nixpkgs/pkgs/development/libraries/vapoursynth/0001-Call-weak-function-to-allow-adding-preloaded-plugins.patch

From 439e2effe1cc372925daf6d5c28569663ffb93ed Mon Sep 17 00:00:00 2001
From: Tadeo Kondrak <me@tadeo.ca>
Date: Mon, 25 Jan 2021 11:17:44 -0700
Subject: [PATCH] Call weak function to allow adding preloaded plugins after
 compile

---
 src/core/vscore.cpp | 19 +++++++++++++++++++
 src/core/vscore.h   |  5 +++++
 2 files changed, 24 insertions(+)

diff --git a/src/core/vscore.cpp b/src/core/vscore.cpp
index f8e69062..4ce4c623 100644
--- a/src/core/vscore.cpp
+++ b/src/core/vscore.cpp
@@ -1791,6 +1791,20 @@ void VSCore::destroyFilterInstance(VSNode *node) {
     freeDepth--;
 }
 
+extern "C" {
+void __attribute__((weak)) VSLoadPluginsNix(void (*load)(void *data, const char *path), void *data);
+
+struct VSLoadPluginsNixCallbackData {
+    VSCore *core;
+    const char *filter;
+};
+
+static void VSLoadPluginsNixCallback(void *data, const char *path) {
+    auto callbackData = static_cast<VSLoadPluginsNixCallbackData *>(data);
+    callbackData->core->loadAllPluginsInPath(path, callbackData->filter);
+}
+}
+
 VSCore::VSCore(int flags) :
     numFilterInstances(1),
     numFunctionInstances(0),
@@ -1918,6 +1932,11 @@ VSCore::VSCore(int flags) :
     } // If neither exists, an empty string will do.
 #endif
 
+    if (VSLoadPluginsNix != nullptr) {
+        VSLoadPluginsNixCallbackData data{this, filter.c_str()};
+        VSLoadPluginsNix(VSLoadPluginsNixCallback, &data);
+    }
+
     VSMap *settings = readSettings(configFile);
     const char *error = vs_internal_vsapi.mapGetError(settings);
     if (error) {
diff --git a/src/core/vscore.h b/src/core/vscore.h
index 2ce0f56b..2982b133 100644
--- a/src/core/vscore.h
+++ b/src/core/vscore.h
@@ -985,6 +985,9 @@ public:
     std::string getV3ArgString() const;
 };
 
+extern "C" {
+static void VSLoadPluginsNixCallback(void *data, const char *path);
+}
 
 struct VSPlugin {
     friend struct VSPluginFunction;
@@ -1140,6 +1143,8 @@ public:
 
     explicit VSCore(int flags);
     void freeCore();
+
+    friend void VSLoadPluginsNixCallback(void *data, const char *path);
 };
 
 #endif // VSCORE_H
-- 
2.32.0