Merge gaps support as-is

This code was copied over unmodified from https://github.com/Airblader/i3-gaps.

I have split out the differences between i3-gaps and i3 into three areas:
1. Gaps
2. i3bar height
3. rgba colors

6 files changed, 50 insertions, 3 deletions

diff --git a/include/commands.h b/include/commands.h
index d0f0140b..2ae2643c 100644
--- a/include/commands.h
+++ b/include/commands.h
@@ -333,6 +333,12 @@ void cmd_shmlog(I3_CMD, const char *argument);
 void cmd_debuglog(I3_CMD, const char *argument);
 
 /**
+ * Implementation of 'gaps inner|outer|top|right|bottom|left|horizontal|vertical current|all set|plus|minus|toggle <px>'
+ *
+ */
+void cmd_gaps(I3_CMD, const char *type, const char *scope, const char *mode, const char *value);
+
+/**
  * Implementation of 'title_window_icon <yes|no|toggle>' and 'title_window_icon <padding|toggle> <px>'
  *
  */
diff --git a/include/con.h b/include/con.h
index 8d344994..6577c2d6 100644
--- a/include/con.h
+++ b/include/con.h
@@ -526,6 +526,13 @@ void con_set_urgency(Con *con, bool urgent);
 char *con_get_tree_representation(Con *con);
 
 /**
+  * Calculates the effective gap sizes for a container depending
+  * on whether it is adjacent to the edge of the screen or another
+  * container.
+  */
+gaps_t calculate_effective_gaps(Con *con);
+
+/**
  * force parent split containers to be redrawn
  *
  */
diff --git a/include/config_directives.h b/include/config_directives.h
index 1cc0340f..600226e9 100644
--- a/include/config_directives.h
+++ b/include/config_directives.h
@@ -43,6 +43,9 @@ CFGFUN(include, const char *pattern);
 CFGFUN(font, const char *font);
 CFGFUN(exec, const char *exectype, const char *no_startup_id, const char *command);
 CFGFUN(for_window, const char *command);
+CFGFUN(gaps, const char *workspace, const char *type, const long value);
+CFGFUN(smart_borders, const char *enable);
+CFGFUN(smart_gaps, const char *enable);
 CFGFUN(floating_minimum_size, const long width, const long height);
 CFGFUN(floating_maximum_size, const long width, const long height);
 CFGFUN(default_orientation, const char *orientation);
diff --git a/include/configuration.h b/include/configuration.h
index 5eae5f87..99f4b64e 100644
--- a/include/configuration.h
+++ b/include/configuration.h
@@ -268,6 +268,15 @@ struct Config {
     int number_barconfigs;
 
     tiling_drag_t tiling_drag;
+
+    /* Gap sizes */
+    gaps_t gaps;
+
+    /* Should single containers on a workspace receive a border? */
+    smart_borders_t smart_borders;
+
+    /* Disable gaps if there is only one container on the workspace */
+    smart_gaps_t smart_gaps;
 };
 
 /**
diff --git a/include/data.h b/include/data.h
index 8078fd3e..67a573c2 100644
--- a/include/data.h
+++ b/include/data.h
@@ -47,6 +47,7 @@ typedef struct Con Con;
 typedef struct Match Match;
 typedef struct Assignment Assignment;
 typedef struct Window i3Window;
+typedef struct gaps_t gaps_t;
 typedef struct mark_t mark_t;
 
 /******************************************************************************
@@ -80,11 +81,20 @@ typedef enum { ADJ_NONE = 0,
                ADJ_UPPER_SCREEN_EDGE = (1 << 2),
                ADJ_LOWER_SCREEN_EDGE = (1 << 4) } adjacent_t;
 
+typedef enum { SMART_BORDERS_OFF,
+               SMART_BORDERS_ON,
+               SMART_BORDERS_NO_GAPS } smart_borders_t;
+
+typedef enum { SMART_GAPS_OFF,
+               SMART_GAPS_ON,
+               SMART_GAPS_INVERSE_OUTER } smart_gaps_t;
+
 typedef enum { HEBM_NONE = ADJ_NONE,
                HEBM_VERTICAL = ADJ_LEFT_SCREEN_EDGE | ADJ_RIGHT_SCREEN_EDGE,
                HEBM_HORIZONTAL = ADJ_UPPER_SCREEN_EDGE | ADJ_LOWER_SCREEN_EDGE,
                HEBM_BOTH = HEBM_VERTICAL | HEBM_HORIZONTAL,
-               HEBM_SMART = (1 << 5) } hide_edge_borders_mode_t;
+               HEBM_SMART = (1 << 5),
+               HEBM_SMART_NO_GAPS = (1 << 6) } hide_edge_borders_mode_t;
 
 typedef enum { MM_REPLACE,
                MM_ADD } mark_mode_t;
@@ -137,6 +147,14 @@ typedef enum {
     POINTER_WARPING_NONE = 1
 } warping_t;
 
+struct gaps_t {
+    int inner;
+    int top;
+    int right;
+    int bottom;
+    int left;
+};
+
 /**
  * Focus wrapping modes.
  */
@@ -204,12 +222,13 @@ struct deco_render_params {
 };
 
 /**
- * Stores which workspace (by name or number) goes to which output.
+ * Stores which workspace (by name or number) goes to which output and its gaps config.
  *
  */
 struct Workspace_Assignment {
     char *name;
     char *output;
+    gaps_t gaps;
 
     TAILQ_ENTRY(Workspace_Assignment) ws_assignments;
 };
@@ -645,6 +664,9 @@ struct Con {
      * workspace is not a named workspace (for named workspaces, num == -1) */
     int num;
 
+    /** Only applicable for containers of type CT_WORKSPACE. */
+    gaps_t gaps;
+
     struct Con *parent;
 
     /* The position and size for this con. These coordinates are absolute. Note
diff --git a/include/render.h b/include/render.h
index 03751c01..8500b71d 100644
--- a/include/render.h
+++ b/include/render.h
@@ -40,7 +40,7 @@ typedef struct render_params {
  * updated in X11.
  *
  */
-void render_con(Con *con);
+void render_con(Con *con, bool already_inset);
 
 /**
  * Returns the height for the decorations