ambrevar/shell: Use magicffi and replace slow file-type function with fast ones.

.local/share/common-lisp/source/ambrevar/all.lisp

@@ -18,6 +18,7 @@
   (:import-from #:iolib)
   (:import-from #:local-time)
   (:import-from #:log4cl)
+  (:import-from #:magicffi)
   (:import-from #:mk-string-metrics)
   (:import-from #:moptilities)
   (:import-from #:osicat)

.local/share/common-lisp/source/ambrevar/shell.lisp

@@ -14,14 +14,37 @@
                    (delete-if #'sera:resolve-executable (cons program more-programs))))
     (error "Missing programs: ~{~a~,^, ~}" missing-programs)))
 
-(export-always 'file-type)
-(defun file-type (file)
-  "Return the file type, as per the `file' program."
-  ;; TODO: This is too slow, is there a pure Common Lisp equivalent?
-  (let ((type-string (second (str:split ": "
-                                        (run* "file" file)
-                                        :limit 2))))
-    (str:split ", " type-string)))
+
+(defvar %magic-cookie-mime-type (magicffi:magic-open '(:symlink :mime-type))
+  "Internal, persistent cookie for `magicffi' calls.
+
+Benchmark on thousands of files shows that
+keeping the same cookie saves about 15% of time.")
+(magicffi:magic-load %magic-cookie-mime-type)
+
+(defvar %magic-cookie-mime (magicffi:magic-open '(:symlink :mime))
+  "See `%magic-cookie-mime-type'. ")
+(magicffi:magic-load %magic-cookie-mime)
+
+(defvar %magic-cookie-description (magicffi:magic-open '(:symlink))
+  "See `%magic-cookie-mime-type'. ")
+(magicffi:magic-load %magic-cookie-description)
+
+(export-always 'file-mime-type)
+(defun file-mime-type (file)
+  "Return the FILE MIME type."
+  (magicffi:magic-file %magic-cookie-mime-type file))
+
+(export-always 'file-mime)
+(defun file-mime (file)
+  "Return a pair of MIME type and MIME encoding for FILE."
+  (str:split "; "
+   (magicffi:magic-file %magic-cookie-mime file)))
+
+(export-always 'file-description)
+(defun file-description (file)
+  "Return the FILE description as per the `file' UNIX command."
+  (magicffi:magic-file %magic-cookie-description file))
 
 (export-always 'file-extension)
 (defun file-extension (file)
@@ -81,13 +104,12 @@ Useful for `walk'."
 (export-always 'match-elf-binary)
 (defun match-elf-binary ()
   (lambda (file)
-    ;; (ppcre:scan "ELF.*executable" (first (file-type file)))
-    (string= "ELF 64-bit LSB executable" (first (file-type file)))))
+    (string= "application/x-executable" (file-mime-type file))))
 
 (export-always 'match-elf-library)
 (defun match-elf-library ()
   (lambda (file)
-    (ppcre:scan "ELF.*shared object" (first (file-type file)))))
+    (ppcre:scan "application/x-sharedlib" (first (file-type file)))))
 
 (export-always '*finder-include-directories*)
 (defvar *finder-include-directories* t