Merge pull request #2 from int-brain-lab/develop

0.3.0

CHANGELOG.md

@@ -7,6 +7,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [0.3.0] - 2024-10-08
+
+### Added
+
+- core.FileWatcher: watch a file for changes
+
 ## [0.2.0] - 2024-10-08
 
 ### Added
@@ -49,7 +55,8 @@ _First release._
 - core.ColoredDataFrameTableModel: An extension of DataFrameTableModel providing color-mapped numerical data.
 - widgets.StatefulButton: A QPushButton that maintains an active/inactive state.
 
+[0.3.0]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.3.0
 [0.2.0]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.2.0
 [0.1.2]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.1.2
 [0.1.1]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.1.1
-[0.1.0]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.1.0
+[0.1.0]: https://github.com/int-brain-lab/iblqt/releases/tag/v0.1.0

iblqt/__init__.py

@@ -1,3 +1,3 @@
 """A collection of extensions to the Qt framework."""
 
-__version__ = '0.2.0'
+__version__ = '0.3.0'

iblqt/core.py

@@ -1,13 +1,16 @@
 """Non-GUI functionality, including event handling, data types, and data management."""
 
 import logging
+from pathlib import Path
 from typing import Any
 
 from pyqtgraph import ColorMap, colormap  # type: ignore
 from qtpy.QtCore import (
     QAbstractTableModel,
+    QFileSystemWatcher,
     Qt,
     QModelIndex,
+    QReadWriteLock,
     QObject,
     Property,
     Signal,
@@ -410,3 +413,48 @@ def data(self, index: QModelIndex, role: int = Qt.ItemDataRole.DisplayRole) -> A
                 lum = self._foreground[row][col]
                 return QColor('black' if (lum * self._alpha) < 32512 else 'white')
         return super().data(index, role)
+
+
+class FileWatcher(QObject):
+    """Watch a file for changes."""
+
+    fileChanged = Signal()  # type: Signal
+    """Emitted when the file's content has changed."""
+
+    fileSizeChanged = Signal(int)  # type: Signal
+    """Emitted when the file's size has changed. The signal carries the new size."""
+
+    def __init__(self, parent: QObject, file: Path | str):
+        """Initialize the FileWatcher.
+
+        Parameters
+        ----------
+        parent : QObject
+            The parent object.
+        file : Path or str
+            The path to the file to watch.
+        """
+        super().__init__(parent=parent)
+        self._file = Path(file)
+        if not self._file.exists():
+            raise FileNotFoundError(self._file)
+        if self._file.is_dir():
+            raise IsADirectoryError(self._file)
+
+        self._size = self._file.stat().st_size
+        self._lock = QReadWriteLock()
+        self._fileWatcher = QFileSystemWatcher([str(file)], parent)
+        self._fileWatcher.fileChanged.connect(self._onFileChanged)
+
+    @Slot(str)
+    def _onFileChanged(self, _):
+        self.fileChanged.emit()
+        new_size = self._file.stat().st_size
+
+        self._lock.lockForWrite()
+        try:
+            if new_size != self._size:
+                self.fileSizeChanged.emit(new_size)
+                self._size = new_size
+        finally:
+            self._lock.unlock()

pyproject.toml

@@ -84,4 +84,3 @@ files = ["iblqt/**/*.py", "tests/**/*.py"]
 addopts    = "--cov=iblqt --cov-report=html --cov-report=xml"
 minversion = "6.0"
 testpaths  = [ "tests" ]
-qt_api     = 'pyqt5'

tests/test_core.py

@@ -1,5 +1,9 @@
+from pathlib import Path
+
+import pytest
 from qtpy.QtCore import Qt, QModelIndex
 from iblqt import core
+import tempfile
 
 import pandas as pd
 
@@ -72,3 +76,27 @@ def test_dataframe_model(qtbot):
     assert model.alpha == 128
     assert model.data(model.index(0, 0), Qt.ItemDataRole.BackgroundRole).alpha() == 128
     assert model.data(model.index(2, 0), Qt.ItemDataRole.BackgroundRole).alpha() == 128
+
+
+def test_fileWatcher(qtbot):
+    with tempfile.NamedTemporaryFile() as file:
+        parent = core.QObject()
+        path = Path(file.name)
+
+        w = core.FileWatcher(parent=parent, file=path)
+
+        # Modify the file to trigger the watcher
+        with qtbot.waitSignal(w.fileChanged):
+            with qtbot.waitSignal(w.fileSizeChanged) as blocker:
+                with open(path, 'a') as f:
+                    f.write('Hello, World!')
+        assert blocker.args[0] == path.stat().st_size
+
+        # Modify the file (without changing its size)
+        with qtbot.waitSignal(w.fileChanged):
+            with qtbot.assertNotEmitted(w.fileSizeChanged, wait=100):
+                with open(path, 'w') as f:
+                    f.write('Hello, World?')
+
+    with pytest.raises(FileNotFoundError):
+        core.FileWatcher(parent=parent, file='non-existent file')