1#
2# Copyright (C) 2007 The Android Open Source Project
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15#
16
17#
18# Clears a list of variables using ":=".
19#
20# E.g.,
21#   $(call clear-var-list,A B C)
22# would be the same as:
23#   A :=
24#   B :=
25#   C :=
26#
27# $(1): list of variable names to clear
28#
29define clear-var-list
30$(foreach v,$(1),$(eval $(v):=))
31endef
32
33#
34# Copies a list of variables into another list of variables.
35# The target list is the same as the source list, but has
36# a dotted prefix affixed to it.
37#
38# E.g.,
39#   $(call copy-var-list, PREFIX, A B)
40# would be the same as:
41#   PREFIX.A := $(A)
42#   PREFIX.B := $(B)
43#
44# $(1): destination prefix
45# $(2): list of variable names to copy
46#
47define copy-var-list
48$(foreach v,$(2),$(eval $(strip $(1)).$(v):=$($(v))))
49endef
50
51#
52# Moves a list of variables into another list of variables.
53# The variable names differ by a prefix.  After moving, the
54# source variable is cleared.
55#
56# NOTE: Spaces are not allowed around the prefixes.
57#
58# E.g.,
59#   $(call move-var-list,SRC,DST,A B)
60# would be the same as:
61#   DST.A := $(SRC.A)
62#   SRC.A :=
63#   DST.B := $(SRC.B)
64#   SRC.B :=
65#
66# $(1): source prefix
67# $(2): destination prefix
68# $(3): list of variable names to move
69#
70define move-var-list
71$(foreach v,$(3), \
72  $(eval $(2).$(v) := $($(1).$(v))) \
73  $(eval $(1).$(v) :=) \
74 )
75endef
76
77#
78# $(1): haystack
79# $(2): needle
80#
81# Guarantees that needle appears at most once in haystack,
82# without changing the order of other elements in haystack.
83# If needle appears multiple times, only the first occurrance
84# will survive.
85#
86define uniq-word
87$(strip \
88  $(if $(filter-out 0 1,$(words $(filter $(2),$(1)))), \
89    $(eval _uniq_word_seen :=) \
90    $(foreach w,$(1), \
91      $(if $(filter $(2),$(w)), \
92        $(if $(_uniq_word_seen),, \
93          $(w) \
94          $(eval _uniq_word_seen := true)), \
95        $(w))), \
96  $(1)))
97endef
98
99INHERIT_TAG := @inherit:
100
101#
102# Walks through the list of variables, each qualified by the prefix,
103# and finds instances of words beginning with INHERIT_TAG.  Scrape
104# off INHERIT_TAG from each matching word, and return the sorted,
105# unique set of those words.
106#
107# E.g., given
108#   PREFIX.A := A $(INHERIT_TAG)aaa B C
109#   PREFIX.B := B $(INHERIT_TAG)aaa C $(INHERIT_TAG)bbb D E
110# Then
111#   $(call get-inherited-nodes,PREFIX,A B)
112# returns
113#   aaa bbb
114#
115# $(1): variable prefix
116# $(2): list of variables to check
117#
118define get-inherited-nodes
119$(sort \
120  $(subst $(INHERIT_TAG),, \
121    $(filter $(INHERIT_TAG)%, \
122      $(foreach v,$(2),$($(1).$(v))) \
123 )))
124endef
125
126#
127# for each variable ( (prefix + name) * vars ):
128#   get list of inherited words; if not empty:
129#     for each inherit:
130#       replace the first occurrence with (prefix + inherited + var)
131#       clear the source var so we can't inherit the value twice
132#
133# $(1): context prefix
134# $(2): name of this node
135# $(3): list of node variable names
136# $(4): list of single value variable names (subset of $(3))
137#
138define _expand-inherited-values
139  $(foreach v,$(3), \
140    $(eval ### "Shorthand for the name of the target variable") \
141    $(eval _eiv_tv := $(1).$(2).$(v)) \
142    $(eval ### "Get the list of nodes that this variable inherits") \
143    $(eval _eiv_i := \
144        $(sort \
145            $(patsubst $(INHERIT_TAG)%,%, \
146                $(filter $(INHERIT_TAG)%, $($(_eiv_tv)) \
147     )))) \
148    $(eval ### "Whether this variable should only take a single value") \
149    $(eval _eiv_sv := $(filter $(v),$(4))) \
150    $(foreach i,$(_eiv_i), \
151      $(eval ### "Make sure that this inherit appears only once") \
152      $(eval $(_eiv_tv) := \
153          $(call uniq-word,$($(_eiv_tv)),$(INHERIT_TAG)$(i))) \
154      $(eval ### "The expanded value, empty if we want a single value and have one") \
155      $(eval _eiv_ev := \
156        $(if $(and $(_eiv_sv),$(filter-out $(INHERIT_TAG)%,$($(_eiv_tv)))),,\
157          $($(1).$(i).$(v)) \
158        ) \
159      ) \
160      $(eval ### "Expand the inherit tag") \
161      $(eval $(_eiv_tv) := \
162          $(strip $(patsubst $(INHERIT_TAG)$(i),$(_eiv_ev),$($(_eiv_tv))))) \
163      $(eval ### "Clear the child so DAGs don't create duplicate entries" ) \
164      $(eval $(1).$(i).$(v) :=) \
165      $(eval ### "If we just inherited ourselves, it's a cycle.") \
166      $(if $(filter $(INHERIT_TAG)$(2),$($(_eiv_tv))), \
167        $(warning Cycle detected between "$(2)" and "$(i)" for context "$(1)") \
168        $(error import of "$(2)" failed) \
169      ) \
170     ) \
171   ) \
172   $(eval _eiv_tv :=) \
173   $(eval _eiv_i :=)
174endef
175
176#
177# $(1): context prefix
178# $(2): makefile representing this node
179# $(3): list of node variable names
180# $(4): list of single value variable names (subset of $(3))
181#
182# _include_stack contains the list of included files, with the most recent files first.
