LanguageServers/Cpp: Add FileDB and pass project_root in Greet()

FileDB wraps the access to the contents of project files.

When asked to fetch a file, FileDB will either return its in-memory
model of the file if it has been "opened" by the language-server
protocol, or otherwise fetch it from the filesystem.

Previously, the cpp language server did not pledge "rpath" and got
access to the contents of files whenever they were opened by the
language client.
However, features like inspection of header files require the language
server to get the content of files that were not opened by the client.

The language server now pledges rpath but makes sure to only unveil
the project's directory and /usr/include.

8 files changed, 248 insertions, 21 deletions

diff --git a/Userland/DevTools/HackStudio/LanguageClient.cpp b/Userland/DevTools/HackStudio/LanguageClient.cpp
index 1afc59bd60..f320bf08e4 100644
--- a/Userland/DevTools/HackStudio/LanguageClient.cpp
+++ b/Userland/DevTools/HackStudio/LanguageClient.cpp
@@ -62,6 +62,7 @@ void LanguageClient::remove_text(const String& path, size_t from_line, size_t fr
 
 void LanguageClient::request_autocomplete(const String& path, size_t cursor_line, size_t cursor_column)
 {
+    set_active_client();
     m_connection.post_message(Messages::LanguageServer::AutoCompleteSuggestions(path, cursor_line, cursor_column));
 }
 
@@ -78,4 +79,9 @@ void LanguageClient::set_autocomplete_mode(const String& mode)
     m_connection.post_message(Messages::LanguageServer::SetAutoCompleteMode(mode));
 }
 
+void LanguageClient::set_active_client()
+{
+    m_connection.attach(*this);
+}
+
 }
diff --git a/Userland/DevTools/HackStudio/LanguageClient.h b/Userland/DevTools/HackStudio/LanguageClient.h
index 51804d8d0f..b5a4085bf5 100644
--- a/Userland/DevTools/HackStudio/LanguageClient.h
+++ b/Userland/DevTools/HackStudio/LanguageClient.h
@@ -45,9 +45,10 @@ class ServerConnection
     : public IPC::ServerConnection<LanguageClientEndpoint, LanguageServerEndpoint>
     , public LanguageClientEndpoint {
 public:
-    ServerConnection(const StringView& socket)
+    ServerConnection(const StringView& socket, const String& project_path)
         : IPC::ServerConnection<LanguageClientEndpoint, LanguageServerEndpoint>(*this, socket)
     {
+        m_project_path = project_path;
     }
 
     void attach(LanguageClient& client)
@@ -62,7 +63,7 @@ public:
 
     virtual void handshake() override
     {
-        send_sync<Messages::LanguageServer::Greet>();
+        send_sync<Messages::LanguageServer::Greet>(m_project_path);
     }
 
     WeakPtr<LanguageClient> language_client() { return m_language_client; }
@@ -75,7 +76,7 @@ public:
         if (auto instance = s_instances_for_projects.get(key); instance.has_value())
             return *instance.value();
 
-        auto connection = ConcreteType::construct();
+        auto connection = ConcreteType::construct(project_path);
         connection->handshake();
         s_instances_for_projects.set(key, *connection);
         return *connection;
@@ -84,6 +85,7 @@ public:
 protected:
     virtual void handle(const Messages::LanguageClient::AutoCompleteSuggestions&) override;
 
+    String m_project_path;
     WeakPtr<LanguageClient> m_language_client;
 };
 
@@ -94,16 +96,19 @@ public:
         , m_server_connection(move(connection))
     {
         m_previous_client = m_connection.language_client();
+        ASSERT(m_previous_client.ptr() != this);
         m_connection.attach(*this);
     }
 
     virtual ~LanguageClient()
     {
         m_connection.detach();
+        ASSERT(m_previous_client.ptr() != this);
         if (m_previous_client)
             m_connection.attach(*m_previous_client);
     }
 
+    void set_active_client();
     virtual void open_file(const String& path, int fd);
     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);
diff --git a/Userland/DevTools/HackStudio/LanguageClients/ServerConnections.h b/Userland/DevTools/HackStudio/LanguageClients/ServerConnections.h
index bcebdb419e..89266e37ca 100644
--- a/Userland/DevTools/HackStudio/LanguageClients/ServerConnections.h
+++ b/Userland/DevTools/HackStudio/LanguageClients/ServerConnections.h
@@ -32,16 +32,16 @@
 #include <DevTools/HackStudio/LanguageServers/LanguageServerEndpoint.h>
 #include <LibIPC/ServerConnection.h>
 
