From c7e1e947486411f1c761addb30684bcf2554f6df Mon Sep 17 00:00:00 2001
From: Cody Northrop <cnorthrop@google.com>
Date: Tue, 31 Oct 2017 17:05:03 -0600
Subject: [PATCH] build: Add optional ccache support to cmake

---
 BUILD.md       | 2 ++
 CMakeLists.txt | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/BUILD.md b/BUILD.md
index bb78c9c..8b884c9 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -40,6 +40,8 @@ cd dbuild
 make
 ```
 
+If your build system supports ccache, you can enable that via cmake option `-DUSE_CCACHE=On`
+
 If you have installed a Vulkan driver obtained from your graphics hardware vendor, the install process should
 have configured the driver so that the Vulkan loader can find and load it.
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2412236..8b91674 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,15 @@ string(TOLOWER ${API_NAME} API_LOWERCASE)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 find_package(PythonInterp 3 REQUIRED)
 
+option(USE_CCACHE "Use ccache" OFF)
+if (USE_CCACHE)
+    find_program(CCACHE_FOUND ccache)
+    if(CCACHE_FOUND)
+        set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
+        set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
+    endif(CCACHE_FOUND)
+endif()
+
 if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
     set(FALLBACK_CONFIG_DIRS "/etc/xdg" CACHE STRING
         "Search path to use when XDG_CONFIG_DIRS is unset or empty or the current process is SUID/SGID. Default is freedesktop compliant.")
-- 
2.7.4