build stamp in its own cu and make it a cmake dependency

CMakeLists.txt

@@ -24,8 +24,8 @@ else ()
 endif (DEFINED glfw3_DIR)
 
 # Get the stamp informations, git hash, time stamp, stuff like that
-add_custom_command(
-  OUTPUT src/Stamp.h
+add_custom_target(stamp
+  BYPRODUCTS src/Stamp.h src/Stamp.cpp
   COMMAND  ${CMAKE_COMMAND}
       -DSRC_DIR="${CMAKE_CURRENT_SOURCE_DIR}"
       -DDST_DIR="${CMAKE_CURRENT_SOURCE_DIR}/src"
@@ -42,14 +42,15 @@ if (APPLE)
     set(myApp_ICON ${CMAKE_CURRENT_SOURCE_DIR}/src/resources/icon.icns)
     set_source_files_properties(${myApp_ICON} PROPERTIES MACOSX_PACKAGE_LOCATION "Resources")
 
-add_executable(usdtweak MACOSX_BUNDLE src/Stamp.h ${myApp_ICON})
+add_executable(usdtweak MACOSX_BUNDLE ${myApp_ICON})
 
 set_target_properties(usdtweak PROPERTIES
     OUTPUT_NAME "usdtweak"
     MACOSX_BUNDLE TRUE)
 else()
-    add_executable(usdtweak src/Stamp.h)
+    add_executable(usdtweak)
 endif()
+add_dependencies(usdtweak stamp)
 
 add_subdirectory(src)
 

cmake/stamp.cmake

@@ -17,6 +17,10 @@ endif()
 
 # Get the current time
 string(TIMESTAMP BUILD_DATE "%Y.%m.%d")
-configure_file(${SRC_DIR}/cmake/stamp.h.in ${DST_DIR}/Stamp.h @ONLY)
+if(NOT EXISTS ${DST_DIR}/Stamp.h)
+    execute_process(COMMAND ${CMAKE_COMMAND} -E copy ${SRC_DIR}/cmake/stamp.h.in ${DST_DIR}/Stamp.h)
+endif()
+
+configure_file(${SRC_DIR}/cmake/stamp.cpp.in ${DST_DIR}/Stamp.cpp @ONLY)
 
 

cmake/stamp.cpp.in

@@ -0,0 +1,4 @@
+#include "Stamp.h"
+
+const char *GetGitHash() { return "@GIT_HASH@"; }
+const char *GetBuildDate() { return "@BUILD_DATE@"; }

cmake/stamp.h.in

@@ -2,7 +2,8 @@
 
 #define STRINGIFY2(s) #s
 #define STRINGIFY(s) STRINGIFY2(s)
-
-#define GIT_HASH "@GIT_HASH@"
-#define BUILD_DATE "@BUILD_DATE@"
 #define USD_VERSION "" STRINGIFY(PXR_MINOR_VERSION) "." STRINGIFY(PXR_PATCH_VERSION)
+
+const char *GetGitHash();
+const char *GetBuildDate();
+

src/CMakeLists.txt

@@ -16,6 +16,8 @@ target_sources(usdtweak PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/UsdHelpers.h
     ${CMAKE_CURRENT_SOURCE_DIR}/Selection.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/Selection.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/Stamp.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/Stamp.h
     ${CMAKE_CURRENT_SOURCE_DIR}/main.cpp
 )
 

src/Editor.cpp

@@ -95,8 +95,8 @@ inline void BringWindowToTabFront(const char *windowName) {
 struct AboutModalDialog : public ModalDialog {
     AboutModalDialog(Editor& editor) : editor(editor) {}
     void Draw() override {
-        ImGui::Text("usdtweak pre-alpha version " BUILD_DATE);
-        ImGui::Text("  revision " GIT_HASH);
+        ImGui::Text("usdtweak pre-alpha version %s", GetBuildDate());
+        ImGui::Text("  revision %s", GetGitHash());
         ImGui::Text("");
         ImGui::Text("This is a pre-alpha version for testing purpose.");
         ImGui::Text("Please send your feedbacks as github issues:");