Move plugin bridge helper functions to utils.h

src/plugin/utils.h

@@ -0,0 +1,142 @@
+// 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/>.
+
+#pragma once
+
+#include <boost/filesystem.hpp>
+#include <boost/process/async_pipe.hpp>
+#include <boost/process/environment.hpp>
+
+/**
+ * Boost 1.72 was released with a known breaking bug caused by a missing
+ * typedef: https://github.com/boostorg/process/issues/116.
+ *
+ * Luckily this is easy to fix since it's not really possible to downgrade Boost
+ * as it would break other applications.
+ *
+ * Check if this is still needed for other distros after Arch starts packaging
+ * Boost 1.73.
+ */
+class patched_async_pipe : public boost::process::async_pipe {
+   public:
+    using boost::process::async_pipe::async_pipe;
+
+    typedef typename handle_type::executor_type executor_type;
+};
+
+/**
+ * A tag to differentiate between 32 and 64-bit plugins, used to determine which
+ * host application to use.
+ */
+enum class PluginArchitecture { vst_32, vst_64 };
+
+/**
+ * Create a logger prefix based on the unique socket path for easy
+ * identification. The socket path contains both the plugin's name and a unique
+ * identifier.
+ *
+ * @param socket_path The path to the socket endpoint in use.
+ *
+ * @return A prefix string for log messages.
+ */
+std::string create_logger_prefix(const boost::filesystem::path& socket_path);
+
+/**
+ * Determine the architecture of a VST plugin (or rather, a .dll file) based on
+ * it's header values.
+ *
+ * See https://docs.microsoft.com/en-us/windows/win32/debug/pe-format for more
+ * information on the PE32 format.
+ *
+ * @param plugin_path The path to the .dll file we're going to check.
+ *
+ * @return The detected architecture.
+ * @throw std::runtime_error If the file is not a .dll file.
+ */
+PluginArchitecture find_vst_architecture(boost::filesystem::path);
+
+/**
+ * Finds the Wine VST hsot (either `yabridge-host.exe` or `yabridge-host.exe`
+ * depending on the plugin). For this we will search in two places:
+ *
+ *   1. Alongside libyabridge.so if the file got symlinked. This is useful
+ *      when developing, as you can simply symlink the the libyabridge.so
+ *      file in the build directory without having to install anything to
+ *      /usr.
+ *   2. In the regular search path.
+ *
+ * @param plugin_arch The architecture of the plugin, either 64-bit or 32-bit.
+ *   Used to determine which host application to use, if available.
+ *
+ * @return The a path to the VST host, if found.
+ * @throw std::runtime_error If the Wine VST host could not be found.
+ */
+boost::filesystem::path find_vst_host(PluginArchitecture plugin_arch);
+
+/**
+ * Find the VST plugin .dll file that corresponds to this copy of
+ * `libyabridge.so`. This should be the same as the name of this file but with a
+ * `.dll` file extension instead of `.so`. In case this file does not exist and
+ * the `.so` file is a symlink, we'll also repeat this check for the file it
+ * links to. This is to support the workflow described in issue #3 where you use
+ * symlinks to copies of `libyabridge.so`.
+ *
+ * @return The a path to the accompanying VST plugin .dll file.
+ * @throw std::runtime_error If no matching .dll file could be found.
+ */
+boost::filesystem::path find_vst_plugin();
+
+/**
+ * Locate the Wine prefix this file is located in, if it is inside of a wine
+ * prefix.
+ *
+ * @return Either the path to the Wine prefix (containing the `drive_c?`
+ *   directory), or `std::nullopt` if it is not inside of a wine prefix.
+ */
+std::optional<boost::filesystem::path> find_wineprefix();
+
+/**
+ * Generate a unique name for the Unix domain socket endpoint based on the VST
+ * plugin's name. This will also generate the parent directory if it does not
+ * yet exist since we're using this in the constructor's initializer list.
+ *
+ * @return A path to a not yet existing Unix domain socket endpoint.
+ * @throw std::runtime_error If no matching .dll file could be found.
+ */
+boost::filesystem::path generate_endpoint_name();
+
+/**
+ * Return a path to this `.so` file. This can be used to find out from where
+ * this link to or copy of `libyabridge.so` was loaded.
+ */
+boost::filesystem::path get_this_file_location();
+
+/**
+ * Return the installed Wine version. This is obtained by from `wine --version`
+ * and then stripping the `wine-` prefix. This respects the `WINELOADER`
+ * environment variable used in the scripts generated by winegcc.
+ *
+ * This will *not* throw when Wine can not be found, but will instead return
+ * '<NOT FOUND>'. This way the user will still get some useful log files.
+ */
+std::string get_wine_version();
+
+/**
+ * Locate the Wine prefix and set the `WINEPREFIX` environment variable if
+ * found. This way it's also possible to run .dll files outside of a Wine prefix
+ * using the user's default prefix.
+ */
+boost::process::environment set_wineprefix();