-#define LANGUAGE_CLIENT(namespace_, socket_name)                                 \
-    namespace namespace_ {                                                       \
-    class ServerConnection : public HackStudio::ServerConnection {               \
-        C_OBJECT(ServerConnection)                                               \
-    private:                                                                     \
-        ServerConnection()                                                       \
-            : HackStudio::ServerConnection("/tmp/portal/language/" #socket_name) \
-        {                                                                        \
-        }                                                                        \
-    };                                                                           \
+#define LANGUAGE_CLIENT(namespace_, socket_name)                                               \
+    namespace namespace_ {                                                                     \
+    class ServerConnection : public HackStudio::ServerConnection {                             \
+        C_OBJECT(ServerConnection)                                                             \
+    private:                                                                                   \
+        ServerConnection(const String& project_path)                                           \
+            : HackStudio::ServerConnection("/tmp/portal/language/" #socket_name, project_path) \
+        {                                                                                      \
+        }                                                                                      \
+    };                                                                                         \
     }
 
 namespace LanguageClients {
diff --git a/Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.cpp b/Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.cpp
index 4f68c06f07..c6dd71cf48 100644
--- a/Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.cpp
+++ b/Userland/DevTools/HackStudio/LanguageServers/Cpp/ClientConnection.cpp
@@ -52,8 +52,17 @@ void ClientConnection::die()
     exit(0);
 }
 
-OwnPtr<Messages::LanguageServer::GreetResponse> ClientConnection::handle(const Messages::LanguageServer::Greet&)
+OwnPtr<Messages::LanguageServer::GreetResponse> ClientConnection::handle(const Messages::LanguageServer::Greet& message)
 {
+    m_filedb.set_project_root(message.project_root());
+    if (unveil(message.project_root().characters(), "r") < 0) {
+        perror("unveil");
+        exit(1);
+    }
+    if (unveil(nullptr, nullptr) < 0) {
+        perror("unveil");
+        exit(1);
+    }
     return make<Messages::LanguageServer::GreetResponse>();
 }
 
