From fe285678a397d28f791dfdbad8c1b64401788b6a Mon Sep 17 00:00:00 2001
From: arch1t3cht <arch1t3cht@gmail.com>
Date: Fri, 6 Mar 2020 00:15:07 -0500
Subject: [PATCH] avisynth: Allow compilation on Linux

Co-authored-by: wangqr <wangqr@wangqr.tk>
---
 meson.build                          |  8 ++++--
 src/avisynth_wrap.cpp                | 40 ++++++++++++++++++++++++----
 src/libresrc/default_config.json     |  2 +-
 src/libresrc/osx/default_config.json |  2 +-
 src/meson.build                      |  7 ++---
 5 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/meson.build b/meson.build
index 39cc7de00..50ec01dde 100644
--- a/meson.build
+++ b/meson.build
@@ -220,9 +220,9 @@ foreach dep: [
     endif
 endforeach
 
-if host_machine.system() == 'windows' and get_option('avisynth').enabled()
+if get_option('avisynth').enabled()
     conf.set('WITH_AVISYNTH', 1) # bundled separately with installer
-    deps += cc.find_library('avifil32', required: true)
+    dep_avail += 'AviSynth'
 
     avs_opt = cmake.subproject_options()
     avs_opt.add_cmake_defines({
@@ -231,6 +231,10 @@ if host_machine.system() == 'windows' and get_option('avisynth').enabled()
 
     avs = cmake.subproject('avisynth', options: avs_opt)
     deps_inc += avs.include_directories('AviSynth-Headers')
+
+    if host_machine.system() == 'windows'
+      deps += cc.find_library('avifil32', required: true)
+    endif
 endif
 
 if host_machine.system() == 'windows' and not get_option('directsound').disabled()
diff --git a/src/avisynth_wrap.cpp b/src/avisynth_wrap.cpp
index fd2246f77..a3b6a3de6 100644
--- a/src/avisynth_wrap.cpp
+++ b/src/avisynth_wrap.cpp
@@ -40,10 +40,24 @@
 
 #include <mutex>
 
+#ifndef _WIN32
+#include <dlfcn.h>
+#endif
+
+#ifdef _WIN32
+#define AVISYNTH_SO "avisynth.dll"
+#else
+#define AVISYNTH_SO "libavisynth.so"
+#endif
+
 // Allocate storage for and initialise static members
 namespace {
 	int avs_refcount = 0;
+#ifdef _WIN32
 	HINSTANCE hLib = nullptr;
+#else
+	void* hLib = nullptr;
+#endif
 	IScriptEnvironment *env = nullptr;
 	std::mutex AviSynthMutex;
 }
@@ -54,14 +68,26 @@ typedef IScriptEnvironment* __stdcall FUNC(int);
 
 AviSynthWrapper::AviSynthWrapper() {
 	if (!avs_refcount++) {
-		hLib = LoadLibrary(L"avisynth.dll");
+#ifdef _WIN32
+#define CONCATENATE(x, y) x ## y
+#define _Lstr(x) CONCATENATE(L, x)
+		hLib = LoadLibraryW(_Lstr(AVISYNTH_SO));
+#undef _Lstr
+#undef CONCATENATE
+#else
+		hLib = dlopen(AVISYNTH_SO, RTLD_LAZY | RTLD_LOCAL | RTLD_DEEPBIND);
+#endif
 
 		if (!hLib)
-			throw AvisynthError("Could not load avisynth.dll");
+			throw AvisynthError("Could not load " AVISYNTH_SO);
 
-		FUNC *CreateScriptEnv = (FUNC*)GetProcAddress(hLib, "CreateScriptEnvironment");
+#ifdef _WIN32
+		FUNC* CreateScriptEnv = (FUNC*)GetProcAddress(hLib, "CreateScriptEnvironment");
+#else
+		FUNC* CreateScriptEnv = (FUNC*)dlsym(hLib, "CreateScriptEnvironment");
+#endif
 		if (!CreateScriptEnv)
-			throw AvisynthError("Failed to get address of CreateScriptEnv from avisynth.dll");
+			throw AvisynthError("Failed to get address of CreateScriptEnv from " AVISYNTH_SO);
 
 		env = CreateScriptEnv(AVISYNTH_INTERFACE_VERSION);
 
@@ -80,8 +106,12 @@ AviSynthWrapper::AviSynthWrapper() {
 AviSynthWrapper::~AviSynthWrapper() {
 	if (!--avs_refcount) {
 		delete env;
-		AVS_linkage = nullptr;
+#ifdef _WIN32
 		FreeLibrary(hLib);
+#else
+		dlclose(hLib);
+#endif
+		AVS_linkage = nullptr;
 	}
 }
 
diff --git a/src/libresrc/default_config.json b/src/libresrc/default_config.json
index f83002436..fbc98dc2e 100644
--- a/src/libresrc/default_config.json
+++ b/src/libresrc/default_config.json
@@ -335,7 +335,7 @@
 			}
 		},
 		"Avisynth" : {
-			"Memory Max" : 128
+			"Memory Max" : 1024
 		},
 		"FFmpegSource" : {
 			"Cache" : {
diff --git a/src/libresrc/osx/default_config.json b/src/libresrc/osx/default_config.json
index 66cecd520..7d0cb9b6a 100644
--- a/src/libresrc/osx/default_config.json
+++ b/src/libresrc/osx/default_config.json
@@ -335,7 +335,7 @@
 			}
 		},
 		"Avisynth" : {
-			"Memory Max" : 128
+			"Memory Max" : 1024
 		},
 		"FFmpegSource" : {
 			"Cache" : {
diff --git a/src/meson.build b/src/meson.build
index 9592cf6e0..b5791e558 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -171,11 +171,8 @@ if host_machine.system() == 'darwin'
     )
 elif host_machine.system() == 'windows'
     aegisub_src += files(
-        'avisynth_wrap.cpp',
         'font_file_lister_gdi.cpp',
         # 'libass_gdi_fontselect.cpp',
-        'audio_provider_avs.cpp',
-        'video_provider_avs.cpp',
     )
 
     if cc.has_header('wingdi.h')
@@ -238,6 +235,10 @@ opt_src = [
                'video_provider_ffmpegsource.cpp',
                'ffmpegsource_common.cpp']],
 
+    ['AviSynth', ['avisynth_wrap.cpp',
+                  'audio_provider_avs.cpp',
+                  'video_provider_avs.cpp']],
+
     ['Hunspell', 'spellchecker_hunspell.cpp'],
 ]