tree.py

# Copyright (C) 2008, 2009 Michael Trier (mtrier@gmail.com) and contributors
#
# This module is part of GitPython and is released under the
# 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/

from git.util import IterableList, join_path
import git.diff as git_diff
from git.util import to_bin_sha

from . import util
from .base import IndexObject, IndexObjUnion
from .blob import Blob
from .submodule.base import Submodule

from .fun import tree_entries_from_data, tree_to_stream


# typing -------------------------------------------------

from typing import (
    Any,
    Callable,
    Dict,
    Iterable,
    Iterator,
    List,
    Tuple,
    Type,
    Union,
    cast,
    TYPE_CHECKING,
)

from git.types import PathLike, Literal

if TYPE_CHECKING:
    from git.repo import Repo
    from io import BytesIO

TreeCacheTup = Tuple[bytes, int, str]

TraversedTreeTup = Union[Tuple[Union["Tree", None], IndexObjUnion, Tuple["Submodule", "Submodule"]]]


# def is_tree_cache(inp: Tuple[bytes, int, str]) -> TypeGuard[TreeCacheTup]:
#     return isinstance(inp[0], bytes) and isinstance(inp[1], int) and isinstance([inp], str)

# --------------------------------------------------------


cmp: Callable[[str, str], int] = lambda a, b: (a > b) - (a < b)

__all__ = ("TreeModifier", "Tree")


def git_cmp(t1: TreeCacheTup, t2: TreeCacheTup) -> int:
    a, b = t1[2], t2[2]
    # assert isinstance(a, str) and isinstance(b, str)
    len_a, len_b = len(a), len(b)
    min_len = min(len_a, len_b)
    min_cmp = cmp(a[:min_len], b[:min_len])

    if min_cmp:
        return min_cmp

    return len_a - len_b


def merge_sort(a: List[TreeCacheTup], cmp: Callable[[TreeCacheTup, TreeCacheTup], int]) -> None:
    if len(a) < 2:
        return

    mid = len(a) // 2
    lefthalf = a[:mid]
    righthalf = a[mid:]

    merge_sort(lefthalf, cmp)
    merge_sort(righthalf, cmp)

    i = 0
    j = 0
    k = 0

    while i < len(lefthalf) and j < len(righthalf):
        if cmp(lefthalf[i], righthalf[j]) <= 0:
            a[k] = lefthalf[i]
            i = i + 1
        else:
            a[k] = righthalf[j]
            j = j + 1
        k = k + 1

    while i < len(lefthalf):
        a[k] = lefthalf[i]
        i = i + 1
        k = k + 1

    while j < len(righthalf):
        a[k] = righthalf[j]
        j = j + 1
        k = k + 1


class TreeModifier:
    """A utility class providing methods to alter the underlying cache in a list-like fashion.

    Once all adjustments are complete, the _cache, which really is a reference to
    the cache of a tree, will be sorted. This ensures it will be in a serializable state.
    """

    __slots__ = ("_cache",)

    def __init__(self, cache: List[TreeCacheTup]) -> None:
        self._cache = cache

    def _index_by_name(self, name: str) -> int:
        """:return: index of an item with name, or -1 if not found"""
        for i, t in enumerate(self._cache):
            if t[2] == name:
                return i
            # END found item
        # END for each item in cache
        return -1

    # { Interface
    def set_done(self) -> "TreeModifier":
        """Call this method once you are done modifying the tree information.

        This may be called several times, but be aware that each call will cause
        a sort operation.

        :return self:
        """
        merge_sort(self._cache, git_cmp)
        return self

    # } END interface

    # { Mutators
    def add(self, sha: bytes, mode: int, name: str, force: bool = False) -> "TreeModifier":
        """Add the given item to the tree.

        If an item with the given name already exists, nothing will be done, but a
        ValueError will be raised if the sha and mode of the existing item do not match
        the one you add, unless force is True

        :param sha: The 20 or 40 byte sha of the item to add

        :param mode: int representing the stat compatible mode of the item

        :param force: If True, an item with your name and information will overwrite any
            existing item with the same name, no matter which information it has

        :return: self
        """
        if "/" in name:
            raise ValueError("Name must not contain '/' characters")
        if (mode >> 12) not in Tree._map_id_to_type:
            raise ValueError("Invalid object type according to mode %o" % mode)

        sha = to_bin_sha(sha)
        index = self._index_by_name(name)

        item = (sha, mode, name)
        # assert is_tree_cache(item)

        if index == -1:
            self._cache.append(item)
        else:
            if force:
                self._cache[index] = item
            else:
                ex_item = self._cache[index]
                if ex_item[0] != sha or ex_item[1] != mode:
                    raise ValueError("Item %r existed with different properties" % name)
                # END handle mismatch
            # END handle force
        # END handle name exists
        return self

    def add_unchecked(self, binsha: bytes, mode: int, name: str) -> None:
        """Add the given item to the tree. Its correctness is assumed, so it is the
        caller's responsibility to ensure that the input is correct.

