branch: elpa/pg
commit 9e384860467ce9881bb015318138ec5929e7bc43
Author: Eric Marsden <eric.mars...@risk-engineering.org>
Commit: Eric Marsden <eric.mars...@risk-engineering.org>
Use the 64-bit backend functions for large object functionality
---
pg-lo.el | 100 +++++++++++++++++++++++++++++++++++++++++----------------------
1 file changed, 65 insertions(+), 35 deletions(-)
diff --git a/pg-lo.el b/pg-lo.el
index ec5d4f5bea..958bbd11c5 100644
--- a/pg-lo.el
+++ b/pg-lo.el
@@ -17,7 +17,9 @@
;; For example, the user can define a new type called "circle", and define a C
;; or Tcl function called `circumference' which will act on circles. There is
;; also an inheritance mechanism in PostgreSQL.
-
+;;
+;; https://www.postgresql.org/docs/current/lo-interfaces.html
+;; https://www.postgresql.org/docs/current/lo-funcs.html
;;; Code:
@@ -38,7 +40,6 @@
(declare-function pg-exec "pg" (con &rest args))
-
(defvar pg-lo-initialized nil)
(defvar pg-lo-functions '())
@@ -51,6 +52,7 @@
"proname = 'lo_unlink' OR "
"proname = 'lo_lseek' OR "
"proname = 'lo_tell' OR "
+ "proname = 'lo_truncate' OR "
"proname = 'loread' OR "
"proname = 'lowrite'")))
(setq pg-lo-functions '())
@@ -121,7 +123,7 @@
;; FunctionCallResult
(?V
- (let ((msg-len (pg-read-net-int con 4))
+ (let ((_msg-len (pg-read-net-int con 4))
(value-len (pg-read-net-int con 4)))
(setq result (if integer-result
(pg-read-net-int con value-len)
@@ -174,8 +176,7 @@ ignored in PostgreSQL releases after v8.1."
(error "Can't create large object"))
(t oid))))
-;; mode = modestring (default "r", or "w" or "rw")
-(defun pg-lo-open (connection oid &optional mode)
+(defun pg-lo-open (con oid &optional mode)
"Open the PostgreSQL large object designated by OID for reading.
Uses PostgreSQL connection CON. The string MODE determines whether the
object is opened for reading (`r'), or writing (`w'), or both (`rw').
@@ -189,47 +190,76 @@ Returns a large object descriptor that can be used with
functions
(logior pg--INV_READ pg--INV_WRITE))
(t (let ((msg (format "pg-lo-open: bad mode %s" mode)))
(signal 'pg-user-error (list msg))))))
- (fd (pg-fn connection "lo_open" t oid mode)))
+ (fd (pg-fn con "lo_open" t oid mode)))
(unless (integerp fd)
(error "Couldn't open large object"))
fd))
-;; TODO: should we be checking the return value and signalling a pg-error on
failure?
-(defsubst pg-lo-close (connection fd)
- (pg-fn connection "lo_close" t fd))
+(defsubst pg-lo-close (con fd)
+ "Closes the PostgreSQL large object designated by FD.
+Uses PostgreSQL connection CON."
+ (pg-fn con "lo_close" t fd))
-(defun pg-lo-read (connection fd bytes)
- (let* ((encoded (pg-fn connection "loread" nil fd bytes))
+(defun pg-lo-read (con fd bytes)
+ "Read BYTES octets from large object designated by FD.
+Uses PostgreSQL connection CON."
+ (let* ((encoded (pg-fn con "loread" nil fd bytes))
(hexdigits (substring encoded 2)))
- ;; (message "lo-read: hex encoded is %s" encoded)
(unless (and (eql 92 (aref encoded 0)) ; \ character
(eql ?x (aref encoded 1)))
(signal 'pg-protocol-error
(list "Unexpected format for BYTEA binary string")))
(decode-hex-string hexdigits)))
-(defsubst pg-lo-write (connection fd buf)
- (pg-fn connection "lowrite" t fd buf))
-
-
-(defconst pg--SEEK_SET 0)
-(defconst pg--SEEK_CUR 1)
-(defconst pg--SEEK_END 2)
-
-
-;; Whence can be SEEK_SET (seek from object start), SEEK_CUR (seek from current
-;; position), and SEEK_END (seek from object end).
