mpd/src/neighbor/Glue.cxx

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project

#include "Glue.hxx"
#include "Registry.hxx"
#include "Explorer.hxx"
#include "NeighborPlugin.hxx"
#include "Info.hxx"
#include "config/Data.hxx"
#include "config/Block.hxx"
#include "lib/fmt/RuntimeError.hxx"

#include <stdexcept>

NeighborGlue::NeighborGlue() noexcept = default;
NeighborGlue::~NeighborGlue() noexcept = default;

static std::unique_ptr<NeighborExplorer>
CreateNeighborExplorer(EventLoop &loop, NeighborListener &listener,
		       const char *plugin_name,
		       const ConfigBlock &block)
{
	const NeighborPlugin *plugin = GetNeighborPluginByName(plugin_name);
	if (plugin == nullptr)
		throw FmtRuntimeError("No such neighbor plugin: {:?}",
				      plugin_name);

	return plugin->create(loop, listener, block);
}

void
NeighborGlue::Init(const ConfigData &config,
		   EventLoop &loop, NeighborListener &listener)
{
	config.WithEach(ConfigBlockOption::NEIGHBORS, [&, this](const auto &block){
		const char *plugin_name = block.GetBlockValue("plugin");
		if (plugin_name == nullptr)
			throw std::runtime_error("Missing \"plugin\" configuration");

		explorers.emplace_front(plugin_name,
					CreateNeighborExplorer(loop, listener,
							       plugin_name,
							       block));
	});
}

void
NeighborGlue::Open()
{
	for (auto i = explorers.begin(), end = explorers.end();
	     i != end; ++i) {
		try {
			i->explorer->Open();
		} catch (...) {
			/* roll back */
			for (auto k = explorers.begin(); k != i; ++k)
				k->explorer->Close();

			std::throw_with_nested(FmtRuntimeError("Failed to open neighblor plugin {:?}",
							       i->name));
		}
	}
}

void
NeighborGlue::Close() noexcept
{
	for (auto & explorer : explorers)
		explorer.explorer->Close();
}

NeighborGlue::List
NeighborGlue::GetList() const noexcept
{
	List result;

	for (const auto &i : explorers)
		result.splice_after(result.before_begin(),
				    i.explorer->GetList());

	return result;
}