LV2: Add turtle-writer program

CMakeLists.txt

@@ -148,3 +148,5 @@ install(FILES "${JUCE_BINARY_DIR}/JUCEConfigVersion.cmake"
               "${JUCE_CMAKE_UTILS_DIR}/copyDir.cmake"
               "${JUCE_CMAKE_UTILS_DIR}/juce_runtime_arch_detection.cpp"
         DESTINATION "${JUCE_INSTALL_DESTINATION}")
+
+install(EXPORT LV2_HELPER NAMESPACE juce:: DESTINATION "${JUCE_INSTALL_DESTINATION}")

modules/CMakeLists.txt

@@ -37,3 +37,5 @@ juce_add_modules(
     juce_osc
     juce_product_unlocking
     juce_video)
+
+add_subdirectory(juce_audio_plugin_client)

modules/juce_audio_plugin_client/CMakeLists.txt

@@ -0,0 +1,22 @@
+# ==============================================================================
+#
+#  This file is part of the JUCE 7 technical preview.
+#  Copyright (c) 2022 - Raw Material Software Limited
+#
+#  You may use this code under the terms of the GPL v3
+#  (see www.gnu.org/licenses).
+#
+#  For the technical preview this file cannot be licensed commercially.
+#
+#  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+#  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+#  DISCLAIMED.
+#
+# ==============================================================================
+
+add_executable(juce_lv2_helper LV2/juce_LV2TurtleDumpProgram.cpp)
+add_executable(juce::juce_lv2_helper ALIAS juce_lv2_helper)
+target_compile_features(juce_lv2_helper PRIVATE cxx_std_14)
+set_target_properties(juce_lv2_helper PROPERTIES BUILD_WITH_INSTALL_RPATH ON)
+target_link_libraries(juce_lv2_helper PRIVATE ${CMAKE_DL_LIBS})
+install(TARGETS juce_lv2_helper EXPORT LV2_HELPER DESTINATION "bin/JUCE-${JUCE_VERSION}")

modules/juce_audio_plugin_client/LV2/juce_LV2TurtleDumpProgram.cpp

@@ -0,0 +1,71 @@
+/*
+  ==============================================================================
+
+   This file is part of the JUCE 7 technical preview.
+   Copyright (c) 2022 - Raw Material Software Limited
+
+   You may use this code under the terms of the GPL v3
+   (see www.gnu.org/licenses).
+
+   For the technical preview this file cannot be licensed commercially.
+
+   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+#ifdef _WIN32
+ #include <windows.h>
+ HMODULE dlopen (const char* filename, int) { return LoadLibrary (filename); }
+ FARPROC dlsym (HMODULE handle, const char* name) { return GetProcAddress (handle, name); }
+ enum { RTLD_LAZY = 0 };
+#else
+ #include <dlfcn.h>
+#endif
+
+#include <cstdint>
+
+// Replicating some of the LV2 header here so that we don't have to set up any
+// custom include paths for this file.
+// Normally this would be a bad idea, but the LV2 API has to keep these definitions
+// in order to remain backwards-compatible.
+
+extern "C"
+{
+    typedef struct LV2_Descriptor
+    {
+        const void* a;
+        const void* b;
+        const void* c;
+        const void* d;
+        const void* e;
+        const void* f;
+        const void* g;
+        const void* (*extension_data)(const char* uri);
+    } LV2_Descriptor;
+}
+
+int main (int argc, const char** argv)
+{
+    if (argc != 2)
+        return 1;
+
+    const auto* libraryPath = argv[1];
+
+    struct RecallFeature
+    {
+        int (*doRecall) (const char*);
+    };
+
+    if (auto* handle = dlopen (libraryPath, RTLD_LAZY))
+        if (auto* getDescriptor = reinterpret_cast<const LV2_Descriptor* (*) (uint32_t)> (dlsym (handle, "lv2_descriptor")))
+            if (auto* descriptor = getDescriptor (0))
+                if (auto* extensionData = descriptor->extension_data)
+                    if (auto* recallFeature = reinterpret_cast<const RecallFeature*> (extensionData ("https://lv2-extensions.juce.com/turtle_recall")))
+                        if (auto* doRecall = recallFeature->doRecall)
+                            return doRecall (libraryPath);
+
+    return 1;
+}