feat: source-code-compatible plugin system (V1) by hybridmachine · Pull Request #99 · hybridmachine/MacNotePlusPlus

hybridmachine · 2026-04-09T03:33:17Z

Summary

Implement a plugin loading system that allows Notepad++ plugins to compile on macOS as .dylib files and load into MacNote++ with zero source code changes
V1 targets command-oriented, non-docking plugins (menu commands, Scintilla messaging, file-path APIs, SCNotification callbacks)
Includes HelloMacNote sample plugin that compiles identically on Windows (.dll) and macOS (.dylib)

What's included

Scintilla HWND registration: Both editor views registered with HandleRegistry at startup so plugins get real HWNDs for SendMessage(sciHandle, SCI_*, ...)
MacPluginManager: Loads .dylib plugins from ~/Library/Application Support/MacNote++/plugins/, resolves 6 required exports, Mach-O arch validation
NPPM message handler: 12 NPPMSG + 8 RUNCOMMAND_USER messages with correct offsets and calling conventions
WndProc routing: Static commands (22000-22999), dynamic relay (23000-24999), catch-all messageProc relay matching upstream
Notifications: SCNotification forwarding from both views, NPPN_READY/NPPN_SHUTDOWN lifecycle
Plugin SDK: Headers + shim includes + HelloMacNote sample
Plugins menu: Between Tools and Language

Known limitations (V2)

Buffer APIs (NPPM_GETCURRENTBUFFERID, NPPN_BUFFERACTIVATED) — need stable buffer IDs
File/language notifications (NPPN_FILEOPENED, etc.) — require BufferID in nmhdr.idFrom
Docking panels, lexer plugins, modeless dialog registration, Plugin Admin

Test plan

cmake --build . --target MacNotePlusPlus builds successfully
cmake --build . --target HelloMacNote builds sample plugin as .dylib
cmake --build . --target install_sample_plugin installs to plugin directory
App launches and logs "Loaded plugin: HelloMacNote"
Plugins menu appears with HelloMacNote submenu
Click "Hello World" — MessageBox appears
Click "Insert Timestamp" — text inserted at cursor
Click "Show Version" — displays version info
Split/unsplit works correctly with pre-created second view

Closes #49

🤖 Generated with Claude Code

Implement a plugin loading system that allows Notepad++ plugins to be compiled on macOS as .dylib files and loaded into MacNote++ without any source code modifications to the plugin. V1 scope: command-oriented, non-docking plugins that register menu commands via FuncItem, use SendMessage(sciHandle, SCI_*), and receive SCNotification callbacks. Key changes: - Register both Scintilla views with HandleRegistry at startup so plugins get real HWNDs that route SCI_* messages through the bridge - Pre-create second Scintilla view (hidden) for stable NppData handles - New MacPluginManager: loads .dylib plugins from ~/Library/Application Support/MacNote++/plugins/, resolves 6 required exports, builds menus - Mach-O architecture validation for ARM64/x86_64 - NPPM message handler (12 NPPMSG + 8 RUNCOMMAND_USER messages) with correct offsets and calling conventions - WndProc routing: static commands (22000-22999), dynamic relay (23000-24999), catch-all messageProc relay matching upstream - SCNotification forwarding from both Scintilla views to plugins - NPPN_READY/NPPN_SHUTDOWN lifecycle notifications - Plugins menu between Tools and Language - Plugin SDK with HelloMacNote sample plugin - Host exports symbols via -export_dynamic for plugin resolution Closes #49 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

This PR introduces a first-pass macOS plugin system intended to load Notepad++-style plugins compiled as .dylib into MacNote++ with no source changes, including message routing, command dispatch, and a sample plugin.

Changes:

