# Copyright 2009-2010 Gregory P. Ward

# Copyright 2009-2010 Intelerad Medical Systems Incorporated

# Copyright 2010-2011 Fog Creek Software

# Copyright 2010-2011 Unity Technologies

#

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

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

'''largefiles utility code: must not import other modules in this package.'''

import os

import errno

import inspect

import shutil

import stat

import hashlib

from mercurial import cmdutil, dirstate, httpconnection, match as match_, \

        url as url_, util

from mercurial.i18n import _

try:

    from mercurial import scmutil

except ImportError:

    pass

shortname = '.hglf'

longname = 'largefiles'

# -- Portability wrappers ----------------------------------------------

if 'subrepos' in inspect.getargspec(dirstate.dirstate.status)[0]:

    # for Mercurial >= 1.5

    def dirstate_walk(dirstate, matcher, unknown=False, ignored=False):

        return dirstate.walk(matcher, [], unknown, ignored)

else:

    # for Mercurial <= 1.4

    def dirstate_walk(dirstate, matcher, unknown=False, ignored=False):

        return dirstate.walk(matcher, unknown, ignored)

def repo_add(repo, list):

    try:

        # Mercurial <= 1.5

        add = repo.add

    except AttributeError:

        # Mercurial >= 1.6

        add = repo[None].add

    return add(list)

def repo_remove(repo, list, unlink=False):

    try:

        # Mercurial <= 1.5

        remove = repo.remove

    except AttributeError:

        # Mercurial >= 1.6

        try:

            # Mercurial <= 1.8

            remove = repo[None].remove

        except AttributeError:

            # Mercurial >= 1.9

            def remove(list, unlink):

                wlock = repo.wlock()

                try:

                    if unlink:

                        for f in list:

                            try:

                                util.unlinkpath(repo.wjoin(f))

                            except OSError, inst:

                                if inst.errno != errno.ENOENT:

                                    raise

                    repo[None].forget(list)

                finally:

                    wlock.release()

    return remove(list, unlink=unlink)

def repo_forget(repo, list):

    try:

        # Mercurial <= 1.5

        forget = repo.forget

    except AttributeError:

        # Mercurial >= 1.6

        forget = repo[None].forget

    return forget(list)

def findoutgoing(repo, remote, force):

    # First attempt is for Mercurial <= 1.5 second is for >= 1.6

    try:

        return repo.findoutgoing(remote)

    except AttributeError:

        from mercurial import discovery

        try:

            # Mercurial <= 1.8

            return discovery.findoutgoing(repo, remote, force=force)

        except AttributeError:

            # Mercurial >= 1.9

            common, _anyinc, _heads = discovery.findcommonincoming(repo,

                remote, force=force)

            return repo.changelog.findmissing(common)

# -- Private worker functions ------------------------------------------

def link(src, dest):

    try:

    except OSError:

        # If hardlinks fail fall back on copy

        shutil.copyfile(src, dest)

        os.chmod(dest, os.stat(src).st_mode)

def systemcachepath(ui, hash):

    path = ui.config(longname, 'systemcache', None)

    if path:

        path = os.path.join(path, hash)

    else:

        if os.name == 'nt':

            path = os.path.join(os.getenv('LOCALAPPDATA') or \

                os.getenv('APPDATA'), longname, hash)

        elif os.name == 'posix':

            path = os.path.join(os.getenv('HOME'), '.' + longname, hash)

        else:

            raise util.Abort(_('Unknown operating system: %s\n') % os.name)

    return path

def insystemcache(ui, hash):

    return os.path.exists(systemcachepath(ui, hash))

def findfile(repo, hash):

    if incache(repo, hash):

        repo.ui.note(_('Found %s in cache\n') % hash)

        return cachepath(repo, hash)

    if insystemcache(repo.ui, hash):

        repo.ui.note(_('Found %s in system cache\n') % hash)

        return systemcachepath(repo.ui, hash)

    return None

class largefiles_dirstate(dirstate.dirstate):

    def __getitem__(self, key):

        return super(largefiles_dirstate, self).__getitem__(unixpath(key))

    def normal(self, f):

        return super(largefiles_dirstate, self).normal(unixpath(f))

    def remove(self, f):

        return super(largefiles_dirstate, self).remove(unixpath(f))

    def add(self, f):

        return super(largefiles_dirstate, self).add(unixpath(f))

    def drop(self, f):

        return super(largefiles_dirstate, self).drop(unixpath(f))

    def forget(self, f):

        return super(largefiles_dirstate, self).forget(unixpath(f))

def openlfdirstate(ui, repo):

    '''

    Return a dirstate object that tracks big files: i.e. its root is the

    repo root, but it is saved in .hg/largefiles/dirstate.

