Allow changing the layout of workspaces by storing it (Thanks mhcerri)

Before commit 4976fa3350, setting the
layout of workspaces to something else than the default would just mess
up the parent container of the workspace (the content container).

After that commit, it would create an unnecessary split container when
you change the layout _before_ opening any containers. To avoid this, we
now store the layout (similar to how the 'workspace_layout'
configuration directive works) and apply it when the first container is
attached to the workspace.

Fixes #796

include/data.h

@@ -514,6 +514,20 @@ struct Con {
     TAILQ_HEAD(swallow_head, Match) swallow_head;
 
     enum { CF_NONE = 0, CF_OUTPUT = 1, CF_GLOBAL = 2 } fullscreen_mode;
+    /* layout is the layout of this container: one of split[v|h], stacked or
+     * tabbed. Special containers in the tree (above workspaces) have special
+     * layouts like dockarea or output.
+     *
+     * last_split_layout is one of splitv or splith to support the old "layout
+     * default" command which by now should be "layout splitv" or "layout
+     * splith" explicitly.
+     *
+     * workspace_layout is only for type == CT_WORKSPACE cons. When you change
+     * the layout of a workspace without any children, i3 cannot just set the
+     * layout (because workspaces need to be splitv/splith to allow focus
+     * parent and opening new containers). Instead, it stores the requested
+     * layout in workspace_layout and creates a new split container with that
+     * layout whenever a new container is attached to the workspace. */
     enum {
         L_DEFAULT = 0,
         L_STACKED = 1,
@@ -522,7 +536,7 @@ struct Con {
         L_OUTPUT = 4,
         L_SPLITV = 5,
         L_SPLITH = 6
-    } layout, last_split_layout;
+    } layout, last_split_layout, workspace_layout;
     border_style_t border_style;
     /** floating? (= not in tiling layout) This cannot be simply a bool
      * because we want to keep track of whether the status was set by the

src/con.c

@@ -135,7 +135,7 @@ void con_attach(Con *con, Con *parent, bool ignore_focus) {
          */
         if (con->window != NULL &&
             parent->type == CT_WORKSPACE &&
-            config.default_layout != L_DEFAULT) {
+            parent->workspace_layout != L_DEFAULT) {
             DLOG("Parent is a workspace. Applying default layout...\n");
             Con *target = workspace_attach_to(parent);
 
@@ -1105,39 +1105,43 @@ void con_set_layout(Con *con, int layout) {
      * need to create a new split container. */
     if (con->type == CT_WORKSPACE &&
         (layout == L_STACKED || layout == L_TABBED)) {
-        DLOG("Creating new split container\n");
+        if (con_num_children(con) == 0) {
-        /* 1: create a new split container */
+            DLOG("Setting workspace_layout to %d\n", layout);
-        Con *new = con_new(NULL, NULL);
+            con->workspace_layout = layout;
-        new->parent = con;
+        } else {
+            DLOG("Creating new split container\n");
+            /* 1: create a new split container */
+            Con *new = con_new(NULL, NULL);
+            new->parent = con;
 
-        /* 2: Set the requested layout on the split container and mark it as
+            /* 2: Set the requested layout on the split container and mark it as
-         * split. */
+             * split. */
-        new->layout = layout;
+            new->layout = layout;
-        new->last_split_layout = con->last_split_layout;
+            new->last_split_layout = con->last_split_layout;
-        new->split = true;
+            new->split = true;
 
-        Con *old_focused = TAILQ_FIRST(&(con->focus_head));
+            Con *old_focused = TAILQ_FIRST(&(con->focus_head));
-        if (old_focused == TAILQ_END(&(con->focus_head)))
+            if (old_focused == TAILQ_END(&(con->focus_head)))
-            old_focused = NULL;
+                old_focused = NULL;
 
