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postgresql.scm @ 14765

Revision 14765, 30.4 KB (checked in by sjamaan, 16 months ago)
Rename to remove obnoxious result- prefix from procedures that happened to take a result object

Line
1	;;; Bindings to the PostgreSQL C library
2	;;
3	;; Copyright (C) 2008-2009 Peter Bex
4	;; Copyright (C) 2004 Johannes Grødem <johs@copyleft.no>
5	;; Redistribution and use in source and binary forms, with or without
6	;; modification, is permitted.
7	;;
8	;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
9	;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
10	;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
11	;; ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
12	;; LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
13	;; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
14	;; OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
15	;; BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
16	;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
17	;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
18	;; USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
19	;; DAMAGE.
20
21	(module postgresql
22	(update-type-parsers! default-type-parsers
23	char-parser bool-parser bytea-parser numeric-parser
24	update-type-unparsers! default-type-unparsers
25	bool-unparser
26
27	connect reset-connection disconnect connection?
28
29	exec-simple-queries exec-query
30
31	result? clear-result! row-count column-count
32	column-index column-name column-names column-format
33	column-type column-type-modifier table-oid table-column-index
34	value-at row-values row-alist column-values affected-rows inserted-oid
35
36	invalid-oid
37
38	escape-string escape-bytea unescape-bytea
39
40	query-fold query-fold* query-fold-right query-fold-right*
41	query-for-each query-for-each* query-map query-map*)
42
43	(import chicken scheme foreign)
44
45	(require-extension srfi-1 srfi-4 srfi-13 srfi-18 srfi-69
46	extras data-structures sql-null)
47
48	(foreign-declare "#include <libpq-fe.h>")
49
50	(define-foreign-type pg-polling-status (enum "PostgresPollingStatusType"))
51	(define-foreign-variable PGRES_POLLING_FAILED pg-polling-status)
52	(define-foreign-variable PGRES_POLLING_READING pg-polling-status)
53	(define-foreign-variable PGRES_POLLING_WRITING pg-polling-status)
54	(define-foreign-variable PGRES_POLLING_OK pg-polling-status)
55
56	(define-foreign-type pg-exec-status (enum "ExecStatusType"))
57	(define-foreign-variable PGRES_EMPTY_QUERY pg-exec-status)
58	(define-foreign-variable PGRES_COMMAND_OK pg-exec-status)
59	(define-foreign-variable PGRES_TUPLES_OK pg-exec-status)
60	(define-foreign-variable PGRES_COPY_OUT pg-exec-status)
61	(define-foreign-variable PGRES_COPY_IN pg-exec-status)
62	(define-foreign-variable PGRES_BAD_RESPONSE pg-exec-status)
63	(define-foreign-variable PGRES_NONFATAL_ERROR pg-exec-status)
64	(define-foreign-variable PGRES_FATAL_ERROR pg-exec-status)
65
66	;(define-foreign-type pgconn* (c-pointer "PGconn"))
67	(define-foreign-type pgconn* c-pointer)
68
69	(define PQconnectStart (foreign-lambda pgconn* PQconnectStart (const c-string)))
70	(define PQconnectPoll (foreign-lambda pg-polling-status PQconnectPoll pgconn*))
71	(define PQresetStart (foreign-lambda bool PQresetStart pgconn*))
72	(define PQresetPoll (foreign-lambda pg-polling-status PQresetPoll pgconn*))
73	(define PQfinish (foreign-lambda void PQfinish pgconn*))
74	(define PQstatus (foreign-lambda (enum "ConnStatusType") PQstatus (const pgconn*)))
75	(define PQerrorMessage (foreign-lambda c-string PQerrorMessage (const pgconn*)))
76
77	;(define-foreign-type oid "Oid")