    '''

    admin = repo.join(longname)

    try:

        # Mercurial >= 1.9

        opener = scmutil.opener(admin)

    except ImportError:

        # Mercurial <= 1.8

        opener = util.opener(admin)

    if util.safehasattr(repo.dirstate, '_validate'):

        lfdirstate = largefiles_dirstate(opener, ui, repo.root,

            repo.dirstate._validate)

    else:

        lfdirstate = largefiles_dirstate(opener, ui, repo.root)

    # If the largefiles dirstate does not exist, populate and create it.  This

    # ensures that we create it on the first meaningful largefiles operation in

    # a new clone.  It also gives us an easy way to forcibly rebuild largefiles

    # state:

    #   rm .hg/largefiles/dirstate && hg status

    # Or even, if things are really messed up:

    #   rm -rf .hg/largefiles && hg status

    if not os.path.exists(os.path.join(admin, 'dirstate')):

        util.makedirs(admin)

        matcher = getstandinmatcher(repo)

        for standin in dirstate_walk(repo.dirstate, matcher):

            lfile = splitstandin(standin)

            hash = readstandin(repo, lfile)

            lfdirstate.normallookup(lfile)

            try:

                if hash == hashfile(lfile):

                    lfdirstate.normal(lfile)

            except IOError, err:

                if err.errno != errno.ENOENT:

                    raise

        lfdirstate.write()

    return lfdirstate

def lfdirstate_status(lfdirstate, repo, rev):

    wlock = repo.wlock()

    try:

        match = match_.always(repo.root, repo.getcwd())

        s = lfdirstate.status(match, [], False, False, False)

        unsure, modified, added, removed, missing, unknown, ignored, clean = s

        for lfile in unsure:

            if repo[rev][standin(lfile)].data().strip() != \

                    hashfile(repo.wjoin(lfile)):

                modified.append(lfile)

            else:

                clean.append(lfile)

                lfdirstate.normal(lfile)

        lfdirstate.write()

    finally:

        wlock.release()

    return (modified, added, removed, missing, unknown, ignored, clean)

def listlfiles(repo, rev=None, matcher=None):

    '''list largefiles in the working copy or specified changeset'''

    if matcher is None:

        matcher = getstandinmatcher(repo)

    # ignore unknown files in working directory

    return [splitstandin(f) for f in repo[rev].walk(matcher) \

            if rev is not None or repo.dirstate[f] != '?']

def incache(repo, hash):

    return os.path.exists(cachepath(repo, hash))

def createdir(dir):

    if not os.path.exists(dir):

        os.makedirs(dir)

def cachepath(repo, hash):

    return repo.join(os.path.join(longname, hash))

def copyfromcache(repo, hash, filename):

    '''copyfromcache copies the specified largefile from the repo or system

    cache to the specified location in the repository.  It will not throw an

    exception on failure, as it is meant to be called only after ensuring that

    the needed largefile exists in the cache.'''

    path = findfile(repo, hash)

    if path is None:

        return False

    util.makedirs(os.path.dirname(repo.wjoin(filename)))

    shutil.copy(path, repo.wjoin(filename))

    return True

def copytocache(repo, rev, file, uploaded=False):

    hash = readstandin(repo, file)

    if incache(repo, hash):

        return

    copytocacheabsolute(repo, repo.wjoin(file), hash)

def copytocacheabsolute(repo, file, hash):

    createdir(os.path.dirname(cachepath(repo, hash)))

    if insystemcache(repo.ui, hash):

        link(systemcachepath(repo.ui, hash), cachepath(repo, hash))

    else:

        shutil.copyfile(file, cachepath(repo, hash))

        os.chmod(cachepath(repo, hash), os.stat(file).st_mode)

        linktosystemcache(repo, hash)

def linktosystemcache(repo, hash):

    createdir(os.path.dirname(systemcachepath(repo.ui, hash)))

    link(cachepath(repo, hash), systemcachepath(repo.ui, hash))

def getstandinmatcher(repo, pats=[], opts={}):

