Intermediate changes

commit_hash:5e2a2254279501ad2bde571fbd53c1a27a00e898

1 files changed, 294 insertions, 0 deletions

diff --git a/contrib/python/fonttools/fontTools/diff/diff.py b/contrib/python/fonttools/fontTools/diff/diff.py
new file mode 100644
index 00000000000..302f2e677ae
--- /dev/null
+++ b/contrib/python/fonttools/fontTools/diff/diff.py
@@ -0,0 +1,294 @@
+import os
+import subprocess
+import tempfile
+from contextlib import contextmanager
+from difflib import unified_diff
+from multiprocessing import Pool, cpu_count
+from typing import Any, Callable, Iterable, Iterator, List, Optional, Text, Tuple
+
+from fontTools.ttLib import TTFont  # type: ignore
+
+from .utils import get_file_modtime
+
+#
+#
+#  Private functions
+#
+#
+
+
+def _get_fonts_and_save_xml(
+    filepath_a: Text,
+    filepath_b: Text,
+    tmpdirpath: Text,
+    include_tables: Optional[List[Text]],
+    exclude_tables: Optional[List[Text]],
+    font_number_a: int,
+    font_number_b: int,
+    use_multiprocess: bool,
+) -> Tuple[Text, Text, Text, Text, Text, Text]:
+    post_pathname, postpath, pre_pathname, prepath = _get_pre_post_paths(
+        filepath_a, filepath_b
+    )
+    # instantiate left and right fontTools.ttLib.TTFont objects
+    tt_left = TTFont(prepath, fontNumber=font_number_a)
+    tt_right = TTFont(postpath, fontNumber=font_number_b)
+    left_ttxpath = os.path.join(tmpdirpath, "left.ttx")
+    right_ttxpath = os.path.join(tmpdirpath, "right.ttx")
+    _mp_save_ttx_xml(
+        tt_left,
+        tt_right,
+        left_ttxpath,
+        right_ttxpath,
+        exclude_tables,
+        include_tables,
+        use_multiprocess,
+    )
+    return left_ttxpath, right_ttxpath, pre_pathname, prepath, post_pathname, postpath
+
+
+def _get_pre_post_paths(
+    filepath_a: Text,
+    filepath_b: Text,
+) -> Tuple[Text, Text, Text, Text]:
+    prepath = filepath_a
+    postpath = filepath_b
+    pre_pathname = filepath_a
+    post_pathname = filepath_b
+    return post_pathname, postpath, pre_pathname, prepath
+
+
+def _mp_save_ttx_xml(
+    tt_left: Any,
+    tt_right: Any,
+    left_ttxpath: Text,
+    right_ttxpath: Text,
+    exclude_tables: Optional[List[Text]],
+    include_tables: Optional[List[Text]],
+    use_multiprocess: bool,
+) -> None:
+    if use_multiprocess and cpu_count() > 1:
+        # Use parallel fontTools.ttLib.TTFont.saveXML dump
+        # by default on multi CPU systems.  This is a performance
+        # optimization. Profiling demonstrates that this can reduce
+        # execution time by up to 30% for some fonts
+        mp_args_list = [
+            (tt_left, left_ttxpath, include_tables, exclude_tables),
+            (tt_right, right_ttxpath, include_tables, exclude_tables),
+        ]
+        with Pool(processes=2) as pool:
+            pool.starmap(_ttfont_save_xml, mp_args_list)
+    else:
+        # use sequential fontTools.ttLib.TTFont.saveXML dumps
+        # when use_multiprocess is False or single CPU system
+        # detected
+        _ttfont_save_xml(tt_left, left_ttxpath, include_tables, exclude_tables)
+        _ttfont_save_xml(tt_right, right_ttxpath, include_tables, exclude_tables)
+
+
+def _ttfont_save_xml(
+    ttf: Any,
+    filepath: Text,
+    include_tables: Optional[List[Text]],
+    exclude_tables: Optional[List[Text]],
+) -> bool:
+    """Writes TTX specification formatted XML to disk on filepath."""
+    ttf.saveXML(filepath, tables=include_tables, skipTables=exclude_tables)
+    return True
+
+
+@contextmanager
+def _saved_ttx_files(
+    filepath_a: Text,
+    filepath_b: Text,
+    include_tables: Optional[List[Text]],
+    exclude_tables: Optional[List[Text]],
+    font_number_a: int,
+    font_number_b: int,
+    use_multiprocess: bool,
+) -> Iterator[Tuple[Text, Text, Text, Text, Text, Text]]:
+    with tempfile.TemporaryDirectory() as tmpdirpath:
+        yield _get_fonts_and_save_xml(
+            filepath_a,
+            filepath_b,
+            tmpdirpath,
+            include_tables,
+            exclude_tables,
+            font_number_a,
+            font_number_b,
+            use_multiprocess,
+        )
+
+
+def _diff_with_saved_ttx_files(
+    filepath_a: Text,
+    filepath_b: Text,
+    include_tables: Optional[List[Text]],
+    exclude_tables: Optional[List[Text]],
+    font_number_a: int,
+    font_number_b: int,
+    use_multiprocess: bool,
+    create_differ: Callable[[Text, Text, Text, Text, Text, Text], Iterable[Text]],
+) -> Iterator[Text]:
+    with _saved_ttx_files(
+        filepath_a,
+        filepath_b,
+        include_tables,
+        exclude_tables,
+        font_number_a,
+        font_number_b,
+        use_multiprocess,
+    ) as (
+        left_ttxpath,
+        right_ttxpath,
+        pre_pathname,
+        prepath,
