racket/collects/db/private/generic/interfaces.rkt
2012-12-05 12:19:16 -05:00

324 lines
10 KiB
Racket

#lang racket/base
(require racket/class
racket/serialize
unstable/error)
(provide connection<%>
dbsystem<%>
prepared-statement<%>
connection?
dbsystem?
prepared-statement?
(struct-out statement-binding)
(struct-out simple-result)
(struct-out rows-result)
(struct-out cursor-result)
init-private
log-db-error
log-db-warning
log-db-info
log-db-debug
(struct-out exn:fail:sql)
raise-sql-error)
;; ----------------------------------------
;; Interfaces
;; connection<%>
(define connection<%>
(interface ()
;; connected? method must return promptly (eg, without acquiring lock)
connected? ;; -> boolean
disconnect ;; -> void
get-dbsystem ;; -> dbsystem<%>
query ;; symbol statement -> QueryResult
prepare ;; symbol preparable boolean -> prepared-statement<%>
fetch/cursor ;; symbol cursor nat -> #f or (listof vector)
get-base ;; -> connection<%> or #f (#f means base isn't fixed)
list-tables ;; symbol symbol -> (listof string)
;; in start-tx and end-tx, the final boolean arg indicates whether the
;; transaction is managed manually (#f) or by call-with-tx (#t)
start-transaction ;; symbol (U 'serializable ...) any boolean -> void
end-transaction ;; symbol (U 'commit 'rollback) boolean -> void
transaction-status ;; symbol -> (U boolean 'invalid)
free-statement)) ;; prepared-statement<%> boolean -> void
;; dbsystem<%>
;; Represents brand of database system, SQL dialect, etc
(define dbsystem<%>
(interface ()
get-short-name ;; -> symbol
get-parameter-handlers ;; (listof typeid) -> (listof ParameterHandler)
field-dvecs->typeids ;; (listof field-dvec) -> (listof typeid)
;; inspection only
get-known-types ;; real -> (listof symbol)
describe-params ;; (listof typeid) -> (listof TypeDesc)
describe-fields)) ;; (listof field-dvec) -> (listof TypeDesc)
;; ParameterHandler = (fsym index datum -> ???)
;; Each system gets to choose its checked-param representation.
;; Maybe check and convert to string. Maybe just check, do binary conversion later.
;; TypeDesc = (list boolean symbol/#f typeid)
;; prepared-statement<%>
(define prepared-statement<%>
(interface ()
get-handle ;; -> Handle (depends on database system)
set-handle ;; Handle -> void
get-close-on-exec? ;; -> boolean
after-exec ;; boolean -> void (for close-on-exec)
get-stmt ;; -> string/#f
get-stmt-type ;; -> symbol/#f
get-param-count ;; -> nat
get-param-typeids ;; -> (listof typeid)
get-result-dvecs ;; -> (listof field-dvec)
get-result-count ;; -> nat
get-result-typeids ;; -> (listof typeid)
check-owner ;; symbol connection any -> #t (or error)
bind ;; symbol (listof param) -> statement-binding
;; inspection only
get-param-types ;; -> (listof TypeDesc)
get-result-types ;; -> (listof TypeDesc)
))
(define (connection? x)
(is-a? x connection<%>))
(define (dbsystem? x)
(is-a? x dbsystem<%>))
(define (prepared-statement? x)
(is-a? x prepared-statement<%>))
;; ----------------------------------------
;; Auxiliary structures
;; A statement-binding is:
;; - (statement-binding prepared-statement (listof ???))
(struct statement-binding (pst params))
;; An query-result is one of:
;; - (simple-result alist)
;; - (rows-result Header data)
;; for user-visible rows-results: headers present, data is (listof vector)
(serializable-struct simple-result (info) #:transparent)
(serializable-struct rows-result (headers rows) #:transparent)
;; A cursor-result is
;; - (cursor-result Header prepared-statement ???)
(struct cursor-result (headers pst extra))
;; A Header is (listof FieldInfo)
;; A FieldInfo is an alist, contents dbsys-dependent
;; ----------------------------------------
;; Class utilities
;; Here just because ...
(define-syntax-rule (init-private iid ...)
(begin (init-private1 iid) ...))
(define-syntax-rule (init-private1 iid)
(begin (init ([private-iid iid]))
(define iid private-iid)))
;; ----------------------------------------
;; Logging
(define-logger db)
;; ----------------------------------------
;; Exceptions
#|
Only errors with an associated SQLSTATE are represented by
exn:fail:sql, specifically only errors originating from a database
backend or library. Other errors are typically raised using 'error',
producing plain old exn:fail.