78	(define-foreign-type oid unsigned-int)
79
80	(define invalid-oid (foreign-value "InvalidOid" oid))
81
82	(define PQisBusy (foreign-lambda bool PQisBusy pgconn*))
83	(define PQconsumeInput (foreign-lambda bool PQconsumeInput pgconn*))
84
85	(define-foreign-type pgresult* (c-pointer "PGresult"))
86
87	(define PQgetResult (foreign-lambda pgresult* PQgetResult pgconn*))
88	(define PQresultStatus (foreign-lambda pg-exec-status PQresultStatus (const pgresult*)))
89	(define PQresultErrorMessage (foreign-lambda c-string PQresultErrorMessage (const pgresult*)))
90	(define PQresultErrorField (foreign-lambda c-string PQresultErrorField (const pgresult*) int))
91
92	(define PQclear (foreign-lambda void PQclear pgresult*))
93	(define PQntuples (foreign-lambda int PQntuples (const pgresult*)))
94	(define PQnfields (foreign-lambda int PQnfields (const pgresult*)))
95	(define PQfname (foreign-lambda c-string PQfname (const pgresult*) int))
96	(define PQfnumber (foreign-lambda int PQfnumber (const pgresult*) (const c-string)))
97	(define PQftable (foreign-lambda oid PQftable (const pgresult*) int))
98	(define PQftablecol (foreign-lambda int PQftablecol (const pgresult*) int))
99	(define PQfformat (foreign-lambda int PQfformat (const pgresult*) int))
100	(define PQftype (foreign-lambda oid PQftype (const pgresult*) int))
101	(define PQfmod (foreign-lambda int PQfmod (const pgresult*) int))
102	(define PQgetisnull (foreign-lambda bool PQgetisnull (const pgresult*) int int))
103	(define PQcmdTuples (foreign-lambda nonnull-c-string PQcmdTuples pgresult*))
104	(define PQoidValue (foreign-lambda oid PQoidValue pgresult*))
105
106	;; TODO: Create a real callback system?
107	(foreign-declare "static void nullNoticeReceiver(void arg, const PGresult res){ }")
108
109	(define-syntax define-foreign-int
110	(er-macro-transformer
111	(lambda (e r c)
112	;; cannot rename define-foreign-variable; it's a really special form
113	`(define-foreign-variable ,(cadr e) int ,(conc "(int) " (cadr e))))))
114
115	(define-foreign-int PG_DIAG_SEVERITY)
116	(define-foreign-int PG_DIAG_SQLSTATE)
117	(define-foreign-int PG_DIAG_MESSAGE_PRIMARY)
118	(define-foreign-int PG_DIAG_MESSAGE_DETAIL)
119	(define-foreign-int PG_DIAG_MESSAGE_HINT)
120	(define-foreign-int PG_DIAG_STATEMENT_POSITION)
121	(define-foreign-int PG_DIAG_CONTEXT)
122	(define-foreign-int PG_DIAG_SOURCE_FILE)
123	(define-foreign-int PG_DIAG_SOURCE_LINE)
124	(define-foreign-int PG_DIAG_SOURCE_FUNCTION)
125
126	(define (postgresql-error loc message . args)
127	(signal (make-pg-condition loc message args: args)))
128
129	(define (make-pg-condition loc message #!key (args '()) severity
130	error-class error-code message-detail
131	message-hint statement-position context
132	source-file source-line
133	source-function)
134	(make-composite-condition
135	(make-property-condition
136	'exn 'location loc 'message message 'arguments args)
137	(make-property-condition
138	'postgresql 'severity severity 'error-class error-class
139	'error-code error-code 'message-detail message-detail
140	'message-hint message-hint 'statement-position statement-position
141	'context context 'source-file source-file 'source-line source-line
142	;; Might break not-terribly-old versions of postgresql
143	;;'internal-position internal-position 'internal-query internal-query
144	'source-function source-function)))
145
146	;;;;;;;;;;;;;;;;;;;;;;;;
147	;;;; Type parsers
148	;;;;;;;;;;;;;;;;;;;;;;;;
149
150	(define (char-parser str) (string-ref str 0))
151
152	(define (bool-parser str) (string=? str "t"))
153
154	(define (numeric-parser str)
155	(or (string->number str)
156	(postgresql-error 'numeric-parser "Unable to parse number" str)))
