Use stored commands for bindings

The preceding commit includes motivation; specifically,
invoking keyboard and mouse bindings should never fail
unless they perform an action which can fail. For instance,
a `bindcode Ctrl+9 exit` should always exit; of course,
`exec` may fail for external reasons.

The core changes are to bind.c and commands.c. As a single
command may actually, on being parsed, generate multiple
commands to be executed (consider `workspace 1; splith`),
the parsing code in execute_command is moved to a separate
function, parse_command, which returns a list_t of stored
commands; leaving execute_command to parse the command,
execute each resulting list element; and then cleanup.

An additional field for the list of parsed stored commands,
is added to struct sway_binding, usurping the name "command".
This is initialized via parse_command, and then
seat_execute_command is adjusted accordingly.

Side effects of this change include:
* Reference counting `struct criteria`, because a criterion
parsed once may apply to multiple stored commands, and
the alternative of duplicating criteria is even more
complicated.
* Adding reading and active arguments to config_handler,
because when bindsyms parse commands, they require handler
lookups to be performed as though it were runtime.
* Reference counting `struct sway_binding`, because the
alternative of updating sway_binding_dup is even more
complicated when allocation failures are be taken into
account.

include/sway/commands.h

@@ -47,7 +47,7 @@ struct cmd_results *checkarg(int argc, const char *name,
 		enum expected_args type, int val);
 
 struct cmd_handler *find_handler(char *line, struct cmd_handler *cmd_handlers,
-		int handlers_size);
+		int handlers_size, bool reading, bool active);
 /**
  * Parse and executes a command.
  */
@@ -56,10 +56,17 @@ struct cmd_results *execute_command(const char *command,  struct sway_seat *seat
 struct stored_command {
 	sway_cmd *handle;
 	int argc;
-	char** argv;
-	struct criteria* criteria;
+	char **argv;
+	struct criteria *criteria;
 };
+void free_stored_command(struct stored_command *command);
 
+/**
+ * Parses a command, and returns a list of stored_commands. If `for_runtime`
+ * is true, then command handler lookup is performed as though it were runtime;
+ * otherwise, as appropriate for the current `config` state.
+ */
+list_t *parse_command(const char *command, bool for_runtime);
 /**
  * Executes a pre-parsed command. (Returns NULL if command was not unsuccessful: TODO, fix)
  */

include/sway/config.h

@@ -38,7 +38,9 @@ enum binding_flags {
 };
 
 /**
- * A key binding and an associated command.
+ * A key binding and an associated command. In order to extend the lifetime
+ * of a binding slightly while executing the reload command, bindings are
+ * reference counted, and should only be freed if the reference count is <= 0.
  */
 struct sway_binding {
 	enum binding_input_type type;
@@ -46,15 +48,9 @@ struct sway_binding {
 	uint32_t flags;
 	list_t *keys; // sorted in ascending order
 	uint32_t modifiers;
-	char *command;
-};
-
-/**
- * A mouse binding and an associated command.
- */
-struct sway_mouse_binding {
-	uint32_t button;
-	char *command;
+	char *command_str; // original command string for IPC compatibility
+	list_t *command; // a preparsed list of struct stored_command
+	int refcount;
 };
 
 /**

include/sway/criteria.h

@@ -36,6 +36,9 @@ struct criteria {
 	bool tiling;
 	char urgent; // 'l' for latest or 'o' for oldest
 	char *workspace;
+	// optional refcount for users (like struct stored_command) for which
+	// a criterion may be referenced multiple times.
+	int refcount;
 };
 
 bool criteria_is_empty(struct criteria *criteria);