From d4acbd39ef5b1aa8a5c1f6dbf0d98feaeb574b9a Mon Sep 17 00:00:00 2001
From: Fred Morcos <fred.morcos@open-xchange.com>
Date: Wed, 18 Oct 2023 10:29:13 +0200
Subject: [PATCH] Meson: Detect C++ filesystem library

---
 meson.build              |  2 +-
 meson/cxx-fs/cxx-fs.cc   |  8 ++++++++
 meson/cxx-fs/meson.build | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 meson/cxx-fs/cxx-fs.cc
 create mode 100644 meson/cxx-fs/meson.build

diff --git a/meson.build b/meson.build
index 230ddf8dbe..0e6584c5c6 100644
--- a/meson.build
+++ b/meson.build
@@ -139,7 +139,7 @@ all_modules = {
   'lua2':     {'deps': [],                              'exts': []},
   'remote':   {'deps': ['prog-curl', 'zeromq'],         'exts': []},
   'tinydns':  {'deps': ['cdb'],                         'exts': []},
-  'geoip':    {'deps': ['geoip', 'mmdb'],               'exts': []},
+  'geoip':    {'deps': ['geoip', 'mmdb', 'cxx-fs'],     'exts': []},
   'lmdb':     {'deps': ['lmdb', 'boost-serialization'], 'exts': ['lmdb-safe']},
 }
 
diff --git a/meson/cxx-fs/cxx-fs.cc b/meson/cxx-fs/cxx-fs.cc
new file mode 100644
index 0000000000..0b87fb3be4
--- /dev/null
+++ b/meson/cxx-fs/cxx-fs.cc
@@ -0,0 +1,8 @@
+#include <iostream>
+#include <filesystem>
+
+int main() {
+  std::filesystem::path path(".");
+  [[maybe_unused]] std::filesystem::file_status status = std::filesystem::status(path);
+  return 0;
+}
diff --git a/meson/cxx-fs/meson.build b/meson/cxx-fs/meson.build
new file mode 100644
index 0000000000..73c22bc9ad
--- /dev/null
+++ b/meson/cxx-fs/meson.build
@@ -0,0 +1,33 @@
+dep_cxx_fs = dependency('', required: false)
+need_cxx_fs = false
+
+prog = fs.read('cxx-fs.cc')
+if not cxx.links(prog, name: '-lstdc++fs and -lc++fs are not needed')
+  lib_cxx_fs = cxx.find_library('stdc++fs', disabler: true, required: false)
+  if lib_cxx_fs.found()
+    if cxx.links(prog, name: '-lstdc++fs is needed', dependencies: lib_cxx_fs)
+      need_cxx_fs = '-lstdc++fs'
+      dep_cxx_fs = declare_dependency(dependencies: lib_cxx_fs)
+      summary('Filesystem library', lib_cxx_fs, section: 'System')
+    endif
+  endif
+
+  if need_cxx_fs == false
+    lib_cxx_fs = cxx.find_library('c++fs', disabler: true, required: false)
+    if lib_cxx_fs.found()
+      if cxx.links(prog, name: '-lc++fs is needed', dependencies: lib_cxx_fs)
+        need_cxx_fs = '-lc++fs'
+        dep_cxx_fs = declare_dependency(dependencies: lib_cxx_fs)
+        summary('Filesystem library', lib_cxx_fs, section: 'System')
+      else
+        error('C++ Filesystem library was found but linking against it failed')
+      endif
+    else
+      error('C++ Filesystem library is needed but could not be found')
+    endif
+  endif
+else
+  dep_cxx_fs = declare_dependency()
+endif
+
+summary('Need -lstdc++fs or -lc++fs', need_cxx_fs, bool_yn: true, section: 'System')
-- 
2.47.3