Add fullscreen mode parameter

Before this commit, `FullScreen` and `FullScreenAllMonitors` could be
used to configure whether to use the current monitor in fullscreen,
or all monitors in fullscreen.

This commit deprecates `FullScreenAllMonitors` in favour of
`FullScreenMode` (which can either be `current` or `all`). This allows
for additional modes to be added, without the risk of having invalid
states (for example two activate two different fullscreen modes at the
same time).

A new concept has been added; read-only parameters. They are parameters
that will be read, but never written back. This allows for migration
paths to be constructed, where a parameter can be taken to consideration
but then for example be discarded, logged or changed into something else.

This has been used for `FullScreenAllMonitors` to provide a migration
path. On startup of vncviewer, if `FullScreenAllMonitors` is enabled,
`FullScreenMode=all` will be automatically enabled instead. The next
time the configuration file is written to disk, `FullScreenAllMonitors`
will then be removed.

7 files changed, 182 insertions, 69 deletions

diff --git a/vncviewer/DesktopWindow.cxx b/vncviewer/DesktopWindow.cxx
index 8c85c4d9..1fdce182 100644
--- a/vncviewer/DesktopWindow.cxx
+++ b/vncviewer/DesktopWindow.cxx
@@ -880,10 +880,11 @@ int DesktopWindow::fltkHandle(int event, Fl_Window *win)
   return ret;
 }
 
-
 void DesktopWindow::fullscreen_on()
 {
-  if (not fullScreenAllMonitors)
+  bool all_monitors = !strcasecmp(fullScreenMode, "all");
+
+  if (not all_monitors)
     fullscreen_screens(-1, -1, -1, -1);
   else {
     int top, bottom, left, right;
@@ -1377,7 +1378,7 @@ void DesktopWindow::handleOptions(void *data)
     self->ungrabKeyboard();
 
   // Call fullscreen_on even if active since it handles
-  // fullScreenAllMonitors
+  // fullScreenMode
   if (fullScreen)
     self->fullscreen_on();
   else if (!fullScreen && self->fullscreen_active())
diff --git a/vncviewer/OptionsDialog.cxx b/vncviewer/OptionsDialog.cxx
index 872a49cf..cbf4571d 100644
--- a/vncviewer/OptionsDialog.cxx
+++ b/vncviewer/OptionsDialog.cxx
@@ -297,7 +297,12 @@ void OptionsDialog::loadOptions(void)
   }
   remoteResizeCheckbox->value(remoteResize);
   fullScreenCheckbox->value(fullScreen);
-  fullScreenAllMonitorsCheckbox->value(fullScreenAllMonitors);
+
+  if (!strcasecmp(fullScreenMode, "all")) {
+    allMonitorsButton->setonly();
+  } else {
+    currentMonitorButton->setonly();
+  }
 
   handleDesktopSize(desktopSizeCheckbox, this);
 
@@ -407,7 +412,12 @@ void OptionsDialog::storeOptions(void)
   }
   remoteResize.setParam(remoteResizeCheckbox->value());
   fullScreen.setParam(fullScreenCheckbox->value());
-  fullScreenAllMonitors.setParam(fullScreenAllMonitorsCheckbox->value());
+
+  if (allMonitorsButton->value()) {
+    fullScreenMode.setParam("All");
+  } else {
+    fullScreenMode.setParam("Current");
+  }
 
   /* Misc. */
   shared.setParam(sharedCheckbox->value());
@@ -755,6 +765,7 @@ void OptionsDialog::createInputPage(int tx, int ty, int tw, int th)
 void OptionsDialog::createScreenPage(int tx, int ty, int tw, int th)
 {
   int x;
+  int width, height;
 
   Fl_Group *group = new Fl_Group(tx, ty, tw, th, _("Screen"));
 
