annotate hgext/highlight/highlight.py @ 42927:a7abc6081bc5

highlight: fix encoding issues to enable Py3 compatibility

This commit fixes various encoding issues with the `highlight` extension
to enable compatibility with Python 3. Python `.encode()` and `.decode()`
requires the target encoding to be passed as a `str`, so the value of
`mercurial.encoding.encoding` must be converted before passing to the
function. Pygments also assumes the `str` type for values it works with,
so we must perform conversions before and after receiving values from its
APIs.

After applying this patch, `test-highlight.t` passes under Python 3. We
add it to `python3-whitelist` as well.

Tested with Pygments 2.4.2.

Differential Revision: https://phab.mercurial-scm.org/D6832

# highlight.py - highlight extension implementation file
#
#  Copyright 2007-2009 Adam Hupp <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# The original module was split in an interface and an implementation
# file to defer pygments loading and speedup extension setup.

from __future__ import absolute_import

from mercurial import demandimport
demandimport.IGNORES.update(['pkgutil', 'pkg_resources', '__main__'])

from mercurial import (
    encoding,
    pycompat,
)

from mercurial.utils import (
    stringutil,
)

with demandimport.deactivated():
    import pygments
    import pygments.formatters
    import pygments.lexers
    import pygments.plugin
    import pygments.util

    for unused in pygments.plugin.find_plugin_lexers():
        pass

highlight = pygments.highlight
ClassNotFound = pygments.util.ClassNotFound
guess_lexer = pygments.lexers.guess_lexer
guess_lexer_for_filename = pygments.lexers.guess_lexer_for_filename
TextLexer = pygments.lexers.TextLexer
HtmlFormatter = pygments.formatters.HtmlFormatter

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

def pygmentize(field, fctx, style, tmpl, guessfilenameonly=False):

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

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

    # str.splitlines() != unicode.splitlines() because "reasons"
    for c in "\x0c\x1c\x1d\x1e":
        if c in text:
            text = text.replace(c, '')

    # Pygments is best used with Unicode strings:
    # <http://pygments.org/docs/unicode/>
    text = text.decode(pycompat.sysstr(encoding.encoding), 'replace')

    # To get multi-line strings right, we can't format line-by-line
    try:
        path = pycompat.sysstr(fctx.path())
        lexer = guess_lexer_for_filename(path, text[:1024],
                                         stripnl=False)
    except (ClassNotFound, ValueError):
        # guess_lexer will return a lexer if *any* lexer matches. There is
        # no way to specify a minimum match score. This can give a high rate of
        # false positives on files with an unknown filename pattern.
        if guessfilenameonly:
            return

        try:
            lexer = guess_lexer(text[:1024], stripnl=False)
        except (ClassNotFound, ValueError):
            # Don't highlight unknown files
            return

    # Don't highlight text files
    if isinstance(lexer, TextLexer):
        return

    formatter = HtmlFormatter(nowrap=True, style=pycompat.sysstr(style))

    colorized = highlight(text, lexer, formatter)
    coloriter = (s.encode(pycompat.sysstr(encoding.encoding), 'replace')
                 for s in colorized.splitlines())

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

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