# -*- test-case-name: buildbot.test.test_transfer -*-

import os.path
from twisted.internet import reactor
from twisted.spread import pb
from twisted.python import log
from buildbot.process.buildstep import RemoteCommand, BuildStep
from buildbot.process.buildstep import SUCCESS, FAILURE
from buildbot.interfaces import BuildSlaveTooOldError


class _FileWriter(pb.Referenceable):
    """
    Helper class that acts as a file-object with write access
    """

    def __init__(self, destfile, maxsize, mode):
        self.destfile = destfile
        self.fp = open(destfile, "wb")
        if mode is not None:
            os.chmod(destfile, mode)
	self.remaining = maxsize

    def remote_write(self, data):
	"""
	Called from remote slave to write L{data} to L{fp} within boundaries
	of L{maxsize}

	@type  data: C{string}
	@param data: String of data to write
	"""
        if self.remaining is not None:
            if len(data) > self.remaining:
                data = data[:self.remaining]
            self.fp.write(data)
            self.remaining = self.remaining - len(data)
        else:
            self.fp.write(data)

    def remote_close(self):
        """
        Called by remote slave to state that no more data will be transfered
        """
        self.fp.close()
        self.fp = None

    def __del__(self):
        # unclean shutdown, the file is probably truncated, so delete it
        # altogether rather than deliver a corrupted file
        fp = getattr(self, "fp", None)
        if fp:
            fp.close()
            os.unlink(self.destfile)


class StatusRemoteCommand(RemoteCommand):
    def __init__(self, remote_command, args):
        RemoteCommand.__init__(self, remote_command, args)

        self.rc = None
        self.stderr = ''

    def remoteUpdate(self, update):
        #log.msg('StatusRemoteCommand: update=%r' % update)
        if 'rc' in update:
            self.rc = update['rc']
        if 'stderr' in update:
            self.stderr = self.stderr + update['stderr'] + '\n'


class FileUpload(BuildStep):
    """
    Build step to transfer a file from the slave to the master.

    arguments:

    - ['slavesrc']   filename of source file at slave, relative to workdir
    - ['masterdest'] filename of destination file at master
    - ['workdir']    string with slave working directory relative to builder
                     base dir, default 'build'
    - ['maxsize']    maximum size of the file, default None (=unlimited)
    - ['blocksize']  maximum size of each block being transfered
    - ['mode']       file access mode for the resulting master-side file.
                     The default (=None) is to leave it up to the umask of
                     the buildmaster process.

    """

    name = 'upload'

    def __init__(self, slavesrc, masterdest,
                 workdir="build", maxsize=None, blocksize=16*1024, mode=None,
                 **buildstep_kwargs):
        BuildStep.__init__(self, **buildstep_kwargs)
        self.addFactoryArguments(slavesrc=slavesrc,
                                 masterdest=masterdest,
                                 workdir=workdir,
                                 maxsize=maxsize,
                                 blocksize=blocksize,
                                 mode=mode,
                                 )

        self.slavesrc = slavesrc
        self.masterdest = masterdest
        self.workdir = workdir
        self.maxsize = maxsize
        self.blocksize = blocksize
        assert isinstance(mode, (int, type(None)))
        self.mode = mode

    def start(self):
        version = self.slaveVersion("uploadFile")
        if not version:
            m = "slave is too old, does not know about uploadFile"
            raise BuildSlaveTooOldError(m)

        source = self.slavesrc
        masterdest = self.masterdest
        # we rely upon the fact that the buildmaster runs chdir'ed into its
        # basedir to make sure that relative paths in masterdest are expanded
        # properly. TODO: maybe pass the master's basedir all the way down
        # into the BuildStep so we can do this better.
        target = os.path.expanduser(masterdest)
        log.msg("FileUpload started, from slave %r to master %r"
                % (source, target))

        self.step_status.setColor('yellow')
        self.step_status.setText(['uploading', os.path.basename(source)])

        # we use maxsize to limit the amount of data on both sides
        fileWriter = _FileWriter(self.masterdest, self.maxsize, self.mode)

