Windows: Fix a regression in 7.0 that caused images referring to files on the disk within comments columns to not display in some circumstances

src/calibre/gui2/__init__.py

@@ -1680,3 +1680,23 @@ def timed_print(*a, **kw):
     if not hasattr(timed_print, 'startup_time'):
         timed_print.startup_time = monotonic()
     print(f'[{monotonic() - timed_print.startup_time:.2f}]', *a, **kw)
+
+
+def local_path_for_resource(qurl: QUrl, base_qurl: 'QUrl | None' = None) -> str:
+    import re
+
+    def fix_qt_bodging_windows_paths(path: str) -> str:
+        # When loading <img src="file:///c:/path/to/img.png"> Qt gives us the
+        # URL: //c/path/to/img.png  Le bubbling sigh
+        if iswindows and re.match(r'//[a-zA-Z]/', path) is not None and not os.path.exists(path):
+            path = os.path.normpath(path[2] + ':' + path[3:])
+        return path
+
+    if base_qurl and qurl.isRelative():
+        qurl = base_qurl.resolved(qurl)
+
+    if qurl.isLocalFile():
+        return fix_qt_bodging_windows_paths(qurl.toLocalFile())
+    if qurl.isRelative():  # this means has no scheme
+        return fix_qt_bodging_windows_paths(qurl.path())
+    return ''

src/calibre/gui2/book_details.py

@@ -998,6 +998,7 @@ class BookInfo(HTMLDisplay):
         HTMLDisplay.__init__(self, parent=parent, save_resources_in_document=False)
         self.vertical = vertical
         self.last_rendered_html = '', '', ''
+        self.base_url_for_current_book = None
         self.anchor_clicked.connect(self.link_activated)
         for x, icon in [
             ('remove_format', 'trash.png'), ('save_format', 'save.png'),
@@ -1088,8 +1089,13 @@ class BookInfo(HTMLDisplay):
 
     def show_data(self, mi):
         html, table, comments = self.last_rendered_html = render_html(mi, self.vertical, self.parent())
+        path = getattr(mi, 'path', None)
+        self.base_url_for_current_book = QUrl.fromLocalFile(os.path.join(path, 'metadata.opf')) if path else None
         set_html(mi, html, self)
 
+    def get_base_qurl(self):
+        return self.base_url_for_current_book
+
     def process_external_css(self, css):
         return resolve_colors(css)
 

src/calibre/gui2/comments_editor.py

@@ -7,7 +7,6 @@ import re
 import sys
 import weakref
 from collections import defaultdict
-from threading import Thread
 from contextlib import contextmanager
 from functools import partial
 from html5_parser import parse
@@ -21,15 +20,16 @@ from qt.core import (
     QTextFrameFormat, QTextImageFormat, QTextListFormat, QTimer, QToolButton, QUrl,
     QVBoxLayout, QWidget, pyqtSignal, pyqtSlot,
 )
+from threading import Thread
 
 from calibre import browser, fit_image, xml_replace_entities
+from calibre.constants import iswindows
 from calibre.db.constants import DATA_DIR_NAME
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.gui2 import (
-    NO_URL_FORMATTING, choose_dir, choose_files, error_dialog, gprefs, is_dark_theme,
-    question_dialog, safe_open_url,
+    NO_URL_FORMATTING, FunctionDispatcher, choose_dir, choose_files, error_dialog,
+    gprefs, is_dark_theme, local_path_for_resource, question_dialog, safe_open_url,
 )
-from calibre.gui2 import FunctionDispatcher
 from calibre.gui2.book_details import resolved_css
 from calibre.gui2.dialogs.progress import ProgressDialog
 from calibre.gui2.flow_toolbar import create_flow_toolbar
@@ -38,6 +38,7 @@ from calibre.gui2.widgets2 import to_plain_text
 from calibre.startup import connect_lambda
 from calibre.utils.cleantext import clean_xml_chars
 from calibre.utils.config import tweaks
+from calibre.utils.filenames import make_long_path_useable
 from calibre.utils.imghdr import what
 from polyglot.builtins import iteritems, itervalues
 
