# grep.py - logic for history walk and grep

#

# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

import difflib

from .i18n import _

from . import (

    error,

    match as matchmod,

    pycompat,

    scmutil,

    util,

)

def matchlines(body, regexp):

    begin = 0

    linenum = 0

    while begin < len(body):

        match = regexp.search(body, begin)

        if not match:

            break

        mstart, mend = match.span()

        linenum += body.count(b'\n', begin, mstart) + 1

        lstart = body.rfind(b'\n', begin, mstart) + 1 or begin

        begin = body.find(b'\n', mend) + 1 or len(body) + 1

        lend = begin - 1

        yield linenum, mstart - lstart, mend - lstart, body[lstart:lend]

class linestate:

    def __init__(self, line, linenum, colstart, colend):

        self.line = line

        self.linenum = linenum

        self.colstart = colstart

        self.colend = colend

    def __hash__(self):

        return hash(self.line)

    def __eq__(self, other):

        return self.line == other.line

    def findpos(self, regexp):

        """Iterate all (start, end) indices of matches"""

        yield self.colstart, self.colend

        p = self.colend

        while p < len(self.line):

            m = regexp.search(self.line, p)

            if not m:

                break

            if m.end() == p:

                p += 1

            else:

                yield m.span()

                p = m.end()

def difflinestates(a, b):

    sm = difflib.SequenceMatcher(None, a, b)

    for tag, alo, ahi, blo, bhi in sm.get_opcodes():

        if tag == 'insert':

            for i in range(blo, bhi):

                yield (b'+', b[i])

        elif tag == 'delete':

            for i in range(alo, ahi):

                yield (b'-', a[i])

        elif tag == 'replace':

            for i in range(alo, ahi):

                yield (b'-', a[i])

            for i in range(blo, bhi):

                yield (b'+', b[i])

class grepsearcher:

    """Search files and revisions for lines matching the given pattern

    Options:

    - all_files to search unchanged files at that revision.

    - diff to search files in the parent revision so diffs can be generated.

    - follow to skip files across copies and renames.

    """

    def __init__(

        self, ui, repo, regexp, all_files=False, diff=False, follow=False

    ):

        self._ui = ui

        self._repo = repo

        self._regexp = regexp

        self._all_files = all_files

        self._diff = diff

        self._follow = follow

        self._getfile = util.lrucachefunc(repo.file)

        self._getrenamed = scmutil.getrenamedfn(repo)

        self._matches = {}

        self._copies = {}

        self._skip = set()

        self._revfiles = {}

    def skipfile(self, fn, rev):

        """Exclude the given file (and the copy at the specified revision)

        from future search"""

        copy = self._copies.get(rev, {}).get(fn)

        self._skip.add(fn)

        if copy:

            self._skip.add(copy)

    def searchfiles(self, revs, makefilematcher):

        """Walk files and revisions to yield (fn, ctx, pstates, states)

        matches

        states is a list of linestate objects. pstates may be empty unless

        diff is True.

        """

        for ctx in scmutil.walkchangerevs(

            self._repo, revs, makefilematcher, self._prep

        ):

            rev = ctx.rev()

            parent = ctx.p1().rev()

            for fn in sorted(self._revfiles.get(rev, [])):

                states = self._matches[rev][fn]

                copy = self._copies.get(rev, {}).get(fn)

                if fn in self._skip:

                    if copy:

                        self._skip.add(copy)

                    continue

                pstates = self._matches.get(parent, {}).get(copy or fn, [])

                if pstates or states:

                    yield fn, ctx, pstates, states

            del self._revfiles[rev]

            # We will keep the matches dict for the duration of the window

            # clear the matches dict once the window is over

            if not self._revfiles:

                self._matches.clear()

    def _grepbody(self, fn, rev, body):

        self._matches[rev].setdefault(fn, [])

        m = self._matches[rev][fn]

        if body is None:

            return

        for lnum, cstart, cend, line in matchlines(body, self._regexp):

            s = linestate(line, lnum, cstart, cend)

            m.append(s)

    def _readfile(self, ctx, fn):

        rev = ctx.rev()

        if rev is None:

            fctx = ctx[fn]

            try:

                return fctx.data()

            except FileNotFoundError:

                pass

        else:

            flog = self._getfile(fn)

            fnode = ctx.filenode(fn)

            try:

                return flog.read(fnode)

            except error.CensoredNodeError:

                self._ui.warn(

                    _(

                        b'cannot search in censored file: '

                        b'%(filename)s:%(revnum)s\n'

                    )

                    % {b'filename': fn, b'revnum': pycompat.bytestr(rev)}

                )

    def _prep(self, ctx, fmatch):

        rev = ctx.rev()

        pctx = ctx.p1()

        self._matches.setdefault(rev, {})

        if self._diff:

            parent = pctx.rev()

            self._matches.setdefault(parent, {})

        files = self._revfiles.setdefault(rev, [])

        if rev is None:

            # in `hg grep pattern`, 2/3 of the time is spent is spent in

            # pathauditor checks without this in mozilla-central

            contextmanager = self._repo.wvfs.audit.cached

        else:

            contextmanager = util.nullcontextmanager

        with contextmanager():

            # TODO: maybe better to warn missing files?

            if self._all_files:

                fmatch = matchmod.badmatch(fmatch, lambda f, msg: None)

                filenames = ctx.matches(fmatch)

            else:

                filenames = (f for f in ctx.files() if fmatch(f))

            for fn in filenames:

                # fn might not exist in the revision (could be a file removed by

                # the revision). We could check `fn not in ctx` even when rev is

                # None, but it's less racy to protect againt that in readfile.

                if rev is not None and fn not in ctx:

                    continue

                copy = None

                if self._follow:

                    copy = self._getrenamed(fn, rev)

                    if copy:

                        self._copies.setdefault(rev, {})[fn] = copy

                        if fn in self._skip:

                            self._skip.add(copy)

                if fn in self._skip:

                    continue

                files.append(fn)

                if fn not in self._matches[rev]:

                    self._grepbody(fn, rev, self._readfile(ctx, fn))

                if self._diff:

                    pfn = copy or fn

                    if pfn not in self._matches[parent] and pfn in pctx:

                        self._grepbody(pfn, parent, self._readfile(pctx, pfn))