commit 96728356628e90ef80dc111269db1593be87aa16
author Pierre Ossman <ossman@cendio.se> Wed Jun 20 11:35:05 2018 +0200
committer Pierre Ossman <ossman@cendio.se> Thu Nov 01 16:11:42 2018 +0100
tree 05293401b2ab227be40d07a2e096d8e913d6cdea
parent ef6881b9db3765ed07db9e1d414b178daae29606

Make arguments explicit in all message writer methods

Make sure all methods only write what is given as arguments, and
avoid side effects by getting data from parameter objects. This keeps
things readable in the calling code.

common/rfb/CConnection.cxx

diff --git a/common/rfb/CConnection.cxx b/common/rfb/CConnection.cxx
index 696a124..e1c4ba5 100644
--- a/common/rfb/CConnection.cxx
+++ b/common/rfb/CConnection.cxx
@@ -25,6 +25,7 @@
 #include <rfb/CMsgReader.h>
 #include <rfb/CMsgWriter.h>
 #include <rfb/CSecurity.h>
+#include <rfb/Decoder.h>
 #include <rfb/Security.h>
 #include <rfb/SecurityClient.h>
 #include <rfb/CConnection.h>
@@ -547,7 +548,7 @@
   }
 
   if (encodingChange) {
-    writer()->writeSetEncodings(preferredEncoding, true);
+    updateEncodings();
     encodingChange = false;
   }
 
@@ -561,3 +562,77 @@
 
   forceNonincremental = false;
 }
+
+// Ask for encodings based on which decoders are supported.  Assumes higher
+// encoding numbers are more desirable.
+
+void CConnection::updateEncodings()
+{
+  int nEncodings = 0;
+  rdr::U32 encodings[encodingMax+3];
+
+  if (server.supportsLocalCursor) {
+    encodings[nEncodings++] = pseudoEncodingCursorWithAlpha;
+    encodings[nEncodings++] = pseudoEncodingCursor;
+    encodings[nEncodings++] = pseudoEncodingXCursor;
+  }
+  if (server.supportsDesktopResize)
+    encodings[nEncodings++] = pseudoEncodingDesktopSize;
+  if (server.supportsExtendedDesktopSize)
+    encodings[nEncodings++] = pseudoEncodingExtendedDesktopSize;
+  if (server.supportsDesktopRename)
+    encodings[nEncodings++] = pseudoEncodingDesktopName;
+  if (server.supportsLEDState)
+    encodings[nEncodings++] = pseudoEncodingLEDState;
+
+  encodings[nEncodings++] = pseudoEncodingLastRect;
+  encodings[nEncodings++] = pseudoEncodingContinuousUpdates;
+  encodings[nEncodings++] = pseudoEncodingFence;
+  encodings[nEncodings++] = pseudoEncodingQEMUKeyEvent;
+
+  if (Decoder::supported(preferredEncoding)) {
+    encodings[nEncodings++] = preferredEncoding;
+  }
+
+  encodings[nEncodings++] = encodingCopyRect;
+
+  /*
+   * Prefer encodings in this order:
+   *
+   *   Tight, ZRLE, Hextile, *
+   */
+
+  if ((preferredEncoding != encodingTight) &&
+      Decoder::supported(encodingTight))
+    encodings[nEncodings++] = encodingTight;
+
+  if ((preferredEncoding != encodingZRLE) &&
+      Decoder::supported(encodingZRLE))
+    encodings[nEncodings++] = encodingZRLE;
+
+  if ((preferredEncoding != encodingHextile) &&
+      Decoder::supported(encodingHextile))
+    encodings[nEncodings++] = encodingHextile;
+
+  // Remaining encodings
+  for (int i = encodingMax; i >= 0; i--) {
+    switch (i) {
+    case encodingCopyRect:
+    case encodingTight:
+    case encodingZRLE:
+    case encodingHextile:
+      /* These have already been sent earlier */
+      break;
+    default:
+      if ((i != preferredEncoding) && Decoder::supported(i))
+        encodings[nEncodings++] = i;
+    }
+  }
+
+  if (server.compressLevel >= 0 && server.compressLevel <= 9)
+      encodings[nEncodings++] = pseudoEncodingCompressLevel0 + server.compressLevel;
+  if (server.qualityLevel >= 0 && server.qualityLevel <= 9)
+      encodings[nEncodings++] = pseudoEncodingQualityLevel0 + server.qualityLevel;
+
+  writer()->writeSetEncodings(nEncodings, encodings);
+}