    '''Return a match object that applies pats to the standin directory'''

    standindir = repo.pathto(shortname)

    if pats:

        # patterns supplied: search standin directory relative to current dir

        cwd = repo.getcwd()

        if os.path.isabs(cwd):

            # cwd is an absolute path for hg -R <reponame>

            # work relative to the repository root in this case

            cwd = ''

        pats = [os.path.join(standindir, cwd, pat) for pat in pats]

    elif os.path.isdir(standindir):

        # no patterns: relative to repo root

        pats = [standindir]

    else:

        # no patterns and no standin dir: return matcher that matches nothing

        match = match_.match(repo.root, None, [], exact=True)

        match.matchfn = lambda f: False

        return match

    return getmatcher(repo, pats, opts, showbad=False)

def getmatcher(repo, pats=[], opts={}, showbad=True):

    '''Wrapper around scmutil.match() that adds showbad: if false, neuter

    the match object\'s bad() method so it does not print any warnings

    about missing files or directories.'''

    try:

        # Mercurial >= 1.9

        match = scmutil.match(repo[None], pats, opts)

    except ImportError:

        # Mercurial <= 1.8

        match = cmdutil.match(repo, pats, opts)

    if not showbad:

        match.bad = lambda f, msg: None

    return match

def composestandinmatcher(repo, rmatcher):

    '''Return a matcher that accepts standins corresponding to the files

    accepted by rmatcher. Pass the list of files in the matcher as the

    paths specified by the user.'''

    smatcher = getstandinmatcher(repo, rmatcher.files())

    isstandin = smatcher.matchfn

    def composed_matchfn(f):

        return isstandin(f) and rmatcher.matchfn(splitstandin(f))

    smatcher.matchfn = composed_matchfn

    return smatcher

def standin(filename):

    '''Return the repo-relative path to the standin for the specified big

    file.'''

    # Notes:

    # 1) Most callers want an absolute path, but _create_standin() needs

    #    it repo-relative so lfadd() can pass it to repo_add().  So leave

    #    it up to the caller to use repo.wjoin() to get an absolute path.

    # 2) Join with '/' because that's what dirstate always uses, even on

    #    Windows. Change existing separator to '/' first in case we are

    #    passed filenames from an external source (like the command line).

    return shortname + '/' + filename.replace(os.sep, '/')

def isstandin(filename):

    '''Return true if filename is a big file standin.  filename must

    be in Mercurial\'s internal form (slash-separated).'''

    return filename.startswith(shortname + '/')

def splitstandin(filename):

    # Split on / because that's what dirstate always uses, even on Windows.

    # Change local separator to / first just in case we are passed filenames

    # from an external source (like the command line).

    bits = filename.replace(os.sep, '/').split('/', 1)

    if len(bits) == 2 and bits[0] == shortname:

        return bits[1]

    else:

        return None

def updatestandin(repo, standin):

    file = repo.wjoin(splitstandin(standin))

    if os.path.exists(file):

        hash = hashfile(file)

        executable = getexecutable(file)

        writestandin(repo, standin, hash, executable)

def readstandin(repo, filename, node=None):

    '''read hex hash from standin for filename at given node, or working

    directory if no node is given'''

    return repo[node][standin(filename)].data().strip()

def writestandin(repo, standin, hash, executable):

    '''write hhash to <repo.root>/<standin>'''

    writehash(hash, repo.wjoin(standin), executable)

def copyandhash(instream, outfile):

    '''Read bytes from instream (iterable) and write them to outfile,

    computing the SHA-1 hash of the data along the way.  Close outfile

    when done and return the binary hash.'''

    hasher = util.sha1('')

    for data in instream:

        hasher.update(data)

        outfile.write(data)

    # Blecch: closing a file that somebody else opened is rude and

    # wrong.  But it's so darn convenient and practical!  After all,

    # outfile was opened just to copy and hash.

    outfile.close()

    return hasher.digest()

def hashrepofile(repo, file):

    return hashfile(repo.wjoin(file))

def hashfile(file):

    if not os.path.exists(file):

        return ''

    hasher = util.sha1('')

    fd = open(file, 'rb')

    for data in blockstream(fd):

        hasher.update(data)

    fd.close()

    return hasher.hexdigest()

class limitreader(object):

    def __init__(self, f, limit):

        self.f = f

        self.limit = limit

    def read(self, length):

        if self.limit == 0:

            return ''

        length = length > self.limit and self.limit or length