feat: add image plugin for jpeg, png and gif comments and tag svg files

tests/test_comment.py

@@ -90,3 +90,15 @@ def test_marker_inside_code_is_ignored(cwd):
     (cwd / 'a.py').write_text('x = "otag: #nope"\n')
     OrvaniTag().scan('.', False)
     assert not (cwd / orvani.CONTEXT_FILE).exists()
+
+
+def test_svg_keeps_xml_declaration_first(cwd):
+    write('a.svg', '<?xml version="1.0"?>\n<svg xmlns="http://www.w3.org/2000/svg"/>\n', '#icon')
+    assert (cwd / 'a.svg').read_text() == '<?xml version="1.0"?>\n<!-- otag: #icon -->\n\n<svg xmlns="http://www.w3.org/2000/svg"/>\n'
+    assert read_back(cwd, 'a.svg') == 'a.svg --- #icon\n'
+
+
+def test_double_dash_is_refused_in_markup_comments(cwd):
+    with pytest.raises(UnsupportedFile):
+        write('a.svg', '<svg/>\n', '#icon', 'before -- after')
+    assert (cwd / 'a.svg').read_text() == '<svg/>\n'

tests/test_image.py

@@ -0,0 +1,132 @@
+import struct
+import zlib
+
+import pytest
+
+import orvanitag.orvani as orvani
+from orvanitag.entry import Entry
+from orvanitag.orvani import OrvaniTag
+from orvanitag.errors import UnsupportedFile
+
+
+@pytest.fixture
+def cwd(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+    return tmp_path
+
+
+def roundtrip(cwd, name, *tags):
+    """Writes the tags and reads them back into a fresh entry"""
+    OrvaniTag().add(name, *tags)
+    OrvaniTag().write_metadata(name, 'image')
+    expected = (cwd / orvani.CONTEXT_FILE).read_text()
+    (cwd / orvani.CONTEXT_FILE).unlink()
+    OrvaniTag().read_metadata(name)
+    assert (cwd / orvani.CONTEXT_FILE).read_text() == expected
+
+
+def clear(name):
+    OrvaniTag().write_metadata(name, 'image', clear=True)
+
+
+def segment(marker, data):
+    return bytes([0xFF, marker]) + (len(data) + 2).to_bytes(2, 'big') + data
+
+
+SOI = b'\xff\xd8'
+APPS = segment(0xE0, b'JFIF\0\1\1\0\0\1\0\1\0\0') + segment(0xE1, b'Exif\0\0')
+REST = segment(0xDB, bytes(65)) + segment(0xDA, bytes(10)) + b'\x12\x34\xff\xd9'
+
+
+def test_jpeg_comment_goes_after_the_app_segments(cwd):
+    (cwd / 'a.jpg').write_bytes(SOI + APPS + REST)
+    roundtrip(cwd, 'a.jpg', '+trip', '#beach', 'sunset')
+    assert (cwd / 'a.jpg').read_bytes() == SOI + APPS + segment(0xFE, b'otag: +trip #beach sunset') + REST
+    clear('a.jpg')
+    assert (cwd / 'a.jpg').read_bytes() == SOI + APPS + REST
+
+
+def test_jpeg_keeps_other_comments(cwd):
+    foreign = segment(0xFE, b'CREATOR: gd-jpeg v1.0')
+    (cwd / 'a.JPEG').write_bytes(SOI + APPS + foreign + REST)
+    assert OrvaniTag().read_metadata('a.JPEG') == Entry()
+    roundtrip(cwd, 'a.JPEG', '#beach')
+    OrvaniTag().add('a.JPEG', '#more')
+    OrvaniTag().write_metadata('a.JPEG', 'image')
+    assert (cwd / 'a.JPEG').read_bytes() == SOI + APPS + segment(0xFE, b'otag: #beach #more') + foreign + REST
+    clear('a.JPEG')
+    assert (cwd / 'a.JPEG').read_bytes() == SOI + APPS + foreign + REST
+
+
+def test_jpeg_comment_length_is_limited(cwd):
+    (cwd / 'a.jpg').write_bytes(SOI + APPS + REST)
