Small optimization in QIODevice::readAll()

.. and more testcases

Reviewed-by: joao

2 files changed, 51 insertions, 2 deletions

diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp
index 0e5a2de..8dcccb4 100644
--- a/src/corelib/io/qiodevice.cpp
+++ b/src/corelib/io/qiodevice.cpp
@@ -965,7 +965,15 @@ QByteArray QIODevice::readAll()
 
     QByteArray result;
     qint64 readBytes = 0;
-    if (d->isSequential() || (readBytes = size()) == 0) {
+
+    // flush internal read buffer
+    if (!(d->openMode & Text) && !d->buffer.isEmpty()) {
+        result = d->buffer.readAll();
+        readBytes = result.size();
+    }
+
+    qint64 theSize;
+    if (d->isSequential() || (theSize = size()) == 0) {
         // Size is unknown, read incrementally.
         qint64 readResult;
         do {
@@ -977,7 +985,7 @@ QByteArray QIODevice::readAll()
     } else {
         // Read it all in one go.
         // If resize fails, don't read anything.
-        result.resize(int(readBytes - d->pos));
+        result.resize(int(theSize - d->pos));
         readBytes = read(result.data(), result.size());
     }
 
diff --git a/tests/auto/qfile/tst_qfile.cpp b/tests/auto/qfile/tst_qfile.cpp
index 2b2f431..e88c222 100644
--- a/tests/auto/qfile/tst_qfile.cpp
+++ b/tests/auto/qfile/tst_qfile.cpp
@@ -129,6 +129,8 @@ private slots:
     void readLine();
     void readLine2();
     void readLineNullInLine();
+    void readAll_data();
+    void readAll();
     void readAllStdin();
     void readLineStdin();
     void readLineStdin_lineByLine();
@@ -752,6 +754,45 @@ void tst_QFile::readLineNullInLine()
     QCOMPARE(file.readLine(), QByteArray());
 }
 
+void tst_QFile::readAll_data()
+{
+    QTest::addColumn<bool>("textMode");
+    QTest::addColumn<QString>("fileName");
+    QTest::newRow( "TextMode unixfile" ) <<  true << SRCDIR "testfile.txt";
+    QTest::newRow( "BinaryMode unixfile" ) <<  false << SRCDIR "testfile.txt";
+    QTest::newRow( "TextMode dosfile" ) <<  true << SRCDIR "dosfile.txt";
+    QTest::newRow( "BinaryMode dosfile" ) <<  false << SRCDIR "dosfile.txt";
+    QTest::newRow( "TextMode bigfile" ) <<  true << SRCDIR "tst_qfile.cpp";
+    QTest::newRow( "BinaryMode  bigfile" ) <<  false << SRCDIR "tst_qfile.cpp";
+    QVERIFY(QFile(SRCDIR "tst_qfile.cpp").size() > 64*1024);
+}
+
+void tst_QFile::readAll()
+{
+    QFETCH( bool, textMode );
+    QFETCH( QString, fileName );
+
+    QFile file(fileName);
+    if (textMode)
+        QVERIFY(file.open(QFile::Text | QFile::ReadOnly));
+    else
+        QVERIFY(file.open(QFile::ReadOnly));
+
+    QByteArray a = file.readAll();
+    file.reset();
+    QVERIFY(file.pos() == 0);
+
+    QVERIFY(file.bytesAvailable() > 7);
+    QByteArray b = file.read(1);
+    char x;
+    file.getChar(&x);
+    b.append(x);
+    b.append(file.read(5));
+    b.append(file.readAll());
+
+    QCOMPARE(a, b);
+}
+
 void tst_QFile::readAllStdin()
 {
 #if defined(Q_OS_WINCE) || defined(Q_OS_SYMBIAN)