#! /usr/bin/env python
"""
Usage:
    dumpstructure.py  [-rREV]  filename.repo  [hostname  fspath]

Create or update the given structural repository dump file
up to the given revision, or HEAD if unspecified.

When creating a dump, the hostname holding the repository and the
filesystem path to the repository must be given.

Example:
    dumpstructure.py codespeak.repo codespeak.net /svn
"""

import sys, os
import repos, cPickle

REVSTEPS = 10000

def loadrepo(filename):
    f = os.popen("gunzip -c '%s'" % (filename.replace("'", "'\\''"),), 'rb')
    repo = cPickle.load(f)
    f.close()
    return repo

def saverepo(repo, filename):
    f = os.popen("gzip > '%s'" % (filename.replace("'", "'\\''"),), 'wb')
    cPickle.dump(repo, f, 1)
    f.close()

def update(repo, filename, rev='HEAD'):
    if rev == 'HEAD':
        g = repos.execute(repo.hostname, "svnlook youngest %s" % repo.fspath)
        rev = g.read().strip()
        g.close()
    rev = int(rev)
    if rev <= repo.getrev():
        print "%s is already at revision %d." % (filename, repo.getrev())
        return
    print "updating %s to revision %d..." % (filename, rev)
    sleep = False
    while rev > repo.getrev():
        if sleep:
            print "sleeping a bit to avoid excessive traffic..."
            import time; time.sleep(10)
        else:
            sleep = True
        nextrev = min(rev, repo.getrev() + REVSTEPS)
        repos.dump_and_parse(repo, lastrev=nextrev)
        print 'writing %s...' % filename
        saverepo(repo, filename)
        print 'wrote %.2f MB' % (os.stat(filename).st_size / 1024.0 / 1024.0,)
    print "done."

# ____________________________________________________________

def main(args):
    def error(msg):
        print >> sys.stderr, msg
        sys.exit(1)
    rev = 'HEAD'
    for i in range(len(args)):
        if args[i].startswith('-r'):
            rev = args[i][2:]
            del args[i]
            break
    if len(args) not in (1, 3):
        print __doc__
        sys.exit(2)
    filename = args[0]
    if os.path.exists(filename):
        repo = loadrepo(filename)
        if len(args) == 3:
            if args[1] != repo.hostname:
                error("hostname %r differs from %r stored in the dump file"
                      % (args[1], repo.hostname))
            if args[2] != repo.fspath:
                error("fspath %r differs from %r stored in the dump file"
                      % (args[2], repo.fspath))
    else:
        if len(args) != 3:
            error("dump file %r not found, please provide hostname/fspath"
                  % filename)
        repo = repos.Repository(args[1], args[2])
    update(repo, filename, rev)

if __name__ == '__main__':
    main(sys.argv[1:])