Support for overriding the syntax highlighting settings (#348)

* Writing support for overrides of highlighting settings

* Automatically creating the "SyntaxHighlighting" overrides directory and passing this path to FileSettingsStorage. Updated some APIs to use std::filesystem::path instead of std::string.

* Reloading the override settings as they change

* Added notes about how overriding of the highlighting settings works.

Docs/SyntaxHighlighting.md

@@ -69,9 +69,9 @@ Here's an example of such settings file:
 
 In addition to the styles mapping, the settings file also provides the name of the lexer to be used, lists of keywords, and lexer properties.
 
-These JSON files are all located in the application directory `SyntaxHighlighting`, which is currently non-modifiable. In the future, Nimble Commander will support overriding with files placed in the `~/Library/Application Support/...` directory.
+These JSON files are located in the application's `SyntaxHighlighting` directory, shipped with the application. This directory also contains the `Main.json` file, which defines the list of known languages, their file masks, and the filenames of the settings for each language. 
 
-This directory also contains the `Main.json` file, which defines the list of known languages, their file masks, and the filenames of the settings for each language.
+Nimble Commander supports overriding these settings with files placed in the `~/Library/Application Support/Nimble Commander/SyntaxHighlighting` directory. Any file will first be looked for in the `Application Support` directory, and if not found, in the application directory. Changes in the overrides directory will be automatically picked up by Nimble Commander, and the next time the Viewer is shown, the updated settings will be used.
 
 ## Helper Tool
 

Source/Config/include/Config/FileOverwritesStorage.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2018-2021 Michael Kazakov. Subject to GNU General Public License version 3.
+// Copyright (C) 2018-2024 Michael Kazakov. Subject to GNU General Public License version 3.
 #pragma once
 
 #include "OverwritesStorage.h"
@@ -12,7 +12,7 @@ namespace nc::config {
 class FileOverwritesStorage : public OverwritesStorage
 {
 public:
-    FileOverwritesStorage(std::string_view _file_path);
+    FileOverwritesStorage(const std::filesystem::path &_file_path);
     FileOverwritesStorage(const FileOverwritesStorage &) = delete;
     ~FileOverwritesStorage();
 

Source/Config/source/FileOverwritesStorage.cpp

@@ -1,4 +1,4 @@
-// Copyright (C) 2018-2022 Michael Kazakov. Subject to GNU General Public License version 3.
+// Copyright (C) 2018-2024 Michael Kazakov. Subject to GNU General Public License version 3.
 #include "FileOverwritesStorage.h"
 #include "Log.h"
 #include <sys/stat.h>
@@ -16,10 +16,10 @@ using utility::FSEventsDirUpdate;
 static std::optional<std::string> Load(const std::string &_filepath);
 static time_t ModificationTime(const std::string &_filepath);
 
-FileOverwritesStorage::FileOverwritesStorage(std::string_view _file_path) : m_Path(_file_path)
+FileOverwritesStorage::FileOverwritesStorage(const std::filesystem::path &_file_path) : m_Path(_file_path)
 {
     Log::Trace(SPDLOC, "Created storage with path: {}", _file_path);
-    auto parent_path = std::filesystem::path{std::string{_file_path}}.parent_path();
+    auto parent_path = _file_path.parent_path();
     Log::Trace(SPDLOC, "Setting observation for directory: {}", parent_path);
     m_DirObservationTicket =
         FSEventsDirUpdate::Instance().AddWatchPath(parent_path.c_str(), [this] { OverwritesDirChanged(); });

Source/NimbleCommander/NimbleCommander/Bootstrap/AppDelegate.h

@@ -4,6 +4,7 @@
 
 #include <VFS/VFS_fwd.h>
 #include <Cocoa/Cocoa.h>
+#include <filesystem>
 
 @class NCConfigObjCBridge;
 @class NCMainWindowController;
@@ -86,18 +87,18 @@ class NativeHost;
  * Support dir, ~/Library/Application Support/Nimble Commander/.
  * Is in Containers for Sandboxes versions
  */
-@property(nonatomic, readonly) const std::string &supportDirectory;
+@property(nonatomic, readonly) const std::filesystem::path &supportDirectory;
 