diff --git a/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.cpp b/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.cpp
new file mode 100644
index 0000000000..f354a2beb8
--- /dev/null
+++ b/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.cpp
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2021, Itamar S. <itamar8910@gmail.com>
+ * 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.
+ */
+
+#include "FileDB.h"
+
+#include <AK/LexicalPath.h>
+#include <LibCore/File.h>
+
+RefPtr<const GUI::TextDocument> FileDB::get(const String& file_name) const
+{
+    auto absolute_path = to_absolute_path(file_name);
+    auto document_optional = m_open_files.get(absolute_path);
+    if (!document_optional.has_value())
+        return create_from_filesystem(absolute_path);
+
+    return document_optional.value();
+}
+
+RefPtr<GUI::TextDocument> FileDB::get(const String& file_name)
+{
+    auto absolute_path = to_absolute_path(file_name);
+    return adopt(*const_cast<GUI::TextDocument*>(reinterpret_cast<const FileDB*>(this)->get(absolute_path).leak_ref()));
+}
+
+bool FileDB::is_open(String file_name) const
+{
+    return m_open_files.contains(to_absolute_path(file_name));
+}
+
+bool FileDB::add(const String& file_name, int fd)
+{
+    auto document = create_from_fd(fd);
+    if (!document)
+        return false;
+
+    m_open_files.set(to_absolute_path(file_name), document.release_nonnull());
+    return true;
+}
+
+String FileDB::to_absolute_path(const String& file_name) const
+{
+    if (LexicalPath { file_name }.is_absolute()) {
+        return file_name;
+    }
+    ASSERT(!m_project_root.is_null());
+    return LexicalPath { String::formatted("{}/{}", m_project_root, file_name) }.string();
+}
+
+RefPtr<GUI::TextDocument> FileDB::create_from_filesystem(const String& file_name) const
+{
+    auto file = Core::File::open(to_absolute_path(file_name), Core::IODevice::ReadOnly);
+    if (file.is_error()) {
+        dbgln("failed to create document for {} from filesystem", file_name);
+        return nullptr;
+    }
+    return create_from_file(*file.value());
+}
+
+RefPtr<GUI::TextDocument> FileDB::create_from_fd(int fd) const
+{
+    auto file = Core::File::construct();
+    if (!file->open(fd, Core::IODevice::ReadOnly, Core::File::ShouldCloseFileDescriptor::Yes)) {
+        errno = file->error();
+        perror("open");
+        dbgln("Failed to open project file");
+        return nullptr;
+    }
+    return create_from_file(*file);
+}
+
+class DefaultDocumentClient final : public GUI::TextDocument::Client {
+public:
+    virtual ~DefaultDocumentClient() override = default;
+    virtual void document_did_append_line() override {};
+    virtual void document_did_insert_line(size_t) override {};
+    virtual void document_did_remove_line(size_t) override {};
+    virtual void document_did_remove_all_lines() override {};
+    virtual void document_did_change() override {};
+    virtual void document_did_set_text() override {};
+    virtual void document_did_set_cursor(const GUI::TextPosition&) override {};
+
+    virtual bool is_automatic_indentation_enabled() const override { return false; }
+    virtual int soft_tab_width() const override { return 4; }
+};
+static DefaultDocumentClient s_default_document_client;
+
+RefPtr<GUI::TextDocument> FileDB::create_from_file(Core::File& file) const
+{
+    auto content = file.read_all();
+    StringView content_view(content);
+    auto document = GUI::TextDocument::create(&s_default_document_client);
+    document->set_text(content_view);
+    return document;
+}
+
+void FileDB::on_file_edit_insert_text(const String& file_name, const String& inserted_text, size_t start_line, size_t start_column)
+{
+    auto document = get(file_name);
+    if (!document) {
+        dbgln("file {} has not been opened", file_name);
+        return;
+    }
+    GUI::TextPosition start_position { start_line, start_column };
+    document->insert_at(start_position, inserted_text, &s_default_document_client);
+
+#if FILE_CONTENT_DEBUG
+    dbgln("{}", document->text());
+#endif
+}
+
+void FileDB::on_file_edit_remove_text(const String& file_name, size_t start_line, size_t start_column, size_t end_line, size_t end_column)
+{
+    auto document = get(file_name);
+    if (!document) {
+        dbgln("file {} has not been opened", file_name);
+        return;
+    }
+    GUI::TextPosition start_position { start_line, start_column };
+    GUI::TextRange range {
+        GUI::TextPosition { start_line, start_column },
+        GUI::TextPosition { end_line, end_column }
+    };
+
+    document->remove(range);
+#if FILE_CONTENT_DEBUG
+    dbgln("{}", document->text());
+#endif
+}
diff --git a/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.h b/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.h
new file mode 100644
index 0000000000..7cace78db8
--- /dev/null
+++ b/Userland/DevTools/HackStudio/LanguageServers/Cpp/FileDB.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2021, Itamar S. <itamar8910@gmail.com>
+ * 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/HashMap.h>
+#include <AK/NonnullRefPtr.h>
+#include <AK/String.h>
+#include <LibGUI/TextDocument.h>
+
+class FileDB final {
+public:
+    RefPtr<const GUI::TextDocument> get(const String& file_name) const;
+    RefPtr<GUI::TextDocument> get(const String& file_name);
+    bool add(const String& file_name, int fd);
+
+    void set_project_root(const String& root_path) { m_project_root = root_path; }
+
+    void on_file_edit_insert_text(const String& file_name, const String& inserted_text, size_t start_line, size_t start_column);
+    void on_file_edit_remove_text(const String& file_name, size_t start_line, size_t start_column, size_t end_line, size_t end_column);
+    String to_absolute_path(const String& file_name) const;
+    bool is_open(String file_name) const;
+
+private:
+    RefPtr<GUI::TextDocument> create_from_filesystem(const String& file_name) const;
+    RefPtr<GUI::TextDocument> create_from_fd(int fd) const;
+    RefPtr<GUI::TextDocument> create_from_file(Core::File&) const;
+
+private:
+    HashMap<String, NonnullRefPtr<GUI::TextDocument>> m_open_files;
+    String m_project_root;
+};
diff --git a/Userland/DevTools/HackStudio/LanguageServers/Cpp/main.cpp b/Userland/DevTools/HackStudio/LanguageServers/Cpp/main.cpp
index 524d6d6f50..a15bd30fd0 100644
--- a/Userland/DevTools/HackStudio/LanguageServers/Cpp/main.cpp
+++ b/Userland/DevTools/HackStudio/LanguageServers/Cpp/main.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * Copyright (c) 2021, Itamar S. <itamar8910@gmail.com>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -36,20 +36,21 @@
 int main(int, char**)
 {
     Core::EventLoop event_loop;
-    if (pledge("stdio unix recvfd", nullptr) < 0) {
+    if (pledge("stdio unix recvfd rpath ", nullptr) < 0) {
         perror("pledge");
         return 1;
     }
 
     auto socket = Core::LocalSocket::take_over_accepted_socket_from_system_server();
     IPC::new_client_connection<LanguageServers::Cpp::ClientConnection>(socket.release_nonnull(), 1);
-    if (pledge("stdio recvfd", nullptr) < 0) {
+    if (pledge("stdio recvfd rpath", nullptr) < 0) {
         perror("pledge");
         return 1;
     }
-    if (unveil(nullptr, nullptr) < 0) {
+
+    if (unveil("/usr/include", "r") < 0)
         perror("unveil");
-        return 1;
-    }
+
+    // unveil will be sealed later, when we know the project's root path.
     return event_loop.exec();
 }
diff --git a/Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc b/Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc
index ae4f55cf89..1eada48bf0 100644
--- a/Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc
+++ b/Userland/DevTools/HackStudio/LanguageServers/LanguageServer.ipc
@@ -1,6 +1,6 @@
 endpoint LanguageServer = 8001
 {
-    Greet() => ()
+    Greet(String project_root) => ()
 
     FileOpened(String file_name, IPC::File file) =|
     FileEditInsertText(String file_name, String text, i32 start_line, i32 start_column) =|