Render gentoo-functions modular in nature

For many years, the implied purpose of gentoo-functions has been to
provided parallel implementations of utilities provided by OpenRC, along
with a handful of peripheral functions. It is probably also fair to say
that it has not seen much in the way of maintenance until comparatively
recently. As of the present day, the status quo is not ideal. For one
thing, the library has never been particularly useful beyond this
definition. It is my hope that some of the recently added functions will
be well received by those needing to write effective shell scripts in
Gentoo for a number of relevant tasks. Certainly, there remains ample
room for improvement in that regard.

For another thing, the implementation of gentoo-functions is presently
inflexible. For instance, it is impossible to source the functions from
an OpenRC runscript without overriding the OpenRC implementations. Nor
may one source the functions from an ebuild or eclass without overriding
the Portage implementations. Indeed, it is has become something of a
mess. Not only does gentoo-functions implement a number of functions
that shadow the OpenRC implementations but so does Portage, owing to the
existence of its "isolated-functions.sh" unit. What's more, the various
implementations are of varying quality and do not necessarily behave in
the same manner.

This commit aims to address some of these issues by rendering
gentoo-functions modular in nature. It establishes the premise of having
a core library, with collections of additional functions being
optionally declarable. As such, all of the functions that shadow OpenRC
have been relocated to a unit named "rc.sh". This first change
encompasses the following public functions:

- ebegin
- eend
- eerrorn
- eindent
- einfon
- eoutdent
- esyslog
- ewarnn
- ewend
- get_bootparam
- is_older_than
- veend
- vewend
- yesno

Similarly, all of the functions that exclusively shadow Portage have
been relocated to a unit named "portage.sh". This second change
encompasses the following public functions:

- die
- edo
- eqatag
- eqawarn

The functions that remain in the "functions.sh" unit may now be
considered as core functions. To accommodate all of this, a new
GENFUN_MODULES variable is supported, whose behaviour is described
herewith.

If GENFUN_MODULES is found to be set at the time of "functions.sh" being
sourced, it shall be taken as a list of zero or more blank-separated
words. In turn, these words shall be taken as the basenames of
potentially available modules - not including the .sh suffix.
Presently, the only supported module names are "rc" and "portage".
Should either or both of these names be present, their respective units
shall be automatically sourced. If neither are present, no additional
units shall be sourced. Consequently, it becomes possible for a consumer
of gentoo-functions to request that only the core functions be declared
by writing:

  GENFUN_MODULES= . /lib/gentoo/functions.sh

If, on the other hand, GENFUN_MODULES is found not to be set then
heuristics shall be employed to determine which of the additional units
should be sourced. The intent of these heuristics is twofold. Firstly,
to maintain an adequate degree of backward-compatibility and, secondly,
to act as is appropriate based on the characteristics of the operating
environment. The exact behaviour of these heuristics is as follows.

If the present shell is neither executing a runscript nor a subprocess
of one, the ensuing behaviour shall be as if "rc" had initially been
among the names defined by the GENFUN_MODULES variable.

If the present shell is not a subprocess of portage, the ensuing
behaviour shall be as if "portage" had initially been among the names
defined by the GENFUN_MODULES variable.

Signed-off-by: Kerin Millar <kfm@plushkava.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/test-functions b/test-functions
index 0b987ab..d086e16 100755
--- a/test-functions
+++ b/test-functions
@@ -664,7 +664,11 @@ export TZ=UTC
 testnum=0
 rc=0
 
-if ! . ./functions.sh; then
+if [ "${PORTAGE_BIN_PATH}" ] && [ "${S}" ]; then
+	genfun_basedir=${S}
+fi
+
+if ! GENFUN_MODULES="portage rc" . ./functions.sh; then
 	bailout "Couldn't source ./functions.sh"
 fi