157
158	(define (bytea-parser str)
159	(blob->u8vector/shared (string->blob (unescape-bytea str))))
160
161	(define default-type-parsers
162	(make-parameter
163	`(("text" . ,identity)
164	("bytea" . ,bytea-parser)
165	("char" . ,char-parser)
166	("bpchar" . ,identity)
167	("bool" . ,bool-parser)
168	("int8" . ,numeric-parser)
169	("int4" . ,numeric-parser)
170	("int2" . ,numeric-parser)
171	("float4" . ,numeric-parser)
172	("float8" . ,numeric-parser)
173	("numeric" . ,numeric-parser)
174	("oid" . ,numeric-parser))))
175
176	;;;;;;;;;;;;;;;;;;;;;;;
177	;;;; Type unparsers
178	;;;;;;;;;;;;;;;;;;;;;;;
179
180	(define (bool-unparser b)
181	(if b "TRUE" "FALSE"))
182
183	(define default-type-unparsers
184	(make-parameter
185	`((,string? . ,identity)
186	(,u8vector? . ,u8vector->blob/shared)
187	(,char? . ,string)
188	(,boolean? . ,bool-unparser)
189	(,number? . ,number->string))))
190
191	;; Retrieve type-oids from PostgreSQL:
192	(define (update-type-parsers! conn #!optional new-type-parsers)
193	(let ((type-parsers (or new-type-parsers (pg-connection-type-parsers conn)))
194	(ht (make-hash-table))
195	(result '()))
196	;; Set the parsers now, so that we will be retrieving raw data
197	(pg-connection-oid-parsers-set! conn ht)
198	(pg-connection-type-parsers-set! conn type-parsers)
199	(unless (null? type-parsers) ; empty IN () clause is not allowed
200	(query-for-each*
201	(lambda (oid typname)
202	(and-let* ((procedure (assoc typname type-parsers)))
203	(hash-table-set! ht (string->number oid) (cdr procedure))))
204	conn
205	(conc "SELECT oid, typname FROM pg_type WHERE typname IN "
206	"('" (string-intersperse
207	(map (lambda (p) (escape-string conn (car p)))
208	type-parsers) "', '") "')")))))
209
210	(define (update-type-unparsers! conn new-type-unparsers)
211	(pg-connection-type-unparsers-set! conn new-type-unparsers))
212
213	;;;;;;;;;;;;;;;;;;;;
214	;;;; Connections
215	;;;;;;;;;;;;;;;;;;;;
216
217	(define-record pg-connection ptr type-parsers oid-parsers type-unparsers)
218	(define connection? pg-connection?)
219
220	(define (pgsql-connection->fd conn)
221	((foreign-lambda int PQsocket pgconn*) (pg-connection-ptr conn)))
222
223	;; TODO: Add timeout code
224	(define (wait-for-connection! conn poll-function)
225	(let ((conn-fd (pgsql-connection->fd conn))
226	(conn-ptr (pg-connection-ptr conn)))
227	(let loop ((result (poll-function conn-ptr)))
228	(cond ((= result PGRES_POLLING_OK) (void))
229	((= result PGRES_POLLING_FAILED)
230	(let ((error-message (PQerrorMessage conn-ptr)))
231	(disconnect conn)
232	(postgresql-error 'connect
233	(conc "Polling Postgres database failed. "
234	error-message))))
235	((member result (list PGRES_POLLING_WRITING PGRES_POLLING_READING))
236	(thread-wait-for-i/o! conn-fd (if (= PGRES_POLLING_READING result)
237	#:output
238	#:input))
239	(loop (poll-function conn-ptr)))
240	(else
241	(postgresql-error 'connect (conc "Unknown status code!")))))))
242
243	(define (alist->connection-spec alist)
244	(string-join
245	(map (lambda (subspec)
246	(sprintf "~A='~A'"
247	(car subspec) ;; this had better not contain [ =\']
248	(string-translate* (->string (cdr subspec))
249	'(("\\" . "\\\\") ("'" . "\\'")))))
250	alist)))
251
252	(define (connect connection-spec
253	#!optional
254	(type-parsers (default-type-parsers))
255	(type-unparsers (default-type-unparsers)))
256	(let* ((connection-spec (if (string? connection-spec)
257	connection-spec
258	(alist->connection-spec connection-spec)))
259	(conn-ptr (PQconnectStart connection-spec)))
260	(cond
261	((not conn-ptr)
262	(postgresql-error 'connect
263	"Unable to allocate a Postgres connection structure."
