From cfcd6e22bb2081fa9f730c4ee0e07d04b1c8fe55 Mon Sep 17 00:00:00 2001
From: Jxtopher <39927513+Jxtopher@users.noreply.github.com>
Date: Fri, 28 Mar 2025 22:30:30 +0100
Subject: [PATCH] Ccache setup

The goal is to speed up recompilation using ccache.

Ccache is a tool that speeds up recompilation of C/C++ code. It does this by caching the results of previous compilations.
When you recompile code, ccache checks if it has already compiled the same code with the same compiler flags. If so, it uses the cached result instead of recompiling.
---
 .github/workflows/build_ubuntu_debug.yml |  9 ++++++++-
 CMakeLists.txt                           | 11 +++++++++++
 README.md                                |  1 +
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/build_ubuntu_debug.yml b/.github/workflows/build_ubuntu_debug.yml
index b68744cb2..58aac6a42 100644
--- a/.github/workflows/build_ubuntu_debug.yml
+++ b/.github/workflows/build_ubuntu_debug.yml
@@ -16,8 +16,15 @@ jobs:
         compiler: [g++-10, g++-9, g++-8, g++-7, clang-6, clang-7, clang-8, clang-9, clang-10, clang-11, clang-12] 
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     
+    - name: Caching objects
+      id: cache-objects
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/ccache
+        key: ${{ runner.os }}-${{env.BUILD_TYPE}}-${{ matrix.compiler }}-objects
+
     - name: Install Dependencies
       shell: bash
       run: |
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5bec9ae43..1b364f35f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,6 +20,17 @@ project("ParadisEO"
 ## Language
 set(CMAKE_CXX_STANDARD 17)
 
+## ccache
+find_program(CCACHE_PROGRAM ccache)
+
+if (CCACHE_PROGRAM)
+    message(NOTICE "-- ccache is enabled (found here: ${CCACHE_PROGRAM})")
+    set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "\"${CCACHE_PROGRAM}\"")
+    set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK "\"${CCACHE_PROGRAM}\"")
+else ()
+    message(NOTICE "-- ccache has not been found")
+endif ()
+
 
 ######################################################################################
 ### 2) Check dependencies
diff --git a/README.md b/README.md
index 686b08334..ff158606d 100644
--- a/README.md
+++ b/README.md
@@ -211,6 +211,7 @@ If you `ENABLE_CMAKE_EXAMPLE`, it will also build the examples.
 If may want to make build scripts more verbose (especially when building the
 doc) by enabling `CMAKE_VERBOSE_MAKEFILE`.
 
+If `ccache` installed in your environment, library recompilation times can be significantly reduced. To clear all cached objects, execute `ccache -C`.
 
 ## Licenses