Add QStorageInfo::blockSize

[ChangeLog][QtCore][QStorageInfo] Added QStorageInfo::blockSize(), which
returns the optimal block size for data transfer to and from the
storage.

Change-Id: Ib306f8f647014b399b87ffff13f4eba6000452d4
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Tobias Koenig <tobias.koenig@kdab.com>

src/corelib/io/qstorageinfo.cpp

@@ -221,6 +221,18 @@ qint64 QStorageInfo::bytesTotal() const
     return d->bytesTotal;
 }
 
+/*!
+    \since 5.6
+    Returns the optimal transfer block size for this filesystem.
+
+    Returns -1 if QStorageInfo could not determine the size or if the QStorageInfo
+    object is not valid.
+ */
+int QStorageInfo::blockSize() const
+{
+    return d->blockSize;
+}
+
 /*!
     Returns the type name of the filesystem.
 

src/corelib/io/qstorageinfo.h

@@ -72,6 +72,7 @@ public:
     qint64 bytesTotal() const;
     qint64 bytesFree() const;
     qint64 bytesAvailable() const;
+    int blockSize() const;
 
     inline bool isRoot() const;
     bool isReadOnly() const;

src/corelib/io/qstorageinfo_mac.cpp

@@ -76,6 +76,7 @@ void QStorageInfoPrivate::retrievePosixInfo()
         device = QByteArray(statfs_buf.f_mntfromname);
         readOnly = (statfs_buf.f_flags & MNT_RDONLY) != 0;
         fileSystemType = QByteArray(statfs_buf.f_fstypename);
+        blockSize = statfs_buf.f_bsize;
     }
 }
 

src/corelib/io/qstorageinfo_p.h

@@ -53,7 +53,7 @@ class QStorageInfoPrivate : public QSharedData
 {
 public:
     inline QStorageInfoPrivate() : QSharedData(),
-        bytesTotal(-1), bytesFree(-1), bytesAvailable(-1),
+        bytesTotal(-1), bytesFree(-1), bytesAvailable(-1), blockSize(-1),
         readOnly(false), ready(false), valid(false)
     {}
 
@@ -84,6 +84,7 @@ public:
     qint64 bytesTotal;
     qint64 bytesFree;
     qint64 bytesAvailable;
+    int blockSize;
 
     bool readOnly;
     bool ready;

src/corelib/io/qstorageinfo_unix.cpp

@@ -510,6 +510,7 @@ void QStorageInfoPrivate::retrieveVolumeInfo()
         bytesTotal = statfs_buf.f_blocks * statfs_buf.f_bsize;
         bytesFree = statfs_buf.f_bfree * statfs_buf.f_bsize;
         bytesAvailable = statfs_buf.f_bavail * statfs_buf.f_bsize;
+        blockSize = statfs_buf.f_bsize;
 #if defined(Q_OS_ANDROID) || defined (Q_OS_BSD4)
 #if defined(_STATFS_F_FLAGS)
         readOnly = (statfs_buf.f_flags & ST_RDONLY) != 0;