Accept full-width parentheses in removeMnemonics()

QPlatformTheme::removeMnemonics() removes any match to /\s*\(&[^&]\)/
from the text it is given (a menu entry). It transpires that
translators are apt to use the full-width parentheses (compatible with
some far-eastern scripts) instead of the plain ASCII ones. This leads
to their translated mnemonics don't match the same pattern unless we
treat the full-width parentheses as a match for the ASCII ones;
consequently, they don't get removed, which this function exists to
do. So teach it to recognize the full-width versions, too.

In the process, break out the pattern-matching (aside from the leading
space) to a lambda to make it easier to read and document.

Fixes: QTBUG-110829
Change-Id: I7335d0bd8dbba66e1fe58fc3eec93caaaf6ec140
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit 86b930f073b6b75790a6af8d021f4daa00f80aae)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 15 insertions, 5 deletions

diff --git a/src/gui/kernel/qplatformtheme.cpp b/src/gui/kernel/qplatformtheme.cpp
index 8e8d7b3be5..3e4516144b 100644
--- a/src/gui/kernel/qplatformtheme.cpp
+++ b/src/gui/kernel/qplatformtheme.cpp
@@ -773,6 +773,19 @@ QString QPlatformTheme::defaultStandardButtonText(int button)
 
 QString QPlatformTheme::removeMnemonics(const QString &original)
 {
+    const auto mnemonicInParentheses = [](QStringView text) {
+        /* Format of mnemonics to remove is /\(&[^&]\)/ but accept full-width
+           forms of ( and ) as equivalent, for cross-platform compatibility with
+           MS (and consequent behavior of translators, see QTBUG-110829).
+        */
+        Q_ASSERT(text.size() == 4); // Caller's responsibility.
+        constexpr QChar wideOpen = u'\uff08', wideClose = u'\uff09';
+        if (!text.startsWith(u'(') && !text.startsWith(wideOpen))
+            return false;
+        if (text[1] != u'&' || text[2] == u'&')
+            return false;
+        return text.endsWith(u')') || text.endsWith(wideClose);
+    };
     QString returnText(original.size(), u'\0');
     int finalDest = 0;
     int currPos = 0;
@@ -783,11 +796,8 @@ QString QPlatformTheme::removeMnemonics(const QString &original)
             --l;
             if (l == 0)
                 break;
-        } else if (original.at(currPos) == u'(' && l >= 4 &&
-                   original.at(currPos + 1) == u'&' &&
-                   original.at(currPos + 2) != u'&' &&
-                   original.at(currPos + 3) == u')') {
-            /* remove mnemonics its format is "\s*(&X)" */
+        } else if (l >= 4 && mnemonicInParentheses(QStringView{original}.sliced(currPos, 4))) {
+            // Also strip any leading space before the mnemonic:
             int n = 0;
             while (finalDest > n && returnText.at(finalDest - n - 1).isSpace())
                 ++n;