+    OrvaniTag().add('a.jpg', 'x' * 0x10000)
+    with pytest.raises(UnsupportedFile, match='too long'):
+        OrvaniTag().write_metadata('a.jpg', 'image')
+    assert (cwd / 'a.jpg').read_bytes() == SOI + APPS + REST
+
+
+def chunk(kind, data):
+    return len(data).to_bytes(4, 'big') + kind + data + zlib.crc32(kind + data).to_bytes(4, 'big')
+
+
+def chunks(data):
+    """The chunks of a PNG, checking their CRCs"""
+    found, pos = [], 8
+    while pos < len(data):
+        size, kind = int.from_bytes(data[pos:pos + 4], 'big'), data[pos + 4:pos + 8]
+        body = data[pos + 8:pos + 8 + size]
+        assert data[pos + 8 + size:pos + 12 + size] == zlib.crc32(kind + body).to_bytes(4, 'big')
+        found.append((kind, body))
+        pos += 12 + size
+    return found
+
+
+PNG = b'\x89PNG\r\n\x1a\n'
+IHDR = chunk(b'IHDR', struct.pack('>IIBBBBB', 1, 1, 8, 0, 0, 0, 0))
+IMAGE = chunk(b'IDAT', zlib.compress(b'\0\0')) + chunk(b'IEND', b'')
+
+
+def test_png_comment_chunk_and_others_kept(cwd):
+    foreign = chunk(b'iTXt', b'Comment\0\0\0\0\0Created with GIMP') + chunk(b'tEXt', b'Software\0x')
+    (cwd / 'a.png').write_bytes(PNG + IHDR + foreign + IMAGE)
+    assert OrvaniTag().read_metadata('a.png') == Entry()
+
+    roundtrip(cwd, 'a.png', '#фото', 'a note')
+    data = (cwd / 'a.png').read_bytes()
+    assert chunks(data)[1] == (b'iTXt', b'Comment\0\0\0\0\0' + 'otag: #фото a note'.encode())
+    assert data == PNG + IHDR + chunk(b'iTXt', b'Comment\0\0\0\0\0' + 'otag: #фото a note'.encode()) + foreign + IMAGE
+
+    clear('a.png')
+    assert (cwd / 'a.png').read_bytes() == PNG + IHDR + foreign + IMAGE
+
+
+GIF_SCREEN = b'\x01\x00\x01\x00\x80\x00\x00' + b'\xff\xff\xff\x00\x00\x00'
+GIF_IMAGE = b',\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02\x44\x01\x00;'
+
+
+def test_gif_comment_in_sub_blocks(cwd):
+    foreign = b'\x21\xfe\x07made by\x00'
+    (cwd / 'a.gif').write_bytes(b'GIF89a' + GIF_SCREEN + foreign + GIF_IMAGE)
+    note = 'n' * 300
+    roundtrip(cwd, 'a.gif', '#anim', note)
+    line = f'otag: #anim {note}'.encode()
+    assert (cwd / 'a.gif').read_bytes() == (b'GIF89a' + GIF_SCREEN + b'\x21\xfe\xff' + line[:255]
+                                            + bytes([len(line) - 255]) + line[255:] + b'\0' + foreign + GIF_IMAGE)
+    clear('a.gif')
+    assert (cwd / 'a.gif').read_bytes() == b'GIF89a' + GIF_SCREEN + foreign + GIF_IMAGE
+
+
+def test_gif87a_becomes_89a(cwd):
+    (cwd / 'a.gif').write_bytes(b'GIF87a' + GIF_SCREEN + GIF_IMAGE)
+    roundtrip(cwd, 'a.gif', '#old')
+    assert (cwd / 'a.gif').read_bytes() == b'GIF89a' + GIF_SCREEN + b'\x21\xfe' + bytes([10]) + b'otag: #old\0' + GIF_IMAGE
+
+
+@pytest.mark.parametrize('name', ['a.jpg', 'a.png', 'a.gif'])
+def test_other_files_are_refused_unchanged(cwd, name):
+    (cwd / name).write_bytes(b'plain text')
+    OrvaniTag().add(name, '#lofi')
+    with pytest.raises(UnsupportedFile):
+        OrvaniTag().write_metadata(name, 'image')
+    assert (cwd / name).read_bytes() == b'plain text'