Changeset 374

Timestamp:

Dec 3, 2009, 2:17:13 AM (15 years ago)

Author:

Dmitry A. Kuminov

Message:

corelib/io: Improved the polling QFileSystemWatcher implementation so that it doesn't eat all CPU when there are more than 100 items to watch any more.

File:

• trunk/src/corelib/io/qfilesystemwatcher.cpp (modified) (9 diffs)

trunk/src/corelib/io/qfilesystemwatcher.cpp

@@ -51 +51 @@
 #include <qmutex.h>
 #include <qset.h>
-#include <qtimer.h>
+#include <q.h>
 
 #if defined(Q_OS_WIN)
@@ -64 +64 @@
 QT_BEGIN_NAMESPACE
 
-enum { PollingInterval = 1000 };
-
 class QPollingFileSystemWatcherEngine : public QFileSystemWatcherEngine
 {
-    Q_OBJECT
+    enum {
+        SmallPollingInterval = 50,  // time to wait after checking each watched
+                                    // item, ms
+        BigPollingInterval = 1000,  // time to wait after checking all watched
+                                    // items, ms
+    };
 
     class FileInfo
@@ -84 +87 @@
               permissions(fileInfo.permissions()),
               lastModified(fileInfo.lastModified())
-        { 
+        {
             if (fileInfo.isDir()) {
                 entries = fileInfo.absoluteDir().entryList(QDir::AllEntries);
@@ -119 +122 @@
     void stop();
 
-private slots:
-    void timeout();
+private:
+    QWaitCondition waitCond;
+    bool askedToFinish;
+    bool startOver;
 };
 
 QPollingFileSystemWatcherEngine::QPollingFileSystemWatcherEngine()
+
 {
 #ifndef QT_NO_THREAD
@@ -132 +138 @@
 void QPollingFileSystemWatcherEngine::run()
 {
-    QTimer timer;
-    connect(&timer, SIGNAL(timeout()), SLOT(timeout()));
-    timer.start(PollingInterval);
-    (void) exec();
+    mutex.lock();
+
+    forever {
+        startOver = false;
+        QMutableHashIterator<QString, FileInfo> fit(files);
+        while (!startOver && fit.hasNext()) {
+            QHash<QString, FileInfo>::iterator x = fit.next();
+            QString path = x.key();
+            QFileInfo fi(path);
+            if (!fi.exists()) {
+                fit.remove();
+                emit fileChanged(path, true);
+            } else if (x.value() != fi) {
+                x.value() = fi;
+                emit fileChanged(path, false);
+            }
+            waitCond.wait(&mutex, SmallPollingInterval);
+        }
+        QMutableHashIterator<QString, FileInfo> dit(directories);
+        while (!startOver && dit.hasNext()) {
+            QHash<QString, FileInfo>::iterator x = dit.next();
+            QString path = x.key();
+            QFileInfo fi(path);
+            if (!path.endsWith(QLatin1Char('/')))
+                fi = QFileInfo(path + QLatin1Char('/'));
+            if (!fi.exists()) {
+                dit.remove();
+                emit directoryChanged(path, true);
+            } else if (x.value() != fi) {
+                x.value() = fi;
+                emit directoryChanged(path, false);
+            }
+            waitCond.wait(&mutex, SmallPollingInterval);
+        }
+        if (!startOver && !askedToFinish) {
+            waitCond.wait(&mutex, BigPollingInterval);
+        }
+        if (askedToFinish) {
+            askedToFinish = false;
+            break;
+        }
+    }
+
+    mutex.unlock();
 }
 
@@ -156 +202 @@
                 fi = QFileInfo(path + QLatin1Char('/'));
             this->directories.insert(path, fi);
+
         } else {
             if (!files->contains(path))
                 files->append(path);
             this->files.insert(path, fi);
+
         }
         it.remove();
     }
-    start();
+    start();
     return p;
 }
@@ -179 +227 @@
             directories->removeAll(path);
             it.remove();
+
         } else if (this->files.remove(path)) {
             files->removeAll(path);
             it.remove();
+
         }
     }
     if (this->files.isEmpty() && this->directories.isEmpty()) {
+
+
         locker.unlock();
-        stop();
         wait();
     }
@@ -194 +245 @@
 void QPollingFileSystemWatcherEngine::stop()
 {
-    QMetaObject::invokeMethod(this, "quit");
-}
-
-void QPollingFileSystemWatcherEngine::timeout()
-{
     QMutexLocker locker(&mutex);
-    QMutableHashIterator<QString, FileInfo> fit(files);
-    while (fit.hasNext()) {
-        QHash<QString, FileInfo>::iterator x = fit.next();
-        QString path = x.key();
-        QFileInfo fi(path);
-        if (!fi.exists()) {
-            fit.remove();
-            emit fileChanged(path, true);
-        } else if (x.value() != fi) {
-            x.value() = fi;
-            emit fileChanged(path, false);
-        }
-    }
-    QMutableHashIterator<QString, FileInfo> dit(directories);
-    while (dit.hasNext()) {
-        QHash<QString, FileInfo>::iterator x = dit.next();
-        QString path = x.key();
-        QFileInfo fi(path);
-        if (!path.endsWith(QLatin1Char('/')))
-            fi = QFileInfo(path + QLatin1Char('/'));
-        if (!fi.exists()) {
-            dit.remove();
-            emit directoryChanged(path, true);
-        } else if (x.value() != fi) {
-            x.value() = fi;
-            emit directoryChanged(path, false);
-        }
-        
-    }
-}
-
-
+    startOver = true;
+    askedToFinish = true;
+    waitCond.wakeAll();
+}
 
 
@@ -615 +633 @@
 #include "moc_qfilesystemwatcher.cpp"
 
-#include "qfilesystemwatcher.moc"
-
 #endif // QT_NO_FILESYSTEMWATCHER