From ac6a830b126e8e582168ca2c97c3fd4f9eba75fb Mon Sep 17 00:00:00 2001
From: Marko Lindqvist <cazfi74@gmail.com>
Date: Fri, 10 Mar 2023 07:18:16 +0200
Subject: [PATCH 33/33] Meson: Add emscripten build support

See osdn #46354

Signed-off-by: Marko Lindqvist <cazfi74@gmail.com>
---
 gen_headers/meson_fc_config.h.in |   4 +-
 meson.build                      | 104 +++++++++++++++++++++++++------
 2 files changed, 88 insertions(+), 20 deletions(-)

diff --git a/gen_headers/meson_fc_config.h.in b/gen_headers/meson_fc_config.h.in
index f1e8544b43..a1cb052efb 100644
--- a/gen_headers/meson_fc_config.h.in
+++ b/gen_headers/meson_fc_config.h.in
@@ -43,10 +43,10 @@
 #mesondefine WORDS_BIGENDIAN
 
 /* Database backend available */
-#define HAVE_FCDB 1
+#mesondefine HAVE_FCDB
 
 /* Have Sqlite3 database backend */
-#define HAVE_FCDB_SQLITE3 1
+#mesondefine HAVE_FCDB_SQLITE3
 
 /* Build in Qt5 mode */
 #mesondefine FC_QT5_MODE
diff --git a/meson.build b/meson.build
index d6aa0fd7ed..0ae88e76d3 100644
--- a/meson.build
+++ b/meson.build
@@ -150,11 +150,22 @@ if meson.is_cross_build()
   cross_inc_path = [cross_inc_str]
   cross_lib_path = [meson.get_cross_property('cross_lib_path')]
   crosser = meson.get_cross_property('crosser')
+
+  # emscripten build is always cross-build, so check it only here
+  if c_compiler.compiles(
+'''#ifndef __EMSCRIPTEN__
+  error fail
+#endif''')
+    emscripten = true
+  else
+    emscripten = false
+  endif
 else
   cross_inc_str = ''
   cross_inc_path = []
   cross_lib_path = []
   crosser = false
+  emscripten = false
 endif
 
 qtver = get_option('qtver')
@@ -487,10 +498,30 @@ int main(void) { int *var = nullptr; return 0; }''',
   pub_conf_data.set('FREECIV_HAVE_CXX_NULLPTR', 1)
 endif
 
-icu_dep = dependency('icu-uc')
+if emscripten
+  icu_dep = []
+  syslua = 'false'
+
+  emscripten_use_args = [
+     '-s', 'USE_ICU=1',
+     '-s', 'USE_ZLIB=1',
+     '-s', 'USE_PTHREADS=1'
+    ]
 
-syslua = get_option('syslua')
-lua_dep_tmp = dependency('lua-5.4', required:false)
+  add_global_arguments(
+     emscripten_use_args,
+     language : [ 'c', 'cpp'])
+  add_global_link_arguments(
+     emscripten_use_args,
+     '-s', 'TOTAL_MEMORY=64MB',
+     language : [ 'c', 'cpp'])
+else
+  priv_conf_data.set('HAVE_FCDB', 1)
+  priv_conf_data.set('HAVE_FCDB_SQLITE3', 1)
+  icu_dep = dependency('icu-uc')
+  syslua = get_option('syslua')
+  lua_dep_tmp = dependency('lua-5.4', required:false)
+endif
 
 if syslua != 'false' and lua_dep_tmp.found()
   lua_inc_path = []
@@ -594,7 +625,29 @@ if get_option('audio') or get_option('clients').contains('sdl2')
                     c_compiler.find_library('SDL2main', dirs: cross_lib_path),
                     c_compiler.find_library('SDL2', dirs: cross_lib_path)]
   else
-    sdl2main_dep = [c_compiler.find_library('SDL2', dirs: cross_lib_path)]
+    if emscripten
+      emscripten_sdl2_args = [
+        '-s', 'USE_SDL=2'
+      ]
+
+      if get_option('audio')
+        emscripten_sdl2_args += [ '-s', 'USE_SDL_MIXER=2' ]
+      endif
+
+      if get_option('clients').contains('sdl2')
+        emscripten_sdl2_args += [
+          '-s', 'USE_SDL_IMAGE=2',
+          '-s', 'USE_SDL_TTF=2',
+          '-s', 'USE_SDL_GFX=2'
+        ]
+      endif
+
+      add_global_arguments(emscripten_sdl2_args, language: ['c', 'cpp'])
+      add_global_link_arguments(emscripten_sdl2_args, language: ['c', 'cpp'])
+      sdl2main_dep = []
+    else
+      sdl2main_dep = [c_compiler.find_library('SDL2', dirs: cross_lib_path)]
+    endif
   endif
 endif
 
@@ -613,9 +666,14 @@ endif
 if get_option('audio')
   priv_conf_data.set('AUDIO_SDL', 1)
 
-  audio_sdl2_dep = c_compiler.find_library('SDL2_mixer',
-                                           dirs: cross_lib_path)
-  audio_dep = [sdl2main_dep, audio_sdl2_dep]
+  if emscripten
+    audio_dep = []
+  else
+    audio_sdl2_dep = c_compiler.find_library('SDL2_mixer',
+                                             dirs: cross_lib_path)
+    audio_dep = [sdl2main_dep, audio_sdl2_dep]
+  endif
+
   audio_sdl_src = 'client/audio_sdl.c'
 else
   audio_dep = []
@@ -650,20 +708,32 @@ else
   gettext_dep = []
 endif
 
-sqlite3_dep = c_compiler.find_library('sqlite3', dirs: cross_lib_path)
-m_dep = c_compiler.find_library('m', dirs: cross_lib_path)
-
-curl_dep = c_compiler.find_library('curl', dirs: cross_lib_path)
+if emscripten
+  sqlite3_dep = []
+  sqlite3_src = []
+  curl_dep = []
+  m_dep = []
+else
+  sqlite3_dep = c_compiler.find_library('sqlite3', dirs: cross_lib_path)
+  sqlite3_src = [
+    'dependencies/luasql/src/luasql.c',
+    'dependencies/luasql/src/ls_sqlite3.c',
+  ]
+  curl_dep = c_compiler.find_library('curl', dirs: cross_lib_path)
+  m_dep = c_compiler.find_library('m', dirs: cross_lib_path)
+endif
 
-if c_compiler.compiles(net_incl + '''
+if not emscripten
+  if c_compiler.compiles(net_incl + '''
 #include <stddef.h>
 #include <curl/curl.h>
 int main(void) { curl_mime *mime = curl_mime_init(NULL); }''',
   include_directories: include_directories(cross_inc_path)
   )
-  priv_conf_data.set('HAVE_CURL_MIME_API', 1)
-else
-  error('Too old libcurl version - does not support mime API')
+    priv_conf_data.set('HAVE_CURL_MIME_API', 1)
+  else
+    error('Too old libcurl version - does not support mime API')
+  endif
 endif
 
 if get_option('gitrev')
@@ -784,9 +854,7 @@ fc_deps = static_library('fc_dependencies',
   'dependencies/tolua-5.2/src/lib/tolua_map.c',
   'dependencies/tolua-5.2/src/lib/tolua_push.c',
   'dependencies/tolua-5.2/src/lib/tolua_to.c',
-  'dependencies/luasql/src/luasql.c',
-  'dependencies/luasql/src/ls_sqlite3.c',
-  tinycthr_files,
+  sqlite3_src, tinycthr_files,
   sources: [verhdr],
   include_directories : common_inc,
   dependencies: lua_dep
-- 
2.39.2