@@ -783,15 +794,35 @@ void OptionsDialog::createScreenPage(int tx, int ty, int tw, int th)
   fullScreenCheckbox = new Fl_Check_Button(LBLRIGHT(tx, ty,
                                                   CHECK_MIN_WIDTH,
                                                   CHECK_HEIGHT,
-                                                  _("Full-screen mode")));
-  ty += CHECK_HEIGHT + TIGHT_MARGIN;
+                                                  _("Enable full-screen")));
+  ty += CHECK_HEIGHT + INNER_MARGIN;
 
-  fullScreenAllMonitorsCheckbox = new Fl_Check_Button(LBLRIGHT(tx + INDENT, ty,
-                                                      CHECK_MIN_WIDTH,
-                                                      CHECK_HEIGHT,
-                                                      _("Enable full-screen mode over all monitors")));
-  ty += CHECK_HEIGHT + TIGHT_MARGIN;
+  width = tw - OUTER_MARGIN * 2;
+  height = th - ty + OUTER_MARGIN * 3;
+    Fl_Group *fullScreenModeGroup = new Fl_Group(tx,
+                                     ty,
+                                     width,
+                                     height);
+
+  {
+    tx += INDENT;
+
+    currentMonitorButton = new Fl_Round_Button(LBLRIGHT(tx, ty,
+                                                        RADIO_MIN_WIDTH,
+                                                        RADIO_HEIGHT,
+                                                        _("Use current monitor")));
+    currentMonitorButton->type(FL_RADIO_BUTTON);
+    ty += RADIO_HEIGHT + TIGHT_MARGIN;
+
+    allMonitorsButton = new Fl_Round_Button(LBLRIGHT(tx, ty,
+                                            RADIO_MIN_WIDTH,
+                                            RADIO_HEIGHT,
+                                            _("Use all monitors")));
+    allMonitorsButton->type(FL_RADIO_BUTTON);
+    ty += RADIO_HEIGHT + TIGHT_MARGIN;
+  }
 
+  fullScreenModeGroup->end();
   group->end();
 }
 
diff --git a/vncviewer/OptionsDialog.h b/vncviewer/OptionsDialog.h
index fd3b9500..1c78ca16 100644
--- a/vncviewer/OptionsDialog.h
+++ b/vncviewer/OptionsDialog.h
@@ -125,7 +125,9 @@ protected:
   Fl_Int_Input *desktopHeightInput;
   Fl_Check_Button *remoteResizeCheckbox;
   Fl_Check_Button *fullScreenCheckbox;
-  Fl_Check_Button *fullScreenAllMonitorsCheckbox;
+
+  Fl_Round_Button *currentMonitorButton;
+  Fl_Round_Button *allMonitorsButton;
 
   /* Misc. */
   Fl_Check_Button *sharedCheckbox;
diff --git a/vncviewer/parameters.cxx b/vncviewer/parameters.cxx
index b28a1112..1525f13f 100644
--- a/vncviewer/parameters.cxx
+++ b/vncviewer/parameters.cxx
@@ -101,10 +101,13 @@ IntParameter qualityLevel("QualityLevel",
                           8);
 
 BoolParameter maximize("Maximize", "Maximize viewer window", false);
-BoolParameter fullScreen("FullScreen", "Full screen mode", false);
+BoolParameter fullScreen("FullScreen", "Enable full screen", false);
+StringParameter fullScreenMode("FullScreenMode", "Specify which monitors to use when in full screen. "
+                                                 "Should be either Current or All",
+                                                 "Current");
 BoolParameter fullScreenAllMonitors("FullScreenAllMonitors",
-                                    "Enable full screen over all monitors",
-                                    true);
+                                    "[DEPRECATED] Enable full screen over all monitors",
+                                    false);
 StringParameter desktopSize("DesktopSize",
                             "Reconfigure desktop size on the server on "
                             "connect (if possible)", "");
@@ -175,7 +178,7 @@ static VoidParameter* parameterArray[] = {
   &noJpeg,
   &qualityLevel,
   &fullScreen,
-  &fullScreenAllMonitors,
+  &fullScreenMode,
   &desktopSize,
   &remoteResize,
   &viewOnly,
@@ -190,6 +193,10 @@ static VoidParameter* parameterArray[] = {
   &fullscreenSystemKeys
 };
 
