from __future__ import absolute_import

import errno

import hashlib

import os

import shutil

import stat

import time

from mercurial.i18n import _

from mercurial.node import bin, hex

from mercurial import (

    error,

    pycompat,

    util,

)

from . import (

    constants,

    shallowutil,

)

class basestore(object):

    def __init__(self, repo, path, reponame, shared=False):

        """Creates a remotefilelog store object for the given repo name.

        `path` - The file path where this store keeps its data

        `reponame` - The name of the repo. This is used to partition data from

        many repos.

        `shared` - True if this store is a shared cache of data from the central

        server, for many repos on this machine. False means this store is for

        the local data for one repo.

        """

        self.repo = repo

        self.ui = repo.ui

        self._path = path

        self._reponame = reponame

        self._shared = shared

        self._uid = os.getuid() if not pycompat.iswindows else None

        if self._validatecache not in ('on', 'strict', 'off'):

            self._validatecache = 'on'

        if self._validatecache == 'off':

            self._validatecache = False

        if shared:

            shallowutil.mkstickygroupdir(self.ui, path)

    def getmissing(self, keys):

        missing = []

        for name, node in keys:

            filepath = self._getfilepath(name, node)

            exists = os.path.exists(filepath)

                exists = False

            if not exists:

                missing.append((name, node))

        return missing

    # BELOW THIS ARE IMPLEMENTATIONS OF REPACK SOURCE

    def markledger(self, ledger, options=None):

        if options and options.get(constants.OPTION_PACKSONLY):

            return

        if self._shared:

            for filename, nodes in self._getfiles():

                for node in nodes:

                    ledger.markdataentry(self, filename, node)

                    ledger.markhistoryentry(self, filename, node)

    def cleanup(self, ledger):

        ui = self.ui

        entries = ledger.sources.get(self, [])

        count = 0

        for entry in entries:

            if entry.gced or (entry.datarepacked and entry.historyrepacked):

                progress.update(count)

                path = self._getfilepath(entry.filename, entry.node)

                util.tryunlink(path)

            count += 1

        progress.complete()

        # Clean up the repo cache directory.

        self._cleanupdirectory(self._getrepocachepath())

    # BELOW THIS ARE NON-STANDARD APIS

    def _cleanupdirectory(self, rootdir):

        """Removes the empty directories and unnecessary files within the root

        directory recursively. Note that this method does not remove the root

        directory itself. """

        oldfiles = set()

        otherfiles = set()

        # osutil.listdir returns stat information which saves some rmdir/listdir

        # syscalls.

        for name, mode in util.osutil.listdir(rootdir):

            if stat.S_ISDIR(mode):

                dirpath = os.path.join(rootdir, name)

                self._cleanupdirectory(dirpath)

                # Now that the directory specified by dirpath is potentially

                # empty, try and remove it.

                try:

                    os.rmdir(dirpath)

                except OSError:

                    pass

            elif stat.S_ISREG(mode):

                if name.endswith('_old'):

                    oldfiles.add(name[:-4])

                else:

                    otherfiles.add(name)

        # Remove the files which end with suffix '_old' and have no

        # corresponding file without the suffix '_old'. See addremotefilelognode

        # method for the generation/purpose of files with '_old' suffix.

        for filename in oldfiles - otherfiles:

            filepath = os.path.join(rootdir, filename + '_old')

            util.tryunlink(filepath)

    def _getfiles(self):

        """Return a list of (filename, [node,...]) for all the revisions that

        exist in the store.

        This is useful for obtaining a list of all the contents of the store

        when performing a repack to another store, since the store API requires

        name+node keys and not namehash+node keys.

        """

        existing = {}

        for filenamehash, node in self._listkeys():

            existing.setdefault(filenamehash, []).append(node)

        filenamemap = self._resolvefilenames(existing.keys())

        for filename, sha in filenamemap.iteritems():

            yield (filename, existing[sha])

    def _resolvefilenames(self, hashes):

        """Given a list of filename hashes that are present in the

        remotefilelog store, return a mapping from filename->hash.

        This is useful when converting remotefilelog blobs into other storage

        formats.

        """

        if not hashes:

            return {}

        filenames = {}

        missingfilename = set(hashes)

        # Start with a full manifest, since it'll cover the majority of files

        for filename in self.repo['tip'].manifest():

            sha = hashlib.sha1(filename).digest()

            if sha in missingfilename:

                filenames[filename] = sha

                missingfilename.discard(sha)

        # Scan the changelog until we've found every file name

        cl = self.repo.unfiltered().changelog

        for rev in pycompat.xrange(len(cl) - 1, -1, -1):

            if not missingfilename:

                break

            files = cl.readfiles(cl.node(rev))

            for filename in files:

                sha = hashlib.sha1(filename).digest()

                if sha in missingfilename:

                    filenames[filename] = sha

                    missingfilename.discard(sha)

        return filenames

    def _getrepocachepath(self):

    def _listkeys(self):

        """List all the remotefilelog keys that exist in the store.

        Returns a iterator of (filename hash, filecontent hash) tuples.