For SQLite, use symbol instead of SQLSTATE string.
|#
;; exn:fail:sql
;; Represents an error with an associated SQLSTATE
(define-struct (exn:fail:sql exn:fail) (sqlstate info))
;; raise-sql-error : symbol string string alist -> raises exn
(define (raise-sql-error who sqlstate message info)
(raise
(make-exn:fail:sql (compose-error-message who message
"SQLSTATE" sqlstate)
(current-continuation-marks)
sqlstate
info)))
;; ----------------------------------------
;; Common Errors
(provide error/internal
error/internal*
error/not-connected
error/no-support
error/need-password
error/comm
error/hopeless
error/unsupported-type
error/no-convert
error/invalid-nested-isolation
error/tx-bad-stmt
error/unbalanced-tx
error/unclosed-tx
error/nested-tx-option
error/exn-in-rollback
error/stmt-arity
error/stmt
error/want-rows
error/want-cursor
error/column-count
error/row-count
error/statement-binding-args)
(define (error/internal fsym fmt . args)
(raise-misc-error fsym "internal error"
#:continued (apply format fmt args)))
(define (error/internal* fsym msg . args)
(apply raise-misc-error fsym "internal error" #:continued msg args))
;; FIXME; clean up
(define (error/comm fsym [when-occurred #f])
(raise-misc-error fsym "communication failure"
"when" when-occurred))
(define (error/no-support fsym feature)
(raise-misc-error fsym "feature not supported"
"feature" feature))
(define (error/hopeless fsym)
(error fsym "connection is permanently locked due to a terminated thread"))
(define (error/not-connected fsym)
(error fsym "not connected"))
;; ----
(define (error/invalid-nested-isolation fsym isolation)
(raise-misc-error fsym "invalid isolation level for nested transaction"
'("isolation level" value) isolation))
(define (error/unbalanced-tx fsym mode saved-cwt?)
(error fsym "~a-transaction without matching start-transaction~a"
mode (if saved-cwt? " (within the extent of call-with-transaction)" "")))
(define (error/unclosed-tx fsym mode saved-cwt?)
(error fsym "unclosed nested transaction~a"
(if saved-cwt? " (within extent of call-with-transaction)" "")))
(define (error/tx-bad-stmt fsym stmt-type-string tx-state)
(raise-misc-error fsym "statement not allowed in current transaction state"
"statement type" stmt-type-string
"transaction state" tx-state))
(define (error/nested-tx-option fsym option)
(raise-misc-error fsym "option not allowed for nested transaction"
'("option" value) option))
(define (error/exn-in-rollback fsym e1 e2)
(raise-misc-error fsym "error during rollback"
#:continued "secondary error occurred during rollback triggered by primary error"
'("primary" value) (exn-message e1)
'("secondary" value) (exn-message e2)))
;; ----
(define (error/stmt-arity fsym expected given)
(raise-misc-error fsym "wrong number of parameters for query"
;; FIXME: add stmt, use error/stmt
"expected" expected
"given" given))
;; ----
(define (error/need-password fsym)
(error fsym "password needed but not supplied"))
;; ----
(define (error/unsupported-type fsym typeid [type #f])
(raise-misc-error fsym "unsupported type"
"type" type
"typeid" typeid))
(define (error/no-convert fsym sys type param [note #f] #:contract [ctc #f])
(raise-misc-error fsym "cannot convert given value to SQL type"
'("given" value) param
"type" type
"expected" (and ctc (format "~.s" ctc))
"dialect" sys
"note" note))
;; ----
(define (error/stmt fsym stmt message . args)
(apply raise-misc-error fsym message
'("statement" value) (or (let loop ([stmt stmt])
(cond [(string? stmt) stmt]
[(statement-binding? stmt) (loop (statement-binding-pst stmt))]
[(prepared-statement? stmt) (loop (send stmt get-stmt))]
[else #f]))
stmt)
;; FIXME: include params from statement-binding values?
;; must first change statement-binding to store raw params
args))
(define (error/want-rows fsym sql executed?)
(error/stmt fsym sql
(if executed?
"query did not return rows"
"query does not return rows")))
(define (error/want-cursor fsym sql)
(error/stmt fsym sql "query did not return cursor"))
(define (error/column-count fsym sql want-columns got-columns executed?)
(error/stmt fsym sql
(if executed?
"query returned wrong number of columns"
"query returns wrong number of columns")
"expected" want-columns
"got" got-columns))
(define (error/row-count fsym sql want-rows got-rows)
(error/stmt fsym sql "query returned wrong number of rows"
"expected" want-rows
"got" got-rows))
(define (error/statement-binding-args fsym stmt args)
(raise-misc-error fsym
"cannot execute statement-binding with additional inline arguments"
'("statement" value) stmt
'("arguments" value) args))