HackStudio: Abstract away language-server details

This commit moves all the logic that deals with the language server
(from HackStudio) into a LanguageClient class, provides some functions
to make constructing them easier, and makes all language servers use a
singular IPC definition.
Also fixes the FIXME about making the autocompletion async.
This makes adding language servers in the future significantly less
duplicate-y, and significantly easier :^)

DevTools/HackStudio/LanguageClient.h

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <AK/LexicalPath.h>
+#include <AK/Types.h>
+#include <DevTools/HackStudio/LanguageServers/LanguageClientEndpoint.h>
+#include <DevTools/HackStudio/LanguageServers/LanguageServerEndpoint.h>
+#include <LibIPC/ServerConnection.h>
+
+namespace HackStudio {
+
+class LanguageClient;
+
+class ServerConnection
+    : public IPC::ServerConnection<LanguageClientEndpoint, LanguageServerEndpoint>
+    , public LanguageClientEndpoint {
+public:
+    ServerConnection(const StringView& socket, const StringView& project_path)
+        : IPC::ServerConnection<LanguageClientEndpoint, LanguageServerEndpoint>(*this, socket)
+        , m_project_path(project_path)
+    {
+    }
+
+    void attach(LanguageClient& client)
+    {
+        m_language_client = &client;
+    }
+
+    void detach()
+    {
+        m_language_client = nullptr;
+    }
+
+    virtual void handshake() override
+    {
+        auto response = send_sync<Messages::LanguageServer::Greet>(m_project_path.string());
+        set_my_client_id(response->client_id());
+    }
+
+    template<typename ConcreteType>
+    static NonnullRefPtr<ServerConnection> get_or_create(const String& project_path)
+    {
+        static HashMap<String, NonnullRefPtr<ConcreteType>> s_instances_for_projects;
+        auto key = LexicalPath { project_path }.string();
+        if (auto instance = s_instances_for_projects.get(key); instance.has_value())
+            return *instance.value();
+
+        auto connection = ConcreteType::construct(project_path);
+        connection->handshake();
+        s_instances_for_projects.set(key, *connection);
+        return *connection;
+    }
+
+protected:
+    virtual void handle(const Messages::LanguageClient::AutoCompleteSuggestions&) override;
+
+    LanguageClient* m_language_client { nullptr };
+    LexicalPath m_project_path;
+};
+
+class LanguageClient {
+public:
+    explicit LanguageClient(NonnullRefPtr<ServerConnection>&& connection)
+        : m_connection(*connection)
+        , m_server_connection(move(connection))
+    {
+        m_connection.attach(*this);
+    }
+
+    virtual ~LanguageClient()
+    {
+        m_connection.detach();
+    }
+
+    virtual void open_file(const String& path);
+    virtual void set_file_content(const String& path, const String& content);
+    virtual void insert_text(const String& path, const String& text, size_t line, size_t column);
+    virtual void remove_text(const String& path, size_t from_line, size_t from_column, size_t to_line, size_t to_column);
+    virtual void request_autocomplete(const String& path, size_t cursor_line, size_t cursor_column);
+
+    void provide_autocomplete_suggestions(const Vector<String>&);
+
+    Function<void(Vector<String>)> on_autocomplete_suggestions;
+
+private:
+    ServerConnection& m_connection;
+    NonnullRefPtr<ServerConnection> m_server_connection;
+};
+
+template<typename ServerConnectionT>
+static inline NonnullOwnPtr<LanguageClient> get_language_client(const String& project_path)
+{
+    return make<LanguageClient>(ServerConnection::get_or_create<ServerConnectionT>(project_path));
+}
+
+}