Prevent UI freeze when opening binary files#732
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Prevent UI freeze when opening binary files#732oxidworks wants to merge 1 commit intolinuxmint:masterfrom
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Binary files typically contain no newline characters, causing the entire file content to be placed in a single GtkTextBuffer line. This triggers extremely slow Pango/HarfBuzz text shaping (O(n²) for varied content) that blocks the GTK main thread indefinitely at 100% CPU. The problem is compounded by the encoding fallback mechanism which converts each byte to a 3-character hex escape (\XX), tripling the line length. This commit adds three mitigations: 1. Pre-load binary detection in _xed_tab_load(): Before starting the file loader, check the content type via GIO and scan the first 8KB for NUL bytes. If the file appears binary, show a warning info bar with "Open Anyway" / "Don't Open" buttons instead of loading immediately. Text-like types (text/*, XML, JSON, JS, SVG) are always allowed through. 2. New xed_binary_file_warning_info_bar_new(): Creates a warning info bar showing the detected file type description and explaining that opening binary files can cause unresponsiveness. 3. Cursor position optimization in update_cursor_position_statusbar(): For lines longer than 10,000 characters, use gtk_text_iter_get_line_offset() directly instead of the O(n) character-by-character tab-width calculation loop. This prevents a secondary freeze vector when the cursor moves on very long lines. Fixes: linuxmint#491 Fixes: linuxmint#591 Related: linuxmint#624
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Summary
Opening a binary file (e.g. an ELF executable, a
.oobject, an image) in xed causes 100% CPU usage and a complete UI freeze that can last indefinitely. The only way to recover is tokillthe process.This has been reported multiple times over the past 7+ years (#174, #491, #591, #624) and affects all xed versions using GtkSourceView.
Root cause
Binary files typically contain no newline characters, so the entire file content ends up as a single
GtkTextBufferline. The encoding fallback mechanism (insert_fallback()in GtkSourceView) converts each byte to a 3-character hex escape (\XX), tripling the length. Pango/HarfBuzz text shaping on a line with millions of characters blocks the GTK main thread indefinitely.A secondary freeze vector exists in
update_cursor_position_statusbar()which iterates character-by-character (O(n)) from the start of the line to calculate the column position.Changes
1. Pre-load binary detection (
xed-tab.c)GtkSourceFileLoader, checks the content type viag_file_query_info()text/*, XML, JSON, JavaScript, SVG) are always allowed through2. Binary file warning info bar (
xed-io-error-info-bar.c/.h)xed_binary_file_warning_info_bar_new()function3. Cursor position optimization (
xed-window.c)gtk_text_iter_get_line_offset()directly instead of the O(n) character-by-character loopTesting
/usr/bin/xed(binary): warning info bar appears, no freezeFixes #491
Fixes #591
Related: #624, #174