Add backandforth attribute to Desktops tag

jwm.1.in

@@ -1870,6 +1870,15 @@ The number of virtual desktops in the vertical direction.
 The default is 1.
 .RE
 .P
+\fBbackandforth\fP \fIstring\fP
+.RS
+Controls whether changing the desktop to the currently active desktop using
+the \fBdesktop#\fP action should instead switch to the previously active
+desktop.
+Default is "off" to do nothing when switching to the currently active desktop.
+Possible values are "on" and "off".
+.RE
+.P
 Within the \fBDesktops\fP tag the following tags are supported:
 .P
 .B Background

src/client.c

@@ -49,6 +49,7 @@ void StartupClients(void)
    clientCount = 0;
    activeClient = NULL;
    currentDesktop = 0;
+   previousDesktop = 0;
 
    /* Clear out the client lists. */
    for(x = 0; x < LAYER_COUNT; x++) {

src/desktop.c

@@ -192,6 +192,7 @@ void ChangeDesktop(unsigned int desktop)
       }
    }
 
+   previousDesktop = currentDesktop;
    currentDesktop = desktop;
 
    SetCardinalAtom(rootWindow, ATOM_NET_CURRENT_DESKTOP, currentDesktop);

src/event.c

@@ -480,12 +480,18 @@ void ProcessBinding(MouseContextType context, ClientNode *np,
 {
    const ActionType key = GetKey(context, state, code);
    const char keyAction = context == MC_NONE;
+   unsigned int desktop;
    switch(key.action) {
    case ACTION_EXEC:
       RunKeyCommand(context, state, code);
       break;
    case ACTION_DESKTOP:
-      ChangeDesktop(key.extra);
+      desktop = key.extra;
+      if(currentDesktop == desktop &&
+         settings.desktopBackAndForth) {
+           desktop = previousDesktop;
+      }
+      ChangeDesktop(desktop);
       break;
    case ACTION_RDESKTOP:
       RightDesktop();

src/main.c

@@ -63,6 +63,7 @@ char initializing = 0;
 char shouldReload = 0;
 
 unsigned int currentDesktop = 0;
+unsigned int previousDesktop = 0;
 
 char *exitCommand = NULL;
 

src/main.h

@@ -25,6 +25,7 @@ extern Atom managerSelection;
 extern char *exitCommand;
 
 extern unsigned int currentDesktop;
+extern unsigned int previousDesktop;
 
 extern char shouldExit;
 extern char shouldRestart;

src/parse.c

@@ -1097,14 +1097,23 @@ void ParseInclude(const TokenNode *tp, int depth)
 
 /** Parse desktop configuration. */
 void ParseDesktops(const TokenNode *tp) {
-
+
+   static const StringMappingType mapping[] = {
+      { "off",       DBACKANDFORTH_OFF },
+      { "on",        DBACKANDFORTH_ON  }
+   };
    TokenNode *np;
    const char *width;
    const char *height;
    int desktop;
+   DesktopBackAndForthType backandforth;
 
    Assert(tp);
 
+   backandforth = ParseAttribute(mapping, ARRAY_LENGTH(mapping), tp,
+                                 "backandforth", DBACKANDFORTH_OFF);
+   settings.desktopBackAndForth = backandforth;
+
    width = FindAttribute(tp->attributes, WIDTH_ATTRIBUTE);
    if(width != NULL) {
       settings.desktopWidth = ParseUnsigned(tp, width);

src/settings.c

@@ -51,6 +51,7 @@ void InitializeSettings(void)
    settings.titleTextAlignment = ALIGN_LEFT;
    settings.desktopWidth = 4;
    settings.desktopHeight = 1;
+   settings.desktopBackAndForth = DBACKANDFORTH_OFF;
    settings.menuOpacity = UINT_MAX;
    settings.windowDecorations = DECO_FLAT;
    settings.trayDecorations = DECO_FLAT;

src/settings.h

@@ -79,6 +79,11 @@ typedef unsigned char MouseContextType;
 #define MC_BORDER_E        0x40  /**< East border. */
 #define MC_BORDER_W        0x80  /**< West border. */
 
+/** Enumeration of desktop back and forth values. */
+typedef unsigned char DesktopBackAndForthType;
+#define DBACKANDFORTH_OFF 0 /**< No back and forth */
+#define DBACKANDFORTH_ON  1 /**< Enable back and forth */
+
 /** Maximimum number of title bar components
  * For now, we allow each component to be used twice. */
 #define TBC_COUNT       9
@@ -117,6 +122,7 @@ typedef struct {
    MouseContextType titleBarLayout[TBC_COUNT + 1];
    char groupTasks;
    char listAllTasks;
+   DesktopBackAndForthType desktopBackAndForth;
 } Settings;
 
 extern Settings settings;