Qt-removal R7.4c: Llama.cpp settings page + native file-picker capability

backend/native_dialogs.py

@@ -0,0 +1,67 @@
+"""Native OS file/folder picker capability (Qt-removal plan R7.4c).
+
+The one genuinely NEW capability gap R7.4 scoping identified (not just a
+port): Llama.cpp's GGUF picker and Ollama's folder-scan picker both need an
+actual on-disk PATH string (llama.cpp's C++ bindings and Ollama's manifest
+walker both need a real filesystem path, not file bytes) - a plain HTML
+<input type="file"> only gives the browser-side bytes, never a path, so
+this has to be a NATIVE OS dialog.
+
+graphlink_desktop.py's webview.create_window(...) call discards its return
+value, but that's a non-issue: pywebview's own webview.windows is a plain
+module-level list that create_window() appends the new Window to
+UNCONDITIONALLY, the moment it runs - reachable from anywhere afterward via
+webview.windows[0], with zero plumbing changes needed in graphlink_desktop.py
+itself. Window.create_file_dialog(...) is safe to call from a worker thread
+(pywebview's own docs/exposed-JS-API pattern already does this) - confirmed
+directly via inspect.signature and the @_shown_call wrapper it goes through,
+which just waits on a plain threading.Event, not anything main-thread-only.
+
+NO WINDOW is a normal, expected, gracefully-handled condition, not an error:
+create_window() never runs under bare `uvicorn`/pytest (the packaged desktop
+entry point is the only caller), so webview.windows is simply `[]` there.
+Both functions below return None in that case - callers must treat a None
+return exactly like a user-cancelled dialog (nothing was picked), which is
+also what pywebview itself returns on cancel.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from typing import Sequence
+
+import webview
+
+
+def _active_window():
+    return webview.windows[0] if webview.windows else None
+
+
+async def pick_file(file_types: Sequence[str] = (), directory: str = "") -> str | None:
+    """Opens a native OPEN file dialog. Returns the selected path, or None
+    if no window exists (bare uvicorn/tests) or the user cancelled.
+
+    `directory` seeds the dialog's starting location - matches legacy's own
+    _pick_gguf_file, which always computed a real starting directory
+    (the staged path's own folder, or a saved scan path, or home) rather
+    than leaving it to whatever the OS defaults to."""
+    window = _active_window()
+    if window is None:
+        return None
+    result = await asyncio.to_thread(
+        window.create_file_dialog,
+        webview.FileDialog.OPEN,
+        directory=directory,
+        file_types=tuple(file_types),
+    )
+    return result[0] if result else None
+
+
+async def pick_folder(directory: str = "") -> str | None:
+    """Opens a native FOLDER dialog. Returns the selected path, or None if
+    no window exists or the user cancelled."""
+    window = _active_window()
+    if window is None:
+        return None
+    result = await asyncio.to_thread(window.create_file_dialog, webview.FileDialog.FOLDER, directory=directory)
+    return result[0] if result else None

backend/tests/test_native_dialogs.py

@@ -0,0 +1,112 @@
+"""Tests for backend/native_dialogs.py (Qt-removal plan R7.4c).
+
+webview.windows is monkeypatched directly (a plain list, per pywebview's
+own source) rather than mocking a whole Window class where not needed -
+the "no window" branch only cares that the list is empty; the "window
+exists" branch needs just enough of a fake Window to satisfy
+create_file_dialog's call signature.
+"""
+
+import asyncio
+
+import webview
+
+from backend import native_dialogs
+
+
+class _FakeWindow:
+    def __init__(self, return_value):
+        self.return_value = return_value
+        self.calls = []
+
+    def create_file_dialog(self, dialog_type=10, directory="", allow_multiple=False, save_filename="", file_types=()):
+        self.calls.append(
+            {
+                "dialog_type": dialog_type,
+                "directory": directory,
+                "allow_multiple": allow_multiple,
+                "save_filename": save_filename,
+                "file_types": file_types,
+            }
+        )
+        return self.return_value
+
+
+def test_pick_file_returns_none_when_no_window_exists(monkeypatch):
+    monkeypatch.setattr(webview, "windows", [])
+
+    result = asyncio.run(native_dialogs.pick_file(file_types=("GGUF files (*.gguf)",)))
+
+    assert result is None
+
+
+def test_pick_file_calls_open_dialog_with_file_types_and_returns_first_path(monkeypatch):
+    fake = _FakeWindow(return_value=("C:/models/a.gguf",))
+    monkeypatch.setattr(webview, "windows", [fake])
+
+    result = asyncio.run(native_dialogs.pick_file(file_types=("GGUF files (*.gguf)",)))
+
+    assert result == "C:/models/a.gguf"
+    assert fake.calls == [
+        {
+            "dialog_type": webview.FileDialog.OPEN,
+            "directory": "",
+            "allow_multiple": False,
+            "save_filename": "",
+            "file_types": ("GGUF files (*.gguf)",),
+        }
+    ]
+
+
+def test_pick_file_returns_none_when_the_user_cancels(monkeypatch):
+    fake = _FakeWindow(return_value=None)
+    monkeypatch.setattr(webview, "windows", [fake])
+
+    result = asyncio.run(native_dialogs.pick_file())
+
+    assert result is None
+
+
+def test_pick_folder_returns_none_when_no_window_exists(monkeypatch):
+    monkeypatch.setattr(webview, "windows", [])
+
+    result = asyncio.run(native_dialogs.pick_folder())
+
+    assert result is None
+
+
+def test_pick_folder_calls_folder_dialog_and_returns_first_path(monkeypatch):
+    fake = _FakeWindow(return_value=("C:/models",))
+    monkeypatch.setattr(webview, "windows", [fake])
+
+    result = asyncio.run(native_dialogs.pick_folder())
+
+    assert result == "C:/models"
+    assert fake.calls[0]["dialog_type"] == webview.FileDialog.FOLDER
+
+
+def test_pick_folder_returns_none_when_the_user_cancels(monkeypatch):
+    fake = _FakeWindow(return_value=None)
+    monkeypatch.setattr(webview, "windows", [fake])
+
+    result = asyncio.run(native_dialogs.pick_folder())
+
+    assert result is None
+
+
+def test_uses_the_first_window_when_multiple_exist():
+    # webview.windows can only ever grow (create_window appends, nothing
+    # removes) - confirms the module reads index 0, not "the last one" or
+    # anything order-sensitive beyond that documented convention.
+    first = _FakeWindow(return_value=("first-picked.gguf",))
+    second = _FakeWindow(return_value=("second-picked.gguf",))
+    import webview as wv
+
+    original = wv.windows
+    try:
+        wv.windows = [first, second]
+        result = asyncio.run(native_dialogs.pick_file())
+        assert result == "first-picked.gguf"
+        assert second.calls == []
+    finally:
+        wv.windows = original