cmake: add reproducible build option (#1370)

* cmake: add reproductible build option

* fix typo + add MSVC

* fix cmake format

* cmake: disable incremental build in reproducible mode

* fix

* cmake: fix format

* fix

CMakeLists.txt

@@ -101,6 +101,7 @@ cmake_dependent_option(
 option(PCAPPP_BUILD_TESTS "Build Tests" ${PCAPPP_MAIN_PROJECT})
 option(PCAPPP_BUILD_COVERAGE "Generate Coverage Report" OFF)
 option(PCAPPP_BUILD_FUZZERS "Build Fuzzers binaries" OFF)
+option(PCAPPP_BUILD_REPRODUCIBLE "Build a reproducible version" OFF)
 
 option(BUILD_SHARED_LIBS "Build using shared libraries" OFF)
 
@@ -259,6 +260,23 @@ if(PCAPPP_TARGET_COMPILER_CLANG
   add_compile_options(-Wall)
 endif()
 
+if(PCAPPP_BUILD_REPRODUCIBLE)
+  add_definitions(-DPCAPPP_BUILD_REPRODUCIBLE)
+  if(APPLE)
+    if(NOT $ENV{ZERO_AR_DATE})
+      message(FATAL_ERROR "You need to set `export ZERO_AR_DATE=1`")
+    endif()
+  elseif(MSVC)
+    message(FATAL_ERROR "Unsupported with MSVC compiler")
+    # Try to build a reproducible static library with MSVC doesn't work but this option should make it work for shared
+    # libraries or executables. add_compile_options(/Brepro) add_compile_options(/experimental:deterministic)
+    # add_link_options(/Brepro) add_link_options(/experimental:deterministic) add_link_options(/INCREMENTAL:NO)
+  else()
+    # We should not use __DATE__ nor __TIME__ in case of reproducible build
+    add_compile_options(-Wdate-time)
+  endif()
+endif()
+
 if(PCAPPP_BUILD_FUZZERS)
   add_compile_options(-w)
 endif()

Common++/header/PcapPlusPlusVersion.h

@@ -37,10 +37,17 @@ namespace pcpp
 	/**
 	 * @return The build date and time in a format of "Mmm dd yyyy hh:mm:ss"
 	 */
+#ifdef PCAPPP_BUILD_REPRODUCIBLE
+	inline std::string getBuildDateTime()
+	{
+		return " ";
+	}
+#else
 	inline std::string getBuildDateTime()
 	{
 		return std::string(__DATE__) + " " + std::string(__TIME__);
 	}
+#endif
 
 	/**
 	 * @return The Git commit (revision) the binaries are built from