# Copyright 2001-2020 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2


# The format for a tbz2/xpak:
#
#  tbz2: tar.bz2 + xpak + (xpak_offset) + "STOP"
#  xpak: "XPAKPACK" + (index_len) + (data_len) + index + data + "XPAKSTOP"
# index: (pathname_len) + pathname + (data_offset) + (data_len)
#        index entries are concatenated end-to-end.
#  data: concatenated data chunks, end-to-end.
#
# [tarball]XPAKPACKIIIIDDDD[index][data]XPAKSTOPOOOOSTOP
#
# (integer) == encodeint(integer)  ===> 4 characters (big-endian copy)
# '+' means concatenate the fields ===> All chunks are strings

__all__ = [
    "addtolist",
    "decodeint",
    "encodeint",
    "getboth",
    "getindex",
    "getindex_mem",
    "getitem",
    "listindex",
    "searchindex",
    "tbz2",
    "xpak_mem",
    "xpak",
    "xpand",
    "xsplit",
    "xsplit_mem",
]

import array
import errno

import portage
from portage import os
from portage import shutil
from portage import normalize_path
from portage import _encodings
from portage import _unicode_decode
from portage import _unicode_encode
from portage.util.file_copy import copyfile


def addtolist(mylist, curdir):
    """(list, dir) --- Takes an array(list) and appends all files from dir down
    the directory tree. Returns nothing. list is modified."""
    curdir = normalize_path(
        _unicode_decode(curdir, encoding=_encodings["fs"], errors="strict")
    )
    for parent, dirs, files in os.walk(curdir):

        parent = _unicode_decode(parent, encoding=_encodings["fs"], errors="strict")
        if parent != curdir:
            mylist.append(parent[len(curdir) + 1 :] + os.sep)

        for x in dirs:
            try:
                _unicode_decode(x, encoding=_encodings["fs"], errors="strict")
            except UnicodeDecodeError:
                dirs.remove(x)

        for x in files:
            try:
                x = _unicode_decode(x, encoding=_encodings["fs"], errors="strict")
            except UnicodeDecodeError:
                continue
            mylist.append(os.path.join(parent, x)[len(curdir) + 1 :])


def encodeint(myint):
    """Takes a 4 byte integer and converts it into a string of 4 characters.
    Returns the characters in a string."""
    a = array.array("B")
    a.append((myint >> 24) & 0xFF)
    a.append((myint >> 16) & 0xFF)
    a.append((myint >> 8) & 0xFF)
    a.append(myint & 0xFF)
    try:
        # Python >= 3.2
        return a.tobytes()
    except AttributeError:
        return a.tostring()


def decodeint(mystring):
    """Takes a 4 byte string and converts it into a 4 byte integer.
    Returns an integer."""
    myint = 0
    myint += mystring[3]
    myint += mystring[2] << 8
    myint += mystring[1] << 16
    myint += mystring[0] << 24
    return myint


def xpak(rootdir, outfile=None):
    """(rootdir, outfile) -- creates an xpak segment of the directory 'rootdir'
    and under the name 'outfile' if it is specified. Otherwise it returns the
    xpak segment."""

    mylist = []

    addtolist(mylist, rootdir)
    mylist.sort()
    mydata = {}
    for x in mylist:
        if x == "CONTENTS":
            # CONTENTS is generated during the merge process.
            continue
        x = _unicode_encode(x, encoding=_encodings["fs"], errors="strict")
        with open(os.path.join(rootdir, x), "rb") as f:
            mydata[x] = f.read()

    xpak_segment = xpak_mem(mydata)
    if outfile:
        outf = open(
            _unicode_encode(outfile, encoding=_encodings["fs"], errors="strict"), "wb"
        )
        outf.write(xpak_segment)
        outf.close()
    else:
        return xpak_segment


def xpak_mem(mydata):
    """Create an xpack segment from a map object."""

