Assistant: Performance fixes for help generator's pattern matching.

Reading a help project was unacceptably slow with pattern matching.
Now we do it only for filenames that contain wildcard symbols.
Also, we cache the results of QDir::entryList() calls.

1 files changed, 36 insertions, 7 deletions

diff --git a/tools/assistant/lib/qhelpprojectdata.cpp b/tools/assistant/lib/qhelpprojectdata.cpp
index 55b4ea7..5df0426 100644
--- a/tools/assistant/lib/qhelpprojectdata.cpp
+++ b/tools/assistant/lib/qhelpprojectdata.cpp
@@ -45,6 +45,7 @@
 #include <QtCore/QFileInfo>
 #include <QtCore/QStack>
 #include <QtCore/QMap>
+#include <QtCore/QRegExp>
 #include <QtCore/QVariant>
 #include <QtXml/QXmlStreamReader>
 
@@ -75,6 +76,8 @@ private:
     void readFiles();
     void raiseUnknownTokenError();
     void addMatchingFiles(const QString &pattern);
+
+    QMap<QString, QStringList> dirEntriesCache;
 };
 
 void QHelpProjectDataPrivate::raiseUnknownTokenError()
@@ -265,14 +268,40 @@ void QHelpProjectDataPrivate::readFiles()
 // meaningful warning later.
 void QHelpProjectDataPrivate::addMatchingFiles(const QString &pattern)
 {
+    // The pattern matching is expensive, so we skip it if no
+    // wildcard symbols occur in the string.
+    if (!pattern.contains('?') && !pattern.contains('*')
+        && !pattern.contains('[') && !pattern.contains(']')) {
+        filterSectionList.last().addFile(pattern);
+        return;
+    }
+
     QFileInfo fileInfo(rootPath + '/' + pattern);
-    const QStringList &matches =
-            fileInfo.dir().entryList(QStringList(fileInfo.fileName()));
-    for (QStringList::ConstIterator it = matches.constBegin();
-         it != matches.constEnd();
-         ++it)
-        filterSectionList.last().addFile(QFileInfo(pattern).dir().path() + '/' + *it);
-    if (matches.empty())
+    const QDir &dir = fileInfo.dir();
+    const QString &path = dir.canonicalPath();
+
+    // QDir::entryList() is expensive, so we cache the results.
+    QMap<QString, QStringList>::ConstIterator it = dirEntriesCache.find(path);
+    const QStringList &entries = it != dirEntriesCache.constEnd() ?
+                                 it.value() : dir.entryList(QDir::Files);
+    if (it == dirEntriesCache.constEnd())
+        dirEntriesCache.insert(path, entries);
+
+    bool matchFound = false;
+#ifdef Q_OS_WIN
+    Qt::CaseSensitivity cs = Qt::CaseInSensitive;
+#else
+    Qt::CaseSensitivity cs = Qt::CaseSensitive;
+#endif
+    QRegExp regExp(fileInfo.fileName(), cs, QRegExp::Wildcard);
+    foreach (const QString &file, entries) {
+        if (regExp.exactMatch(file)) {
+            matchFound = true;
+            filterSectionList.last().
+                addFile(QFileInfo(pattern).dir().path() + '/' + file);
+        }
+    }
+    if (!matchFound)
         filterSectionList.last().addFile(pattern);
 }