discount: fix nix buildHEADmain

Nix doesn't allow network requests while building, so the source for
discount needs to be fetched before the build is initiated.

3 files changed, 38 insertions, 21 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f5d6b44..131f872 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,15 +1,23 @@
 cmake_minimum_required(VERSION 3.21)
 
 include(FetchContent)
-FetchContent_Declare(
-  discount
-  GIT_REPOSITORY "https://github.com/Orc/discount"
-  GIT_TAG "main"
-  SOURCE_DIR "discount"
-)
-FetchContent_MakeAvailable(discount)
 
-add_subdirectory(${discount_SOURCE_DIR}/cmake)
+if (DEFINED DISCOUNT_SRC)
+  FetchContent_Declare(
+    discount
+    SOURCE_DIR "${DISCOUNT_SRC}"
+  )
+else ()
+  FetchContent_Declare(
+    discount
+    GIT_REPOSITORY "https://github.com/Orc/discount.git"
+    GIT_TAG "main"
+    SOURCE_DIR "discount"
+  )
+endif()
+
+FetchContent_MakeAvailable(discount)
+add_subdirectory(${discount_SOURCE_DIR}/cmake discount)
 
 project(msg C)
 
diff --git a/default.nix b/default.nix
index 958091f..14d32d8 100644
--- a/default.nix
+++ b/default.nix
@@ -4,19 +4,28 @@
 , spdlog
 , abseil-cpp }:
 
-llvmPackages.stdenv.mkDerivation rec {
-  pname = "msg";
-  version = "0.1";
+let
+    discount_src = builtins.fetchGit{
+        url = "https://github.com/Orc/discount.git";
+        rev = "c214286f91cb754450121ad1f55a0e9470d3a16c";
+    };
+in llvmPackages.stdenv.mkDerivation rec {
+    pname = "msg";
+    version = "0.1";
 
-  src = ./.;
+    src = ./.;
 
-  nativeBuildInputs = [ cmake ];
+    nativeBuildInputs = [ cmake ];
 
-  meta = with lib; {
-    homepage = "https://github.com/compromyse/msg";
-    description = "Minimal Static Site Generator";
-    licencse = licenses.gpl3;
-    platforms = with platforms; linux ++ darwin;
-    maintainers = [ maintainers.compromyse ];
-  };
+    cmakeFlags = [
+        "-DDISCOUNT_SRC=${discount_src}"
+    ];
+
+    meta = with lib; {
+        homepage = "https://github.com/compromyse/msg";
+        description = "Minimal Static Site Generator";
+        licencse = licenses.gpl3;
+        platforms = with platforms; linux ++ darwin;
+        maintainers = [ maintainers.compromyse ];
+    };
 }
diff --git a/flake.nix b/flake.nix
index 259cd15..0542c2c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,7 +5,7 @@
     };
 
     outputs = { self, nixpkgs, ... }:
-        let
+    let
         pkgs = import nixpkgs { system = "x86_64-linux"; };
     in {
         devShells.x86_64-linux.default = pkgs.mkShell {