perf(escaping): Remove catastrophic backtracking regex for code escape by SystemKeeper · Pull Request #19 · nextcloud-deps/CDMarkdownKit

SystemKeeper · 2025-02-25T10:12:04Z

Performance before
MM: 104.511237791 seconds
MM: 104.49352295899999 seconds
MM: 105.008809959 seconds

Performance after
MM: 0.34015025 seconds
MM: 0.331338208 seconds
MM: 0.351607875 seconds

Code for performance test

func testTime() throws {
        let clock = ContinuousClock()
        let parser = getParser()

        let result = clock.measure {
            for _ in 0 ..< 100
            {
                _ = parser.parse("""
```
                             Name              Application ID               Version                  Branch      Installation
                             AnyDesk           com.anydesk.Anydesk          6.4.0                    stable      user
                             draw.io           com.jgraph.drawio.desktop    26.0.4                   stable      user
                             Nextcloud Desktop …oud.desktopclient.nextcloud 3.15.3                   stable      user
                             0 A.D.            com.play0ad.zeroad           0.0.26                   stable      user
                             Visual Studio Co… com.visualstudio.code        1.96.4                   stable      user
                             Floorp            one.ablaze.floorp            11.23.0                  stable      user
                             Freedesktop Plat… org.freedesktop.Platform     freedesktop-sdk-22.08.27 22.08       user
                             Freedesktop Plat… org.freedesktop.Platform     freedesktop-sdk-24.08.11 24.08       user
                             Mesa              …desktop.Platform.GL.default 24.0.9                   22.08       user
                             Mesa (Extra)      …desktop.Platform.GL.default 24.0.9                   22.08-extra user
                             Mesa              …desktop.Platform.GL.default 24.3.1                   23.08       user
                             Mesa (Extra)      …desktop.Platform.GL.default 24.3.1                   23.08-extra user
                             Mesa              …desktop.Platform.GL.default 24.3.4                   24.08       user
                             Mesa (Extra)      …desktop.Platform.GL.default 24.3.4                   24.08extra  user
                             Intel             …esktop.Platform.VAAPI.Intel                          22.08       user
                             Intel VAAPI driv… …esktop.Platform.VAAPI.Intel                          23.08       user
                             Intel VAAPI driv… …esktop.Platform.VAAPI.Intel                          24.08       user
                             FFmpeg extension… …esktop.Platform.ffmpeg-full                          24.08       user
                             openh264          …eedesktop.Platform.openh264 2.1.0                    2.2.0       user
                             openh264          …eedesktop.Platform.openh264 2.4.1                    2.4.1       user
                             Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-22.08.27 22.08       user
                             Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-23.08.27 23.08       user
                             Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-24.08.10 24.08       user
                             Evolution         org.gnome.Evolution          3.54.3                   stable      user
                             GNOME Applicatio… org.gnome.Platform                                    47          user
                             Pop Gtk theme     org.gtk.Gtk3theme.Pop-dark                            3.22        user
                             KDE Application … org.kde.Platform                                      5.15-24.08  user
                             KDE Application … org.kde.Platform                                      6.7         user
                             KDE Application … org.kde.Platform                                      6.8         user
                             QGnomePlatform    …latformTheme.QGnomePlatform                          5.15-24.08  user
                             QAdwaitaDecorati… …oration.QAdwaitaDecorations                          5.15-24.08  user
                             QAdwaitaDecorati… …oration.QAdwaitaDecorations                          6.7         user
                             KeePassXC         org.keepassxc.KeePassXC      2.7.9                    stable      user
                             Signal Desktop    org.signal.Signal            7.41.0                   stable      user
                             Wireshark         org.wireshark.Wireshark      4.4.3                    stable      user
""")
            }
        }

        print("MM: \(result)")
    }

(note the non-closing three-backticks)

How to test manually

Post the following message