Added MacPluginManager to discover/load .dylib plugins and populate a new “Plugins” menu.
Implemented routing/handling for key NPPM_* and RUNCOMMAND_USER messages and relayed window messages to plugins’ messageProc.
Updated split-view and startup initialization to provide stable Scintilla HWNDs (including a pre-created hidden second view) and forward Scintilla notifications to plugins.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
macos/platform/plugin_manager.mm	Implements dylib loading, export resolution, command ID allocation, plugin menu population, and notification/message relays
macos/platform/plugin_manager.h	Declares plugin manager types and singleton accessor
macos/platform/nppm_handler.mm	Adds handlers for `NPPM_*` / `RUNCOMMAND_USER` messages used by plugins
macos/platform/nppm_handler.h	Declares handler entry points for wndproc routing
macos/platform/wndproc.mm	Routes plugin command IDs and relays NPPM/RUNCOMMAND/window messages to plugins
macos/platform/menu_builder.mm	Adds a top-level “Plugins” menu and exposes its handle
macos/platform/menu_builder.h	Declares `getPluginsMenuHandle()`
macos/platform/app_delegate.mm	Registers Scintilla HWNDs, pre-creates second view, initializes plugin system, and sends READY/SHUTDOWN notifications
macos/platform/split_view.mm	Reuses pre-created second Scintilla view; forwards notifications to plugins
macos/platform/app_state.h	Stores Scintilla HWNDs for both views in `AppContext`
macos/plugin-sdk/CMakeLists.txt	Adds a plugin-SDK CMake entry for building example plugins
macos/plugin-sdk/example/HelloMacNote/HelloMacNote.cpp	Adds a sample plugin implementing standard N++ exports and a few commands
macos/plugin-sdk/example/HelloMacNote/CMakeLists.txt	Builds the example plugin as a `.dylib` module
macos/CMakeLists.txt	Builds/installs the sample plugin and exports host symbols for `dlopen`-loaded plugins

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Copilot · 2026-04-09T03:41:49Z

macos/platform/plugin_manager.mm

+	// Allocate command IDs from the static range and register commands
+	pi->_cmdIdBase = static_cast<int>(_pluginsCommands.size());
+	for (int i = 0; i < pi->_nbFuncItem; ++i)
+	{
+		int cmdId = _staticCmdAlloc.allocate(1);
+		if (cmdId < 0)
+		{
+			NSLog(@"Exhausted static plugin command IDs.");
+			break;
+		}
+		pi->_funcItems[i]._cmdID = cmdId;
+
+		PluginCommand cmd;
+		cmd._pluginName = pi->_displayName;
+		cmd._pFunc = pi->_funcItems[i]._pFunc;
+		_pluginsCommands.push_back(cmd);
+	}


Command ID assignment currently allocates an ID and pushes an entry into _pluginsCommands for every FuncItem, even when the FuncItem represents a separator/placeholder (i.e., _pFunc == nullptr). Upstream Notepad++ only assigns command IDs and stores commands for non-null _pFunc items, and uses ID_PLUGINS_CMD + (commands.size()-1) as the cmdID. To maximize source-level compatibility (and ensure cmdId→index mapping stays correct), skip null _pFunc items when assigning IDs / pushing commands, and derive cmdID from the command vector index (rather than allocating for every FuncItem).

Copilot · 2026-04-09T03:41:50Z

macos/platform/plugin_manager.mm

+		for (int i = 0; i < pi->_nbFuncItem; ++i)
+		{
+			FuncItem& fi = pi->_funcItems[i];
+			if (fi._itemName[0] == L'-')
+			{
+				::AppendMenuW(pluginSub, MF_SEPARATOR, 0, nullptr);
+			}
+			else
+			{
+				UINT flags = MF_STRING;
+				if (fi._init2Check)
+					flags |= MF_CHECKED;
+				::AppendMenuW(pluginSub, flags, static_cast<UINT_PTR>(fi._cmdID), fi._itemName);
+			}


Separator handling in initMenu() is based on fi._itemName[0] == L'-', but upstream treats a FuncItem with _pFunc == nullptr as a separator. As written, plugins that follow the standard pattern (null _pFunc separators) will get clickable menu items instead of separators. Update the separator check to use fi._pFunc == nullptr (and avoid appending a command item in that case).

Copilot · 2026-04-09T03:41:50Z

macos/platform/nppm_handler.mm

+	wchar_t* buf = reinterpret_cast<wchar_t*>(lParam);
+	size_t copyLen = src.size();
+	if (maxChars > 0 && copyLen >= static_cast<size_t>(maxChars))
+		copyLen = static_cast<size_t>(maxChars) - 1;


copyWideToBuffer() truncates the string when wParam indicates the destination buffer is too small, and still returns TRUE. In Notepad++ message handling, these APIs instead fail when the buffer is insufficient (return FALSE for most path getters, and return 0 for NPPM_GETPLUGINSCONFIGDIR) without writing a partial string. For better plugin compatibility, mirror upstream behavior: if wParam!=0 and src.length() >= wParam, return failure and do not write; only copy when the buffer is large enough (or wParam==0 compatibility mode).

