allnoconfig: Move from examples/ to root

Put to-be-packaged stuff in the root.

Use allnoconfig_simpler.py, and rename allnoconfig.py to
allnoconfig_walk.py and keep it as an example.

1 files changed, 60 insertions, 0 deletions

diff --git a/examples/allnoconfig_walk.py b/examples/allnoconfig_walk.py
new file mode 100644
index 0000000..8e22cd9
--- /dev/null
+++ b/examples/allnoconfig_walk.py
@@ -0,0 +1,60 @@
+# This is tree-walking version of allnoconfig.py, for demonstration purposes.
+# Verified by the test suite to generate identical output to 'make allnoconfig'
+# for all ARCHes.
+#
+# Usage for the Linux kernel:
+#
+#   $ make [ARCH=<arch>] scriptconfig SCRIPT=Kconfiglib/examples/allnoconfig_walk.py
+
+from kconfiglib import Kconfig, Symbol
+import sys
+
+def do_allnoconfig(node):
+    global changed
+
+    # Walk the tree of menu nodes. You can imagine this as going down/into menu
+    # entries in the menuconfig interface, setting each to n (or the lowest
+    # assignable value).
+
+    while node:
+        if isinstance(node.item, Symbol):
+            sym = node.item
+
+            # Is the symbol a non-allnoconfig_y symbol that can be set to a
+            # lower value than its current value?
+            if (not sym.is_allnoconfig_y and
+                sym.assignable and
+                sym.assignable[0] < sym.tri_value):
+
+                # Yup, lower it
+                sym.set_value(sym.assignable[0])
+                changed = True
+
+        # Recursively lower children
+        if node.list:
+            do_allnoconfig(node.list)
+
+        node = node.next
+
+# Parse the Kconfig files
+kconf = Kconfig(sys.argv[1])
+
+# Do an initial pass to set 'option allnoconfig_y' symbols to y
+for sym in kconf.defined_syms:
+    if sym.is_allnoconfig_y:
+        sym.set_value(2)
+
+while True:
+    # Changing later symbols in the configuration can sometimes allow earlier
+    # symbols to be lowered, e.g. if a later symbol 'select's an earlier
+    # symbol. To handle such situations, we do additional passes over the tree
+    # until we're no longer able to change the value of any symbol in a pass.
+    changed = False
+
+    do_allnoconfig(kconf.top_node)
+
+    # Did the pass change any symbols?
+    if not changed:
+        break
+
+kconf.write_config(".config")