From 4fdbba0207f1dbabedb86c26fca200d082b82871 Mon Sep 17 00:00:00 2001
From: lethosor <lethosor@gmail.com>
Date: Mon, 24 Oct 2016 22:28:51 -0400
Subject: [PATCH] Only touch protobuf generated files if they actually changed

---
 library/CMakeLists.txt       | 28 +++++++++++++++++++++++++---
 library/proto/.gitignore     |  1 +
 library/proto/tmp/.gitignore |  1 +
 plugins/CMakeLists.txt       | 26 +++++++++++++++++++++++---
 plugins/proto/.gitignore     |  1 +
 plugins/proto/tmp/.gitignore |  1 +
 6 files changed, 52 insertions(+), 6 deletions(-)
 create mode 100644 library/proto/tmp/.gitignore
 create mode 100644 plugins/proto/tmp/.gitignore

diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 0958a6efc..cb919f935 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -215,20 +215,42 @@ ENDIF()
 # Protobuf
 FILE(GLOB PROJECT_PROTOS ${CMAKE_CURRENT_SOURCE_DIR}/proto/*.proto)
 
+SET(PROTO_STATUS_FILE ${CMAKE_CURRENT_SOURCE_DIR}/proto/status.txt)
 STRING(REPLACE ".proto" ".pb.cc" PROJECT_PROTO_SRCS "${PROJECT_PROTOS}")
 STRING(REPLACE ".proto" ".pb.h" PROJECT_PROTO_HDRS "${PROJECT_PROTOS}")
+STRING(REPLACE "/proto/" "/proto/tmp/" PROJECT_PROTO_TMP_FILES "${PROJECT_PROTO_SRCS};${PROJECT_PROTO_HDRS}")
+SET_SOURCE_FILES_PROPERTIES(${PROJECT_PROTO_SRCS} ${PROJECT_PROTO_HDRS}
+    PROPERTIES GENERATED TRUE)
+
+# Force a re-gen if any *.pb.* files are missing
+IF(EXISTS ${PROTO_STATUS_FILE})
+    FOREACH(file IN LISTS PROJECT_PROTO_SRCS PROJECT_PROTO_HDRS)
+        IF(NOT EXISTS ${file})
+            MESSAGE("Resetting generate_proto_core because '${file}' is missing")
+            FILE(REMOVE ${PROTO_STATUS_FILE})
+            BREAK()
+        ENDIF()
+    ENDFOREACH()
+ENDIF()
 
 LIST(APPEND PROJECT_HEADERS ${PROJECT_PROTO_HDRS})
 LIST(APPEND PROJECT_SOURCES ${PROJECT_PROTO_SRCS})
 
 ADD_CUSTOM_COMMAND(
-    OUTPUT ${PROJECT_PROTO_SRCS} ${PROJECT_PROTO_HDRS}
+    OUTPUT ${PROTO_STATUS_FILE}
     COMMAND protoc-bin -I=${CMAKE_CURRENT_SOURCE_DIR}/proto/
-            --cpp_out=dllexport_decl=DFHACK_EXPORT:${CMAKE_CURRENT_SOURCE_DIR}/proto/
+            --cpp_out=dllexport_decl=DFHACK_EXPORT:${CMAKE_CURRENT_SOURCE_DIR}/proto/tmp/
             ${PROJECT_PROTOS}
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            ${PROJECT_PROTO_TMP_FILES}
+            ${CMAKE_CURRENT_SOURCE_DIR}/proto/
+    COMMAND ${CMAKE_COMMAND} -E touch ${PROTO_STATUS_FILE}
+    COMMENT "Generating core protobufs"
     DEPENDS protoc-bin ${PROJECT_PROTOS}
 )
 
+ADD_CUSTOM_TARGET(generate_proto_core DEPENDS ${PROTO_STATUS_FILE})
+
 # Merge headers into sources
 SET_SOURCE_FILES_PROPERTIES( ${PROJECT_HEADERS} PROPERTIES HEADER_FILE_ONLY TRUE )
 LIST(APPEND PROJECT_SOURCES ${PROJECT_HEADERS})
@@ -299,7 +321,7 @@ ADD_CUSTOM_TARGET(git-describe
 ADD_DEPENDENCIES(dfhack-version git-describe)
 
 ADD_LIBRARY(dfhack SHARED ${PROJECT_SOURCES})
-ADD_DEPENDENCIES(dfhack generate_headers)
+ADD_DEPENDENCIES(dfhack generate_headers generate_proto_core)
 
