diff options
Diffstat (limited to 'guix/utils.scm')
| -rw-r--r-- | guix/utils.scm | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/guix/utils.scm b/guix/utils.scm index de541799fa..6c01edde21 100644 --- a/guix/utils.scm +++ b/guix/utils.scm @@ -41,6 +41,7 @@ #:use-module (ice-9 regex) #:use-module (ice-9 match) #:use-module (ice-9 format) + #:use-module ((ice-9 iconv) #:select (bytevector->string)) #:use-module (system foreign) #:export (bytevector->base16-string base16-string->bytevector @@ -60,6 +61,7 @@ location-line location-column source-properties->location + location->source-properties nix-system->gnu-triplet gnu-triplet->nix-system @@ -86,6 +88,7 @@ split cache-directory readlink* + edit-expression filtered-port compressed-port @@ -318,6 +321,44 @@ a list of command-line arguments passed to the compression program." (unless (every (compose zero? cdr waitpid) pids) (error "compressed-output-port failure" pids)))))) +(define* (edit-expression source-properties proc #:key (encoding "UTF-8")) + "Edit the expression specified by SOURCE-PROPERTIES using PROC, which should +be a procedure that takes the original expression in string and returns a new +one. ENCODING will be used to interpret all port I/O, it default to UTF-8. +This procedure returns #t on success." + (with-fluids ((%default-port-encoding encoding)) + (let* ((file (assq-ref source-properties 'filename)) + (line (assq-ref source-properties 'line)) + (column (assq-ref source-properties 'column)) + (in (open-input-file file)) + ;; The start byte position of the expression. + (start (begin (while (not (and (= line (port-line in)) + (= column (port-column in)))) + (when (eof-object? (read-char in)) + (error (format #f "~a: end of file~%" in)))) + (ftell in))) + ;; The end byte position of the expression. + (end (begin (read in) (ftell in)))) + (seek in 0 SEEK_SET) ; read from the beginning of the file. + (let* ((pre-bv (get-bytevector-n in start)) + ;; The expression in string form. + (str (bytevector->string + (get-bytevector-n in (- end start)) + (port-encoding in))) + (post-bv (get-bytevector-all in)) + (str* (proc str))) + ;; Verify the edited expression is still a scheme expression. + (call-with-input-string str* read) + ;; Update the file with edited expression. + (with-atomic-file-output file + (lambda (out) + (put-bytevector out pre-bv) + (display str* out) + ;; post-bv maybe the end-of-file object. + (when (not (eof-object? post-bv)) + (put-bytevector out post-bv)) + #t)))))) + ;;; ;;; Advisory file locking. @@ -767,7 +808,8 @@ elements after E." (define (cache-directory) "Return the cache directory for Guix, by default ~/.cache/guix." (or (getenv "XDG_CONFIG_HOME") - (and=> (getenv "HOME") + (and=> (or (getenv "HOME") + (passwd:dir (getpwuid (getuid)))) (cut string-append <> "/.cache/guix")))) (define (readlink* file) @@ -855,3 +897,10 @@ etc." ;; In accordance with the GCS, start line and column numbers at 1. Note ;; that unlike LINE and `port-column', COL is actually 1-indexed here... (location file (and line (+ line 1)) col))) + +(define (location->source-properties loc) + "Return the source property association list based on the info in LOC, +a location object." + `((line . ,(and=> (location-line loc) 1-)) + (column . ,(location-column loc)) + (filename . ,(location-file loc)))) |