264	connection-spec))
265	((= (foreign-value "CONNECTION_BAD" int) (PQstatus conn-ptr))
266	(let ((error-message (PQerrorMessage conn-ptr)))
267	(PQfinish conn-ptr)
268	(postgresql-error 'connect
269	(conc "Connection to Postgres database failed: "
270	error-message)
271	connection-spec)))
272	(else
273	(let ((conn (make-pg-connection conn-ptr type-parsers
274	(make-hash-table) type-unparsers)))
275	;; We don't want libpq to piss in our stderr stream
276	((foreign-lambda* void ((pgconn* conn))
277	"PQsetNoticeReceiver(conn, nullNoticeReceiver, NULL);") conn-ptr)
278	(wait-for-connection! conn PQconnectPoll)
279	(set-finalizer! conn disconnect)
280	;; Retrieve type-information from PostgreSQL metadata for use by
281	;; the various value-parsers.
282	(update-type-parsers! conn)
283	conn)))))
284
285	(define (reset-connection connection)
286	(let ((conn-ptr (pg-connection-ptr connection)))
287	(if (PQresetStart conn-ptr) ;; Update oid-parsers?
288	(wait-for-connection! connection PQresetPoll)
289	(let ((error-message (PQerrorMessage conn-ptr)))
290	(disconnect connection)
291	(postgresql-error 'reset-connection
292	(conc "Reset of connection failed " error-message)
293	connection)))))
294
295	(define (disconnect connection)
296	(and-let* ((conn-ptr (pg-connection-ptr connection)))
297	(pg-connection-ptr-set! connection #f)
298	(pg-connection-type-parsers-set! connection #f)
299	(pg-connection-oid-parsers-set! connection #f)
300	(PQfinish conn-ptr))
301	(void))
302
303	;;;;;;;;;;;;;;;
304	;;;; Results
305	;;;;;;;;;;;;;;;
306
307	(define-record pg-result ptr value-parsers)
308	(define result? pg-result?)
309
310	(define (clear-result! result)
311	(and-let* ((result-ptr (pg-result-ptr result)))
312	(pg-result-ptr-set! result #f)
313	(PQclear result-ptr)))
314
315	(define (row-count result)
316	(PQntuples (pg-result-ptr result)))
317
318	(define (column-count result)
319	(PQnfields (pg-result-ptr result)))
320
321	;; Helper procedures for bounds checking; so we can distinguish between
322	;; out of bounds and nonexistant columns, and signal it.
323	(define (check-column-index! result index location)
324	(when (>= index (column-count result))
325	(postgresql-error
326	location (sprintf "Result column ~A out of bounds" index) result index)))
327
328	(define (check-row-index! result index location)
329	(when (>= index (row-count result))
330	(postgresql-error
331	location (sprintf "Result row ~A out of bounds" index) result index)))
332
333	(define (column-name result index)
334	(check-column-index! result index 'column-name)
335	(string->symbol (PQfname (pg-result-ptr result) index)))
336
337	(define (column-names result)
338	(let ((ptr (pg-result-ptr result)))
339	(let loop ((names '())
340	(column (column-count result)))
341	(if (= column 0)
342	names
343	(loop (cons (string->symbol (PQfname ptr (sub1 column))) names)
344	(sub1 column))))))
345
346	(define (column-index result name)
347	(let ((idx (PQfnumber (pg-result-ptr result) (symbol->string name))))
348	(and (>= idx 0) idx)))
349
350	(define (table-oid result index)
351	(check-column-index! result index 'table-oid)
352	(let ((oid (PQftable (pg-result-ptr result) index)))
353	(and (not (= oid invalid-oid)) oid)))
354
355	;; Fixes the off-by-1 unexpectedness in libpq/the protocol to make it more
356	;; consistent with the rest of Scheme. However, this is inconsistent with
357	;; almost all other PostgreSQL interfaces...