    mydata_encoded = {}
    for k, v in mydata.items():
        k = _unicode_encode(
            k, encoding=_encodings["repo.content"], errors="backslashreplace"
        )
        v = _unicode_encode(
            v, encoding=_encodings["repo.content"], errors="backslashreplace"
        )
        mydata_encoded[k] = v
    mydata = mydata_encoded
    del mydata_encoded

    indexglob = b""
    indexpos = 0
    dataglob = b""
    datapos = 0
    for x, newglob in mydata.items():
        mydatasize = len(newglob)
        indexglob = (
            indexglob
            + encodeint(len(x))
            + x
            + encodeint(datapos)
            + encodeint(mydatasize)
        )
        indexpos = indexpos + 4 + len(x) + 4 + 4
        dataglob = dataglob + newglob
        datapos = datapos + mydatasize
    return (
        b"XPAKPACK"
        + encodeint(len(indexglob))
        + encodeint(len(dataglob))
        + indexglob
        + dataglob
        + b"XPAKSTOP"
    )


def xsplit(infile):
    """(infile) -- Splits the infile into two files.
    'infile.index' contains the index segment.
    'infile.dat' contails the data segment."""
    infile = _unicode_decode(infile, encoding=_encodings["fs"], errors="strict")
    myfile = open(
        _unicode_encode(infile, encoding=_encodings["fs"], errors="strict"), "rb"
    )
    mydat = myfile.read()
    myfile.close()

    splits = xsplit_mem(mydat)
    if not splits:
        return False

    myfile = open(
        _unicode_encode(infile + ".index", encoding=_encodings["fs"], errors="strict"),
        "wb",
    )
    myfile.write(splits[0])
    myfile.close()
    myfile = open(
        _unicode_encode(infile + ".dat", encoding=_encodings["fs"], errors="strict"),
        "wb",
    )
    myfile.write(splits[1])
    myfile.close()
    return True


def xsplit_mem(mydat):
    if mydat[0:8] != b"XPAKPACK":
        return None
    if mydat[-8:] != b"XPAKSTOP":
        return None
    indexsize = decodeint(mydat[8:12])
    return (mydat[16 : indexsize + 16], mydat[indexsize + 16 : -8])


def getindex(infile):
    """(infile) -- grabs the index segment from the infile and returns it."""
    myfile = open(
        _unicode_encode(infile, encoding=_encodings["fs"], errors="strict"), "rb"
    )
    myheader = myfile.read(16)
    if myheader[0:8] != b"XPAKPACK":
        myfile.close()
        return
    indexsize = decodeint(myheader[8:12])
    myindex = myfile.read(indexsize)
    myfile.close()
    return myindex


def getboth(infile):
    """(infile) -- grabs the index and data segments from the infile.
    Returns an array [indexSegment, dataSegment]"""
    myfile = open(
        _unicode_encode(infile, encoding=_encodings["fs"], errors="strict"), "rb"
    )
    myheader = myfile.read(16)
    if myheader[0:8] != b"XPAKPACK":
        myfile.close()
        return
    indexsize = decodeint(myheader[8:12])
    datasize = decodeint(myheader[12:16])
    myindex = myfile.read(indexsize)
    mydata = myfile.read(datasize)
    myfile.close()
    return myindex, mydata


def listindex(myindex):
    """Print to the terminal the filenames listed in the indexglob passed in."""
    for x in getindex_mem(myindex):
        print(x)


def getindex_mem(myindex):
    """Returns the filenames listed in the indexglob passed in."""
    myindexlen = len(myindex)
    startpos = 0
    myret = []
    while (startpos + 8) < myindexlen:
        mytestlen = decodeint(myindex[startpos : startpos + 4])
        myret = myret + [myindex[startpos + 4 : startpos + 4 + mytestlen]]
        startpos = startpos + mytestlen + 12
    return myret


def searchindex(myindex, myitem):
    """(index, item) -- Finds the offset and length of the file 'item' in the
    datasegment via the index 'index' provided."""
    myitem = _unicode_encode(
        myitem, encoding=_encodings["repo.content"], errors="backslashreplace"
    )
    mylen = len(myitem)
    myindexlen = len(myindex)
    startpos = 0
    while (startpos + 8) < myindexlen:
        mytestlen = decodeint(myindex[startpos : startpos + 4])
        if mytestlen == mylen:
            if myitem == myindex[startpos + 4 : startpos + 4 + mytestlen]:
                # found
                datapos = decodeint(
                    myindex[startpos + 4 + mytestlen : startpos + 8 + mytestlen]
                )
                datalen = decodeint(
                    myindex[startpos + 8 + mytestlen : startpos + 12 + mytestlen]
                )
                return datapos, datalen
        startpos = startpos + mytestlen + 12


def getitem(myid, myitem):
    myindex = myid[0]
    mydata = myid[1]
    myloc = searchindex(myindex, myitem)
    if not myloc:
        return None
    return mydata[myloc[0] : myloc[0] + myloc[1]]