183define _import-node
184  $(eval _include_stack := $(2) $$(_include_stack))
185  $(call clear-var-list, $(3))
186  $(eval LOCAL_PATH := $(patsubst %/,%,$(dir $(2))))
187  $(eval MAKEFILE_LIST :=)
188  $(call dump-import-start,$(_include_stack))
189  $(call dump-config-vals,$(2),before)
190  $(eval include $(2))
191  $(call dump-import-done,$(_include_stack))
192  $(call dump-config-vals,$(2),after)
193  $(eval _included := $(filter-out $(2),$(MAKEFILE_LIST)))
194  $(eval MAKEFILE_LIST :=)
195  $(eval LOCAL_PATH :=)
196  $(call copy-var-list, $(1).$(2), $(3))
197  $(call clear-var-list, $(3))
198
199  $(eval $(1).$(2).inherited := \
200      $(call get-inherited-nodes,$(1).$(2),$(3)))
201  $(call _import-nodes-inner,$(1),$($(1).$(2).inherited),$(3),$(4))
202
203  $(call _expand-inherited-values,$(1),$(2),$(3),$(4))
204
205  $(eval $(1).$(2).inherited :=)
206  $(eval _include_stack := $(wordlist 2,9999,$(_include_stack)))
207endef
208
209#
210# This will generate a warning for _included above
211#  $(if $(_included), \
212#      $(eval $(warning product spec file: $(2)))\
213#      $(foreach _inc,$(_included),$(eval $(warning $(space)$(space)$(space)includes: $(_inc)))),)
214#
215
216#
217# $(1): context prefix
218# $(2): list of makefiles representing nodes to import
219# $(3): list of node variable names
220# $(4): list of single value variable names (subset of $(3))
221#
222#TODO: Make the "does not exist" message more helpful;
223#      should print out the name of the file trying to include it.
224define _import-nodes-inner
225  $(foreach _in,$(2), \
226    $(if $(wildcard $(_in)), \
227      $(if $($(1).$(_in).seen), \
228        $(eval ### "skipping already-imported $(_in)") \
229       , \
230        $(eval $(1).$(_in).seen := true) \
231        $(call _import-node,$(1),$(strip $(_in)),$(3),$(4)) \
232       ) \
233     , \
234      $(error $(1): "$(_in)" does not exist) \
235     ) \
236   )
237endef
238
239#
240# $(1): output list variable name, like "PRODUCTS" or "DEVICES"
241# $(2): list of makefiles representing nodes to import
242# $(3): list of node variable names
243# $(4): list with subset of variable names that take only a single value, instead
244#       of the default list semantics
245#
246define import-nodes
247$(call dump-phase-start,$(1),$(2),$(3),$(4),build/make/core/node_fns.mk) \
248$(if \
249  $(foreach _in,$(2), \
250    $(eval _node_import_context := _nic.$(1).[[$(_in)]]) \
251    $(if $(_include_stack),$(eval $(error ASSERTION FAILED: _include_stack \
252                should be empty here: $(_include_stack))),) \
253    $(eval _include_stack := ) \
254    $(call _import-nodes-inner,$(_node_import_context),$(_in),$(3),$(4)) \
255    $(call move-var-list,$(_node_import_context).$(_in),$(1).$(_in),$(3)) \
256    $(eval _node_import_context :=) \
257    $(eval $(1) := $($(1)) $(_in)) \
258    $(if $(_include_stack),$(eval $(error ASSERTION FAILED: _include_stack \
259                should be empty here: $(_include_stack))),) \
260   ) \
261,) \
262$(call dump-phase-end,build/make/core/node_fns.mk)
263endef
264