Implement special value 'current' for output. (#2483)

This commit introduces the special 'current' value for outputs in both of

* move con to output current
* move workspace to output current

fixes #2357

src/commands.c

@@ -87,17 +87,6 @@ static bool definitelyGreaterThan(float a, float b, float epsilon) {
     return (a - b) > ((fabs(a) < fabs(b) ? fabs(b) : fabs(a)) * epsilon);
 }
 
-/*
- * Returns the output containing the given container.
- */
-static Output *get_output_of_con(Con *con) {
-    Con *output_con = con_get_output(con);
-    Output *output = get_output_by_name(output_con->name);
-    assert(output != NULL);
-
-    return output;
-}
-
 /*
  * Checks whether we switched to a new workspace and returns false in that case,
  * signaling that further workspace switching should be done by the calling function
@@ -1036,7 +1025,7 @@ void cmd_move_con_to_output(I3_CMD, const char *name) {
     TAILQ_FOREACH(current, &owindows, owindows) {
         DLOG("matching: %p / %s\n", current->con, current->con->name);
 
-        Output *current_output = get_output_of_con(current->con);
+        Output *current_output = get_output_for_con(current->con);
         assert(current_output != NULL);
 
         Output *output = get_output_from_string(current_output, name);
@@ -1648,7 +1637,7 @@ void cmd_focus_output(I3_CMD, const char *name) {
     Output *output;
 
     TAILQ_FOREACH(current, &owindows, owindows)
-    current_output = get_output_of_con(current->con);
+    current_output = get_output_for_con(current->con);
     assert(current_output != NULL);
 
     output = get_output_from_string(current_output, name);

src/move.c

@@ -101,8 +101,7 @@ static void attach_to_workspace(Con *con, Con *ws, direction_t direction) {
  */
 static void move_to_output_directed(Con *con, direction_t direction) {
     Con *old_ws = con_get_workspace(con);
-    Con *current_output_con = con_get_output(con);
-    Output *current_output = get_output_by_name(current_output_con->name);
+    Output *current_output = get_output_for_con(con);
     Output *output = get_output_next(direction, current_output, CLOSEST_OUTPUT);
 
     if (!output) {

src/output.c

@@ -31,18 +31,33 @@ Con *output_get_content(Con *output) {
  *
  */
 Output *get_output_from_string(Output *current_output, const char *output_str) {
-    Output *output;
+    if (strcasecmp(output_str, "current") == 0) {
+        return get_output_for_con(focused);
+    } else if (strcasecmp(output_str, "left") == 0) {
+        return get_output_next_wrap(D_LEFT, current_output);
+    } else if (strcasecmp(output_str, "right") == 0) {
+        return get_output_next_wrap(D_RIGHT, current_output);
+    } else if (strcasecmp(output_str, "up") == 0) {
+        return get_output_next_wrap(D_UP, current_output);
+    } else if (strcasecmp(output_str, "down") == 0) {
+        return get_output_next_wrap(D_DOWN, current_output);
+    }
 
-    if (strcasecmp(output_str, "left") == 0)
-        output = get_output_next_wrap(D_LEFT, current_output);
-    else if (strcasecmp(output_str, "right") == 0)
-        output = get_output_next_wrap(D_RIGHT, current_output);
-    else if (strcasecmp(output_str, "up") == 0)
-        output = get_output_next_wrap(D_UP, current_output);
-    else if (strcasecmp(output_str, "down") == 0)
-        output = get_output_next_wrap(D_DOWN, current_output);
-    else
-        output = get_output_by_name(output_str);
+    return get_output_by_name(output_str);
+}
+
+Output *get_output_for_con(Con *con) {
+    Con *output_con = con_get_output(con);
+    if (output_con == NULL) {
+        ELOG("Could not get the output container for con = %p.\n", con);
+        return NULL;
+    }
+
+    Output *output = get_output_by_name(output_con->name);
+    if (output == NULL) {
+        ELOG("Could not get output from name \"%s\".\n", output_con->name);
+        return NULL;
+    }
 
     return output;
 }

src/workspace.c

@@ -911,17 +911,12 @@ Con *workspace_encapsulate(Con *ws) {
 bool workspace_move_to_output(Con *ws, const char *name) {
     LOG("Trying to move workspace %p / %s to output \"%s\".\n", ws, ws->name, name);
 
-    Con *current_output_con = con_get_output(ws);
-    if (!current_output_con) {
-        ELOG("Could not get the output container for workspace %p / %s.\n", ws, ws->name);
-        return false;
-    }
-
-    Output *current_output = get_output_by_name(current_output_con->name);
-    if (!current_output) {
+    Output *current_output = get_output_for_con(ws);
+    if (current_output == NULL) {
         ELOG("Cannot get current output. This is a bug in i3.\n");
         return false;
     }
+
     Output *output = get_output_from_string(current_output, name);
     if (!output) {
         ELOG("Could not get output from string \"%s\"\n", name);