        """

        for root, dirs, files in os.walk(self._getrepocachepath()):

            for filename in files:

                if len(filename) != 40:

                    continue

                node = filename

                if self._shared:

                    # .../1a/85ffda..be21

                    filenamehash = root[-41:-39] + root[-38:]

                else:

                    filenamehash = root[-40:]

                yield (bin(filenamehash), bin(node))

    def _getfilepath(self, name, node):

        node = hex(node)

        if self._shared:

            key = shallowutil.getcachekey(self._reponame, name, node)

        else:

            key = shallowutil.getlocalkey(name, node)

        return os.path.join(self._path, key)

    def _getdata(self, name, node):

        filepath = self._getfilepath(name, node)

        try:

            data = shallowutil.readfile(filepath)

            if self._validatecache and not self._validatedata(data, filepath):

                if self._validatecachelog:

                    with open(self._validatecachelog, 'a+') as f:

                        f.write("corrupt %s during read\n" % filepath)

                os.rename(filepath, filepath + ".corrupt")

                raise KeyError("corrupt local cache file %s" % filepath)

        except IOError:

        return data

    def addremotefilelognode(self, name, node, data):

        filepath = self._getfilepath(name, node)

        oldumask = os.umask(0o002)

        try:

            # if this node already exists, save the old version for

            # recovery/debugging purposes.

            if os.path.exists(filepath):

                newfilename = filepath + '_old'

                # newfilename can be read-only and shutil.copy will fail.

                # Delete newfilename to avoid it

                if os.path.exists(newfilename):

                    shallowutil.unlinkfile(newfilename)

                shutil.copy(filepath, newfilename)

            shallowutil.mkstickygroupdir(self.ui, os.path.dirname(filepath))

            shallowutil.writefile(filepath, data, readonly=True)

            if self._validatecache:

                if not self._validatekey(filepath, 'write'):

        finally:

            os.umask(oldumask)

    def markrepo(self, path):

        """Call this to add the given repo path to the store's list of

        repositories that are using it. This is useful later when doing garbage

        collection, since it allows us to insecpt the repos to see what nodes

        they want to be kept alive in the store.

        """

        repospath = os.path.join(self._path, "repos")

        with open(repospath, 'ab') as reposfile:

            reposfile.write(os.path.dirname(path) + "\n")

        repospathstat = os.stat(repospath)

        if repospathstat.st_uid == self._uid:

            os.chmod(repospath, 0o0664)

    def _validatekey(self, path, action):

        with open(path, 'rb') as f:

            data = f.read()

        if self._validatedata(data, path):

            return True

        if self._validatecachelog:

            with open(self._validatecachelog, 'ab+') as f:

                f.write("corrupt %s during %s\n" % (path, action))

        os.rename(path, path + ".corrupt")

        return False

    def _validatedata(self, data, path):

        try:

            if len(data) > 0:

                # see remotefilelogserver.createfileblob for the format

                offset, size, flags = shallowutil.parsesizeflags(data)

                if len(data) <= size:

                    # it is truncated

                    return False

                # extract the node from the metadata

                offset += size

                # and compare against the path

                if os.path.basename(path) == hex(datanode):

                    # Content matches the intended path

                    return True

                return False

        except (ValueError, RuntimeError):

            pass

        return False

    def gc(self, keepkeys):

        ui = self.ui

        cachepath = self._path

        # prune cache

        queue = pycompat.queue.PriorityQueue()

        originalsize = 0

        size = 0

        count = 0

        removed = 0

        # keep files newer than a day even if they aren't needed

        limit = time.time() - (60 * 60 * 24)

        progress.update(0)

        for root, dirs, files in os.walk(cachepath):

            for file in files:

                if file == 'repos':

                    continue

                # Don't delete pack files

                if '/packs/' in root:

                    continue

                progress.update(count)

                path = os.path.join(root, file)

                key = os.path.relpath(path, cachepath)

                count += 1

                try:

                    pathstat = os.stat(path)

                except OSError as e:

                    # errno.ENOENT = no such file or directory

                    if e.errno != errno.ENOENT:

                        raise

                    msg = _("warning: file %s was removed by another process\n")

                    ui.warn(msg % path)

                    continue

                originalsize += pathstat.st_size

                if key in keepkeys or pathstat.st_atime > limit:

                    queue.put((pathstat.st_atime, path, pathstat))

                    size += pathstat.st_size

                else:

                    try:

                        shallowutil.unlinkfile(path)

                    except OSError as e:

                        # errno.ENOENT = no such file or directory

                        if e.errno != errno.ENOENT:

                            raise

                        ui.warn(msg % path)

                        continue

                    removed += 1

        progress.complete()

        # remove oldest files until under limit

        limit = ui.configbytes("remotefilelog", "cachelimit")

        if size > limit:

            excess = size - limit

            removedexcess = 0

            while queue and size > limit and size > 0:

                progress.update(removedexcess)

                atime, oldpath, oldpathstat = queue.get()

                try:

                    shallowutil.unlinkfile(oldpath)

                except OSError as e:

                    # errno.ENOENT = no such file or directory

                    if e.errno != errno.ENOENT:

                        raise

                    msg = _("warning: file %s was removed by another process\n")

                    ui.warn(msg % oldpath)

                size -= oldpathstat.st_size

                removed += 1

                removedexcess += oldpathstat.st_size

            progress.complete()