Optimize mime type matching

Don't count "*", don't search for "[" and for "?"
inside m_pattern on every call to matchFileName().
Do it once, when constructing the MimeGlobPattern.

Fix matching the pattern for names without any
wildcard: index of question mark should be -1, not
just different from 0.

This shortens loading a Qt6 project by about 500 ms.

Change-Id: I868fa5c024233467c8e717a8482268da8e9e4a66
Reviewed-by: hjk <hjk@qt.io>

2 files changed, 20 insertions, 13 deletions

diff --git a/src/libs/utils/mimetypes/mimeglobpattern.cpp b/src/libs/utils/mimetypes/mimeglobpattern.cpp
index 9ab335b862..d595a17b7b 100644
--- a/src/libs/utils/mimetypes/mimeglobpattern.cpp
+++ b/src/libs/utils/mimetypes/mimeglobpattern.cpp
@@ -104,12 +104,10 @@ bool MimeGlobPattern::matchFileName(const QString &inputFilename) const
         return false;
     const int len = filename.length();
 
-    const int starCount = m_pattern.count(QLatin1Char('*'));
-
     // Patterns like "*~", "*.extension"
-    if (m_pattern[0] == QLatin1Char('*') && m_pattern.indexOf(QLatin1Char('[')) == -1 && starCount == 1)
-    {
-        if (len + 1 < pattern_len) return false;
+    if (m_pattern[0] == QLatin1Char('*') && m_openingSquareBracketPos == -1 && m_starCount == 1) {
+        if (len + 1 < pattern_len)
+            return false;
 
         const QChar *c1 = m_pattern.unicode() + pattern_len - 1;
         const QChar *c2 = filename.unicode() + len - 1;
@@ -120,8 +118,9 @@ bool MimeGlobPattern::matchFileName(const QString &inputFilename) const
     }
 
     // Patterns like "README*" (well this is currently the only one like that...)
-    if (starCount == 1 && m_pattern.at(pattern_len - 1) == QLatin1Char('*')) {
-        if (len + 1 < pattern_len) return false;
+    if (m_starCount == 1 && m_pattern.at(pattern_len - 1) == QLatin1Char('*')) {
+        if (len + 1 < pattern_len)
+            return false;
         if (m_pattern.at(0) == QLatin1Char('*'))
             return filename.indexOf(QStringView(m_pattern).mid(1, pattern_len - 2)) != -1;
 
@@ -134,7 +133,7 @@ bool MimeGlobPattern::matchFileName(const QString &inputFilename) const
     }
 
     // Names without any wildcards like "README"
-    if (m_pattern.indexOf(QLatin1Char('[')) == -1 && starCount == 0 && m_pattern.indexOf(QLatin1Char('?')))
+    if (m_openingSquareBracketPos == -1 && m_starCount == 0 && m_questionMarkPos == -1)
         return (m_pattern == filename);
 
     // Other (quite rare) patterns, like "*.anim[1-9j]": use slow but correct method
diff --git a/src/libs/utils/mimetypes/mimeglobpattern_p.h b/src/libs/utils/mimetypes/mimeglobpattern_p.h
index ecbfb02ce9..28fa01551c 100644
--- a/src/libs/utils/mimetypes/mimeglobpattern_p.h
+++ b/src/libs/utils/mimetypes/mimeglobpattern_p.h
@@ -73,12 +73,17 @@ public:
     static const unsigned DefaultWeight = 50;
     static const unsigned MinWeight = 1;
 
-    explicit MimeGlobPattern(const QString &thePattern, const QString &theMimeType, unsigned theWeight = DefaultWeight, Qt::CaseSensitivity s = Qt::CaseInsensitive) :
-        m_pattern(thePattern), m_mimeType(theMimeType), m_weight(theWeight), m_caseSensitivity(s)
+    explicit MimeGlobPattern(const QString &thePattern, const QString &theMimeType,
+                             unsigned theWeight = DefaultWeight,
+                             Qt::CaseSensitivity s = Qt::CaseInsensitive) :
+        m_pattern(s == Qt::CaseInsensitive ? thePattern.toLower() : thePattern),
+        m_mimeType(theMimeType),
+        m_weight(theWeight),
+        m_starCount(m_pattern.count(QLatin1Char('*'))),
+        m_openingSquareBracketPos(m_pattern.indexOf(QLatin1Char('['))),
+        m_questionMarkPos(m_pattern.indexOf(QLatin1Char('?'))),
+        m_caseSensitivity(s)
     {
-        if (s == Qt::CaseInsensitive) {
-            m_pattern = m_pattern.toLower();
-        }
     }
     ~MimeGlobPattern() {}
 
@@ -93,6 +98,9 @@ private:
     QString m_pattern;
     QString m_mimeType;
     int m_weight;
+    int m_starCount;
+    int m_openingSquareBracketPos;
+    int m_questionMarkPos;
     Qt::CaseSensitivity m_caseSensitivity;
 };