+        post_pathname,
+        postpath,
+    ):
+        yield from create_differ(
+            left_ttxpath,
+            right_ttxpath,
+            pre_pathname,
+            prepath,
+            post_pathname,
+            postpath,
+        )
+
+
+#
+#
+#  Public functions
+#
+#
+
+
+def u_diff(
+    filepath_a: Text,
+    filepath_b: Text,
+    context_lines: int = 3,
+    include_tables: Optional[List[Text]] = None,
+    exclude_tables: Optional[List[Text]] = None,
+    font_number_a: int = -1,
+    font_number_b: int = -1,
+    use_multiprocess: bool = True,
+) -> Iterator[Text]:
+    """Performs a unified diff on a TTX serialized data format dump of font binary data using
+    a modified version of the Python standard libary difflib module.
+
+    filepath_a: (string) pre-file local file path
+    filepath_b: (string) post-file local file path
+    context_lines: (int) number of context lines to include in the diff (default=3)
+    include_tables: (list of str) Python list of OpenType tables to include in the diff
+    exclude_tables: (list of str) Python list of OpentType tables to exclude from the diff
+    use_multiprocess: (bool) use multi-processor optimizations (default=True)
+
+    include_tables and exclude_tables are mutually exclusive arguments.  Only one should
+    be defined
+
+    :returns: Generator of ordered diff line strings that include newline line endings
+    :raises: KeyError if include_tables or exclude_tables includes a mis-specified table
+    that is not included in filepath_a OR filepath_b
+    """
+
+    def _create_unified_diff(
+        left_ttxpath: Text,
+        right_ttxpath: Text,
+        pre_pathname: Text,
+        prepath: Text,
+        post_pathname: Text,
+        postpath: Text,
+    ) -> Iterable[Text]:
+        with open(left_ttxpath) as ff:
+            fromlines = ff.readlines()
+        with open(right_ttxpath) as tf:
+            tolines = tf.readlines()
+
+        fromdate = get_file_modtime(prepath)
+        todate = get_file_modtime(postpath)
+
+        yield from unified_diff(
+            fromlines,
+            tolines,
+            pre_pathname,
+            post_pathname,
+            fromdate,
+            todate,
+            n=context_lines,
+        )
+
+    yield from _diff_with_saved_ttx_files(
+        filepath_a,
+        filepath_b,
+        include_tables,
+        exclude_tables,
+        font_number_a,
+        font_number_b,
+        use_multiprocess,
+        _create_unified_diff,
+    )
+
+
+def run_external_diff(
+    diff_tool: Text,
+    diff_args: List[Text],
+    filepath_a: Text,
+    filepath_b: Text,
+    include_tables: Optional[List[Text]] = None,
+    exclude_tables: Optional[List[Text]] = None,
+    font_number_a: int = -1,
+    font_number_b: int = -1,
+    use_multiprocess: bool = True,
+) -> Iterator[Text]:
+    """Performs a unified diff on a TTX serialized data format dump of font binary data using
+    an external diff executable that is requested by the caller via `command`
+
+    diff_tool: (string) command line executable string
+    diff_args: (list of strings) arguments for the diff tool
+    filepath_a: (string) pre-file local file path
+    filepath_b: (string) post-file local file path
+    include_tables: (list of str) Python list of OpenType tables to include in the diff
+    exclude_tables: (list of str) Python list of OpentType tables to exclude from the diff
+    use_multiprocess: (bool) use multi-processor optimizations (default=True)
+
+    include_tables and exclude_tables are mutually exclusive arguments.  Only one should
+    be defined
+
+    :returns: Generator of ordered diff line strings that include newline line endings
+    :raises: KeyError if include_tables or exclude_tables includes a mis-specified table
+    that is not included in filepath_a OR filepath_b
+    :raises: IOError if exception raised during execution of `command` on TTX files
+    """
+
+    def _create_external_diff(
+        left_ttxpath: Text,
+        right_ttxpath: Text,
+        _pre_pathname: Text,
+        _prepath: Text,
+        _post_pathname: Text,
+        _postpath: Text,
+    ) -> Iterable[Text]:
+        command = [diff_tool] + diff_args + [left_ttxpath, right_ttxpath]
+        process = subprocess.Popen(
+            command,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            encoding="utf8",
+        )
+
+        for line in process.stdout:
+            yield line
+        err = process.stderr.read()
+        if err:
+            raise IOError(err)
+
+    yield from _diff_with_saved_ttx_files(
+        filepath_a,
+        filepath_b,
+        include_tables,
+        exclude_tables,
+        font_number_a,
+        font_number_b,
+        use_multiprocess,
+        _create_external_diff,
+    )