Add option to download dependencies with CMake

This is another step in reaching feature parity between CMake and meson.
When using the `fetch-deps` preset, or when setting
`CMAKE_PROJECT_TOP_LEVEL_INCLUDES` to `subprojects/provider.cmake`, the
dependencies will be downloaded and built from source.

.editorconfig

@@ -14,7 +14,7 @@ insert_final_newline = true
 [meson.build]
 indent_size = 2
 
-[CMakeLists.txt]
+[{CMakeLists.txt,*.cmake}]
 indent_size = 2
 
 [*.{toml,yml,json}]

.github/workflows/cmake.yml

@@ -29,11 +29,8 @@ jobs:
     strategy:
       matrix:
         cfg:
-          - {
-              id: ubuntu-gcc,
-              platform: ubuntu,
-              preset: default,
-            }
+          - { id: ubuntu-gcc, platform: ubuntu, preset: default }
+          - { id: ubuntu-gcc-fetch, platform: ubuntu, preset: fetch-deps }
 
     steps:
       - uses: actions/checkout@v2

.gitignore

@@ -1,4 +1,5 @@
 subprojects/*
 !subprojects/*.wrap
+!subprojects/*.cmake
 .pixi/
 .cache/

CMakePresets.json

@@ -4,7 +4,6 @@
     {
       "name": "default",
       "generator": "Ninja Multi-Config",
-      "binaryDir": "${sourceDir}/build",
       "cacheVariables": {
         "CMAKE_EXPORT_COMPILE_COMMANDS": true,
         "BUILD_TESTING": true
@@ -13,6 +12,21 @@
         "CC": "gcc",
         "CXX": "g++"
       }
+    },
+    {
+      "name": "fetch-deps",
+      "inherits": "default",
+      "cacheVariables": {
+        "CMAKE_PROJECT_TOP_LEVEL_INCLUDES": "subprojects/provider.cmake"
+      }
+    },
+    {
+      "name": "shared",
+      "inherits": "fetch-deps",
+      "cacheVariables": {
+        "BUILD_SHARED_LIBS": true,
+        "CMAKE_POSITION_INDEPENDENT_CODE": true
+      }
     }
   ]
 }

subprojects/provider.cmake

@@ -0,0 +1,41 @@
+cmake_minimum_required(VERSION 3.24)
+
+include(FetchContent)
+FetchContent_Declare(
+  GTest
+  URL https://github.com/google/googletest/archive/refs/tags/v1.14.0.tar.gz
+  URL_HASH SHA256=8ad598c73ad796e0d8280b082cebd82a630d73e73cd3c70057938a6501bba5d7
+)
+FetchContent_Declare(
+  tl-expected
+  URL https://github.com/TartanLlama/expected/archive/v1.1.0.tar.gz
+  URL_HASH SHA256=1db357f46dd2b24447156aaf970c4c40a793ef12a8a9c2ad9e096d9801368df6
+)
+FetchContent_Declare(
+  jsoncpp
+  URL https://github.com/open-source-parsers/jsoncpp/archive/1.9.5.tar.gz
+  URL_HASH SHA256=f409856e5920c18d0c2fb85276e24ee607d2a09b5e7d5f0a371368903c275da2
+)
+FetchContent_Declare(
+  fmt
+  URL https://github.com/fmtlib/fmt/archive/10.1.1.tar.gz
+  URL_HASH SHA256=78b8c0a72b1c35e4443a7e308df52498252d1cefc2b08c9a97bc9ee6cfe61f8b
+)
+FetchContent_Declare(
+  CLI11
+  URL https://github.com/CLIUtils/CLI11/archive/refs/tags/v2.1.2.tar.gz
+  URL_HASH SHA256=26291377e892ba0e5b4972cdfd4a2ab3bf53af8dac1f4ea8fe0d1376b625c8cb
+)
+
+macro(provide_dependency method dep_name)
+  if ("${dep_name}" MATCHES "^(GTest|tl-expected|jsoncpp|fmt|CLI11)$")
+    FetchContent_MakeAvailable(${dep_name})
+    set(${dep_name}_FOUND TRUE)
+  endif()
+endmacro()
+
+cmake_language(
+  SET_DEPENDENCY_PROVIDER provide_dependency
+  SUPPORTED_METHODS
+    FIND_PACKAGE
+)