-        /* 3: move the existing cons of this workspace below the new con */
+            /* 3: move the existing cons of this workspace below the new con */
-        DLOG("Moving cons\n");
+            DLOG("Moving cons\n");
-        Con *child;
+            Con *child;
-        while (!TAILQ_EMPTY(&(con->nodes_head))) {
+            while (!TAILQ_EMPTY(&(con->nodes_head))) {
-            child = TAILQ_FIRST(&(con->nodes_head));
+                child = TAILQ_FIRST(&(con->nodes_head));
-            con_detach(child);
+                con_detach(child);
-            con_attach(child, new, true);
+                con_attach(child, new, true);
+            }
+
+            /* 4: attach the new split container to the workspace */
+            DLOG("Attaching new split to ws\n");
+            con_attach(new, con, false);
+
+            if (old_focused)
+                con_focus(old_focused);
+
+            tree_flatten(croot);
         }
-
-        /* 4: attach the new split container to the workspace */
-        DLOG("Attaching new split to ws\n");
-        con_attach(new, con, false);
-
-        if (old_focused)
-            con_focus(old_focused);
-
-        tree_flatten(croot);
-
         return;
     }
 

src/ipc.c

@@ -231,6 +231,23 @@ void dump_node(yajl_gen gen, struct Con *con, bool inplace_restart) {
             break;
     }
 
+    ystr("workspace_layout");
+    switch (con->workspace_layout) {
+        case L_DEFAULT:
+            ystr("default");
+            break;
+        case L_STACKED:
+            ystr("stacked");
+            break;
+        case L_TABBED:
+            ystr("tabbed");
+            break;
+        default:
+            DLOG("About to dump workspace_layout=%d (none of default/stacked/tabbed), this is a bug.\n", con->workspace_layout);
+            assert(false);
+            break;
+    }
+
     ystr("last_split_layout");
     switch (con->layout) {
         case L_SPLITV:

src/load_layout.c

@@ -211,6 +211,17 @@ static int json_string(void *ctx, const unsigned char *val, unsigned int len) {
                 json_node->layout = L_SPLITV;
             else LOG("Unhandled \"layout\": %s\n", buf);
             free(buf);
+        } else if (strcasecmp(last_key, "workspace_layout") == 0) {
+            char *buf = NULL;
+            sasprintf(&buf, "%.*s", (int)len, val);
+            if (strcasecmp(buf, "default") == 0)
+                json_node->workspace_layout = L_DEFAULT;
+            else if (strcasecmp(buf, "stacked") == 0)
+                json_node->workspace_layout = L_STACKED;
+            else if (strcasecmp(buf, "tabbed") == 0)
+                json_node->workspace_layout = L_TABBED;
+            else LOG("Unhandled \"workspace_layout\": %s\n", buf);
+            free(buf);
         } else if (strcasecmp(last_key, "last_split_layout") == 0) {
             char *buf = NULL;
             sasprintf(&buf, "%.*s", (int)len, val);

src/workspace.c

@@ -73,6 +73,7 @@ Con *workspace_get(const char *num, bool *created) {
         workspace->type = CT_WORKSPACE;
         FREE(workspace->name);
         workspace->name = sstrdup(num);
+        workspace->workspace_layout = config.default_layout;
         /* We set ->num to the number if this workspace’s name begins with a
          * positive number. Otherwise it’s a named ws and num will be -1. */
         char *endptr = NULL;
@@ -742,7 +743,7 @@ void ws_force_orientation(Con *ws, orientation_t orientation) {
 Con *workspace_attach_to(Con *ws) {
     DLOG("Attaching a window to workspace %p / %s\n", ws, ws->name);
 
-    if (config.default_layout == L_DEFAULT) {
+    if (ws->workspace_layout == L_DEFAULT) {
         DLOG("Default layout, just attaching it to the workspace itself.\n");
         return ws;
     }
@@ -754,7 +755,7 @@ Con *workspace_attach_to(Con *ws) {
     new->split = true;
 
     /* 2: set the requested layout on the split con */
-    new->layout = config.default_layout;
+    new->layout = ws->workspace_layout;
 
     /* 4: attach the new split container to the workspace */
     DLOG("Attaching new split %p to workspace %p\n", new, ws);

testcases/t/116-nestedcons.t

@@ -68,6 +68,7 @@ my $expected = {
     urgent => JSON::XS::false,
     border => 'normal',
     'floating_nodes' => $ignore,
+    workspace_layout => 'default',
 };
 
 # a shallow copy is sufficient, since we only ignore values at the root