summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLudovic Courtès <ludo@gnu.org>2015-10-14 18:40:33 +0200
committerLudovic Courtès <ludo@gnu.org>2015-10-14 21:39:06 +0200
commit80a67734834a0981ca65cf1757a7d8408d02f1fd (patch)
tree4f622b3c5a725544736a75eaee52c6b4db6b29e0
parentc5d735f798e0e58774b9ce0c6197695bc6f0daa9 (diff)
services: Add 'dmd-service-back-edges'.
* gnu/services/dmd.scm (dmd-service-back-edges): New procedure. * tests/services.scm ("dmd-service-back-edges"): New test.
-rw-r--r--gnu/services/dmd.scm34
-rw-r--r--tests/services.scm10
2 files changed, 43 insertions, 1 deletions
diff --git a/gnu/services/dmd.scm b/gnu/services/dmd.scm
index 7b6434a0ae..e87b9e4415 100644
--- a/gnu/services/dmd.scm
+++ b/gnu/services/dmd.scm
@@ -27,7 +27,9 @@
#:use-module (gnu services)
#:use-module (gnu packages admin)
#:use-module (ice-9 match)
+ #:use-module (ice-9 vlist)
#:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:export (dmd-root-service-type
@@ -42,7 +44,9 @@
dmd-service-respawn?
dmd-service-start
dmd-service-stop
- dmd-service-auto-start?))
+ dmd-service-auto-start?
+
+ dmd-service-back-edges))
;;; Commentary:
;;;
@@ -179,4 +183,32 @@ failure."
(gexp->file "dmd.conf" config)))
+(define (dmd-service-back-edges services)
+ "Return a procedure that, when given a <dmd-service> from SERVICES, returns
+the list of <dmd-service> that depend on it."
+ (define provision->service
+ (let ((services (fold (lambda (service result)
+ (fold (cut vhash-consq <> service <>)
+ result
+ (dmd-service-provision service)))
+ vlist-null
+ services)))
+ (lambda (name)
+ (match (vhash-assq name services)
+ ((_ . service) service)
+ (#f #f)))))
+
+ (define edges
+ (fold (lambda (service edges)
+ (fold (lambda (requirement edges)
+ (vhash-consq (provision->service requirement) service
+ edges))
+ edges
+ (dmd-service-requirement service)))
+ vlist-null
+ services))
+
+ (lambda (service)
+ (vhash-foldq* cons '() service edges)))
+
;;; dmd.scm ends here
diff --git a/tests/services.scm b/tests/services.scm
index ae2d999fee..7d2e31b3a9 100644
--- a/tests/services.scm
+++ b/tests/services.scm
@@ -18,6 +18,7 @@
(define-module (test-services)
#:use-module (gnu services)
+ #:use-module (gnu services dmd)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
@@ -104,6 +105,15 @@
(fold-services (list s) #:target-type t1)
#f)))
+(test-assert "dmd-service-back-edges"
+ (let* ((s1 (dmd-service (provision '(s1)) (start #f)))
+ (s2 (dmd-service (provision '(s2)) (requirement '(s1)) (start #f)))
+ (s3 (dmd-service (provision '(s3)) (requirement '(s1 s2)) (start #f)))
+ (e (dmd-service-back-edges (list s1 s2 s3))))
+ (and (lset= eq? (e s1) (list s2 s3))
+ (lset= eq? (e s2) (list s3))
+ (null? (e s3)))))
+
(test-end)