 /**
  * By default this dir is ~/Library/Application Support/Nimble Commander/Config/.
  * May change in the future.
  */
-@property(nonatomic, readonly) const std::string &configDirectory;
+@property(nonatomic, readonly) const std::filesystem::path &configDirectory;
 
 /**
  * This dir is ~/Library/Application Support/Nimble Commander/State/.
  */
-@property(nonatomic, readonly) const std::string &stateDirectory;
+@property(nonatomic, readonly) const std::filesystem::path &stateDirectory;
 
 @property(nonatomic, readonly) NCConfigObjCBridge *config;
 

Source/NimbleCommander/NimbleCommander/Bootstrap/AppDelegate.mm

@@ -226,9 +226,9 @@ @implementation NCAppDelegate {
     std::vector<NCMainWindowController *> m_MainWindows;
     std::vector<InternalViewerWindowController *> m_ViewerWindows;
     nc::spinlock m_ViewerWindowsLock;
-    std::string m_SupportDirectory;
-    std::string m_ConfigDirectory;
-    std::string m_StateDirectory;
+    std::filesystem::path m_SupportDirectory;
+    std::filesystem::path m_ConfigDirectory;
+    std::filesystem::path m_StateDirectory;
     std::vector<nc::config::Token> m_ConfigObservationTickets;
     upward_flag m_FinishedLaunching;
     std::shared_ptr<nc::panel::FavoriteLocationsStorageImpl> m_Favorites;
@@ -478,19 +478,19 @@ - (void)setupConfigs
 
     g_Config = new nc::config::ConfigImpl(
         *config_defaults,
-        std::make_shared<nc::config::FileOverwritesStorage>(self.configDirectory + "Config.json"),
+        std::make_shared<nc::config::FileOverwritesStorage>(self.configDirectory / "Config.json"),
         std::make_shared<nc::config::DelayedAsyncExecutor>(write_delay),
         std::make_shared<nc::config::DelayedAsyncExecutor>(reload_delay));
 
     g_State = new nc::config::ConfigImpl(
         *state_defaults,
-        std::make_shared<nc::config::FileOverwritesStorage>(self.stateDirectory + "State.json"),
+        std::make_shared<nc::config::FileOverwritesStorage>(self.stateDirectory / "State.json"),
         std::make_shared<nc::config::DelayedAsyncExecutor>(write_delay),
         std::make_shared<nc::config::DelayedAsyncExecutor>(reload_delay));
 
     g_NetworkConnectionsConfig = new nc::config::ConfigImpl(
         "",
-        std::make_shared<nc::config::FileOverwritesStorage>(self.configDirectory + "NetworkConnections.json"),
+        std::make_shared<nc::config::FileOverwritesStorage>(self.configDirectory / "NetworkConnections.json"),
         std::make_shared<nc::config::DelayedAsyncExecutor>(write_delay),
         std::make_shared<nc::config::DelayedAsyncExecutor>(reload_delay));
 
@@ -971,8 +971,20 @@ - (IBAction)onMainMenuShowLogs:(id)_sender
 
 - (nc::viewer::hl::SettingsStorage &)syntaxHighlightingSettingsStorage
 {
+    // if the overrides directory doesn't exist - create it. Check it only once per run
+    static std::once_flag once;
+    std::call_once(once, [self] {
+        const std::filesystem::path overrides_dir = self.supportDirectory / "SyntaxHighlighting";
+        std::error_code ec = {};
+        if( !std::filesystem::exists(overrides_dir, ec) ) {
+            std::filesystem::create_directory(overrides_dir, ec);
+        }
+    });
+
     [[clang::no_destroy]] static nc::viewer::hl::FileSettingsStorage storage{
-        [NSBundle.mainBundle pathForResource:@"SyntaxHighlighting" ofType:@""].fileSystemRepresentation, ""};
+        [NSBundle.mainBundle pathForResource:@"SyntaxHighlighting" ofType:@""].fileSystemRepresentation,
+        self.supportDirectory / "SyntaxHighlighting"};
+
     return storage;
 }
 

