vcs.jam

# Version Control System module
#
# @todo propose a minimal interface for vcs (checkout, etc.)

import path ;
import errors ;
import assert ;

# the list of supported vcs
supported-vcs = archive git svn ;

for vcs in $(supported-vcs)
{
  import vcs-$(vcs) ;
}

# Generates a version string from the auto-detected VCS repository.
rule generate-version-string ( directory )
{
  # @todo need to fix this
  # if ! [ path.exists $(directory) ]
  # {
  #   errors.user-error "$(directory) does not exist." ;
  # }

  vcs = [ type $(directory) ] ;
  assert.in $(vcs) : $(supported-vcs) ;

  return [ vcs-$(vcs).generate-version-string $(directory) ] ;
}

# Returns a string describing the version control system.
rule type ( directory )
{
  t = ;
  for vcs in $(supported-vcs)
  {
    if [ vcs-$(vcs).is-repository $(directory) ]
    {
      t = $(vcs) ;
    }
  }

  if ! $(t)
  {
    errors.error "unknown vcs system at $(directory)" ;
  }

  return $(t) ;
}

# Fetches from the given url to the given directory using the
# indicated vcs.  If the directory already exists, the system will
# check that the url matches, it is an error if it doesn't.
rule fetch ( vcs : root-url : directory )
{
  assert.in $(vcs) : $(supported-vcs) ;

  if [ path.exists $(directory) ]
  {
    assert.true type $(directory) : $(vcs) ;

    local current-url = [ vcs-$(vcs).root-url $(directory) ] ;

    if $(current-url) != $(root-url)
    {
      errors.error "vcs:$(vcs): $(directory) is at $(current-url) not $(root-url)" ;
    }
  }
  else
  {
    echo "vcs: fetching $(root-url) to $(directory)" ;

    local r1 = [ vcs-$(vcs).fetch $(root-url) : $(directory) ] ;
  }
}

# check out a particular ref
rule checkout ( directory : symbolic-ref )
{
  echo $(directory) ;

  local vcs = [ type $(directory) ] ;

  assert.in $(vcs) : $(supported-vcs) ;

  echo "vcs: checking out $(symbolic-ref) at $(directory)" ;

  local r = [ vcs-$(vcs).checkout $(directory) : $(symbolic-ref) ] ;
}

# return the url associated with directory
rule root-url ( directory )
{
  local vcs = [ type $(directory) ] ;

  assert.in $(vcs) : $(supported-vcs) ;

  return [ vcs-$(vcs).root-url $(directory) ] ;
}

# return the ref associated with directory
rule ref ( directory : symbolic-ref ? )
{
  local vcs = [ type $(directory) ] ;

  assert.in $(vcs) : $(supported-vcs) ;

  return [ vcs-$(vcs).ref $(directory) : $(symbolic-ref) ] ;
}