Suggested change

wchar_t* buf = reinterpret_cast<wchar_t*>(lParam);

size_t copyLen = src.size();

if (maxChars > 0 && copyLen >= static_cast<size_t>(maxChars))

copyLen = static_cast<size_t>(maxChars) - 1;

if (maxChars != 0 && src.size() >= static_cast<size_t>(maxChars))

{

// Mirror Notepad++ behavior: fail without writing when the provided

// buffer is too small for the full string plus terminator.

return 0;

}

wchar_t* buf = reinterpret_cast<wchar_t*>(lParam);

const size_t copyLen = src.size();

Copilot · 2026-04-09T03:41:50Z

macos/plugin-sdk/example/HelloMacNote/CMakeLists.txt

+target_include_directories(HelloMacNote PRIVATE
+    "${CMAKE_CURRENT_SOURCE_DIR}/../../include"
+)
+


This target adds an include path to "${CMAKE_CURRENT_SOURCE_DIR}/../../include", but macos/plugin-sdk/include doesn't exist in the tree. This extra include dir is misleading and can hide real include-path issues; consider removing it or pointing it at the actual SDK header locations (shim, PluginsManager, scintilla) like macos/plugin-sdk/CMakeLists.txt does.

Suggested change

target_include_directories(HelloMacNote PRIVATE

"${CMAKE_CURRENT_SOURCE_DIR}/../../include"

)

- Skip null _pFunc items when allocating command IDs (separators don't get IDs, matching upstream behavior) - Use _pFunc == nullptr for separator detection in menu building instead of checking _itemName[0] == '-' - copyWideToBuffer() now fails without writing when buffer is too small instead of truncating (matches upstream Notepad++ behavior) - Remove non-existent include path from HelloMacNote standalone CMakeLists Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

The HelloMacNote sample plugin's "Insert Timestamp" command now inserts the current date/time (e.g. 2026-04-09 14:32:05) instead of the placeholder string "[HelloMacNote timestamp]". Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Copy SCNotification per plugin in notify() to prevent mutation (high) - NPPM_GETCURRENTWORD returns selected text when selection exists (medium) - NPPM_GETNBOPENFILES deduplicates split-view mirrors (medium) - Emit NPPN_FILEOPENED, NPPN_FILESAVED, NPPN_FILEBEFORECLOSE, NPPN_FILECLOSED, and NPPN_LANGCHANGED lifecycle notifications (medium) - Normalize allocation failure to 0 instead of -1 (low) - Align INDICATOR_PLUGINS to 8 to match documented range Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 7 comments.

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Copilot · 2026-04-10T02:57:10Z

macos/platform/wndproc.mm

+			{
+				pluginManager().relayNppMessages(WM_COMMAND, cmdId, 0);
+				return 0;
+			}


The relayNppMessages “catch-all” at the end of MainWndProc is bypassed by the many early return 0; paths in WM_COMMAND handling (including the plugin static command path). Upstream relays messages to plugins after processing regardless of whether the message was handled, so messageProc will miss many messages here. Consider refactoring to compute a result/handled flag and always call pluginManager().relayNppMessages(msg, wParam, lParam) just before returning.

Copilot · 2026-04-10T02:57:10Z

macos/platform/plugin_manager.mm

+	// Create plugin submenu
+	pi->_pluginMenu = ::CreateMenu();


loadPluginFromPath creates a menu with CreateMenu() and assigns it to pi->_pluginMenu, but initMenu() later overwrites _pluginMenu with a new CreatePopupMenu() handle. This leaks the original menu handle. Remove the unused CreateMenu() call (or destroy the previous handle before overwriting).

Suggested change

// Create plugin submenu

pi->_pluginMenu = ::CreateMenu();

// Plugin submenu is created later during menu initialization.

Copilot · 2026-04-10T02:57:10Z

macos/platform/nppm_handler.mm

+static LRESULT copyWideToBuffer(const std::wstring& src, WPARAM maxChars, LPARAM lParam)
+{
+	if (!lParam)
+	{
+		// First call: return number of wchar_t needed (not including null)
+		return static_cast<LRESULT>(src.size());
+	}
+
+	// Fail without writing when the buffer is too small (matches upstream behavior)
+	if (maxChars != 0 && src.size() >= static_cast<size_t>(maxChars))
+		return 0;
+
+	wchar_t* buf = reinterpret_cast<wchar_t*>(lParam);
+	const size_t copyLen = src.size();
+	wcsncpy(buf, src.c_str(), copyLen);
+	buf[copyLen] = L'\0';
+	return TRUE;


copyWideToBuffer skips the size check when maxChars == 0, and will write into lParam even though a 0-sized buffer is invalid in the Notepad++ two-call contract (upstream treats length >= wParam as failure). This can lead to buffer overflow if a plugin passes wParam=0 with a non-null buffer. Consider always enforcing src.size() < maxChars when lParam != 0.

