add ram cache for project-server sessions

cache.rkt

@@ -1,5 +1,5 @@
 #lang racket/base
-(require racket/file file/cache sugar/coerce "project.rkt" "world.rkt" "rerequire.rkt")
+(require racket/path racket/file file/cache sugar/coerce "project.rkt" "world.rkt" "rerequire.rkt")
 
 ;; The cache is a hash with paths as keys.
 ;; The cache values are also hashes, with key/value pairs for that path.
@@ -7,21 +7,22 @@
 (provide reset-cache cached-require paths->key)
 
 
-(define (get-cache-dir)
+(define cache-dir
   (build-path (world:current-project-root) (world:current-cache-dir-name)))
 
 
 (define (reset-cache)
-  (cache-remove #f (get-cache-dir)))
+  (cache-remove #f cache-dir))
 
 
 (define (paths->key source-path [template-path #f])
   ;; key is list of file + mod-time pairs
-  (define path-strings (map (compose1 ->string ->complete-path)
-                            (append (list source-path)
-                                    (if template-path (list template-path) null)
-                                    (or (get-directory-require-files source-path) null))))
-  (map cons path-strings (map file-or-directory-modify-seconds path-strings)))
+  (define path-strings (append (list source-path)
+                        (if template-path (list template-path) null)
+                        (or (get-directory-require-files source-path) null)))
+  (define project-root (world:current-project-root))
+  (map (λ(ps) (define cp (->complete-path ps))
+         (cons (path->string (find-relative-path project-root cp)) (file-or-directory-modify-seconds cp))) path-strings))
 
 
 
@@ -40,6 +41,8 @@
           (world:current-meta-export) (dynamic-require path (world:current-meta-export)))))
 
 
+(define ram-cache (make-hash))
+
 (define (cached-require path-string subkey)  
   (define path (with-handlers ([exn:fail? (λ _ (error 'cached-require (format "~a is not a valid path" path-string)))])
                  (->complete-path path-string)))
@@ -49,14 +52,15 @@
   
   (cond
     [(world:current-compile-cache-active)
-     (define pickup-file (build-path (get-cache-dir) "pickup.rktd"))
-     (let ([key (paths->key path)])
-       (cache-file pickup-file
-                   #:exists-ok? #t
-                   key
-                   (get-cache-dir)
-                   (λ _ (write-to-file (path->hash path) pickup-file #:exists 'replace))
-                   #:max-cache-size (world:current-compile-cache-max-size)))
-     (hash-ref (file->value pickup-file) subkey)]
+     (define key (paths->key path))
+     (define pickup-file (build-path cache-dir "pickup.rktd"))
+     (hash-ref (hash-ref! ram-cache key (λ _
+                                          (cache-file pickup-file
+                                                      #:exists-ok? #t
+                                                      key
+                                                      cache-dir
+                                                      (λ _ (write-to-file (path->hash path) pickup-file #:exists 'replace))
+                                                      #:max-cache-size (world:current-compile-cache-max-size))
+                                          (file->value pickup-file))) subkey)]
     [else (parameterize ([current-namespace (make-base-namespace)])
             (dynamic-require path subkey))]))