Re: [PATCHv4 1/3] lists.bbclass: add class

[Uladzimir Bely <ubely@ilbers.de>]

On Thu, 2025-02-13 at 14:41 -0700, chris.larson via isar-users wrote:
> From: Christopher Larson <chris.larson@siemens.com>
> 
> This class provides functions to improve the functionality of bitbake
> list variables.
> 
> - Add the ability to remove items from a list variable without using
> :remove.
> - Add the ability for a list item to imply the addition of other list
> items.
> 
> Usage requires either adding the variable name to LIST_VARIABLES, or
> manually
> adding a :remove and a :prepend to each fully supported list
> variable.
> 
> To remove items from a configured list, simply append the item to be
> removed
> to the variable with a '-' or '~' prefix. For example, to remove
> 'alpha' from
> a configured variable, append '-alpha' to it.
> 
> To support implied list items, create a mapping of items to be
> appended to
> the variable when a specific item is present. For example, to append
> 'beta'
> to ROOTFS_FEATURES when 'alpha' is present, configure ROOTFS_FEATURES
> as such,
> then set IMPLIED_ROOTFS_FEATURES[alpha] = "beta".
> 
> Signed-off-by: Christopher Larson <chris.larson@siemens.com>
> ---
>  meta/classes/lists.bbclass | 105
> +++++++++++++++++++++++++++++++++++++
>  1 file changed, 105 insertions(+)
>  create mode 100644 meta/classes/lists.bbclass
> 
> diff --git a/meta/classes/lists.bbclass b/meta/classes/lists.bbclass
> new file mode 100644
> index 00000000..db8f5837
> --- /dev/null
> +++ b/meta/classes/lists.bbclass
> @@ -0,0 +1,105 @@
> +# Functions to improve the functionality of bitbake list variables.
> +#
> +# - Add the ability to remove items from a list variable without
> using :remove.
> +# - Add the ability for a list item to imply the addition of other
> list items.
> +#
> +
> +# Usage requires either adding the variable name to LIST_VARIABLES,
> or manually
> +# adding a :remove and a :prepend to each fully supported list
> variable.
> +#
> +# To remove items from a configured list, simply append the item to
> be removed
> +# to the variable with a '-' or '~' prefix. For example, to remove
> 'alpha' from
> +# ROOTFS_FEATURES, add '-alpha' to ROOTFS_FEATURES.
> +#
> +# To support implied list items, create a mapping of items to be
> appended to
> +# the variable when a specific item is present. For example, to
> append 'beta'
> +# to ROOTFS_FEATURES when 'alpha' is present, configure
> ROOTFS_FEATURES as such,
> +# then set IMPLIED_ROOTFS_FEATURES[alpha] = "beta".
> +#
> +# Boilerplate example:
> +#
> +#   # Either this:
> +#   LIST_VARIABLES += "ROOTFS_FEATURES"
> +#
> +#   # Or this:
> +#   ROOTFS_FEATURES:remove =
> "${@remove_prefixed_items('ROOTFS_FEATURES', d)}"
> +#   ROOTFS_FEATURES:prepend =
> "${@add_implied_items('ROOTFS_FEATURES', 'IMPLIED_ROOTFS_FEATURES',
> d)} "
> +#
> +# Usage example:
> +#
> +#   # ROOTFS_FEATURES will be "beta alpha" if the following
> configuration is used:
> +#   IMPLIED_ROOTFS_FEATURES[alpha] = "beta"
> +#   ROOTFS_FEATURES += "alpha"
> +#
> +#   # ROOTFS_FEATURES will be "first" if the following configuration
> is used:
> +#   ROOTFS_FEATURES = "first second"
> +#   ROOTFS_FEATURES += "-second"
> +
> +python enable_list_variables() {
> +    """Enable list variable functionality."""
> +    for variable in d.getVar("LIST_VARIABLES").split():
> +        d.setVar(variable + ':remove', '
> ${@remove_prefixed_items("%s", d)}' % variable)
> +        d.setVar(variable + ':prepend', '${@add_implied_items("%s",
> "IMPLIED_%s", d)} ' % (variable, variable))
> +}
> +enable_list_variables[eventmask] = "bb.event.ConfigParsed"
> +addhandler enable_list_variables
> +
> +def remove_prefixed_items(var, d):
> +    """Return the items to be removed from var with :remove.
> +
> +    This function is intended to be used in a :remove handler to
> remove
> +    items from a variable. It will interpret items prefixed with a
> '-'
> +    or '~' as items to be removed.
> +    """
> +    # Use a flag to avoid infinite recursion.
> +    if d.getVarFlag(var, 'remove_prefixed_items_internal') == '1':
> +        return ''
> +
> +    from collections import Counter
> +
> +    d.setVarFlag(var, 'remove_prefixed_items_internal', '1')
> +    try:
> +        value = d.getVar(var)
> +        counter = Counter()
> +        for v in value.split():
> +            if v.startswith('-') or v.startswith('~'):
> +                counter[v[1:]] -= 1
> +                counter[v] -= 1
> +            else:
> +                counter[v] += 1
> +        return ' '.join(v for v, c in counter.items() if c < 1)
> +    finally:
> +        d.delVarFlag(var, 'remove_prefixed_items_internal')
> +
> +
> +def add_implied_items(var, implied_var, d):
> +    """Return the items to be appended due to the presence of other
> items in var.
> +
> +    This function is intended to be used in a :append handler to
> append
> +    items from a variable. It will rely on the supplied mapping of
> implied items
> +    to append the corresponding items.
> +    """
> +    # Use a flag to avoid infinite recursion.
> +    if d.getVarFlag(var, 'add_implied_items_internal') == '1':
> +        return ''
> +
> +    def implied_items(item, implied_mapping, d, seen=None):
> +        """Return the implied items for a given item."""
> +        if seen is None:
> +            seen = set()
> +        if item in seen:
> +            return ''
> +        seen.add(item)
> +        implied = implied_mapping.get(item, '').split()
> +        return ' '.join(implied + [implied_items(f, implied_mapping,
> d, seen) for f in implied])
> +
> +    d.setVarFlag(var, 'add_implied_items_internal', '1')
> +    try:
> +        value = d.getVar(var)
> +        implied_mapping = d.getVarFlags(implied_var)
> +        if implied_mapping is None:
> +            return ''
> +
> +        return ' '.join(implied_items(f, implied_mapping, d) for f
> in value.split())
> +    finally:
> +        d.delVarFlag(var, 'add_implied_items_internal')
> -- 
> 2.47.1
> 

Applied to next, thanks.

-- 
Best regards,
Uladzimir.



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