        For more information on the parameters, see :meth:`add`.

        :param binsha: 20 byte binary sha
        """
        assert isinstance(binsha, bytes) and isinstance(mode, int) and isinstance(name, str)
        tree_cache = (binsha, mode, name)

        self._cache.append(tree_cache)

    def __delitem__(self, name: str) -> None:
        """Delete an item with the given name if it exists."""
        index = self._index_by_name(name)
        if index > -1:
            del self._cache[index]

    # } END mutators


class Tree(IndexObject, git_diff.Diffable, util.Traversable, util.Serializable):
    """Tree objects represent an ordered list of Blobs and other Trees.

    ``Tree as a list``::

        Access a specific blob using the
        tree['filename'] notation.

        You may as well access by index
        blob = tree[0]
    """

    type: Literal["tree"] = "tree"

    __slots__ = ("_cache",)

    # Actual integer IDs for comparison.
    commit_id = 0o16  # Equals stat.S_IFDIR | stat.S_IFLNK - a directory link.
    blob_id = 0o10
    symlink_id = 0o12
    tree_id = 0o04

    _map_id_to_type: Dict[int, Type[IndexObjUnion]] = {
        commit_id: Submodule,
        blob_id: Blob,
        symlink_id: Blob
        # Tree ID added once Tree is defined.
    }

    def __init__(
        self,
        repo: "Repo",
        binsha: bytes,
        mode: int = tree_id << 12,
        path: Union[PathLike, None] = None,
    ):
        super().__init__(repo, binsha, mode, path)

    @classmethod
    def _get_intermediate_items(
        cls,
        index_object: IndexObjUnion,
    ) -> Union[Tuple["Tree", ...], Tuple[()]]:
        if index_object.type == "tree":
            return tuple(index_object._iter_convert_to_object(index_object._cache))
        return ()

    def _set_cache_(self, attr: str) -> None:
        if attr == "_cache":
            # Set the data when we need it.
            ostream = self.repo.odb.stream(self.binsha)
            self._cache: List[TreeCacheTup] = tree_entries_from_data(ostream.read())
        else:
            super()._set_cache_(attr)
        # END handle attribute

    def _iter_convert_to_object(self, iterable: Iterable[TreeCacheTup]) -> Iterator[IndexObjUnion]:
        """Iterable yields tuples of (binsha, mode, name), which will be converted
        to the respective object representation.
        """
        for binsha, mode, name in iterable:
            path = join_path(self.path, name)
            try:
                yield self._map_id_to_type[mode >> 12](self.repo, binsha, mode, path)
            except KeyError as e:
                raise TypeError("Unknown mode %o found in tree data for path '%s'" % (mode, path)) from e
        # END for each item

    def join(self, file: str) -> IndexObjUnion:
        """Find the named object in this tree's contents.

        :return: ``git.Blob`` or ``git.Tree`` or ``git.Submodule``
        :raise KeyError: if given file or tree does not exist in tree
        """
        msg = "Blob or Tree named %r not found"
        if "/" in file:
            tree = self
            item = self
            tokens = file.split("/")
            for i, token in enumerate(tokens):
                item = tree[token]
                if item.type == "tree":
                    tree = item
                else:
                    # Safety assertion - blobs are at the end of the path.
                    if i != len(tokens) - 1:
                        raise KeyError(msg % file)
                    return item
                # END handle item type
            # END for each token of split path
            if item == self:
                raise KeyError(msg % file)
            return item
        else:
            for info in self._cache:
                if info[2] == file:  # [2] == name
                    return self._map_id_to_type[info[1] >> 12](
                        self.repo, info[0], info[1], join_path(self.path, info[2])
                    )
            # END for each obj
            raise KeyError(msg % file)
        # END handle long paths

    def __truediv__(self, file: str) -> IndexObjUnion:
        """The ``/`` operator is another syntax for joining.

