scratch/native-comp-eln-caches 94666b0 4/6: * Memoize eln cache dirs content during search to access those once

[Andrea Corallo]

branch: scratch/native-comp-eln-caches
commit 94666b0a2b5e17dc93cd09378845efba9102ba88
Author: Andrea Corallo <akrl@sdf.org>
Commit: Andrea Corallo <akrl@sdf.org>

    * Memoize eln cache dirs content during search to access those once
    
        * src/lread.c (openp): Define an a-list 'eln_caches_mem' and
        use it in order to memoize the eln cache dirs content.
---
 src/lread.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/lread.c b/src/lread.c
index 4ab21ab..7b1e43b 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1672,6 +1672,11 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object 
suffixes,
   if (NILP (path))
     path = just_use_str;
 
+#ifdef HAVE_NATIVE_COMP
+  /* A-list eln cache dir -> contentained files.  */
+  Lisp_Object eln_caches_mem = Qnil;
+#endif
+
   /* Go through all entries in the path and see whether we find the
      executable. */
   FOR_EACH_TAIL_SAFE (path)
@@ -1746,22 +1751,36 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object 
suffixes,
 #ifdef HAVE_NATIVE_COMP
        if (suffix_p (string, ".elc"))
          {
-           /* Search eln in the eln-cache directories.  */
+           /* Search for a matching eln file in the eln-cache
+              directories.  If a suitable eln is found replace the
+              value of 'string' with it to have it loaded.  */
            Lisp_Object eln_path_tail = Vcomp_eln_load_path;
            FOR_EACH_TAIL_SAFE (eln_path_tail)
              {
+               Lisp_Object dir =
+                 concat2 (XCAR (eln_path_tail), Vcomp_native_path_postfix);
                Lisp_Object el_name =
                  Fsubstring (string, Qnil, make_fixnum (-1));
                Lisp_Object eln_name =
                  Fcomp_el_to_eln_filename (el_name, XCAR (eln_path_tail));
-               /* FIXME memoize using Fdirectory_files */
-               if (!NILP (Ffile_exists_p (eln_name))
+               Lisp_Object eln_name_nodir = Ffile_name_nondirectory (eln_name);
+               Lisp_Object files = CDR_SAFE (Fassoc (dir, eln_caches_mem, 
Qnil));
+               if (NILP (files))
+                 {
+                   if (NILP (Ffile_exists_p (dir)))
+                     files = Qt;
+                   else
+                     files = Fdirectory_files (dir, Qnil, Qnil, Qt);
+                   eln_caches_mem =
+                     Fcons (Fcons (dir, files), eln_caches_mem);
+                 }
+               if (CONSP (files)
+                   && !NILP (Fmember (eln_name_nodir, files))
                    && !NILP (Ffile_newer_than_file_p (eln_name, string)))
                  {
                    string = eln_name;
                    /* Store the eln -> el relation.  */
-                   Fputhash (Ffile_name_nondirectory (eln_name),
-                             el_name, Vcomp_eln_to_el_h);
+                   Fputhash (eln_name_nodir, el_name, Vcomp_eln_to_el_h);
                    break;
                  }
              }