1 files changed, 133 insertions, 0 deletions
diff --git a/qutebrowser/utils/resources.py b/qutebrowser/utils/resources.py
new file mode 100644
index 000000000..e812ece99
--- /dev/null
+++ b/qutebrowser/utils/resources.py
@@ -0,0 +1,133 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2014-2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <https://www.gnu.org/licenses/>.
+
+"""Resources related utilities."""
+
+import os.path
+import sys
+import contextlib
+import posixpath
+import pathlib
+from typing import (Iterator, Iterable)
+
+
+# We cannot use the stdlib version on 3.7-3.8 because we need the files() API.
+if sys.version_info >= (3, 9):
+    import importlib.resources as importlib_resources
+else:  # pragma: no cover
+    import importlib_resources
+
+import qutebrowser
+cache = {}
+
+def path(filename: str) -> pathlib.Path:
+    """Get a pathlib.Path object for a resource."""
+    assert not posixpath.isabs(filename), filename
+    assert os.path.pardir not in filename.split(posixpath.sep), filename
+
+    if hasattr(sys, 'frozen'):
+        # For PyInstaller, where we can't store resource files in a qutebrowser/ folder
+        # because the executable is already named "qutebrowser" (at least on macOS).
+        return pathlib.Path(sys.executable).parent / filename
+
+    return importlib_resources.files(qutebrowser) / filename
+
+@contextlib.contextmanager
+def keyerror_workaround() -> Iterator[None]:
+    """Re-raise KeyErrors as FileNotFoundErrors.
+
+    WORKAROUND for zipfile.Path resources raising KeyError when a file was notfound:
+    https://bugs.python.org/issue43063
+
+    Only needed for Python 3.8 and 3.9.
+    """
+    try:
+        yield
+    except KeyError as e:
+        raise FileNotFoundError(str(e))
+
+
+def _glob(
+    resource_path: pathlib.Path,
+    subdir: str,
+    ext: str,
+) -> Iterable[str]:
+    """Find resources with the given extension.
+
+    Yields a resource name like "html/log.html" (as string).
+    """
+    assert '*' not in ext, ext
+    assert ext.startswith('.'), ext
+    glob_path = resource_path / subdir
+
+    if isinstance(resource_path, pathlib.Path):
+        for full_path in glob_path.glob(f'*{ext}'):  # . is contained in ext
+            yield full_path.relative_to(resource_path).as_posix()
+    else:  # zipfile.Path or importlib_resources compat object
+        # Unfortunately, we can't tell mypy about resource_path being of type
+        # Union[pathlib.Path, zipfile.Path] because we set "python_version = 3.6" in
+        # .mypy.ini, but the zipfiel stubs (correctly) only declare zipfile.Path with
+        # Python 3.8...
+        assert glob_path.is_dir(), path  # type: ignore[unreachable]
+        for subpath in glob_path.iterdir():
+            if subpath.name.endswith(ext):
+                yield posixpath.join(subdir, subpath.name)
+
+
+def preload() -> None:
+    """Load resource files into the cache."""
+    resource_path = path('')
+    for subdir, ext in [
+            ('html', '.html'),
+            ('javascript', '.js'),
+            ('javascript/quirks', '.js'),
+    ]:
+        for name in _glob(resource_path, subdir, ext):
+            cache[name] = read_file(name)
+
+
+def read_file(filename: str) -> str:
+    """Get the contents of a file contained with qutebrowser.
+
+    Args:
+        filename: The filename to open as string.
+
+    Return:
+        The file contents as string.
+    """
+    if filename in cache:
+        return cache[filename]
+
+    file_path = path(filename)
+    with keyerror_workaround():
+        return file_path.read_text(encoding='utf-8')
+
+
+def read_file_binary(filename: str) -> bytes:
+    """Get the contents of a binary file contained with qutebrowser.
+
+    Args:
+        filename: The filename to open as string.
+
+    Return:
+        The file contents as a bytes object.
+    """
+    file_binary_path = path(filename)
+    with keyerror_workaround():
+        return file_binary_path.read_bytes()