358	(define (table-column-index result index)
359	(check-column-index! result index 'table-column-index)
360	(let ((idx (PQftablecol (pg-result-ptr result) index)))
361	(and (> idx 0) (sub1 idx))))
362
363	(define format-table
364	'((0 . text) (1 . binary)))
365
366	(define (format->symbol format)
367	(or (alist-ref format format-table eq?)
368	(postgresql-error 'format->symbol "Unknown format" format)))
369
370	(define (symbol->format symbol)
371	(or (and-let* ((res (rassoc symbol format-table eq?)))
372	(car res))
373	(postgresql-error 'format->symbol "Unknown format" symbol)))
374
375	(define (column-format result index)
376	(check-column-index! result index 'column-format)
377	(format->symbol (PQfformat (pg-result-ptr result) index)))
378
379	(define (column-type result index)
380	(check-column-index! result index 'column-type)
381	(PQftype (pg-result-ptr result) index))
382
383	;; This is really not super-useful as it requires intimate knowledge
384	;; about the internal implementations of types in PostgreSQL.
385	(define (column-type-modifier result index)
386	(check-column-index! result index 'column-type)
387	(let ((mod (PQfmod (pg-result-ptr result) index)))
388	(and (>= mod 0) mod)))
389
390	;; Unchecked version, for speed
391	(define (value-at* result row column #!key raw)
392	(if (PQgetisnull (pg-result-ptr result) row column)
393	(sql-null)
394	(let ((value ((foreign-safe-lambda*
395	scheme-object ((c-pointer res) (int row) (int col))
396	"C_word fin, str; char val; int len;"
397	"len = PQgetlength(res, row, col);"
398	"str = C_alloc(C_bytestowords(len + sizeof(C_header)));"
399	"val = PQgetvalue(res, row, col);"
400	"fin = C_string(&str, len, val);"
401	"if (PQfformat(res, col) == 1) /* binary? */"
402	" C_string_to_bytevector(fin);"
403	"C_return(fin);")
404	(pg-result-ptr result) row column)))
405	(if (or raw (blob? value))
406	value
407	((vector-ref (pg-result-value-parsers result) column) value)))))
408
409	(define (value-at result row column #!key raw)
410	(check-row-index! result row 'value)
411	(check-column-index! result column 'value)
412	(value-at* result row column raw: raw))
413
414	(define (row-values result row #!key raw)
415	(check-row-index! result row 'row)
416	(let loop ((list '())
417	(column (column-count result)))
418	(if (= column 0)
419	list
420	(loop (cons (value-at* result row (sub1 column) raw: raw) list)
421	(sub1 column)))))
422
423	(define (column-values result column #!key raw)
424	(check-column-index! result column 'column)
425	(let loop ((list '())
426	(row (row-count result)))
427	(if (= row 0)
428	list
429	(loop (cons (value-at* result (sub1 row) column raw: raw) list)
430	(sub1 row)))))
431
432	;; (define (row-alist result row)
433	;; (map cons (column-names result) (row-values result row)))
434	(define (row-alist result row)
435	(check-row-index! result row 'row-alist)
436	(let loop ((alist '())
437	(column (column-count result)))
438	(if (= column 0)
439	alist
440	(loop (cons (cons (string->symbol
441	(PQfname (pg-result-ptr result) (sub1 column)))
442	(value-at* result row (sub1 column))) alist)
443	(sub1 column)))))
444
445	;;; TODO: Do we want/need PQnparams and PQparamtype bindings?
446
447	(define (affected-rows result)
448	(string->number (PQcmdTuples (pg-result-ptr result))))
449
450	(define (inserted-oid result)
451	(let ((oid (PQoidValue (pg-result-ptr result))))
452	(and (not (= oid invalid-oid)) oid)))
453
454
455	;;;;;;;;;;;;;;;;;;;;;;;;
456	;;;; Query procedures
457	;;;;;;;;;;;;;;;;;;;;;;;;
458
459	;; Buffer all available input, yielding if nothing is available:
460	(define (buffer-available-input! conn)
461	(let ((conn-ptr (pg-connection-ptr conn))
462	(conn-fd (pgsql-connection->fd conn)))
463	(let loop ()
464	(if (PQconsumeInput conn-ptr)
465	(when (PQisBusy conn-ptr)
466	(thread-wait-for-i/o! conn-fd #:input)
467	(loop))
468	(postgresql-error 'buffer-available-input!
