3 files changed, 39 insertions, 3 deletions

diff --git a/include/sway/commands.h b/include/sway/commands.h
index 41858ccc..f83907b2 100644
--- a/include/sway/commands.h
+++ b/include/sway/commands.h
@@ -150,6 +150,7 @@ sway_cmd cmd_splitt;
 sway_cmd cmd_splitv;
 sway_cmd cmd_sticky;
 sway_cmd cmd_swaybg_command;
+sway_cmd cmd_swaynag_command;
 sway_cmd cmd_swap;
 sway_cmd cmd_title_format;
 sway_cmd cmd_unmark;
diff --git a/include/sway/config.h b/include/sway/config.h
index 909b6827..632aca14 100644
--- a/include/sway/config.h
+++ b/include/sway/config.h
@@ -7,6 +7,7 @@
 #include <wlr/types/wlr_box.h>
 #include <xkbcommon/xkbcommon.h>
 #include "list.h"
+#include "swaynag.h"
 #include "tree/layout.h"
 #include "tree/container.h"
 #include "wlr-layer-shell-unstable-v1-protocol.h"
@@ -308,6 +309,8 @@ enum focus_wrapping_mode {
  * The configuration struct. The result of loading a config file.
  */
 struct sway_config {
+        char *swaynag_command;
+        struct swaynag_instance swaynag_config_errors;
         list_t *symbols;
         list_t *modes;
         list_t *bars;
@@ -345,6 +348,7 @@ struct sway_config {
         bool failed;
         bool reloading;
         bool reading;
+        bool validating;
         bool auto_back_and_forth;
         bool show_marks;
 
@@ -403,17 +407,19 @@ struct sway_config {
  * Loads the main config from the given path. is_active should be true when
  * reloading the config.
  */
-bool load_main_config(const char *path, bool is_active);
+bool load_main_config(const char *path, bool is_active, bool validating);
 
 /**
  * Loads an included config. Can only be used after load_main_config.
  */
-bool load_include_configs(const char *path, struct sway_config *config);
+bool load_include_configs(const char *path, struct sway_config *config,
+                struct swaynag_instance *swaynag);
 
 /**
  * Reads the config from the given FILE.
  */
-bool read_config(FILE *file, struct sway_config *config);
+bool read_config(FILE *file, struct sway_config *config,
+                struct swaynag_instance *swaynag);
 
 /**
  * Free config struct
diff --git a/include/sway/swaynag.h b/include/sway/swaynag.h
new file mode 100644
index 00000000..5a178739
--- /dev/null
+++ b/include/sway/swaynag.h
@@ -0,0 +1,29 @@
+#ifndef _SWAY_SWAYNAG_H
+#define _SWAY_SWAYNAG_H
+
+struct swaynag_instance {
+        const char *args;
+        pid_t pid;
+        int fd[2];
+        bool detailed;
+};
+
+// Spawn swaynag. If swaynag->detailed, then swaynag->fd[1] will left open
+// so it can be written to. Call swaynag_show when done writing. This will
+// be automatically called by swaynag_log if the instance is not spawned and
+// swaynag->detailed is true.
+bool swaynag_spawn(const char *swaynag_command,
+                struct swaynag_instance *swaynag);
+
+// Kill the swaynag instance
+void swaynag_kill(struct swaynag_instance *swaynag);
+
+// Write a log message to swaynag->fd[1]. This will fail when swaynag->detailed
+// is false.
+void swaynag_log(const char *swaynag_command, struct swaynag_instance *swaynag,
+                const char *fmt, ...);
+
+// If swaynag->detailed, close swaynag->fd[1] so swaynag displays
+void swaynag_show(struct swaynag_instance *swaynag);
+
+#endif