vcs-archive.jam

# Version Control System - Web Archives
#
# @todo detect if curl or wget is available

import path ;
import errors ;
import assert ;

# Generates a version string from an archive directory assuming a
# naming convention.
#
#    <tag-name>
rule generate-version-string ( directory )
{
  # @todo not sure why this doesn't work
  # assert.true path.exists $(directory)/.vcs-archive-version-string ;

  return [ read-file $(directory)/.vcs-archive-version-string ] ;
}

# Fetches from the given url to the given directory.
rule fetch ( root-url : directory )
{
  path.makedirs $(directory) ;

  # @todo check results
  # @todo lots more work, package types, etc
  local r = [ fetch-url $(root-url) : $(directory)/.vcs-archive.tar.gz ] ;

  # @todo should work, but doesn't
  # assert.true path.exists $(directory) ;

  # store the root-url for use later
  write-file $(directory)/.vcs-archive-root-url : $(root-url) ;
}

# Checks out the indicated symbolic reference for the archive
# repository at directory.
#
# A symbolic reference for an archive repository is the URL it was
# fetched from.
#
#    trunk
#    tags/1.1.1
#    branches/devel-fixes
rule checkout ( directory : symbolic-ref )
{
###  program-string = "
###import tarfile
###
###archive = tarfile.open('$(directory)/.vcs-archive.tar.gz')
###archive.extractall('$(directory)', members=stripped_leading_directory)
###archive.close()
###" ;
###
###  python-with-string $(program-string) ;

  # @todo check results
  local r = [ SHELL "tar -x -C $(directory) --strip-components 1 -z -f $(directory)/.vcs-archive.tar.gz" ] ;

  write-file $(directory)/.vcs-archive-version-string : $(symbolic-ref) ;
}

# Returns the root URL of the archive repository at the given
# directory.
rule root-url ( directory )
{
  return [ read-file $(directory)/.vcs-archive-root-url ] ;
}

# Returns the ref for the symbolic-ref if it is not empty or HEAD for
# the archive repository at directory.
#
# For an archive repository, a ref is the URL fragment beyond the root
# and the last changed revision.
#
#    tags/1.1.1@12345
rule ref ( directory : symbolic-ref ? )
{
  if $(symbolic-ref)
  {
    # @todo not sure why this doesn't work
    # assert.true path.exists $(directory)/.vcs-archive-version-string ;

    local current-symbolic-ref = [ read-file $(directory)/.vcs-archive-version-string ] ;

    if $(current-symbolic-ref) = $(symbolic-ref)
    {
      return [ read-file $(directory)/.vcs-archive-root-url ] ;
    }
    else
    {
      # we only know the "ref" to what we have, so return nothing
      return ;
    }
  }
  else
  {
    return [ read-file $(directory)/.vcs-archive-root-url ] ;
  }
}

# Returns true if the given directory is an archive repository.
rule is-repository ( directory )
{
  # @todo is there a better way?
  return [ path.exists $(directory)/.vcs-archive-root-url ] ;
}

# Return true if the executable exists to operate on archives.
#
# @todo maybe we should just require python and 7z.
#
# - python and 7z
#
# OR
#
# - wget or curl
# - tar + gzip/bzip2
# - unzip
# - 7z
rule executable-exists ( )
{
  # @todo always say true for now
  return 1 == 1 ;
}

local rule fetch-url ( url : filename )
{
  program-string = "
import urllib

urllib.urlretrieve('$(url)','$(filename)')
" ;

  local r = [ python-with-string $(program-string) ] ;
}

# Returns the contents of file referenced by filename as a string.
local rule read-file ( filename )
{
  program-string = "
import sys

with open('$(filename)', 'r') as fp:
    sys.stdout.write(fp.read())
" ;

  return [ python-with-string $(program-string) ] ;
}

# Writes the string to the contents of the file referenced to by
# filename.
local rule write-file ( filename : string )
{
  echo $(string) ;

  program-string = "
with open('$(filename)', 'w') as fp:
    fp.write('$(string)')
" ;

  python-with-string $(program-string) ;
}

local rule python-with-string ( program-string )
{
  return [ SHELL "echo \"$(program-string)\" | python -" ] ;
}