469	(conc "Error reading reply from server. "
470	(PQerrorMessage conn-ptr))
471	conn-ptr)))))
472
473	(define (make-value-parsers conn pqresult)
474	(let ((nfields (PQnfields pqresult)))
475	(do ([col 0 (+ col 1)]
476	[parsers (make-vector nfields)])
477	([= col nfields] parsers)
478	(vector-set! parsers col
479	(hash-table-ref (pg-connection-oid-parsers conn)
480	(PQftype pqresult col)
481	(lambda () identity))))))
482
483	;; Collect the result pointers from the last query.
484	;;
485	;; A pgresult represents an entire resultset and is always read into memory
486	;; all at once.
487	(define (collect-results conn)
488	(buffer-available-input! conn)
489	(let loop ((results (list)))
490	(let* ((conn-ptr (pg-connection-ptr conn))
491	(result (PQgetResult conn-ptr)))
492	(if result
493	(cond
494	((member (PQresultStatus result) (list PGRES_BAD_RESPONSE
495	PGRES_FATAL_ERROR))
496	(let* ((get-error-field (lambda (d) (PQresultErrorField result d)))
497	(sqlstate (get-error-field PG_DIAG_SQLSTATE))
498	(maybe-severity (get-error-field PG_DIAG_SEVERITY))
499	(maybe-statement-position
500	(get-error-field PG_DIAG_STATEMENT_POSITION))
501	(condition
502	(make-pg-condition
503	'collect-results
504	(PQresultErrorMessage result)
505	severity: (and maybe-severity
506	(string->symbol
507	(string-downcase maybe-severity)))
508	error-class: (and sqlstate (string-take sqlstate 2))
509	error-code: sqlstate
510	message-detail: (get-error-field PG_DIAG_MESSAGE_DETAIL)
511	message-hint: (get-error-field PG_DIAG_MESSAGE_HINT)
512	statement-position: (and maybe-statement-position
513	(string->number
514	maybe-statement-position))
515	context: (get-error-field PG_DIAG_CONTEXT)
516	source-file: (get-error-field PG_DIAG_SOURCE_FILE)
517	source-line: (get-error-field PG_DIAG_SOURCE_LINE)
518	source-function: (get-error-field PG_DIAG_SOURCE_FUNCTION))))
519	;; Read out all remaining results (including the current one).
520	;; TODO: Is this really needed? libpq does it (in pqExecFinish),
521	;; but ostensibly only to concatenate the error messages for
522	;; each query. OTOH, maybe we want to do that, too.
523	(let clean-results! ((result result))
524	(when result
525	(PQclear result)
526	(clean-results! (PQgetResult (pg-connection-ptr conn)))))
527	(signal condition)))
528	(else
529	(let ((result-obj (make-pg-result result
530	(make-value-parsers conn result))))
531	(set-finalizer! result-obj clear-result!)
532	(loop (cons result-obj results)))))
533	(reverse! results)))))
534
535	(define (exec-simple-queries conn query)
536	(if ((foreign-lambda bool PQsendQuery pgconn* (const c-string))
537	(pg-connection-ptr conn) query)
538	(collect-results conn)
539	(postgresql-error 'exec-simple-queries
540	(conc "Unable to send query to server. "
541	(PQerrorMessage (pg-connection-ptr conn)))
542	conn query)))
543
544	(define (exec-query conn query #!optional (params '()) #!key (format 'text) raw)
545	(let* ((unparsers (pg-connection-type-unparsers conn))
546	(unparse (lambda (x)
547	(cond ((find (lambda (parse?)
