1#!/usr/bin/env python
2from hashlib import md5
3from pathlib import Path
4import re
5import sys
6
7import sphinx
8from sphinx.application import Sphinx
9
10# This extension uses pyyaml, report an explicit
11# error message if it's not installed
12try:
13    import yaml
14except ImportError:
15    sys.stderr.write("The Yocto Project Sphinx documentation requires PyYAML.\
16    \nPlease make sure to install pyyaml Python package.\n")
17    sys.exit(1)
18
19__version__  = '1.0'
20
21# Variables substitutions. Uses {VAR} subst using variables defined in poky.yaml
22# Each .rst file is processed after source-read event (subst_vars_replace runs once per file)
23subst_vars = {}
24
25poky_hash = ""
26
27def subst_vars_replace(app: Sphinx, docname, source):
28    result = source[0]
29    for k in subst_vars:
30        result = result.replace("&"+k+";", subst_vars[k])
31    source[0] = result
32
33def yocto_vars_env_get_outdated(app: Sphinx, env, added, changed, removed):
34    '''
35    If poky.yaml changed (BUILDDIR/.poky.yaml.cache does not exist or contains
36    an md5sum different from poky.yaml's current md5sum), force rebuild of all
37    *.rst files in SOURCEDIR whose content has at least one occurence of `&.*;`
38    (see PATTERN global variable).
39    '''
40    try:
41        poky_cache = Path(app.outdir) / ".poky.yaml.cache"
42        cache_hash = poky_cache.read_text()
43    except FileNotFoundError:
44        cache_hash = None
45
46    if poky_hash == cache_hash:
47        return []
48
49    docs = []
50    for p in Path(app.srcdir).rglob("*.rst"):
51        if PATTERN.search(p.read_text()):
52            p_rel_no_ext = p.relative_to(app.srcdir).parent / p.stem
53            docs.append(str(p_rel_no_ext))
54    return docs
55
56def yocto_vars_build_finished(app: Sphinx, exception):
57    poky_cache = Path(app.outdir) / ".poky.yaml.cache"
58    poky_cache.write_text(poky_hash)
59    return []
60
61PATTERN = re.compile(r'&(.*?);')
62def expand(val, src):
63    return PATTERN.sub(lambda m: expand(src.get(m.group(1), ''), src), val)
64
65def setup(app: Sphinx):
66    global poky_hash
67
68    with open("poky.yaml") as file:
69        hasher = md5()
70        buff = file.read()
71        hasher.update(buff.encode('utf-8'))
72        poky_hash = hasher.hexdigest()
73        subst_vars.update(yaml.safe_load(buff))
74
75    for k in subst_vars:
76        subst_vars[k] = expand(subst_vars[k], subst_vars)
77
78    app.connect('source-read', subst_vars_replace)
79    app.connect('env-get-outdated', yocto_vars_env_get_outdated)
80    app.connect('build-finished', yocto_vars_build_finished)
81
82    return dict(
83        version = __version__,
84        parallel_read_safe = True,
85        parallel_write_safe = True
86    )
87