Merge branch '4.6' of scm.dev.nokia.troll.no:qt/oslo-staging-2 into 4.6-integration

* '4.6' of scm.dev.nokia.troll.no:qt/oslo-staging-2: (21 commits)
  Fixed a failure in tst_qgl.
  4.6.2 changes
  Avoids a possible crash when saving the state of a main window
  Implemented QGifHandler::imageCount().
  Fixed compilation of the GL2 engine for OpenGL ES 2.
  fix whitespace
  Document that QModelIndex::child does not work for the root item
  Fixed missing textures in the boxes demo.
  Fix QTBUG_7714_fullUpdateDiscardingOpacityUpdate2 autotest in qws-linux
  Assert failure when setting a widget focus proxy as its successor in tab order
  Fixed garbled 3D Qt logo in the overpainting example.
  fix crash in Phonon::DS9 backend
  Don't crash when running Qt on KDE with Oxygen style.
  Fixes missing update when setting opacity on an item that had opacity 0.0
  Avoids missing opacity updates by not propagating the ignoreOpacity flag
  Cleanup in graphicsitem autotest
  Adds convenience functions QGraphicsItemPrivate::isOpacityNull
  Fixed a crash when QPixmaps are destroyed after the ~QApplication.
  Fix GL texture leaks when pixmaps are deleted
  Doc fix. No need to put something deprecated if it's not.
  ...

2 files changed, 235 insertions, 1 deletions

diff --git a/src/plugins/imageformats/gif/qgifhandler.cpp b/src/plugins/imageformats/gif/qgifhandler.cpp
index 6f049be..6cd7841 100644
--- a/src/plugins/imageformats/gif/qgifhandler.cpp
+++ b/src/plugins/imageformats/gif/qgifhandler.cpp
@@ -72,6 +72,7 @@ public:
 
     int decode(QImage *image, const uchar* buffer, int length,
                int *nextFrameDelay, int *loopCount, QSize *nextSize);
+    static int imageCount(QIODevice *device);
 
     bool newFrame;
     bool partialNewFrame;
@@ -645,6 +646,234 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
     return initial-length;
 }
 
+/*!
+   Returns the number of images that can be read from \a device.
+*/
+
+int QGIFFormat::imageCount(QIODevice *device)
+{
+    if (!device)
+        return 0;
+
+    qint64 oldPos = device->pos();
+    if (!device->seek(0))
+        return 0;
+
+    int colorCount = 0;
+    int localColorCount = 0;
+    int globalColorCount = 0;
+    int colorReadCount = 0;
+    bool localColormap = false;
+    bool globalColormap = false;
+    int count = 0;
+    int blockSize = 0;
+    bool done = false;
+    uchar hold[16];
+    int imageCount = 0;
+    State state = Header;
+
+    const int readBufferSize = 40960; // 40k read buffer
+    QByteArray readBuffer(device->read(readBufferSize));
+
+    if (readBuffer.isEmpty())
+        return 0;
+
+    // this is a specialized version of the state machine from decode(),
+    // which doesn't do any image decoding or mallocing, and has an
+    // optimized way of skipping SkipBlocks, ImageDataBlocks and
+    // Global/LocalColorMaps.
+
+    while (!readBuffer.isEmpty()) {
+        int length = readBuffer.size();
+        const uchar *buffer = (const uchar *) readBuffer.constData();
+        while (!done && length) {
+            length--;
+            uchar ch = *buffer++;
+            switch (state) {
+            case Header:
+                hold[count++] = ch;
+                if (count == 6) {
+                    state = LogicalScreenDescriptor;
+                    count = 0;
+                }
+                break;
+            case LogicalScreenDescriptor:
+                hold[count++] = ch;
+                if (count == 7) {
+                    globalColormap = !!(hold[4] & 0x80);
+                    globalColorCount = 2 << (hold[4] & 0x7);
+                    count = 0;
+                    colorCount = globalColorCount;
+                    if (globalColormap) {
+                        int colorTableSize = 3 * globalColorCount;
+                        if (length >= colorTableSize) {
+                            // skip the global color table in one go
+                            length -= colorTableSize;
+                            buffer += colorTableSize;
+                            state = Introducer;
+                        } else {
+                            colorReadCount = 0;
+                            state = GlobalColorMap;
+                        }
+                    } else {
+                        state=Introducer;
+                    }
+                }
+                break;
+            case GlobalColorMap:
+            case LocalColorMap:
+                hold[count++] = ch;
+                if (count == 3) {
+                    if (++colorReadCount >= colorCount) {
+                        if (state == LocalColorMap)
+                            state = TableImageLZWSize;
+                        else
+                            state = Introducer;
+                    }
+                    count = 0;
+                }
+                break;
+            case Introducer:
+                hold[count++] = ch;
+                switch (ch) {
+                case 0x2c:
+                    state = ImageDescriptor;
+                    break;
+                case 0x21:
+                    state = ExtensionLabel;
+                    break;
+                case 0x3b:
+                    state = Done;
+                    break;
+                default:
+                    done = true;
+                    state = Error;
+                }
+                break;
+            case ImageDescriptor:
+                hold[count++] = ch;
+                if (count == 10) {
+                    localColormap = !!(hold[9] & 0x80);
+                    localColorCount = localColormap ? (2 << (hold[9] & 0x7)) : 0;
+                    if (localColorCount)
+                        colorCount = localColorCount;
+                    else
+                        colorCount = globalColorCount;
+                    imageCount++;
+
+                    count = 0;
+                    if (localColormap) {
+                        int colorTableSize = 3 * localColorCount;
+                        if (length >= colorTableSize) {
+                            // skip the local color table in one go
+                            length -= colorTableSize;
+                            buffer += colorTableSize;
+                            state = TableImageLZWSize;
+                        } else {
+                            colorReadCount = 0;
+                            state = LocalColorMap;
+                        }
+                    } else {
+                        state = TableImageLZWSize;
+                    }
+                }
+                break;
+            case TableImageLZWSize:
+                if (ch > max_lzw_bits)
+                    state = Error;
+                else
+                    state = ImageDataBlockSize;
+                count = 0;
+                break;
+            case ImageDataBlockSize:
+                blockSize = ch;
+                if (blockSize) {
+                    if (length >= blockSize) {
+                        // we can skip the block in one go
+                        length -= blockSize;
+                        buffer += blockSize;
+                        count = 0;
+                    } else {
+                        state = ImageDataBlock;
+                    }
+                } else {
+                    state = Introducer;
+                }
+                break;
+            case ImageDataBlock:
+                ++count;
+                if (count == blockSize) {
+                    count = 0;
+                    state = ImageDataBlockSize;
+                }
+                break;
+            case ExtensionLabel:
+                switch (ch) {
+                case 0xf9:
+                    state = GraphicControlExtension;
+                    break;
+                case 0xff:
+                    state = ApplicationExtension;
+                    break;
+                default:
+                    state = SkipBlockSize;
+                }
+                count = 0;
+                break;
+            case ApplicationExtension:
+                if (count < 11)
+                    hold[count] = ch;
+                ++count;
+                if (count == hold[0] + 1) {
+                    state = SkipBlockSize;
+                    count = 0;
+                }
+                break;
+            case GraphicControlExtension:
+                if (count < 5)
+                    hold[count] = ch;
+                ++count;
+                if (count == hold[0] + 1) {
+                    count = 0;
+                    state = SkipBlockSize;
+                }
+                break;
+            case NetscapeExtensionBlockSize: // fallthrough
+            case SkipBlockSize:
+                blockSize = ch;
+                count = 0;
+                if (blockSize) {
+                    if (length >= blockSize) {
+                        // we can skip the block in one go
+                        length -= blockSize;
+                        buffer += blockSize;
+                    } else {
+                        state = SkipBlock;
+                    }
+                } else {
+                    state = Introducer;
+                }
+                break;
+            case NetscapeExtensionBlock: // fallthrough
+            case SkipBlock:
+                ++count;
+                if (count == blockSize)
+                    state = SkipBlockSize;
+                break;
+            case Done:
+                done = true;
+                break;
+            case Error:
+                device->seek(oldPos);
+                return 0;
+            }
+        }
+        readBuffer = device->read(readBufferSize);
+    }
+    device->seek(oldPos);
+    return imageCount;
+}
+
 void QGIFFormat::fillRect(QImage *image, int col, int row, int w, int h, QRgb color)
 {
     if (w>0) {
@@ -766,6 +995,7 @@ QGifHandler::QGifHandler()
     loopCnt = 0;
     frameNumber = -1;
     nextSize = QSize();
+    imageCnt = -1;
 }
 
 QGifHandler::~QGifHandler()
@@ -883,7 +1113,10 @@ int QGifHandler::nextImageDelay() const
 
 int QGifHandler::imageCount() const
 {
-    return 0; // Don't know
+    if (imageCnt != -1)
+        return imageCnt;
+    imageCnt = QGIFFormat::imageCount(device());
+    return imageCnt;
 }
 
 int QGifHandler::loopCount() const
diff --git a/src/plugins/imageformats/gif/qgifhandler.h b/src/plugins/imageformats/gif/qgifhandler.h
index a6e520f..830cd38 100644
--- a/src/plugins/imageformats/gif/qgifhandler.h
+++ b/src/plugins/imageformats/gif/qgifhandler.h
@@ -88,6 +88,7 @@ private:
     mutable int loopCnt;
     int frameNumber;
     mutable QSize nextSize;
+    mutable int imageCnt;
 };
 
 QT_END_NAMESPACE