548	((car parse?) x))
549	unparsers) => (lambda (parse)
550	((cdr parse) x)))
551	(else x))))
552	(params ;; Check all params and ensure they are proper pairs
553	(map ;; See if this can be moved into C
554	(lambda (p)
555	(let ((obj (if raw p (unparse p))))
556	(when (and (not (string? obj))
557	(not (blob? obj))
558	(not (sql-null? obj)))
559	(postgresql-error
560	'exec-query
561	(sprintf "Param value is not a string, sql-null or blob: ~S" p)
562	conn query params format))
563	(if (sql-null? obj) #f obj))) params))
564	(send-query
565	(foreign-lambda*
566	bool ((pgconn* conn) (nonnull-c-string query)
567	(int num) (scheme-object params) (int resfmt))
568	"int res = 0, i = 0, *lens = NULL;"
569	"char **vals = NULL;"
570	"int *fmts = NULL;"
571	"C_word obj, cons;"
572	"if (num > 0) {"
573	" vals = C_malloc(num * sizeof(char *));"
574	" lens = C_malloc(num * sizeof(int));"
575	" fmts = C_malloc(num * sizeof(int));"
576	"}"
577	"for (i=0,cons=params; i < num; ++i,cons=C_u_i_cdr(cons)) {"
578	" obj = C_u_i_car(cons);"
579	" if (obj == C_SCHEME_FALSE) {"
580	" fmts[i] = 0; /* don't care */"
581	" lens[i] = 0;"
582	" vals[i] = NULL;"
583	" } else if (C_header_bits(obj) == C_BYTEVECTOR_TYPE) {"
584	" fmts[i] = 1; /* binary */"
585	" lens[i] = C_header_size(obj);"
586	" vals[i] = C_c_string(obj);"
587	" } else {"
588	" /* text needs to be copied; it expects ASCIIZ */"
589	" fmts[i] = 0; /* text */"
590	" lens[i] = C_header_size(obj);"
591	" vals[i] = malloc(lens[i] + 1);"
592	" memcpy(vals[i], C_c_string(obj), lens[i]);"
593	" vals[i][lens[i]] = '\\0';"
594	" }"
595	"}"
596	"res = PQsendQueryParams(conn, query, num, NULL,"
597	" vals, lens, fmts, resfmt);"
598	"for (i=0,cons=params; i < num; ++i,cons=C_u_i_cdr(cons)) {"
599	" obj = C_u_i_car(cons);"
600	" if (!C_immediatep(obj) && C_header_bits(obj) == C_STRING_TYPE)"
601	" free(vals[i]); /* Clear copied strings only */"
602	"}"
603	"if (num > 0) {"
604	" free(fmts);"
605	" free(lens);"
606	" free(vals);"
607	"}"
608	"C_return(res);")))
609	(if (send-query (pg-connection-ptr conn) query
610	(length params) params (symbol->format format))
611	(car (collect-results conn)) ;; assumed to always return one result...
612	(postgresql-error 'exec-query
613	(conc "Unable to send query to server. "
614	(PQerrorMessage (pg-connection-ptr conn)))
615	conn query params format))))
616
617	;;;;;;;;;;;;;;;;;;;;;;
618	;;;; Value escaping
619	;;;;;;;;;;;;;;;;;;;;;;
620
621	(define (escape-string conn str)
622	(define %escape-string-conn
623	;; This could be more efficient by copying straight into a Scheme object.
624	;; Now it's being copied by PQescapeStringConn, and Chicken copies it again.
625	;; This can allocate up to twice as much memory than the string actually
626	;; uses; in extreme cases this could be a problem.
627	(foreign-lambda* c-string* ((pointer conn) (c-string from) (int fromlen))
628	"int err = 0; char *to;"
629	"to = malloc(sizeof(char) * (fromlen * 2 + 1));"
630	"PQescapeStringConn(conn, to, from, fromlen, &err);"
631	"if (err) {"
632	" free(to);"
633	" C_return(NULL);"
634	"}"
635	"C_return(to);"))
636	(or (%escape-string-conn conn str (string-length str))
637	(postgresql-error 'escape-string
638	(conc "String escaping failed. "
639	(PQerrorMessage conn)) conn str)))
640
641	(define (escape-bytea conn str)
642	(define %escape-bytea-conn
643	;; This must copy because libpq returns a malloced ptr...
