branch: master
commit fe2b73c2353d106431ed0659345391f14ed64600
Author: Clément Lassieur <clem...@lassieur.org>
Date: Sun Sep 30 17:26:12 2018 +0200
database: Return #f when one row is expected and there is none.
* src/cuirass/database.scm (expect-one-row): New procedure.
(db-get-build, db-get-evaluations-id-min, db-get-evaluations-id-max,
db-get-builds-min, db-get-builds-max, db-get-evaluation-specification): Use
it.
---
src/cuirass/database.scm | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/src/cuirass/database.scm b/src/cuirass/database.scm
index e949d1b..25058b7 100644
--- a/src/cuirass/database.scm
+++ b/src/cuirass/database.scm
@@ -251,6 +251,13 @@ database object."
(vector-ref (car (sqlite-exec db "SELECT last_insert_rowid();"))
0))
+(define (expect-one-row rows)
+ "Several SQL queries expect one result, or zero if not found. This gets rid
+of the list, and returns #f when there is no result."
+ (match rows
+ ((row) row)
+ (() #f)))
+
(define (db-add-input spec-name input)
(with-db-critical-section db
(sqlite-exec db "\
@@ -621,10 +628,7 @@ ORDER BY ~a, rowid ASC;" order))
"Retrieve a build in the database which corresponds to DERIVATION-OR-ID."
(with-db-critical-section db
(let ((key (if (number? derivation-or-id) 'id 'derivation)))
- (match (db-get-builds `((,key . ,derivation-or-id)))
- ((build)
- build)
- (() #f)))))
+ (expect-one-row (db-get-builds `((,key . ,derivation-or-id)))))))
(define (db-get-pending-derivations)
"Return the list of derivation file names corresponding to pending builds in
@@ -705,7 +709,7 @@ ORDER BY E.id ASC;"))
(let ((rows (sqlite-exec db "
SELECT MIN(id) FROM Evaluations
WHERE specification=" spec)))
- (vector-ref (car rows) 0))))
+ (and=> (expect-one-row rows) (cut vector-ref <> 0)))))
(define (db-get-evaluations-id-max spec)
"Return the max id of evaluations for the given specification SPEC."
@@ -713,7 +717,7 @@ WHERE specification=" spec)))
(let ((rows (sqlite-exec db "
SELECT MAX(id) FROM Evaluations
WHERE specification=" spec)))
- (vector-ref (car rows) 0))))
+ (and=> (expect-one-row rows) (cut vector-ref <> 0)))))
(define (db-get-builds-min eval status)
"Return the min build (stoptime, rowid) pair for the given evaluation EVAL
@@ -732,7 +736,7 @@ AND (" status " IS NULL OR (" status " = 'pending'
AND Builds.status = 0)
OR (" status " = 'failed'
AND Builds.status > 0))))")))
- (vector->list (car rows)))))
+ (and=> (expect-one-row rows) vector->list))))
(define (db-get-builds-max eval status)
"Return the max build (stoptime, rowid) pair for the given evaluation EVAL
@@ -751,7 +755,7 @@ AND (" status " IS NULL OR (" status " = 'pending'
AND Builds.status = 0)
OR (" status " = 'failed'
AND Builds.status > 0))))")))
- (vector->list (car rows)))))
+ (and=> (expect-one-row rows) vector->list))))
(define (db-get-evaluation-specification eval)
"Return specification of evaluation with id EVAL."
@@ -759,6 +763,4 @@ AND (" status " IS NULL OR (" status " = 'pending'
(let ((rows (sqlite-exec db "
SELECT specification FROM Evaluations
WHERE id = " eval)))
- (match rows
- ((row) (vector-ref row 0))
- (() #f)))))
+ (and=> (expect-one-row rows) (cut vector-ref <> 0)))))
