_basic_setup()")
+        conan_basic_setup(TARGETS)
+        set(USE_CONAN True)
+    endif()
+endif()
+
+###############################
+# Check compiler's capabilities
+###############################
+
+include (CheckCXXCompilerFlag)
+
+if(CMAKE_C_COMPILER_ID MATCHES "Clang")
+    set (CMAKE_COMPILER_IS_CLANG true)
+elseif(CMAKE_C_COMPILER_ID MATCHES "MSVC")
+    set (CMAKE_COMPILER_IS_MSVC true)
+endif()
+
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLANG)
+    find_program (LINKER_BIN gold)
+    if(LINKER_BIN)
+        set(LINKER_BIN "gold")
+    else()
+        find_program (LINKER_BIN ld.gold)
+        if(LINKER_BIN)
+            set(LINKER_BIN "ld.gold")
+        else()
+            set(LINKER_BIN "ld")
+        endif()
+    endif()
+
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -W")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wextra")
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
+
+    CHECK_CXX_COMPILER_FLAG("-fuse-ld=${LINKER_BIN}" USE_LINKER_FLAG)
+    if(USE_LINKER_FLAG)
+        set (CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=${LINKER_BIN} ${CMAKE_SHARED_LINKER_FLAGS}")
+    endif()
+elseif(CMAKE_COMPILER_IS_MSVC)
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_SECURE_SCL=0")
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_CRT_SECURE_NO_DEPRECATE")
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_CRT_NONSTDC_NO_DEPRECATE")
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_SCL_SECURE_NO_DEPRECATE")
+    #set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Zi")
+endif()
+
+message(STATUS "CMAKE_INSTALL_PREFIX: ${CMAKE_INSTALL_PREFIX}")
+set (CMAKE_INSTALL_INCLUDEDIR "${CMAKE_INSTALL_PREFIX}/include")
+
 add_library(utf8cpp INTERFACE)
 target_include_directories(utf8cpp INTERFACE
     "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/source>"
@@ -26,12 +87,13 @@ if(UTF8_INSTALL)
 endif()
 
 if(UTF8_SAMPLES)
-    add_executable(docsample ${PROJECT_SOURCE_DIR}/samples/docsample.cpp)
-    target_link_libraries(docsample PRIVATE utf8::cpp)
+    add_subdirectory(samples)
 endif()
 
 if(UTF8_TESTS)
     enable_testing()
-    add_subdirectory(extern/gtest)
+    if (NOT USE_CONAN)
+        add_subdirectory(extern/gtest)
+    endif()
     add_subdirectory(tests)
 endif()

conanfile.txt

@@ -0,0 +1,5 @@
+[build_requires]
+gtest/1.8.1@bincrafters/stable
+
+[generators]
+cmake

samples/CMakeLists.txt

@@ -0,0 +1,3 @@
+add_executable(docsample
+    "docsample.cpp")
+target_link_libraries(docsample PRIVATE utf8::cpp)

tests/CMakeLists.txt

@@ -1,35 +1,46 @@
-add_executable(negative ${PROJECT_SOURCE_DIR}/tests/negative.cpp)
-add_executable(cpp11 ${PROJECT_SOURCE_DIR}/tests/test_cpp11.cpp)
-add_executable(apitests
-    ${PROJECT_SOURCE_DIR}/tests/test_checked_api.cpp
-    ${PROJECT_SOURCE_DIR}/tests/test_unchecked_api.cpp
-    ${PROJECT_SOURCE_DIR}/tests/test_checked_iterator.cpp
-    ${PROJECT_SOURCE_DIR}/tests/test_unchecked_iterator.cpp
-)
+find_package (GTest REQUIRED)
 
-add_executable(noexceptionstests
-    ${PROJECT_SOURCE_DIR}/tests/test_unchecked_api.cpp
-    ${PROJECT_SOURCE_DIR}/tests/test_unchecked_iterator.cpp
-)
+#include(CMakeParseArguments)
+function(add_unittest)
+    set(options _empty)
+    set(oneValueArgs TESTNAME)
+    set(multiValueArgs SOURCES LIBRARIES ARGUMENTS)
+    cmake_parse_arguments(PARSE_ARGV 0 "impl" "${options}" "${oneValueArgs}" "${multiValueArgs}")
 
-target_link_libraries(negative PRIVATE utf8::cpp)
-target_link_libraries(cpp11 PRIVATE
-    utf8::cpp
-    gtest_main
-    )
-target_link_libraries(apitests PRIVATE
-    utf8::cpp
-    gtest_main
-)
+    add_executable(${impl_TESTNAME} ${impl_SOURCES})
+    target_link_libraries(${impl_TESTNAME} PRIVATE
+        utf8::cpp
+        ${impl_LIBRARIES}
+        )
+    if (NOT ${impl_ARGUMENTS})
+        add_test(NAME "${impl_TESTNAME}_test"
+            COMMAND "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${impl_TESTNAME}" ${impl_ARGUMENTS})
+    else()
+        add_test(NAME "${impl_TESTNAME}_test"
+            COMMAND "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${impl_TESTNAME}")
+    endif()
+endfunction()
 
-target_link_libraries(noexceptionstests PRIVATE
-    utf8::cpp
-    gtest_main
-)
-target_compile_options(noexceptionstests PUBLIC -fno-exceptions)
+add_unittest(TESTNAME negative
+    SOURCES "negative.cpp"
+    ARGUMENTS "${PROJECT_SOURCE_DIR}/tests/test_data/utf8_invalid.txt")
 
-add_test(negative_test negative ${PROJECT_SOURCE_DIR}/tests/test_data/utf8_invalid.txt)
-add_test(cpp11_test cpp11)
-add_test(api_test apitests)
-add_test(noexceptions_test noexceptionstests)
+add_unittest(TESTNAME cpp11
+    SOURCES "test_cpp11.cpp"
+    LIBRARIES GTest::Main)
+
+add_unittest(TESTNAME apitests
+    SOURCES
+    "test_checked_api.cpp"
+    "test_unchecked_api.cpp"
+    "test_checked_iterator.cpp"
+    "test_unchecked_iterator.cpp"
+    LIBRARIES GTest::Main)
+
+add_unittest(TESTNAME noexceptionstests
+    SOURCES
+    "test_unchecked_api.cpp"
+    "test_unchecked_iterator.cpp"
+    LIBRARIES GTest::Main)
+target_compile_options(noexceptionstests PUBLIC "-fno-exceptions")