QFileSystemEngine::fillMetaData for Unix platforms

This shuffles a lot of code out of QFSFileEngine. fillMetaData, however
is almost a reimplementation of the logic. Goals for this function are
to maximize data gathered and minimize file system queries.

Symbian had an optimization to lstat first and only stat again on links,
having noticed a lot of lstat were being done that weren't really
necessary. That optimization was also made in the new fillMetaData
function and extended to all platforms, whenever the LinkType attribute
is requested (QFSFileEngine will now typically request this in reply to
a fileFlags request).

We now try to cache all meta data we get from the file system, while
still requesting "refreshes" as often as we did before. Client code
going straight to QFileSystemEngine API can choose it's behaviour by
clearing and querying specific flags in the QFileSystemMetaData
instance.

Reviewed-by: Prasanth Ullattil

1 files changed, 9 insertions, 24 deletions

diff --git a/src/corelib/io/qfsfileengine.cpp b/src/corelib/io/qfsfileengine.cpp
index 5d7b354..1b0a28c 100644
--- a/src/corelib/io/qfsfileengine.cpp
+++ b/src/corelib/io/qfsfileengine.cpp
@@ -447,24 +447,13 @@ qint64 QFSFileEngine::size() const
 qint64 QFSFileEnginePrivate::sizeFdFh() const
 {
     Q_Q(const QFSFileEngine);
-    // ### Fix this function, it should not stat unless the file is closed.
-    QT_STATBUF st;
-    int ret = 0;
     const_cast<QFSFileEngine *>(q)->flush();
-    if (fh && fileEntry.isEmpty()) {
-        // Buffered stdlib mode.
-        // ### This should really be an ftell
-        ret = QT_FSTAT(QT_FILENO(fh), &st);
-    } else if (fd == -1) {
-        // Stateless stat.
-        ret = QT_STAT(fileEntry.nativeFilePath().constData(), &st);
-    } else {
-        // Unbuffered stdio mode.
-        ret = QT_FSTAT(fd, &st);
-    }
-    if (ret == -1)
+
+    tried_stat = 0;
+    metaData.clearFlags(QFileSystemMetaData::SizeAttribute);
+    if (!doStat(QFileSystemMetaData::SizeAttribute))
         return 0;
-    return st.st_size;
+    return metaData.size();
 }
 #endif
 
@@ -773,18 +762,14 @@ bool QFSFileEngine::isSequential() const
 /*!
     \internal
 */
+#ifdef Q_OS_UNIX
 bool QFSFileEnginePrivate::isSequentialFdFh() const
 {
-    if (!tried_stat)
-        doStat();
-    if (could_stat) {
-#ifdef Q_OS_UNIX
-        return (st.st_mode & S_IFMT) != S_IFREG;
-        // ### WINDOWS!
-#endif
-    }
+    if (doStat(QFileSystemMetaData::SequentialType))
+        return metaData.isSequential();
     return true;
 }
+#endif
 
 /*!
     \reimp