profile: upgrade the "profile" context manager to a full class
So far we have been able to use a simple decorator for this. However using the
current context manager makes the scope of the profiling in dispatch
constrainted and the time frame to decide to enable profiling quite limited
(using "maybeprofile")
This is the first step toward the ability to enable the profiling from within
the profiling scope. eg::
with maybeprofiling(ui) as profiler:
...
bar.foo():
...
if options['profile']:
profiler.start()
...
fooz()
...
My target usecase is adding support for "--profile" to alias definitions with
effect. These are to be used with "profiling.output=blackbox" to gather data
about operation that get slow from time to time (eg: pull being minutes instead
of seconds from time to time).
Of course, in such case, the scope of the profiling would be smaller since
profiler would be started after running extensions 'reposetup' (and other
potentially costly logic), but these are not relevant for my target usecase
(multiple second commits, multiple tens of seconds pull).
Currently adding '--profile' to a command through alias requires to re-spin a
Mercurial binary (using "!$HG" in alias), which as a significant performance
impact, especially in context where startup performance is being worked on...
An alternative approach would be to stop using the context manager in dispatch
and move back to a try/finally setup.
;; hg-test-mode.el - Major mode for editing Mercurial tests
;;
;; Copyright 2014 Matt Mackall <mpm@selenic.com>
;; "I have no idea what I'm doing"
;;
;; This software may be used and distributed according to the terms of the
;; GNU General Public License version 2 or any later version.
;;
;; To enable, add something like the following to your .emacs:
;;
;; (if (file-exists-p "~/hg/contrib/hg-test-mode.el")
;; (load "~/hg/contrib/hg-test-mode.el"))
(defvar hg-test-mode-hook nil)
(defvar hg-test-mode-map
(let ((map (make-keymap)))
(define-key map "\C-j" 'newline-and-indent)
map)
"Keymap for hg test major mode")
(add-to-list 'auto-mode-alist '("\\.t\\'" . hg-test-mode))
(defconst hg-test-font-lock-keywords-1
(list
'("^ \\(\\$\\|>>>\\) " 1 font-lock-builtin-face)
'("^ \\(>\\|\\.\\.\\.\\) " 1 font-lock-constant-face)
'("^ \\([[][0-9]+[]]\\)$" 1 font-lock-warning-face)
'("^ \\(.*?\\)\\(\\( [(][-a-z]+[)]\\)*\\)$" 1 font-lock-string-face)
'("\\$?\\(HG\\|TEST\\)\\w+=?" . font-lock-variable-name-face)
'("^ \\(.*?\\)\\(\\( [(][-a-z]+[)]\\)+\\)$" 2 font-lock-type-face)
'("^#.*" . font-lock-preprocessor-face)
'("^\\([^ ].*\\)$" 1 font-lock-comment-face)
)
"Minimal highlighting expressions for hg-test mode")
(defvar hg-test-font-lock-keywords hg-test-font-lock-keywords-1
"Default highlighting expressions for hg-test mode")
(defvar hg-test-mode-syntax-table
(let ((st (make-syntax-table)))
(modify-syntax-entry ?\" "w" st) ;; disable standard quoting
st)
"Syntax table for hg-test mode")
(defun hg-test-mode ()
(interactive)
(kill-all-local-variables)
(use-local-map hg-test-mode-map)
(set-syntax-table hg-test-mode-syntax-table)
(set (make-local-variable 'font-lock-defaults) '(hg-test-font-lock-keywords))
(setq major-mode 'hg-test-mode)
(setq mode-name "hg-test")
(run-hooks 'hg-test-mode-hook))
(provide 'hg-test-mode)