def xpand(myid, mydest):
    mydest = normalize_path(mydest) + os.sep
    myindex = myid[0]
    mydata = myid[1]
    myindexlen = len(myindex)
    startpos = 0
    while (startpos + 8) < myindexlen:
        namelen = decodeint(myindex[startpos : startpos + 4])
        datapos = decodeint(myindex[startpos + 4 + namelen : startpos + 8 + namelen])
        datalen = decodeint(myindex[startpos + 8 + namelen : startpos + 12 + namelen])
        myname = myindex[startpos + 4 : startpos + 4 + namelen]
        myname = _unicode_decode(
            myname, encoding=_encodings["repo.content"], errors="replace"
        )
        filename = os.path.join(mydest, myname.lstrip(os.sep))
        filename = normalize_path(filename)
        if not filename.startswith(mydest):
            # myname contains invalid ../ component(s)
            continue
        dirname = os.path.dirname(filename)
        if dirname:
            if not os.path.exists(dirname):
                os.makedirs(dirname)
        mydat = open(
            _unicode_encode(filename, encoding=_encodings["fs"], errors="strict"), "wb"
        )
        mydat.write(mydata[datapos : datapos + datalen])
        mydat.close()
        startpos = startpos + namelen + 12


class tbz2:
    def __init__(self, myfile):
        self.file = myfile
        self.filestat = None
        self.index = b""
        self.infosize = 0
        self.xpaksize = 0
        self.indexsize = None
        self.datasize = None
        self.indexpos = None
        self.datapos = None

    def decompose(self, datadir, cleanup=1):
        """Alias for unpackinfo() --- Complement to recompose() but optionally
        deletes the destination directory. Extracts the xpak from the tbz2 into
        the directory provided. Raises IOError if scan() fails.
        Returns result of upackinfo()."""
        if not self.scan():
            raise IOError
        if cleanup:
            self.cleanup(datadir)
        if not os.path.exists(datadir):
            os.makedirs(datadir)
        return self.unpackinfo(datadir)

    def compose(self, datadir, cleanup=0):
        """Alias for recompose()."""
        return self.recompose(datadir, cleanup)

    def recompose(self, datadir, cleanup=0, break_hardlinks=True):
        """Creates an xpak segment from the datadir provided, truncates the tbz2
        to the end of regular data if an xpak segment already exists, and adds
        the new segment to the file with terminating info."""
        xpdata = xpak(datadir)
        self.recompose_mem(xpdata, break_hardlinks=break_hardlinks)
        if cleanup:
            self.cleanup(datadir)

    def recompose_mem(self, xpdata, break_hardlinks=True):
        """
        Update the xpak segment.
        @param xpdata: A new xpak segment to be written, like that returned
                from the xpak_mem() function.
        @param break_hardlinks: If hardlinks exist, create a copy in order
                to break them. This makes it safe to use hardlinks to create
                cheap snapshots of the repository, which is useful for solving
                race conditions on binhosts as described here:
                https://crbug.com/185031
                Default is True.
        """
        self.scan()  # Don't care about condition... We'll rewrite the data anyway.

        if break_hardlinks and self.filestat and self.filestat.st_nlink > 1:
            tmp_fname = "%s.%d" % (self.file, portage.getpid())
            copyfile(self.file, tmp_fname)
            try:
                portage.util.apply_stat_permissions(self.file, self.filestat)
            except portage.exception.OperationNotPermitted:
                pass
            os.rename(tmp_fname, self.file)

        myfile = open(
            _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"),
            "ab+",
        )
        if not myfile:
            raise IOError
        myfile.seek(-self.xpaksize, 2)  # 0,2 or -0,2 just mean EOF.
        myfile.truncate()
        myfile.write(xpdata + encodeint(len(xpdata)) + b"STOP")
        myfile.flush()
        myfile.close()
        return 1

    def cleanup(self, datadir):
        datadir_split = os.path.split(datadir)
        if len(datadir_split) >= 2 and len(datadir_split[1]) > 0:
            # This is potentially dangerous,
            # thus the above sanity check.
            try:
                shutil.rmtree(datadir)
            except OSError as oe:
                if oe.errno == errno.ENOENT:
                    pass
                else:
                    raise oe