+static VoidParameter* readOnlyParameterArray[] = {
+  &fullScreenAllMonitors
+};
+
 // Encoding Table
 static struct {
   const char first;
@@ -399,6 +406,30 @@ static bool getKeyInt(const char* _name, int* dest, HKEY* hKey) {
   return true;
 }
 
+static bool removeValue(const char* _name, HKEY* hKey) {
+  const DWORD buffersize = 256;
+  wchar_t name[buffersize];
+
+  unsigned size = fl_utf8towc(_name, strlen(_name)+1, name, buffersize);
+  if (size >= buffersize) {
+    vlog.error(_("The name of the parameter %s was too large to remove from the registry"), _name);
+    return false;
+  }
+
+  LONG res = RegDeleteValueW(*hKey, name);
+  if (res != ERROR_SUCCESS) {
+    if (res == ERROR_FILE_NOT_FOUND) {
+      // The value does not exist, no need to remove it.
+      return true;
+    } else {
+      vlog.error(_("Failed to remove parameter %s from the registry: %ld"),
+                 _name, res);
+      return false;
+    }
+  }
+
+  return true;
+}
 
 void saveHistoryToRegKey(const vector<string>& serverHistory) {
   HKEY hKey;
@@ -456,6 +487,12 @@ static void saveToReg(const char* servername) {
     }
   }
 
+  // Remove read-only parameters to replicate the behaviour of Linux/macOS when they
+  // store a config to disk. If the parameter hasn't been migrated at this point it
+  // will be lost.
+  for (size_t i = 0; i < sizeof(readOnlyParameterArray)/sizeof(VoidParameter*); i++)
+    removeValue(readOnlyParameterArray[i]->getName(), &hKey);
+
   res = RegCloseKey(hKey);
   if (res != ERROR_SUCCESS) {
     vlog.error(_("Failed to close registry key: %ld"), res);
@@ -500,6 +537,29 @@ void loadHistoryFromRegKey(vector<string>& serverHistory) {
   }
 }
 
+static void findAndSetViewerParametersFromReg(VoidParameter* parameters[], size_t parameters_len, HKEY* hKey) {
+
+  const size_t buffersize = 256;
+  int intValue = 0;
+  char stringValue[buffersize];
+
+  for (size_t i = 0; i < parameters_len/sizeof(VoidParameter*); i++) {
+    if (dynamic_cast<StringParameter*>(parameters[i]) != NULL) {
+      if (getKeyString(parameters[i]->getName(), stringValue, buffersize, hKey))
+        parameters[i]->setParam(stringValue);
+    } else if (dynamic_cast<IntParameter*>(parameters[i]) != NULL) {
+      if (getKeyInt(parameters[i]->getName(), &intValue, hKey))
+        ((IntParameter*)parameters[i])->setParam(intValue);
+    } else if (dynamic_cast<BoolParameter*>(parameters[i]) != NULL) {
+      if (getKeyInt(parameters[i]->getName(), &intValue, hKey))
+        ((BoolParameter*)parameters[i])->setParam(intValue);
+    } else {
+      vlog.error(_("Unknown parameter type for parameter %s"),
+                 parameters[i]->getName());
+    }
+  }
+}
+
 static char* loadFromReg() {
 
   HKEY hKey;
@@ -523,24 +583,8 @@ static char* loadFromReg() {
   if (getKeyString("ServerName", servernameBuffer, buffersize, &hKey))
     snprintf(servername, buffersize, "%s", servernameBuffer);
   
