hgext/highlight.py

Truncate input to 1K when using pygments guess_lexer.
This function appears to be exponential with input length.

"""
This is Mercurial extension for syntax highlighting in the file
revision view of hgweb.

It depends on the pygments syntax highlighting library:
http://pygments.org/

To enable the extension add this to hgrc:

[extensions]
hgext.highlight =

There is a single configuration option:

[web]
pygments_style = <style>

The default is 'colorful'.

-- Adam Hupp <[e-mail]>
"""

from mercurial import demandimport
demandimport.ignore.extend(['pkgutil', 'pkg_resources', '__main__',])

from mercurial.hgweb import webcommands, webutil, common
from mercurial import util
from mercurial.templatefilters import filters

from pygments import highlight
from pygments.util import ClassNotFound
from pygments.lexers import guess_lexer, guess_lexer_for_filename, TextLexer
from pygments.formatters import HtmlFormatter

SYNTAX_CSS = ('\n<link rel="stylesheet" href="{url}highlightcss" '
              'type="text/css" />')

def pygmentize(field, fctx, style, tmpl):

    # append a <link ...> to the syntax highlighting css
    old_header = ''.join(tmpl('header'))
    if SYNTAX_CSS not in old_header:
        new_header =  old_header + SYNTAX_CSS
        tmpl.cache['header'] = new_header

    text = fctx.data()
    if util.binary(text):
        return

    # To get multi-line strings right, we can't format line-by-line
    try:
        lexer = guess_lexer_for_filename(fctx.path(), text[:1024],
                                         encoding=util._encoding)
    except (ClassNotFound, ValueError):
        try:
            lexer = guess_lexer(text[:1024], encoding=util._encoding)
        except (ClassNotFound, ValueError):
            lexer = TextLexer(encoding=util._encoding)

    formatter = HtmlFormatter(style=style, encoding=util._encoding)

    colorized = highlight(text, lexer, formatter)
    # strip wrapping div
    colorized = colorized[:colorized.find('\n</pre>')]
    colorized = colorized[colorized.find('<pre>')+5:]
    coloriter = iter(colorized.splitlines())

    filters['colorize'] = lambda x: coloriter.next()

    oldl = tmpl.cache[field]
    newl = oldl.replace('line|escape', 'line|colorize')
    tmpl.cache[field] = newl

web_filerevision = webcommands._filerevision
web_annotate = webcommands.annotate

def filerevision_highlight(web, tmpl, fctx):
    style = web.config('web', 'pygments_style', 'colorful')
    pygmentize('fileline', fctx, style, tmpl)
    return web_filerevision(web, tmpl, fctx)

def annotate_highlight(web, req, tmpl):
    fctx = webutil.filectx(web.repo, req)
    style = web.config('web', 'pygments_style', 'colorful')
    pygmentize('annotateline', fctx, style, tmpl)
    return web_annotate(web, req, tmpl)

def generate_css(web, req, tmpl):
    pg_style = web.config('web', 'pygments_style', 'colorful')
    fmter = HtmlFormatter(style = pg_style)
    req.respond(common.HTTP_OK, 'text/css')
    return ['/* pygments_style = %s */\n\n' % pg_style, fmter.get_style_defs('')]


# monkeypatch in the new version

webcommands._filerevision = filerevision_highlight
webcommands.annotate = annotate_highlight
webcommands.highlightcss = generate_css
webcommands.__all__.append('highlightcss')