    def scan(self):
        """Scans the tbz2 to locate the xpak segment and setup internal values.
        This function is called by relevant functions already."""
        a = None
        try:
            mystat = os.stat(self.file)
            if self.filestat:
                changed = 0
                if (
                    mystat.st_size != self.filestat.st_size
                    or mystat.st_mtime != self.filestat.st_mtime
                    or mystat.st_ctime != self.filestat.st_ctime
                ):
                    changed = True
                if not changed:
                    return 1
            self.filestat = mystat
            a = open(
                _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"),
                "rb",
            )
            a.seek(-16, 2)
            trailer = a.read()
            self.infosize = 0
            self.xpaksize = 0
            if trailer[-4:] != b"STOP":
                return 0
            if trailer[0:8] != b"XPAKSTOP":
                return 0
            self.infosize = decodeint(trailer[8:12])
            self.xpaksize = self.infosize + 8
            a.seek(-(self.xpaksize), 2)
            header = a.read(16)
            if header[0:8] != b"XPAKPACK":
                return 0
            self.indexsize = decodeint(header[8:12])
            self.datasize = decodeint(header[12:16])
            self.indexpos = a.tell()
            self.index = a.read(self.indexsize)
            self.datapos = a.tell()
            return 2
        except SystemExit:
            raise
        except:
            return 0
        finally:
            if a is not None:
                a.close()

    def filelist(self):
        """Return an array of each file listed in the index."""
        if not self.scan():
            return None
        return getindex_mem(self.index)

    def getfile(self, myfile, mydefault=None):
        """Finds 'myfile' in the data segment and returns it."""
        if not self.scan():
            return None
        myresult = searchindex(self.index, myfile)
        if not myresult:
            return mydefault
        a = open(
            _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"), "rb"
        )
        a.seek(self.datapos + myresult[0], 0)
        myreturn = a.read(myresult[1])
        a.close()
        return myreturn

    def getelements(self, myfile):
        """A split/array representation of tbz2.getfile()"""
        mydat = self.getfile(myfile)
        if not mydat:
            return []
        return mydat.split()

    def unpackinfo(self, mydest):
        """Unpacks all the files from the dataSegment into 'mydest'."""
        if not self.scan():
            return 0
        mydest = normalize_path(mydest) + os.sep
        a = open(
            _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"), "rb"
        )
        if not os.path.exists(mydest):
            os.makedirs(mydest)
        startpos = 0
        while (startpos + 8) < self.indexsize:
            namelen = decodeint(self.index[startpos : startpos + 4])
            datapos = decodeint(
                self.index[startpos + 4 + namelen : startpos + 8 + namelen]
            )
            datalen = decodeint(
                self.index[startpos + 8 + namelen : startpos + 12 + namelen]
            )
            myname = self.index[startpos + 4 : startpos + 4 + namelen]
            myname = _unicode_decode(
                myname, encoding=_encodings["repo.content"], errors="replace"
            )
            filename = os.path.join(mydest, myname.lstrip(os.sep))
            filename = normalize_path(filename)
            if not filename.startswith(mydest):
                # myname contains invalid ../ component(s)
                continue
            dirname = os.path.dirname(filename)
            if dirname:
                if not os.path.exists(dirname):
                    os.makedirs(dirname)
            mydat = open(
                _unicode_encode(filename, encoding=_encodings["fs"], errors="strict"),
                "wb",
            )
            a.seek(self.datapos + datapos)
            mydat.write(a.read(datalen))
            mydat.close()
            startpos = startpos + namelen + 12
        a.close()
        return 1

    def get_data(self):
        """Returns all the files from the dataSegment as a map object."""
        if not self.scan():
            return {}
        a = open(
            _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"), "rb"
        )
        mydata = {}
        startpos = 0
        while (startpos + 8) < self.indexsize:
            namelen = decodeint(self.index[startpos : startpos + 4])
            datapos = decodeint(
                self.index[startpos + 4 + namelen : startpos + 8 + namelen]
            )
            datalen = decodeint(
                self.index[startpos + 8 + namelen : startpos + 12 + namelen]
            )
            myname = self.index[startpos + 4 : startpos + 4 + namelen]
            a.seek(self.datapos + datapos)
            mydata[myname] = a.read(datalen)
            startpos = startpos + namelen + 12
        a.close()
        return mydata

    def getboth(self):
        """Returns an array [indexSegment, dataSegment]"""
        if not self.scan():
            return None

        a = open(
            _unicode_encode(self.file, encoding=_encodings["fs"], errors="strict"), "rb"
        )
        a.seek(self.datapos)
        mydata = a.read(self.datasize)
        a.close()

        return self.index, mydata