[nongnu] elpa/emacsql 649fc6b0b4 312/427: Add emacsql-pg using pg.el as a back-end.

[ELPA Syncer]

branch: elpa/emacsql
commit 649fc6b0b4164456e36c9cdd099a03d4a97212ae
Author: Christopher Wellons <wellons@nullprogram.com>
Commit: Christopher Wellons <wellons@nullprogram.com>

    Add emacsql-pg using pg.el as a back-end.
---
 Makefile        |  2 +-
 emacsql-pg.el   | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 emacsql-psql.el |  2 +-
 emacsql.el      |  2 +-
 4 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 90f49dbcf9..58e39ff9b6 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ PACKAGE := emacsql
 VERSION := $(shell $(CASK) version)
 
 EL = emacsql-compiler.el emacsql-system.el emacsql.el \
-     emacsql-sqlite.el emacsql-psql.el emacsql-mysql.el
+     emacsql-sqlite.el emacsql-psql.el emacsql-mysql.el emacsql-pg.el
 ELC = $(EL:.el=.elc)
 EXTRA_DIST = README.md UNLICENSE
 
diff --git a/emacsql-pg.el b/emacsql-pg.el
new file mode 100644
index 0000000000..80508249db
--- /dev/null
+++ b/emacsql-pg.el
@@ -0,0 +1,70 @@
+;;; emacsql-pg.el --- PostgreSQL (pg.el) back-end -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;; Unlike emacsql-psql, this connection type uses Eric Marsden's pg.el
+;; to connect to PostgreSQL. It speaks directly to the database, so
+;; unlike the other EmacSQL connection types, this one requires no
+;; external command line programs.
+
+;; The only pg functions required are pg:connect, pg:disconnect,
+;; pg:exec, and pg:result. Unfortunately, since pg.el is synchronous
+;; it will not be fully compliant once EmacSQL supports asynchronous
+;; queries. But, on the plus side, this means the implementation below
+;; is dead simple.
+
+;;; Code:
+
+(require 'pg)
+(require 'eieio)
+(require 'cl-lib)
+(require 'emacsql)
+(require 'emacsql-psql)  ; for reserved words
+
+(defclass emacsql-pg-connection (emacsql-connection)
+  ((pgcon :reader emacsql-pg-pgcon :initarg :pgcon)
+   (dbname :reader emacsql-pg-dbname :initarg :dbname)
+   (result :accessor emacsql-pg-result)
+   (types :allocation :class
+          :reader emacsql-types
+          :initform '((integer "BIGINT")
+                      (float "DOUBLE PRECISION")
+                      (object "TEXT")
+                      (nil "TEXT"))))
+  (:documentation "A connection to a PostgreSQL database via pg.el."))
+
+(cl-defun emacsql-pg (dbname user &key
+                             (host "localhost") (password "") (port 5432) 
debug)
+  "Connect to a PostgreSQL server using pg.el."
+  (let* ((pgcon (pg:connect dbname user password host port))
+         (connection (make-instance 'emacsql-pg-connection
+                                    :process (pgcon-process pgcon)
+                                    :pgcon pgcon
+                                    :dbname dbname)))
+    (when debug (emacsql-enable-debugging connection))
+    (emacsql connection [:set (= default-transaction-isolation 'SERIALIZABLE)])
+    (emacsql-register connection)))
+
+(defmethod emacsql-close ((connection emacsql-pg-connection))
+  (ignore-errors (pg:disconnect (emacsql-pg-pgcon connection))))
+
+(defmethod emacsql-send-message ((connection emacsql-pg-connection) message)
+  (condition-case error
+      (setf (emacsql-pg-result connection)
+            (pg:exec (emacsql-pg-pgcon connection) message))
+    (error (signal 'emacsql-error error))))
+
+(defmethod emacsql-waiting-p ((_connection emacsql-pg-connection))
+  ;; pg:exec will block
+  t)
+
+(defmethod emacsql-parse ((connection emacsql-pg-connection))
+  (let ((tuples (pg:result (emacsql-pg-result connection) :tuples)))
+    (cl-loop for tuple in tuples collect
+             (cl-loop for value in tuple
+                      when (stringp value) collect (read value)
+                      else collect value))))
+
+(provide 'emacsql-pg)
+
+;;; emacsql-pg.el ends here
diff --git a/emacsql-psql.el b/emacsql-psql.el
index 86df1e355e..26ce9067df 100644
--- a/emacsql-psql.el
+++ b/emacsql-psql.el
@@ -49,7 +49,7 @@ 
http://www.postgresql.org/docs/7.3/static/sql-keywords-appendix.html";)
                       (float "DOUBLE PRECISION")
                       (object "TEXT")
                       (nil "TEXT"))))
-  (:documentation "A connection to a PostgreSQL database."))
+  (:documentation "A connection to a PostgreSQL database via psql."))
 
 (cl-defun emacsql-psql (dbname &key username hostname port debug)
   "Connect to a PostgreSQL server using the psql command line program."
diff --git a/emacsql.el b/emacsql.el
index 5a86a53eed..bc8f07f5e5 100644
--- a/emacsql.el
+++ b/emacsql.el
@@ -5,7 +5,7 @@
 ;; Author: Christopher Wellons <wellons@nullprogram.com>
 ;; URL: https://github.com/skeeto/emacsql
 ;; Version: 1.0.2
-;; Package-Requires: ((emacs "24.3") (cl-lib "0.3") (finalize "1.0.0"))
+;; Package-Requires: ((emacs "24.3") (cl-lib "0.3") (finalize "1.0.0") (pg 
"0.12"))
 
 ;;; Commentary: