Cache HTML/JS resource files when starting

This mostly reverts 9edc5a665e414ae2ec8f5bc04a99bce2bc4e6d33 (see #1362). Fixes #1943
author: Florian Bruhin <git@the-compiler.org> 2018-03-05 09:03:58 +0100
committer: Florian Bruhin <git@the-compiler.org> 2018-03-05 09:08:06 +0100
commit: b4a2352833bfb06c86c1afb8b088cead0ef7c6d5 (patch)
tree: fc6a7286288670470242e12e349296028eba3688
parent: 78623f4ec8f9fc98a90ace5efe581bac7262d52a (diff)
download: qutebrowser-b4a2352833bfb06c86c1afb8b088cead0ef7c6d5.tar.gz
qutebrowser-b4a2352833bfb06c86c1afb8b088cead0ef7c6d5.zip
7 files changed, 30 insertions, 45 deletions
diff --git a/doc/changelog.asciidoc b/doc/changelog.asciidoc
index ffbf9ebfc..d30eb3ca8 100644
--- a/doc/changelog.asciidoc
+++ b/doc/changelog.asciidoc
@@ -117,6 +117,8 @@ Fixed
 - Crash when opening an invalid URL from an application on macOS.
 - Crash with an empty `completion.timestamp_format`.
 - Crash when `completion.min_chars` is set in some cases.
+- HTML/JS resource files are now read into RAM on start to avoid crashes when
+  changing qutebrowser versions while it's open.
 
 Removed
 ~~~~~~~
diff --git a/qutebrowser/app.py b/qutebrowser/app.py
index e9f9d2229..014e02c5f 100644
--- a/qutebrowser/app.py
+++ b/qutebrowser/app.py
@@ -95,6 +95,7 @@ def run(args):
 
     log.init.debug("Initializing directories...")
     standarddir.init(args)
+    utils.preload_resources()
 
     log.init.debug("Initializing config...")
     configinit.early_init(args)
diff --git a/qutebrowser/html/undef_error.html b/qutebrowser/html/undef_error.html
deleted file mode 100644
index 55a47ca95..000000000
--- a/qutebrowser/html/undef_error.html
+++ /dev/null
@@ -1,22 +0,0 @@
-<!DOCTYPE html>
-<!--
-vim: ft=html fileencoding=utf-8 sts=4 sw=4 et:
--->
-
-<html>
-    <head>
-        <meta charset="utf-8">
-        <title>Error while rendering HTML</title>
-    </head>
-    <body>
-      <h1>Error while rendering internal qutebrowser page</h1>
-      <p>There was an error while rendering {pagename}.</p>
-
-      <p>This most likely happened because you updated qutebrowser but didn't restart yet.</p>
-
-      <p>If you believe this isn't the case and this is a bug, please do :report.<p>
-
-      <h2>Traceback</h2>
-      <pre>{traceback}</pre>
-    </body>
-</html>
diff --git a/qutebrowser/utils/jinja.py b/qutebrowser/utils/jinja.py
index d4ce3368f..b06444f93 100644
--- a/qutebrowser/utils/jinja.py
+++ b/qutebrowser/utils/jinja.py
@@ -22,12 +22,10 @@
 import os
 import os.path
 import contextlib
-import traceback
 import mimetypes
 import html
 
 import jinja2
-import jinja2.exceptions
 from PyQt5.QtCore import QUrl
 
 from qutebrowser.utils import utils, urlutils, log
@@ -125,14 +123,7 @@ class Environment(jinja2.Environment):
 
 def render(template, **kwargs):
     """Render the given template and pass the given arguments to it."""
-    try:
-        return environment.get_template(template).render(**kwargs)
-    except jinja2.exceptions.UndefinedError:
-        log.misc.exception("UndefinedError while rendering " + template)
-        err_path = os.path.join('html', 'undef_error.html')
-        err_template = utils.read_file(err_path)
-        tb = traceback.format_exc()
-        return err_template.format(pagename=template, traceback=tb)
+    return environment.get_template(template).render(**kwargs)
 
 
 environment = Environment()
diff --git a/qutebrowser/utils/utils.py b/qutebrowser/utils/utils.py
index f03d42844..9f3acde5a 100644
--- a/qutebrowser/utils/utils.py
+++ b/qutebrowser/utils/utils.py
@@ -32,6 +32,7 @@ import functools
 import contextlib
 import socket
 import shlex
+import glob
 
 from PyQt5.QtCore import QUrl
 from PyQt5.QtGui import QColor, QClipboard, QDesktopServices
@@ -51,6 +52,7 @@ from qutebrowser.utils import qtutils, log
 
 fake_clipboard = None
 log_clipboard = False
+_resource_cache = {}
 
 is_mac = sys.platform.startswith('darwin')
 is_linux = sys.platform.startswith('linux')
@@ -140,6 +142,15 @@ def compact_text(text, elidelength=None):
     return out
 
 
+def preload_resources():
+    """Load resource files into the cache."""
