[PATCH 04/10] meta: Add bbclass to retrieve selected WKS file

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

This implements a lookup service for the target's WKS_FILE. The goal is
to concentrate the search in a single place in order to provide a
consistent logic.

In addition to permitting absolute paths, get_wks_full_path() implements
almost all search paths of OE:

 - <BBPATH>/wic
 - <BBPATH>/scripts/lib/wic/canned-wks
 - <COREBASE>/scripts/lib/wic/canned-wks

It does not support THISDIR for wic-image recipes because that would
restrict the visibility of that file to a single recipe while we would
like to use it freely, also in other recipes such as u-boot-script.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 meta/classes/wks-file.bbclass | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 meta/classes/wks-file.bbclass

diff --git a/meta/classes/wks-file.bbclass b/meta/classes/wks-file.bbclass
new file mode 100644
index 0000000..493fea7
--- /dev/null
+++ b/meta/classes/wks-file.bbclass
@@ -0,0 +1,30 @@
+# This software is a part of ISAR.
+# Copyright (C) 2018 Siemens AG
+#
+# SPDX-License-Identifier: MIT
+
+def get_wks_full_path(d):
+    if (d.getVar('IMAGE_TYPE', True) or '') != 'wic-img':
+        return ""
+
+    wks_full_path = None
+
+    wks_file = d.getVar('WKS_FILE', True)
+    if not wks_file.endswith('.wks'):
+        wks_file += '.wks'
+
+    if os.path.isabs(wks_file):
+        if os.path.exists(wks_file):
+            wks_full_path = wks_file
+    else:
+        bbpaths = d.getVar('BBPATH', True).split(':')
+        corebase = d.getVar('COREBASE', True)
+        search_path = ':'.join('%s/wic' % p for p in bbpaths) + ':' + \
+            ':'.join('%s/scripts/lib/wic/canned-wks' % l \
+                     for l in (bbpaths + [corebase]))
+        wks_full_path = bb.utils.which(search_path, wks_file)
+
+    if not wks_full_path:
+        bb.fatal("WKS_FILE '%s' not found" % wks_file)
+
+    return wks_full_path
-- 
2.16.4