-  int intValue = 0;
-  char stringValue[buffersize];
-  
-  for (size_t i = 0; i < sizeof(parameterArray)/sizeof(VoidParameter*); i++) {
-    if (dynamic_cast<StringParameter*>(parameterArray[i]) != NULL) {
-      if (getKeyString(parameterArray[i]->getName(), stringValue, buffersize, &hKey))
-        parameterArray[i]->setParam(stringValue);
-    } else if (dynamic_cast<IntParameter*>(parameterArray[i]) != NULL) {
-      if (getKeyInt(parameterArray[i]->getName(), &intValue, &hKey))
-        ((IntParameter*)parameterArray[i])->setParam(intValue);
-    } else if (dynamic_cast<BoolParameter*>(parameterArray[i]) != NULL) {
-      if (getKeyInt(parameterArray[i]->getName(), &intValue, &hKey))
-        ((BoolParameter*)parameterArray[i])->setParam(intValue);
-    } else {      
-      vlog.error(_("Unknown parameter type for parameter %s"),
-                 parameterArray[i]->getName());
-    }
-  }
+  findAndSetViewerParametersFromReg(parameterArray, sizeof(parameterArray), &hKey);
+  findAndSetViewerParametersFromReg(readOnlyParameterArray, sizeof(readOnlyParameterArray), &hKey);
 
   res = RegCloseKey(hKey);
   if (res != ERROR_SUCCESS){
@@ -607,6 +651,48 @@ void saveViewerParameters(const char *filename, const char *servername) {
   fclose(f);
 }
 
+static bool findAndSetViewerParameterFromValue(
+  VoidParameter* parameters[], size_t parameters_len,
+  char* value, char* line, int lineNr, char* filepath)
+{
+  const size_t buffersize = 256;
+  char decodingBuffer[buffersize];
+
+  // Find and set the correct parameter
+  for (size_t i = 0; i < parameters_len/sizeof(VoidParameter*); i++) {
+
+    if (dynamic_cast<StringParameter*>(parameters[i]) != NULL) {
+      if (strcasecmp(line, ((StringParameter*)parameters[i])->getName()) == 0) {
+
+        if(!decodeValue(value, decodingBuffer, sizeof(decodingBuffer))) {
+          vlog.error(_("Failed to read line %d in file %s: %s"),
+                      lineNr, filepath, _("Invalid format or too large value"));
+          continue;
+        }
+        ((StringParameter*)parameters[i])->setParam(decodingBuffer);
+        return false;
+      }
+
+    } else if (dynamic_cast<IntParameter*>(parameters[i]) != NULL) {
+      if (strcasecmp(line, ((IntParameter*)parameters[i])->getName()) == 0) {
+        ((IntParameter*)parameters[i])->setParam(atoi(value));
+        return false;
+      }
+
+    } else if (dynamic_cast<BoolParameter*>(parameters[i]) != NULL) {
+      if (strcasecmp(line, ((BoolParameter*)parameters[i])->getName()) == 0) {
+        ((BoolParameter*)parameters[i])->setParam(atoi(value));
+        return false;
+      }
+
+    } else {
+      vlog.error(_("Unknown parameter type for parameter %s"),
+                  parameters[i]->getName());
+    }
+  }
+
+  return true;
+}
 
 char* loadViewerParameters(const char *filename) {
 
@@ -705,38 +791,12 @@ char* loadViewerParameters(const char *filename) {
       invalidParameterName = false;
 
     } else {
+      invalidParameterName = findAndSetViewerParameterFromValue(parameterArray, sizeof(parameterArray),
+                                                                value, line, lineNr, filepath);
 
