Changeset 774 for trunk/src/network/access

Timestamp:

Aug 3, 2010, 3:18:00 PM (15 years ago)

Author:

Dmitry A. Kuminov

Message:

network: Improve network disk cache performance by reducing the number of stat() calls twice when expiring the cache items [based on patch by rudi].

File:

• trunk/src/network/access/qnetworkdiskcache.cpp (modified) (3 diffs)

trunk/src/network/access/qnetworkdiskcache.cpp

@@ -512 +512 @@
     QDirIterator it(cacheDirectory(), filters, QDirIterator::Subdirectories);
 
-    QMultiMap<QDateTime, QString> cacheItems;
+    // performance tweak: we store the size together with the name in
+    // order to avoid querying the size again before the file is deleted
+    typedef QPair<QString, qint64> ExpireInfo;
+
+    QMultiMap<QDateTime, ExpireInfo> cacheItems;
     qint64 totalSize = 0;
     while (it.hasNext()) {
@@ -519 +523 @@
         QString fileName = info.fileName();
         if (fileName.endsWith(CACHE_POSTFIX) && fileName.startsWith(CACHE_PREFIX)) {
-            cacheItems.insert(info.created(), path);
-            totalSize += info.size();
+            ExpireInfo item = qMakePair(path, info.size());
+            cacheItems.insert(info.created(), item);
+            totalSize += item.second;
         }
     }
@@ -526 +531 @@
     int removedFiles = 0;
     qint64 goal = (maximumCacheSize() * 9) / 10;
-    QMultiMap<QDateTime, QString>::const_iterator i = cacheItems.constBegin();
+    QMultiMap<QDateTime, >::const_iterator i = cacheItems.constBegin();
     while (i != cacheItems.constEnd()) {
         if (totalSize < goal)
             break;
-        QString name = i.value();
-        QFile file(name);
-        qint64 size = file.size();
-        file.remove();
-        totalSize -= size;
+        const ExpireInfo &item = i.value();
+        QFile::remove(item.first);
+        totalSize -= item.second;
         ++removedFiles;
         ++i;