-(defsubst pg-lo-lseek (connection fd offset whence)
- (pg-fn connection "lo_lseek" t fd offset whence))
-
-(defsubst pg-lo-tell (connection oid)
- (pg-fn connection "lo_tell" t oid))
-
-(defsubst pg-lo-truncate (con oid len)
- (pg-fn con "lo_truncate" oid len))
-
-(defsubst pg-lo-unlink (connection oid)
- (pg-fn connection "lo_unlink" t oid))
+(defsubst pg-lo-write (con fd buf)
+ "Write the contents of BUF to the large object designated by FD.
+Uses PostgreSQL connection CON."
+ (pg-fn con "lowrite" t fd buf))
+
+
+(defconst pg-SEEK_SET 0)
+(defconst pg-SEEK_CUR 1)
+(defconst pg-SEEK_END 2)
+
+(defun pg-lo-lseek (con fd offset whence)
+ "Seek to position OFFSET in PostgreSQL large object designated by FD.
+WHENCE can be `pg-SEEK_SET' (seek from object start),
+`pg-SEEK_CUR' (seek from current position), or `pg-SEEK_END' (seek from
+object end). OFFSET may be a large integer (int8 type in PostgreSQL;
+this function calls the PostgreSQL backend function `lo_lseek64'). Uses
+PostgreSQL connection CON."
+ (let* ((res (pg-exec-prepared con "SELECT lo_lseek64($1, $2, $3)"
+ `((,fd . "int4") (,offset . "int8") (,whence .
"int4"))))
+ (ret (cl-first (pg-result res :tuple 0))))
+ (if (eql -1 ret)
+ (signal 'pg-operational-error (list "lo_lseek64 function call failed"))
+ ret)))
+
+(defun pg-lo-tell (con fd)
+ "Return the current file position in PostgreSQL large object FD.
+Uses PostgreSQL connection CON. Uses the PostgreSQL backend function
+`lo_tell64' to work with large objects."
+ (let* ((res (pg-exec-prepared con "SELECT lo_tell64($1)" `((,fd . "int4"))))
+ (ret (cl-first (pg-result res :tuple 0))))
+ (if (eql -1 ret)
+ (signal 'pg-operational-error (list "lo_tell64 function call failed"))
+ ret)))
+
+(defun pg-lo-truncate (con fd len)
+ "Truncate the PostgreSQL large object FD to size LEN.
+LEN may be a large integer (int8 type in PostgreSQL); this calls the
+PostgreSQL backend function `lo_truncate64'. Uses PostgreSQL connection
+CON."
+ (let* ((res (pg-exec-prepared con "SELECT lo_truncate64($1, $2)"
+ `((,fd . "int4") (,len . "int8"))))
+ (ret (cl-first (pg-result res :tuple 0))))
+ (unless (zerop ret)
+ (signal 'pg-operational-error (list "lo_truncate64 function call
failed")))))
+
+(defun pg-lo-unlink (con oid)
+ "Unlink the PostgreSQL large object identified by OID.
+Uses PostgreSQL connection CON."
+ (pg-fn con "lo_unlink" t oid))
;; FIXME should use unwind-protect here
(defun pg-lo-import (con filename)
@@ -249,7 +279,7 @@ Uses PostgreSQL connection CON. Returns the OID of the new
object."
oid))
(defun pg-lo-export (con oid filename)
- "Export PostgreSQL large object desingated by OID to FILENAME.
+ "Export PostgreSQL large object identified by OID to FILENAME.
Uses PostgreSQL connection CON."
(let* ((buf (get-buffer-create (format " *pg-%d" oid)))
(fdin (pg-lo-open con oid "r")))