-      // Find and set the correct parameter
-      for (size_t i = 0; i < sizeof(parameterArray)/sizeof(VoidParameter*); i++) {
-
-        if (dynamic_cast<StringParameter*>(parameterArray[i]) != NULL) {
-          if (strcasecmp(line, ((StringParameter*)parameterArray[i])->getName()) == 0) {
-
-            if(!decodeValue(value, decodingBuffer, sizeof(decodingBuffer))) {
-              vlog.error(_("Failed to read line %d in file %s: %s"),
-                         lineNr, filepath, _("Invalid format or too large value"));
-              continue;
-            }
-            ((StringParameter*)parameterArray[i])->setParam(decodingBuffer);
-            invalidParameterName = false;
-          }
-
-        } else if (dynamic_cast<IntParameter*>(parameterArray[i]) != NULL) {
-          if (strcasecmp(line, ((IntParameter*)parameterArray[i])->getName()) == 0) {
-            ((IntParameter*)parameterArray[i])->setParam(atoi(value));
-            invalidParameterName = false;
-          }
-
-        } else if (dynamic_cast<BoolParameter*>(parameterArray[i]) != NULL) {
-          if (strcasecmp(line, ((BoolParameter*)parameterArray[i])->getName()) == 0) {
-            ((BoolParameter*)parameterArray[i])->setParam(atoi(value));
-            invalidParameterName = false;
-          }
-
-        } else {
-          vlog.error(_("Unknown parameter type for parameter %s"),
-                     parameterArray[i]->getName());
-        }
+      if (invalidParameterName) {
+        invalidParameterName = findAndSetViewerParameterFromValue(readOnlyParameterArray, sizeof(readOnlyParameterArray),
+                                                                  value, line, lineNr, filepath);
       }
     }
 
diff --git a/vncviewer/parameters.h b/vncviewer/parameters.h
index 3d8ac24f..fee37ee8 100644
--- a/vncviewer/parameters.h
+++ b/vncviewer/parameters.h
@@ -49,7 +49,8 @@ extern rfb::IntParameter qualityLevel;
 
 extern rfb::BoolParameter maximize;
 extern rfb::BoolParameter fullScreen;
-extern rfb::BoolParameter fullScreenAllMonitors;
+extern rfb::StringParameter fullScreenMode;
+extern rfb::BoolParameter fullScreenAllMonitors; // deprecated
 extern rfb::StringParameter desktopSize;
 extern rfb::StringParameter geometry;
 extern rfb::BoolParameter remoteResize;
diff --git a/vncviewer/vncviewer.cxx b/vncviewer/vncviewer.cxx
index bb41a2f7..6a84c7cb 100644
--- a/vncviewer/vncviewer.cxx
+++ b/vncviewer/vncviewer.cxx
@@ -435,6 +435,16 @@ potentiallyLoadConfigurationFile(char *vncServerName)
   }
 }
 
+static void
+migrateDeprecatedOptions()
+{
+  if (fullScreenAllMonitors) {
+    vlog.info(_("FullScreenAllMonitors is deprecated, set FullScreenMode to 'all' instead."));
+
+    fullScreenMode.setParam("all");
+  }
+}
+
 #ifndef WIN32
 static int
 interpretViaParam(char *remoteHost, int *remotePort, int localPort)
@@ -613,6 +623,8 @@ int main(int argc, char** argv)
   // Check if the server name in reality is a configuration file
   potentiallyLoadConfigurationFile(vncServerName);
 
+  migrateDeprecatedOptions();
+
   mkvnchomedir();
 
   CSecurity::upg = &dlg;
diff --git a/vncviewer/vncviewer.man b/vncviewer/vncviewer.man
index 868e6aeb..ff81b914 100644
--- a/vncviewer/vncviewer.man
+++ b/vncviewer/vncviewer.man
@@ -205,9 +205,15 @@ Maximize viewer window.
 Start in full-screen mode.
 .
 .TP
-.B \-FullScreenAllMonitors
+.B \-FullScreenAllMonitors (DEPRECATED)
 Use all local monitors and not just the current one when switching to
-full-screen mode.
+full-screen mode. Replaced by \fB-FullScreenMode=all\fP
+.
+.TP
+.B \-FullScreenMode \fImode\fP
+Specify which monitors to use when in full screen. It should be either "Current" or "All". 
+The default is "Current".
+.
 .
 .TP
 .B \-FullscreenSystemKeys