        See :meth:`join` for details.
        """
        return self.join(file)

    @property
    def trees(self) -> List["Tree"]:
        """:return: list(Tree, ...) list of trees directly below this tree"""
        return [i for i in self if i.type == "tree"]

    @property
    def blobs(self) -> List[Blob]:
        """:return: list(Blob, ...) list of blobs directly below this tree"""
        return [i for i in self if i.type == "blob"]

    @property
    def cache(self) -> TreeModifier:
        """
        :return: An object allowing to modify the internal cache. This can be used
            to change the tree's contents. When done, make sure you call ``set_done``
            on the tree modifier, or serialization behaviour will be incorrect.
            See :class:`TreeModifier` for more information on how to alter the cache.
        """
        return TreeModifier(self._cache)

    def traverse(
        self,  # type: ignore[override]
        predicate: Callable[[Union[IndexObjUnion, TraversedTreeTup], int], bool] = lambda i, d: True,
        prune: Callable[[Union[IndexObjUnion, TraversedTreeTup], int], bool] = lambda i, d: False,
        depth: int = -1,
        branch_first: bool = True,
        visit_once: bool = False,
        ignore_self: int = 1,
        as_edge: bool = False,
    ) -> Union[Iterator[IndexObjUnion], Iterator[TraversedTreeTup]]:
        """For documentation, see util.Traversable._traverse().

        Trees are set to ``visit_once = False`` to gain more performance in the traversal.
        """

        # """
        # # To typecheck instead of using cast.
        # import itertools
        # def is_tree_traversed(inp: Tuple) -> TypeGuard[Tuple[Iterator[Union['Tree', 'Blob', 'Submodule']]]]:
        #     return all(isinstance(x, (Blob, Tree, Submodule)) for x in inp[1])

        # ret = super().traverse(predicate, prune, depth, branch_first, visit_once, ignore_self)
        # ret_tup = itertools.tee(ret, 2)
        # assert is_tree_traversed(ret_tup), f"Type is {[type(x) for x in list(ret_tup[0])]}"
        # return ret_tup[0]"""
        return cast(
            Union[Iterator[IndexObjUnion], Iterator[TraversedTreeTup]],
            super()._traverse(
                predicate,
                prune,
                depth,  # type: ignore
                branch_first,
                visit_once,
                ignore_self,
            ),
        )

    def list_traverse(self, *args: Any, **kwargs: Any) -> IterableList[IndexObjUnion]:
        """
        :return: IterableList with the results of the traversal as produced by
            traverse()
            Tree -> IterableList[Union['Submodule', 'Tree', 'Blob']]
        """
        return super()._list_traverse(*args, **kwargs)

    # List protocol

    def __getslice__(self, i: int, j: int) -> List[IndexObjUnion]:
        return list(self._iter_convert_to_object(self._cache[i:j]))

    def __iter__(self) -> Iterator[IndexObjUnion]:
        return self._iter_convert_to_object(self._cache)

    def __len__(self) -> int:
        return len(self._cache)

    def __getitem__(self, item: Union[str, int, slice]) -> IndexObjUnion:
        if isinstance(item, int):
            info = self._cache[item]
            return self._map_id_to_type[info[1] >> 12](self.repo, info[0], info[1], join_path(self.path, info[2]))

        if isinstance(item, str):
            # compatibility
            return self.join(item)
        # END index is basestring

        raise TypeError("Invalid index type: %r" % item)

    def __contains__(self, item: Union[IndexObjUnion, PathLike]) -> bool:
        if isinstance(item, IndexObject):
            for info in self._cache:
                if item.binsha == info[0]:
                    return True
                # END compare sha
            # END for each entry
        # END handle item is index object
        # compatibility

        # Treat item as repo-relative path.
        else:
            path = self.path
            for info in self._cache:
                if item == join_path(path, info[2]):
                    return True
        # END for each item
        return False

    def __reversed__(self) -> Iterator[IndexObjUnion]:
        return reversed(self._iter_convert_to_object(self._cache))  # type: ignore

    def _serialize(self, stream: "BytesIO") -> "Tree":
        """Serialize this tree into the stream. Assumes sorted tree data.

        .. note:: We will assume our tree data to be in a sorted state. If this is not
            the case, serialization will not generate a correct tree representation as
            these are assumed to be sorted by algorithms.
        """
        tree_to_stream(self._cache, stream.write)
        return self

    def _deserialize(self, stream: "BytesIO") -> "Tree":
        self._cache = tree_entries_from_data(stream.read())
        return self


# END tree

# Finalize map definition.
Tree._map_id_to_type[Tree.tree_id] = Tree