From fc1ba35366166464486e02899ed5e86dd0e7d159 Mon Sep 17 00:00:00 2001
From: Daniel Hahler <github@thequod.de>
Date: Sun, 9 Jul 2017 18:45:14 +0200
Subject: [PATCH] CMake: only run ldoc with changed input (#1911)

This adds a custom command to build the documentation, where you can
specify the generated output then. "ldoc" then depends on this output.

This way "ldoc" is not being run every time, but only if the input files
have changed.  ldoc's config is added therefore to the list of
dependencies to make config changes trigger a rebuild.
---
 CMakeLists.txt | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 364968f3..1916d5ce 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -294,10 +294,14 @@ if(GENERATE_DOC)
     file(COPY ${SOURCE_DIR}/docs/aliases DESTINATION ${BUILD_DIR}/docs)
 
     add_custom_target(ldoc ALL
+        DEPENDS ${BUILD_DIR}/doc/index.html)
+    add_custom_command(
         COMMAND ${LDOC_EXECUTABLE} .
+        OUTPUT  ${BUILD_DIR}/doc/index.html
         WORKING_DIRECTORY ${AWE_DOC_DIR}
-        DEPENDS ${AWE_LUA_FILES} ${AWE_MD_FILES}
-    )
+        DEPENDS ${AWE_LUA_FILES} ${AWE_MD_FILES} ${BUILD_DIR}/docs/config.ld
+        COMMENT "Generating API documentation"
+        VERBATIM)
 
     # Run ldoc and make it fail if any warnings are generated. The
     # redirection-magic swaps stdout and stderr and awk exits with a non-zero