Move communication.h to communication/vst2.h

src/common/communication/vst2.cpp

@@ -0,0 +1,107 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020  Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "vst2.h"
+
+#include <random>
+
+#include "../utils.h"
+
+namespace fs = boost::filesystem;
+
+/**
+ * Used for generating random identifiers.
+ */
+constexpr char alphanumeric_characters[] =
+    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+EventPayload DefaultDataConverter::read(const int /*opcode*/,
+                                        const int /*index*/,
+                                        const intptr_t /*value*/,
+                                        const void* data) const {
+    if (!data) {
+        return nullptr;
+    }
+
+    // This is a simple fallback that will work in almost every case.
+    // Because some plugins don't zero out their string buffers when sending
+    // host callbacks, we will explicitely list all callbacks that expect a
+    // string in `DispatchDataConverter` adn `HostCallbackDataConverter`.
+    const char* c_string = static_cast<const char*>(data);
+    if (c_string[0] != 0) {
+        return std::string(c_string);
+    } else {
+        return WantsString{};
+    }
+}
+
+std::optional<EventPayload> DefaultDataConverter::read_value(
+    const int /*opcode*/,
+    const intptr_t /*value*/) const {
+    return std::nullopt;
+}
+
+void DefaultDataConverter::write(const int /*opcode*/,
+                                 void* data,
+                                 const EventResult& response) const {
+    // The default behavior is to handle this as a null terminated C-style
+    // string
+    std::visit(overload{[&](const auto&) {},
+                        [&](const std::string& s) {
+                            char* output = static_cast<char*>(data);
+
+                            // We use std::string for easy transport but in
+                            // practice we're always writing null terminated
+                            // C-style strings
+                            std::copy(s.begin(), s.end(), output);
+                            output[s.size()] = 0;
+                        }},
+               response.payload);
+}
+
+void DefaultDataConverter::write_value(const int /*opcode*/,
+                                       intptr_t /*value*/,
+                                       const EventResult& /*response*/) const {}
+
+intptr_t DefaultDataConverter::return_value(const int /*opcode*/,
+                                            const intptr_t original) const {
+    return original;
+}
+
+boost::filesystem::path generate_endpoint_base(const std::string& plugin_name) {
+    fs::path temp_directory = get_temporary_directory();
+
+    std::random_device random_device;
+    std::mt19937 rng(random_device());
+    fs::path candidate_endpoint;
+    do {
+        std::string random_id;
+        std::sample(
+            alphanumeric_characters,
+            alphanumeric_characters + strlen(alphanumeric_characters) - 1,
+            std::back_inserter(random_id), 8, rng);
+
+        // We'll get rid of the file descriptors immediately after accepting the
+        // sockets, so putting them inside of a subdirectory would only leave
+        // behind an empty directory
+        std::ostringstream socket_name;
+        socket_name << "yabridge-" << plugin_name << "-" << random_id;
+
+        candidate_endpoint = temp_directory / socket_name.str();
+    } while (fs::exists(candidate_endpoint));
+
+    return candidate_endpoint;
+}