From: Qiantan Hong <qhong@alum.mit.edu>
To: "tomas@tuxteam.de" <tomas@tuxteam.de>
Cc: "emacs-devel@gnu.org" <emacs-devel@gnu.org>
Subject: Against sqlite3!!! (Was: sqlite3)
Date: Tue, 7 Dec 2021 07:44:42 +0000 [thread overview]
Message-ID: <MN2PR12MB33914BC24AA74F3DC389CF04946E9@MN2PR12MB3391.namprd12.prod.outlook.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 77 bytes --]
I’ve attached a pure Emacs Lisp implementation of persistent key value store.
[-- Attachment #2: resist!.el --]
[-- Type: application/octet-stream, Size: 1624 bytes --]
;;; resist!.el --- Against SQLite3! -*- lexical-binding: t; -*-
(defvar kv-store-table)
(defmacro --kv (key value)
(puthash key value kv-store-table)
nil)
(cl-defstruct (kv-store (:constructor make-kv-store-1)) path table)
(defun make-kv-store (path)
(let* ((kv-store (make-kv-store-1 :path path))
(kv-store-table (make-hash-table :test 'equal))
need-compactification)
(when (file-exists-p path)
(condition-case c
(load-file path)
(end-of-file
;; We might encounter trailing unbalanced form if Emacs
;; crashed in the middle of `kv-put'. We compact the file
;; and fix unbalanced form as a side effect
(setq need-compactification t)))
(setf (kv-store-table kv-store) kv-store-table))
(when need-compactification
(compact-kv-store kv-store))
kv-store))
(defsubst kv-put-log (key value kv-store)
(let ((print-length nil) (print-level nil))
(prin1 `(--kv ,key ,value) (current-buffer)))
(insert "\n"))
(defun compact-kv-store (kv-store)
;; dump the full content of kv-store-table at once
;; to compress the log
(with-temp-buffer
(maphash (lambda (key value) (kv-put-log key value kv-store))
(kv-store-table kv-store))
(let ((file-precious-flag t))
(write-file (kv-store-path kv-store)))))
(defun kv-put (key value kv-store)
(with-temp-buffer
(kv-put-log key value kv-store)
(append-to-file nil nil (kv-store-path kv-store)))
(puthash key value (kv-store-table kv-store)))
(defun kv-get (key kv-store)
(gethash key (kv-store-table kv-store)))
(provide 'resist!)
next reply other threads:[~2021-12-07 7:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 7:44 Qiantan Hong [this message]
[not found] <MN2PR12MB3391BC76A0D05236AC76C94E946E9@MN2PR12MB3391.namprd12.prod.outlook.com>
2021-12-07 8:13 ` Against sqlite3!!! (Was: sqlite3) Qiantan Hong
2021-12-07 9:14 ` Qiantan Hong
2021-12-07 13:45 ` Zhu Zihao
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