Fixes for sequential devices

src/imageformats/kra.cpp

@@ -57,6 +57,9 @@ bool KraHandler::canRead(QIODevice *device)
         qWarning("KraHandler::canRead() called with no device");
         return false;
     }
+    if (device->isSequential()) {
+        return false;
+    }
 
     char buff[57];
     if (device->peek(buff, sizeof(buff)) == sizeof(buff)) {

src/imageformats/ora.cpp

@@ -56,6 +56,9 @@ bool OraHandler::canRead(QIODevice *device)
         qWarning("OraHandler::canRead() called with no device");
         return false;
     }
+    if (device->isSequential()) {
+        return false;
+    }
 
     char buff[54];
     if (device->peek(buff, sizeof(buff)) == sizeof(buff)) {

src/imageformats/pcx.cpp

@@ -174,7 +174,7 @@ static QDataStream &operator>>(QDataStream &s, PCXHEADER &ph)
 
     // Skip the rest of the header
     quint8 byte;
-    while (s.device()->pos() < 128) {
+    for (auto i = 0; i < 54; ++i) {
         s >> byte;
     }
 
@@ -684,12 +684,6 @@ bool PCXHandler::canRead(QIODevice *device)
         return false;
     }
 
-    // We do not support sequential images
-    // We need to know the current position to properly read the header
-    if (device->isSequential()) {
-        return false;
-    }
-
     qint64 oldPos = device->pos();
 
     char head[1];

src/imageformats/psd.cpp

@@ -1249,6 +1249,9 @@ bool PSDHandler::canRead(QIODevice *device)
         qWarning("PSDHandler::canRead() called with no device");
         return false;
     }
+    if (device->isSequential()) {
+        return false;
+    }
 
     qint64 oldPos = device->pos();
 

src/imageformats/raw.cpp

@@ -855,6 +855,14 @@ int RAWHandler::currentImageNumber() const
 
 bool RAWHandler::canRead(QIODevice *device)
 {
+    if (!device) {
+        qWarning("RAWHandler::canRead() called with no device");
+        return false;
+    }
+    if (device->isSequential()) {
+        return false;
+    }
+
     device->startTransaction();
 
     std::unique_ptr<LibRaw> rawProcessor(new LibRaw);

src/imageformats/xcf.cpp

@@ -3341,6 +3341,9 @@ bool XCFHandler::canRead(QIODevice *device)
         qCDebug(XCFPLUGIN) << "XCFHandler::canRead() called with no device";
         return false;
     }
+    if (device->isSequential()) {
+        return false;
+    }
 
     qint64 oldPos = device->pos();