Source/NimbleCommander/NimbleCommander/Bootstrap/AppDelegateCPP.h

@@ -1,7 +1,7 @@
-// Copyright (C) 2016-2018 Michael Kazakov. Subject to GNU General Public License version 3.
+// Copyright (C) 2016-2024 Michael Kazakov. Subject to GNU General Public License version 3.
 #pragma once
 
-#include <string>
+#include <filesystem>
 #include <memory>
 
 class NetworkConnectionsManager;
@@ -11,9 +11,9 @@ namespace nc {
 class AppDelegate
 {
 public:
-    static const std::string &ConfigDirectory();
-    static const std::string &StateDirectory();
-    static const std::string &SupportDirectory();
+    static const std::filesystem::path &ConfigDirectory();
+    static const std::filesystem::path &StateDirectory();
+    static const std::filesystem::path &SupportDirectory();
     static const std::shared_ptr<NetworkConnectionsManager> &NetworkConnectionsManager();
 };
 

Source/NimbleCommander/NimbleCommander/Bootstrap/AppDelegateCPP.mm

@@ -1,4 +1,4 @@
-// Copyright (C) 2016-2020 Michael Kazakov. Subject to GNU General Public License version 3.
+// Copyright (C) 2016-2024 Michael Kazakov. Subject to GNU General Public License version 3.
 #include "AppDelegateCPP.h"
 #include <Utility/PathManip.h>
 #include <Utility/StringExtras.h>
@@ -7,21 +7,21 @@
 
 namespace nc {
 
-const std::string &AppDelegate::ConfigDirectory()
+const std::filesystem::path &AppDelegate::ConfigDirectory()
 {
     return NCAppDelegate.me.configDirectory;
 }
 
-const std::string &AppDelegate::StateDirectory()
+const std::filesystem::path &AppDelegate::StateDirectory()
 {
     return NCAppDelegate.me.stateDirectory;
 }
 
-const std::string &AppDelegate::SupportDirectory()
+const std::filesystem::path &AppDelegate::SupportDirectory()
 {
     // this is a duplicate of NCAppDelegate.supportDirectory,
     // but it has to be here to break down an initialization dependency circle
-    [[clang::no_destroy]] static const std::string support_dir = [] {
+    [[clang::no_destroy]] static const std::filesystem::path support_dir = [] {
         auto path = NSFileManager.defaultManager.applicationSupportDirectory;
         return EnsureTrailingSlash(path.fileSystemRepresentationSafe);
     }();

Source/Viewer/include/Viewer/Highlighting/FileSettingsStorage.h

@@ -12,6 +12,9 @@ class FileSettingsStorage : public SettingsStorage
 {
 public:
     FileSettingsStorage(const std::filesystem::path &_base_dir, const std::filesystem::path &_overrides_dir);
+    FileSettingsStorage(const FileSettingsStorage &) = delete;
+    ~FileSettingsStorage();
+    FileSettingsStorage &operator=(const FileSettingsStorage &) = delete;
 
     std::optional<std::string> Language(std::string_view _filename) noexcept override;
 
@@ -24,9 +27,20 @@ class FileSettingsStorage : public SettingsStorage
         nc::utility::FileMask mask;
     };
 
-    std::vector<Lang> LoadLangs();
+    // Loads and parses the contents of the "Main.json" file
+    std::vector<Lang> LoadLangs(const std::filesystem::path &_path) const;
+
+    void ReloadLangs();
+
+    void SubscribeToOverridesChanges();
+    void UnsubscribeFromOverridesChanges();
+    void OverridesChanged();
 
     std::filesystem::path m_BaseDir;
+    std::filesystem::path m_OverridesDir;
+    uint64_t m_OverridesObservationToken = 0;
+    bool m_Outdated = false;
+
     std::vector<Lang> m_Langs;
     robin_hood::unordered_flat_map<std::string,
                                    std::shared_ptr<const std::string>,