+    for subdir, pattern in [('html', '*.html'), ('javascript', '*.js')]:
+        path = resource_filename(subdir)
+        for full_path in glob.glob(os.path.join(path, pattern)):
+            sub_path = os.path.join(subdir, os.path.basename(full_path))
+            _resource_cache[sub_path] = read_file(sub_path)
+
+
 def read_file(filename, binary=False):
     """Get the contents of a file contained with qutebrowser.
 
@@ -151,6 +162,9 @@ def read_file(filename, binary=False):
     Return:
         The file contents as string.
     """
+    if not binary and filename in _resource_cache:
+        return _resource_cache[filename]
+
     if hasattr(sys, 'frozen'):
         # PyInstaller doesn't support pkg_resources :(
         # https://github.com/pyinstaller/pyinstaller/wiki/FAQ#misc
diff --git a/tests/unit/utils/test_jinja.py b/tests/unit/utils/test_jinja.py
index f47155f91..b1a50772e 100644
--- a/tests/unit/utils/test_jinja.py
+++ b/tests/unit/utils/test_jinja.py
@@ -23,6 +23,7 @@ import os
 import os.path
 import logging
 
+import jinja2.exceptions
 import pytest
 from PyQt5.QtCore import QUrl
 
@@ -32,7 +33,6 @@ from qutebrowser.utils import utils, jinja
 @pytest.fixture(autouse=True)
 def patch_read_file(monkeypatch):
     """pytest fixture to patch utils.read_file."""
-    real_read_file = utils.read_file
     real_resource_filename = utils.resource_filename
 
     def _read_file(path, binary=False):
@@ -52,9 +52,6 @@ def patch_read_file(monkeypatch):
         elif path == os.path.join('html', 'undef.html'):
             assert not binary
             return """{{ does_not_exist() }}"""
-        elif path == os.path.join('html', 'undef_error.html'):
-            assert not binary
-            return real_read_file(path)
         elif path == os.path.join('html', 'attributeerror.html'):
             assert not binary
             return """{{ obj.foobar }}"""
@@ -129,15 +126,9 @@ def test_utf8():
 
 
 def test_undefined_function(caplog):
-    """Make sure we don't crash if an undefined function is called."""
-    with caplog.at_level(logging.ERROR):
-        data = jinja.render('undef.html')
-    assert 'There was an error while rendering undef.html' in data
-    assert "'does_not_exist' is undefined" in data
-    assert data.startswith('<!DOCTYPE html>')
-
-    assert len(caplog.records) == 1
-    assert caplog.records[0].msg == "UndefinedError while rendering undef.html"
+    """Make sure undefined attributes crash since we preload resources.."""
+    with pytest.raises(jinja2.exceptions.UndefinedError):
+        jinja.render('undef.html')
 
 
 def test_attribute_error():
diff --git a/tests/unit/utils/test_utils.py b/tests/unit/utils/test_utils.py
index b2eef0237..df0eb9ecb 100644
--- a/tests/unit/utils/test_utils.py
+++ b/tests/unit/utils/test_utils.py
@@ -133,6 +133,14 @@ class TestReadFile:
         content = utils.read_file(os.path.join('utils', 'testfile'))
         assert content.splitlines()[0] == "Hello World!"
 
+    @pytest.mark.parametrize('filename', ['javascript/scroll.js',
+                                          'html/error.html'])
+    def test_read_cached_file(self, mocker, filename):
+        utils.preload_resources()
+        m = mocker.patch('pkg_resources.resource_string')
+        utils.read_file(filename)
+        m.assert_not_called()
+
     def test_readfile_binary(self):
         """Read a test file in binary mode."""
         content = utils.read_file(os.path.join('utils', 'testfile'),
author	Florian Bruhin <git@the-compiler.org>	2018-03-05 09:03:58 +0100
committer	Florian Bruhin <git@the-compiler.org>	2018-03-05 09:08:06 +0100
commit	b4a2352833bfb06c86c1afb8b088cead0ef7c6d5 (patch)
tree	fc6a7286288670470242e12e349296028eba3688
parent	78623f4ec8f9fc98a90ace5efe581bac7262d52a (diff)
download	qutebrowser-b4a2352833bfb06c86c1afb8b088cead0ef7c6d5.tar.gz qutebrowser-b4a2352833bfb06c86c1afb8b088cead0ef7c6d5.zip