1 files changed, 82 insertions, 0 deletions
diff --git a/src/option.lisp b/src/option.lisp
new file mode 100644
index 0000000..6f9129c
--- /dev/null
+++ b/src/option.lisp
@@ -0,0 +1,82 @@
+;;;; Command line options.
+
+(in-package :extreload)
+
+;; Available command line options.
+(opts:define-opts
+  (:name :socket-url
+         :description "DevTools protocol WebSocket URL"
+         :long "socket-url"
+         :arg-parser #'identity
+         :meta-var "SOCKET_URL")
+  (:name :reload-current-tab
+         :description "pass this to reload the active Chrome tab"
+         :long "reload-current-tab")
+  (:name :debug
+         :description "print debug output"
+         :long "debug")
+  (:name :help
+         :description "print this help menu"
+         :short #\h
+         :long "help")
+  (:name :version
+         :description "show the program version"
+         :short #\V
+         :long "version"))
+
+(defmacro when-option ((options option) &body body)
+  "When `option` is present in `options`, run `body`."
+  `(let ((value (getf ,options ,option)))
+     (when value
+       ,@body)))
+
+(defun exit-with-error (condition exit-code)
+  "Print the error associated with `condition` on standard error, then exit
+with code `exit-code`."
+  (format *error-output* "error: ~a~%" condition)
+
+  (opts:exit exit-code))
+
+(defun handle-option-error (condition)
+  "Handle errors related to command line options. Prints the error specified by
+`condition` and exits with EX_USAGE."
+  (exit-with-error condition sysexits:+usage+))
+
+(defun parse-options ()
+  "Parse command line options."
+  (multiple-value-bind (options free-args)
+    (handler-bind
+      ((opts:unknown-option #'handle-option-error)
+       (opts:missing-arg #'handle-option-error)
+       (opts:arg-parser-failed #'handle-option-error)
+       (opts:missing-required-option #'handle-option-error))
+
+      (opts:get-opts))
+
+    (when-option (options :help)
+      (opts:describe
+        :usage-of "extreload"
+        :args "EXTENSION_ID...")
+
+      (opts:exit sysexits:+usage+))
+
+    (when-option (options :version)
+      (format t "~a~%" (asdf:component-version (asdf:find-system :extreload)))
+
+      (opts:exit sysexits:+ok+))
+
+    (when (null (getf options :socket-url))
+        (format *error-output* "error: '--socket-url' is required~%")
+
+        (opts:exit sysexits:+usage+))
+
+    ;; Error if no extension IDs were given.
+    (when (null free-args)
+      (format *error-output* "error: missing extension IDs~%")
+
+      (opts:exit sysexits:+usage+))
+
+    (make-config :socket-url (getf options :socket-url)
+                 :reload-current-tab (getf options :reload-current-tab)
+                 :debug-output (getf options :debug)
+                 :extension-ids free-args)))