[bitbake-devel] [PATCH 1/2] bb.utils: add get_referenced_vars
Chris Laplante
chris.laplante at agilent.com
Fri Jan 17 19:39:54 UTC 2020
Given a start expression, bb.utils.get_referenced_vars returns the
referenced variable names in a quasi-BFS order (variables within the
same level are ordered aribitrarily).
For example, given an empty data store:
bb.utils.get_referenced_vars("${A} ${B} ${d.getVar('C')}", d)
returns either ["A", "B", "C"], ["A", "C", "B"], or another
permutation.
If we then set A = "${F} ${G}", then the same call will return a
permutation of [A, B, C] concatenated with a permutation of [F, G].
This method is like a version of d.expandWithRefs().references that
gives some insight into the depth of variable references.
Signed-off-by: Chris Laplante <chris.laplante at agilent.com>
---
lib/bb/utils.py | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/lib/bb/utils.py b/lib/bb/utils.py
index d65265c..a2fd1fd 100644
--- a/lib/bb/utils.py
+++ b/lib/bb/utils.py
@@ -1026,6 +1026,43 @@ def filter(variable, checkvalues, d):
checkvalues = set(checkvalues)
return ' '.join(sorted(checkvalues & val))
+
+def get_referenced_vars(start_expr, d):
+ """
+ :return: names of vars referenced in start_expr (recursively), in quasi-BFS order (variables within the same level
+ are ordered arbitrarily)
+ """
+
+ seen = set()
+ ret = []
+
+ # The first entry in the queue is the unexpanded start expression
+ queue = collections.deque([start_expr])
+ # Subsequent entries will be variable names, so we need to track whether or not entry requires getVar
+ is_first = True
+
+ empty_data = bb.data.init()
+ while queue:
+ entry = queue.popleft()
+ if is_first:
+ # Entry is the start expression - no expansion needed
+ is_first = False
+ expression = entry
+ else:
+ # This is a variable name - need to get the value
+ expression = d.getVar(entry, False)
+ ret.append(entry)
+
+ # expandWithRefs is how we actually get the referenced variables in the expression. We call it using an empty
+ # data store because we only want the variables directly used in the expression. It returns a set, which is what
+ # dooms us to only ever be "quasi-BFS" rather than full BFS.
+ new_vars = empty_data.expandWithRefs(expression, None).references - set(seen)
+
+ queue.extend(new_vars)
+ seen.update(new_vars)
+ return ret
+
+
def cpu_count():
return multiprocessing.cpu_count()
--
2.7.4
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