@@ -929,14 +930,11 @@ class EditorWidget(QTextEdit, LineEditECM):  # {{{
 
     @pyqtSlot(int, 'QUrl', result='QVariant')
     def loadResource(self, rtype, qurl):
-        if self.base_url:
-            if qurl.isRelative():
-                qurl = self.base_url.resolved(qurl)
-            if qurl.isLocalFile():
+        path = local_path_for_resource(qurl, base_qurl=self.base_url)
+        if path:
             data = None
-                path = qurl.toLocalFile()
             try:
-                    with open(path, 'rb') as f:
+                with open(make_long_path_useable(path), 'rb') as f:
                     data = f.read()
             except OSError:
                 if path.rpartition('.')[-1].lower() in {'jpg', 'jpeg', 'gif', 'png', 'bmp', 'webp'}:

src/calibre/gui2/dialogs/book_info.py

@@ -129,6 +129,9 @@ class Details(HTMLDisplay):
         self.allow_context_menu = allow_context_menu
         self.is_locked = is_locked
 
+    def get_base_qurl(self):
+        return getattr(self.book_info, 'base_url_for_current_book', None)
+
     def sizeHint(self):
         return QSize(350, 350)
 

src/calibre/gui2/widgets2.py

@@ -16,7 +16,9 @@ from qt.core import (
 from calibre import prepare_string_for_xml
 from calibre.constants import builtin_colors_dark, builtin_colors_light
 from calibre.ebooks.metadata import rating_to_stars
-from calibre.gui2 import UNDEFINED_QDATETIME, gprefs, rating_font
+from calibre.gui2 import (
+    UNDEFINED_QDATETIME, gprefs, local_path_for_resource, rating_font,
+)
 from calibre.gui2.complete2 import EditWithComplete, LineEdit
 from calibre.gui2.widgets import history
 from calibre.utils.config_base import tweaks
@@ -543,6 +545,9 @@ class HTMLDisplay(QTextBrowser):
         self.setAcceptDrops(False)
         self.anchorClicked.connect(self.on_anchor_clicked)
 
+    def get_base_qurl(self):
+        return None
+
     def setHtml(self, html):
         self.last_set_html = html
         QTextBrowser.setHtml(self, html)
@@ -573,11 +578,10 @@ class HTMLDisplay(QTextBrowser):
                 return
         self.anchor_clicked.emit(qurl)
 
-    def loadResource(self, rtype, qurl):
-        if qurl.isLocalFile():
-            path = qurl.toLocalFile()
+    def load_local_file_resource(self, rtype, qurl, path):
+        from calibre.utils.filenames import make_long_path_useable
         try:
-                with open(path, 'rb') as f:
+            with open(make_long_path_useable(path), 'rb') as f:
                 data = f.read()
         except OSError:
             if path.rpartition('.')[-1].lower() in {'jpg', 'jpeg', 'gif', 'png', 'bmp', 'webp'}:
@@ -595,7 +599,13 @@ class HTMLDisplay(QTextBrowser):
             if self.save_resources_in_document:
                 self.document().addResource(rtype, qurl, r)
             return r
-        elif qurl.scheme() == 'calibre-icon':
+        return super().loadResource(rtype, qurl)
+
+    def loadResource(self, rtype, qurl):
+        path = local_path_for_resource(qurl, base_qurl=self.get_base_qurl())
+        if path:
+            return self.load_local_file_resource(rtype, qurl, path)
+        if qurl.scheme() == 'calibre-icon':
             r = QIcon.icon_as_png(qurl.path().lstrip('/'), as_bytearray=True)
             self.document().addResource(rtype, qurl, r)
             return r
@@ -611,7 +621,7 @@ class HTMLDisplay(QTextBrowser):
                         self.document().addResource(rtype, qurl, r)
                     return r
         else:
-            return QTextBrowser.loadResource(self, rtype, qurl)
+            return super().loadResource(rtype, qurl)
 
     def anchorAt(self, pos):
         # Anchors in a document can be "focused" with the tab key.