Copilot · 2026-04-10T02:57:10Z

macos/plugin-sdk/example/HelloMacNote/CMakeLists.txt

+    PREFIX ""
+    SUFFIX ".dylib"
+    OUTPUT_NAME "HelloMacNote"
+)


The standalone SDK example target doesn’t set -undefined dynamic_lookup (or equivalent) for the plugin dylib. Since the plugin intentionally references host-provided symbols (e.g., SendMessage, MessageBox) without linking against a shim library, this will typically fail to link when building via macos/plugin-sdk as its own CMake project.

Suggested change

)

)

target_link_options(HelloMacNote PRIVATE

"LINKER:-undefined,dynamic_lookup"

)

Copilot · 2026-04-10T02:57:11Z

macos/platform/file_operations.mm

+	// Notify plugins that a file was opened
+	{
+		SCNotification notif{};
+		notif.nmhdr.hwndFrom = ctx().mainHwnd;
+		notif.nmhdr.code = NPPN_FILEOPENED;
+		notif.nmhdr.idFrom = 0; // V1: no stable buffer ID yet
+		pluginManager().notify(&notif);
+	}


This adds NPPN_FILEOPENED notifications but always sets nmhdr.idFrom = 0. The PR description lists file notifications as a V2 limitation specifically because they require stable buffer IDs; sending these events in V1 (without IDs) can mislead plugins that treat the notification as fully supported. Either defer emitting these notifications until buffer IDs exist, or update the PR description/limitations to clarify the partial semantics.

Copilot · 2026-04-10T02:57:11Z

macos/platform/file_operations.mm

+			// Notify plugins that the file was saved
+			{
+				SCNotification notif{};
+				notif.nmhdr.hwndFrom = ctx().mainHwnd;
+				notif.nmhdr.code = NPPN_FILESAVED;
+				notif.nmhdr.idFrom = 0; // V1: no stable buffer ID yet
+				pluginManager().notify(&notif);
+			}


Same as the file-open case: NPPN_FILESAVED is emitted with nmhdr.idFrom = 0, despite the PR description calling file notifications a V2 item due to needing stable buffer IDs. Consider deferring or clearly documenting that these are emitted with an invalid/placeholder BufferID in V1.

Copilot · 2026-04-10T02:57:11Z

macos/platform/wndproc.mm

+
+						// Notify plugins that the language changed
+						SCNotification notif{};
+						notif.nmhdr.hwndFrom = ctx().mainHwnd;
+						notif.nmhdr.code = NPPN_LANGCHANGED;
+						notif.nmhdr.idFrom = 0; // V1: no stable buffer ID yet
+						pluginManager().notify(&notif);


NPPN_LANGCHANGED is emitted here with nmhdr.idFrom = 0. The PR description lists file/language notifications as a V2 item due to needing stable buffer IDs; emitting the notification in V1 with a placeholder BufferID can lead plugins to assume full support. Consider deferring it until BufferIDs exist, or explicitly documenting the placeholder semantics.

- Fix menu handle leak: remove unused CreateMenu() in loadPluginFromPath since initMenu() creates the real submenu later - Fix copyWideToBuffer buffer overflow when wParam=0 with non-null buffer - Fix relayNppMessages bypass: relay WM_COMMAND to plugins at top of handler since individual command paths return early - Add -undefined dynamic_lookup linker flag to SDK example so plugin dylibs can reference host-provided symbols Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot AI review requested due to automatic review settings April 9, 2026 03:33

Copilot started reviewing on behalf of hybridmachine April 9, 2026 03:33 View session

Copilot AI reviewed Apr 9, 2026

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Brian Tabone and others added 3 commits April 8, 2026 22:51

hybridmachine requested a review from Copilot April 10, 2026 02:49

Copilot started reviewing on behalf of hybridmachine April 10, 2026 02:51 View session

Copilot AI reviewed Apr 10, 2026

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hybridmachine merged commit f0df450 into macos-port Apr 10, 2026
26 of 31 checks passed

	target_include_directories(HelloMacNote PRIVATE
	"${CMAKE_CURRENT_SOURCE_DIR}/../../include"
	)

	// Create plugin submenu
	pi->_pluginMenu = ::CreateMenu();
	// Plugin submenu is created later during menu initialization.

-)
+)
+target_link_options(HelloMacNote PRIVATE
+    "LINKER:-undefined,dynamic_lookup"
+)

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hybridmachine commented Apr 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Known limitations (V2)

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hybridmachine commented Apr 9, 2026 •

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