@@ -196,21 +196,34 @@ (define (lines-to-first-change hunk)
(string-ref line 0)))
(hunk-diff-lines hunk))))
-(define (old-sexp hunk)
- "Using the diff information in HUNK return the unmodified S-expression
-corresponding to the top-level definition containing the staged changes."
- ;; TODO: We can't seek with a pipe port...
+(define %original-file-cache
+ (make-hash-table))
+
+(define (read-original-file file-name)
+ "Return the contents of FILE-NAME prior to any changes."
(let* ((port (open-pipe* OPEN_READ
"git" "cat-file" "-p" (string-append
- "HEAD:"
- (hunk-file-name hunk))))
+ "HEAD:" file-name)))
(contents (get-string-all port)))
(close-pipe port)
- (call-with-input-string contents
- (lambda (port)
- (surrounding-sexp port
- (+ (lines-to-first-change hunk)
- (hunk-old-line-number hunk)))))))
+ contents))
+
+(define (read-original-file* file-name)
+ "Caching variant of READ-ORIGINAL-FILE."
+ (or (hashv-ref %original-file-cache file-name)
+ (let ((value (read-original-file file-name)))
+ (hashv-set! %original-file-cache file-name value)
+ value)))
+
+(define (old-sexp hunk)
+ "Using the diff information in HUNK return the unmodified S-expression
+corresponding to the top-level definition containing the staged changes."
+ ;; TODO: We can't seek with a pipe port...
+ (call-with-input-string (read-original-file* (hunk-file-name hunk))
+ (lambda (port)
+ (surrounding-sexp port
+ (+ (lines-to-first-change hunk)
+ (hunk-old-line-number hunk))))))
(define (new-sexp hunk)
"Using the diff information in HUNK return the modified S-expression