644	(foreign-safe-lambda* scheme-object ((pointer conn)
645	;; not copied/NUL interpreted:
646	((const unsigned-c-string*) from)
647	(int fromlen))
648	"size_t tolen=0; C_word res, fin; unsigned char esc;"
649	"esc = PQescapeByteaConn(conn, from, (size_t)fromlen, &tolen);"
650	"if (esc == NULL)"
651	" C_return(C_SCHEME_FALSE);"
652	"fin = C_alloc(C_bytestowords(tolen + sizeof(C_header)));"
653	"/* tolen includes the resulting NUL byte */"
654	"res = C_string(&fin, tolen - 1, (char *)esc);"
655	"PQfreemem(esc);"
656	"C_return(res);"))
657	(or (%escape-bytea-conn conn str (string-length str))
658	(postgresql-error 'escape-bytea
659	(conc "Byte array escaping failed. "
660	(PQerrorMessage conn)) conn str)))
661
662	(define (unescape-bytea str)
663	(define %unescape-bytea
664	;; This must copy because libpq returns a malloced ptr...
665	(foreign-safe-lambda* scheme-object (((const unsigned-c-string*) from))
666	"size_t tolen=0; C_word res, fin; unsigned char unesc;"
667	"unesc = PQunescapeBytea(from, &tolen);"
668	"if (unesc == NULL)"
669	" C_return(C_SCHEME_FALSE);"
670	"fin = C_alloc(C_bytestowords(tolen + sizeof(C_header)));"
671	"res = C_string(&fin, tolen, (char *)unesc);"
672	"PQfreemem(unesc);"
673	"C_return(res);"
674	))
675	(or (%unescape-bytea str)
676	(postgresql-error 'unescape-bytea
677	"Byte array unescaping failed (out of memory?)" str)))
678
679
680	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
681	;;;; High-level interface
682	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
683
684	(define (%query-fold kons knil conn query params)
685	(let* ((result (exec-query conn query params))
686	(rows (row-count result)))
687	(let loop ((seed knil)
688	(row 0))
689	(if (= row rows)
690	seed
691	(loop (kons (row-values result row) seed) (add1 row))))))
692
693	(define (%query-fold-right kons knil conn query params)
694	(let* ((result (exec-query conn query params))
695	(rows (row-count result)))
696	(let loop ((seed knil)
697	(row 0))
698	(if (= row rows)
699	seed
700	(kons (row-values result row) (loop seed (add1 row)))))))
701
702	(define (query-fold kons knil conn query . params)
703	(%query-fold kons knil conn query params))
704	(define (query-fold* kons knil conn query . params)
705	(%query-fold (lambda (values seed) (apply kons (append values (list seed))))
706	knil conn query params))
707	(define (query-fold-right kons knil conn query . params)
708	(%query-fold-right kons knil conn query params))
709	(define (query-fold-right* kons knil conn query . params)
710	(%query-fold-right (lambda (val seed) (apply kons (append val (list seed))))
711	knil conn query params))
712
713	(define (query-for-each proc conn query . params)
714	(%query-fold (lambda (values seed) (proc values)) #f conn query params)
715	(void))
716
717	(define (query-for-each* proc conn query . params)
718	(%query-fold (lambda (values seed) (apply proc values)) #f conn query params)
719	(void))
720
721	;; Like regular Scheme map, the order in which the procedure is applied is
722	;; undefined. We make good use of that by traversing the resultset from
723	;; the end back to the beginning, thereby avoiding a reverse! on the result.
724	(define (%query-map proc conn query params)
725	(let ((result (exec-query conn query params)))
726	(let loop ((lst '())
727	(row (row-count result)))
728	(if (= row 0)
729	lst
730	(loop (cons (proc (row-values result (sub1 row))) lst) (sub1 row))))))
731	(define (query-map proc conn query . params)
732	(%query-map proc conn query params))
733
734	(define (query-map* proc conn query . params)
735	(%query-map (lambda (values) (apply proc values)) conn query params))
736
737	)

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