Decode rectangles in order if needed

Some encodings must be handled in the order they are received.
Make sure we respect this in the decode manager.

common/rfb/DecodeManager.cxx

@@ -251,18 +251,27 @@ DecodeManager::QueueEntry* DecodeManager::DecodeThread::findEntry()
        ++iter) {
     DecodeManager::QueueEntry* entry;
 
+    std::list<DecodeManager::QueueEntry*>::iterator iter2;
+
     entry = *iter;
 
     // Another thread working on this?
     if (entry->active)
       goto next;
 
+    // If this is an ordered decoder then make sure this is the first
+    // rectangle in the queue for that decoder
+    if (entry->decoder->flags & DecoderOrdered) {
+      for (iter2 = manager->workQueue.begin(); iter2 != iter; ++iter2) {
+        if (entry->encoding == (*iter2)->encoding)
+          goto next;
+      }
+    }
+
     // Check overlap with earlier rectangles
     if (!lockedRegion.intersect(entry->affectedRegion).is_empty())
       goto next;
 
-    // FIXME: check dependencies between rects
-
     return entry;
 
 next:

common/rfb/Decoder.h

@@ -33,6 +33,8 @@ namespace rfb {
   enum DecoderFlags {
     // A constant for decoders that don't need anything special
     DecoderPlain = 0,
+    // All rects for this decoder must be handled in order
+    DecoderOrdered = 1 << 0,
   };
 
   class Decoder {

common/rfb/TightDecoder.cxx

@@ -46,7 +46,7 @@ static const int TIGHT_MIN_TO_COMPRESS = 12;
 #include <rfb/tightDecode.h>
 #undef BPP
 
-TightDecoder::TightDecoder() : Decoder(DecoderPlain)
+TightDecoder::TightDecoder() : Decoder(DecoderOrdered)
 {
 }
 

common/rfb/ZRLEDecoder.cxx

@@ -62,7 +62,7 @@ static inline rdr::U32 readOpaque24B(rdr::InStream* is)
 #undef CPIXEL
 #undef BPP
 
-ZRLEDecoder::ZRLEDecoder() : Decoder(DecoderPlain)
+ZRLEDecoder::ZRLEDecoder() : Decoder(DecoderOrdered)
 {
 }