```
                          Name              Application ID               Version                  Branch      Installation
                          AnyDesk           com.anydesk.Anydesk          6.4.0                    stable      user
                          draw.io           com.jgraph.drawio.desktop    26.0.4                   stable      user
                          Nextcloud Desktop …oud.desktopclient.nextcloud 3.15.3                   stable      user
                          0 A.D.            com.play0ad.zeroad           0.0.26                   stable      user
                          Visual Studio Co… com.visualstudio.code        1.96.4                   stable      user
                          Floorp            one.ablaze.floorp            11.23.0                  stable      user
                          Freedesktop Plat… org.freedesktop.Platform     freedesktop-sdk-22.08.27 22.08       user
                          Freedesktop Plat… org.freedesktop.Platform     freedesktop-sdk-24.08.11 24.08       user
                          Mesa              …desktop.Platform.GL.default 24.0.9                   22.08       user
                          Mesa (Extra)      …desktop.Platform.GL.default 24.0.9                   22.08-extra user
                          Mesa              …desktop.Platform.GL.default 24.3.1                   23.08       user
                          Mesa (Extra)      …desktop.Platform.GL.default 24.3.1                   23.08-extra user
                          Mesa              …desktop.Platform.GL.default 24.3.4                   24.08       user
                          Mesa (Extra)      …desktop.Platform.GL.default 24.3.4                   24.08extra  user
                          Intel             …esktop.Platform.VAAPI.Intel                          22.08       user
                          Intel VAAPI driv… …esktop.Platform.VAAPI.Intel                          23.08       user
                          Intel VAAPI driv… …esktop.Platform.VAAPI.Intel                          24.08       user
                          FFmpeg extension… …esktop.Platform.ffmpeg-full                          24.08       user
                          openh264          …eedesktop.Platform.openh264 2.1.0                    2.2.0       user
                          openh264          …eedesktop.Platform.openh264 2.4.1                    2.4.1       user
                          Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-22.08.27 22.08       user
                          Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-23.08.27 23.08       user
                          Freedesktop SDK   org.freedesktop.Sdk          freedesktop-sdk-24.08.10 24.08       user
                          Evolution         org.gnome.Evolution          3.54.3                   stable      user
                          GNOME Applicatio… org.gnome.Platform                                    47          user
                          Pop Gtk theme     org.gtk.Gtk3theme.Pop-dark                            3.22        user
                          KDE Application … org.kde.Platform                                      5.15-24.08  user
                          KDE Application … org.kde.Platform                                      6.7         user
                          KDE Application … org.kde.Platform                                      6.8         user
                          QGnomePlatform    …latformTheme.QGnomePlatform                          5.15-24.08  user
                          QAdwaitaDecorati… …oration.QAdwaitaDecorations                          5.15-24.08  user
                          QAdwaitaDecorati… …oration.QAdwaitaDecorations                          6.7         user
                          KeePassXC         org.keepassxc.KeePassXC      2.7.9                    stable      user
                          Signal Desktop    org.signal.Signal            7.41.0                   stable      user
                          Wireshark         org.wireshark.Wireshark      4.4.3                    stable      user

Try to scroll the conversation list, when this message is the last message (it hangs)
Try to enter a conversation with that message (it shows a spinner while opening the conversation)

Info on catastrophic backtracking: https://www.regular-expressions.info/possessive.html

Signed-off-by: Marcel Müller <marcel-mueller@gmx.de>

SystemKeeper · 2025-02-25T12:34:16Z

Missed the non-greedy quantifier 😓 Added a test for that.

SystemKeeper requested a review from Ivansss February 25, 2025 10:12

SystemKeeper marked this pull request as draft February 25, 2025 12:24

perf(escaping): Remove catastrophic backtracking regex for code escape

e3549eb

Signed-off-by: Marcel Müller <marcel-mueller@gmx.de>

SystemKeeper force-pushed the fix/noid/code-escaping-performance branch from 679816e to e3549eb Compare February 25, 2025 12:32

SystemKeeper marked this pull request as ready for review February 25, 2025 12:33

Ivansss approved these changes Feb 25, 2025

View reviewed changes

Ivansss merged commit 60c7cf1 into master Feb 25, 2025
2 checks passed

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perf(escaping): Remove catastrophic backtracking regex for code escape#19

perf(escaping): Remove catastrophic backtracking regex for code escape#19
Ivansss merged 1 commit intomasterfrom
fix/noid/code-escaping-performance

SystemKeeper commented Feb 25, 2025

Uh oh!

SystemKeeper commented Feb 25, 2025

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SystemKeeper commented Feb 25, 2025

Uh oh!

SystemKeeper commented Feb 25, 2025

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