        # default arguments
        args = {
            'slavesrc': source,
            'workdir': self.workdir,
            'writer': fileWriter,
            'maxsize': self.maxsize,
            'blocksize': self.blocksize,
            }

        self.cmd = StatusRemoteCommand('uploadFile', args)
        d = self.runCommand(self.cmd)
        d.addCallback(self.finished).addErrback(self.failed)

    def finished(self, result):
        if self.cmd.stderr != '':
            self.addCompleteLog('stderr', self.cmd.stderr)

        if self.cmd.rc is None or self.cmd.rc == 0:
            self.step_status.setColor('green')
            return BuildStep.finished(self, SUCCESS)
        self.step_status.setColor('red')
        return BuildStep.finished(self, FAILURE)





class _FileReader(pb.Referenceable):
    """
    Helper class that acts as a file-object with read access
    """

    def __init__(self, fp):
        self.fp = fp

    def remote_read(self, maxlength):
	"""
	Called from remote slave to read at most L{maxlength} bytes of data

	@type  maxlength: C{integer}
	@param maxlength: Maximum number of data bytes that can be returned

        @return: Data read from L{fp}
        @rtype: C{string} of bytes read from file
	"""
        if self.fp is None:
            return ''

        data = self.fp.read(maxlength)
        return data

    def remote_close(self):
        """
        Called by remote slave to state that no more data will be transfered
        """
        if self.fp is not None:
            self.fp.close()
            self.fp = None


class FileDownload(BuildStep):
    """
    Download the first 'maxsize' bytes of a file, from the buildmaster to the
    buildslave. Set the mode of the file

    Arguments::

     ['mastersrc'] filename of source file at master
     ['slavedest'] filename of destination file at slave
     ['workdir']   string with slave working directory relative to builder
                   base dir, default 'build'
     ['maxsize']   maximum size of the file, default None (=unlimited)
     ['blocksize'] maximum size of each block being transfered
     ['mode']      use this to set the access permissions of the resulting
                   buildslave-side file. This is traditionally an octal
                   integer, like 0644 to be world-readable (but not
                   world-writable), or 0600 to only be readable by
                   the buildslave account, or 0755 to be world-executable.
                   The default (=None) is to leave it up to the umask of
                   the buildslave process.

    """

    name = 'download'

    def __init__(self, mastersrc, slavedest,
                 workdir="build", maxsize=None, blocksize=16*1024, mode=None,
                 **buildstep_kwargs):
        BuildStep.__init__(self, **buildstep_kwargs)
        self.addFactoryArguments(mastersrc=mastersrc,
                                 slavedest=slavedest,
                                 workdir=workdir,
                                 maxsize=maxsize,
                                 blocksize=blocksize,
                                 mode=mode,
                                 )

        self.mastersrc = mastersrc
        self.slavedest = slavedest
        self.workdir = workdir
        self.maxsize = maxsize
        self.blocksize = blocksize
        assert isinstance(mode, (int, type(None)))
        self.mode = mode

    def start(self):
        version = self.slaveVersion("downloadFile")
        if not version:
            m = "slave is too old, does not know about downloadFile"
            raise BuildSlaveTooOldError(m)

        # we are currently in the buildmaster's basedir, so any non-absolute
        # paths will be interpreted relative to that
        source = os.path.expanduser(self.mastersrc)
        slavedest = self.slavedest
        log.msg("FileDownload started, from master %r to slave %r" %
                (source, slavedest))

        self.step_status.setColor('yellow')
        self.step_status.setText(['downloading', "to",
                                  os.path.basename(slavedest)])

        # setup structures for reading the file
        try:
            fp = open(source, 'rb')
        except IOError:
            # if file does not exist, bail out with an error
            self.addCompleteLog('stderr',
                                'File %r not available at master' % source)
            # TODO: once BuildStep.start() gets rewritten to use
            # maybeDeferred, just re-raise the exception here.
            reactor.callLater(0, BuildStep.finished, self, FAILURE)
            return
        fileReader = _FileReader(fp)

        # default arguments
        args = {
            'slavedest': self.slavedest,
            'maxsize': self.maxsize,
            'reader': fileReader,
            'blocksize': self.blocksize,
            'workdir': self.workdir,
            'mode': self.mode,
            }

        self.cmd = StatusRemoteCommand('downloadFile', args)
        d = self.runCommand(self.cmd)
        d.addCallback(self.finished).addErrback(self.failed)

    def finished(self, result):
        if self.cmd.stderr != '':
            self.addCompleteLog('stderr', self.cmd.stderr)

        if self.cmd.rc is None or self.cmd.rc == 0:
            self.step_status.setColor('green')
            return BuildStep.finished(self, SUCCESS)
        self.step_status.setColor('red')
        return BuildStep.finished(self, FAILURE)