 ADD_LIBRARY(dfhack-client SHARED RemoteClient.cpp ColorText.cpp MiscUtils.cpp ${PROJECT_PROTO_SRCS})
 ADD_DEPENDENCIES(dfhack-client dfhack)
diff --git a/library/proto/.gitignore b/library/proto/.gitignore
index befabf79d..3a96bb3d9 100644
--- a/library/proto/.gitignore
+++ b/library/proto/.gitignore
@@ -1,3 +1,4 @@
 *.pb.cc
 *.pb.cc.rule
 *.pb.h
+status.txt
diff --git a/library/proto/tmp/.gitignore b/library/proto/tmp/.gitignore
new file mode 100644
index 000000000..75feca5b1
--- /dev/null
+++ b/library/proto/tmp/.gitignore
@@ -0,0 +1 @@
+*.pb.*
diff --git a/plugins/CMakeLists.txt b/plugins/CMakeLists.txt
index 9522491dd..f0bb847bf 100644
--- a/plugins/CMakeLists.txt
+++ b/plugins/CMakeLists.txt
@@ -42,18 +42,38 @@ install(DIRECTORY raw/
 # Protobuf
 FILE(GLOB PROJECT_PROTOS ${CMAKE_CURRENT_SOURCE_DIR}/proto/*.proto)
 
+SET(PROTO_STATUS_FILE ${CMAKE_CURRENT_SOURCE_DIR}/proto/status.txt)
 STRING(REPLACE ".proto" ".pb.cc" PROJECT_PROTO_SRCS "${PROJECT_PROTOS}")
 STRING(REPLACE ".proto" ".pb.h" PROJECT_PROTO_HDRS "${PROJECT_PROTOS}")
+STRING(REPLACE "/proto/" "/proto/tmp/" PROJECT_PROTO_TMP_FILES "${PROJECT_PROTO_SRCS};${PROJECT_PROTO_HDRS}")
+SET_SOURCE_FILES_PROPERTIES(${PROJECT_PROTO_SRCS} ${PROJECT_PROTO_HDRS}
+    PROPERTIES GENERATED TRUE)
+
+# Force a re-gen if any *.pb.* files are missing
+IF(EXISTS ${PROTO_STATUS_FILE})
+    FOREACH(file IN LISTS PROJECT_PROTO_SRCS PROJECT_PROTO_HDRS)
+        IF(NOT EXISTS ${file})
+            MESSAGE("Resetting generate_proto because '${file}' is missing")
+            FILE(REMOVE ${PROTO_STATUS_FILE})
+            BREAK()
+        ENDIF()
+    ENDFOREACH()
+ENDIF()
 
 ADD_CUSTOM_COMMAND(
-    OUTPUT ${PROJECT_PROTO_SRCS} ${PROJECT_PROTO_HDRS}
+    OUTPUT ${PROTO_STATUS_FILE}
     COMMAND protoc-bin -I=${dfhack_SOURCE_DIR}/library/proto/
                        -I=${CMAKE_CURRENT_SOURCE_DIR}/proto/
-            --cpp_out=${CMAKE_CURRENT_SOURCE_DIR}/proto/
+            --cpp_out=${CMAKE_CURRENT_SOURCE_DIR}/proto/tmp/
             ${PROJECT_PROTOS}
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different
+            ${PROJECT_PROTO_TMP_FILES}
+            ${CMAKE_CURRENT_SOURCE_DIR}/proto/
+    COMMAND ${CMAKE_COMMAND} -E touch ${PROTO_STATUS_FILE}
+    COMMENT "Generating plugin protobufs"
     DEPENDS protoc-bin ${PROJECT_PROTOS}
 )
-add_custom_target(generate_proto DEPENDS ${PROJECT_PROTO_SRCS} ${PROJECT_PROTO_HDRS})
+add_custom_target(generate_proto DEPENDS ${PROTO_STATUS_FILE})
 
 SET_SOURCE_FILES_PROPERTIES( Brushes.h PROPERTIES HEADER_FILE_ONLY TRUE )
 
diff --git a/plugins/proto/.gitignore b/plugins/proto/.gitignore
index befabf79d..3a96bb3d9 100644
--- a/plugins/proto/.gitignore
+++ b/plugins/proto/.gitignore
@@ -1,3 +1,4 @@
 *.pb.cc
 *.pb.cc.rule
 *.pb.h
+status.txt
diff --git a/plugins/proto/tmp/.gitignore b/plugins/proto/tmp/.gitignore
new file mode 100644
index 000000000..75feca5b1
--- /dev/null
+++ b/plugins/proto/tmp/.gitignore
@@ -0,0 +1 @@
+*.pb.*