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# $(2): needle
80#
81# Guarantees that needle appears at most once in haystack,
82# without changing the order of other elements in haystack.
83# If needle appears multiple times, only the first occurrance
84# will survive.
85#
86# How it works:
87#
88# - Stick everything in haystack into a single word,
89#   with "|||" separating the words.
90# - Replace occurrances of "|||$(needle)|||" with "||| |||",
91#   breaking haystack back into multiple words, with spaces
92#   where needle appeared.
93# - Add needle between the first and second words of haystack.
94# - Replace "|||" with spaces, breaking haystack back into
95#   individual words.
96#
97define uniq-word
98$(strip \
99  $(if $(filter-out 0 1,$(words $(filter $(2),$(1)))), \
100    $(eval h := |||$(subst $(space),|||,$(strip $(1)))|||) \
101    $(eval h := $(subst |||$(strip $(2))|||,|||$(space)|||,$(h))) \
102    $(eval h := $(word 1,$(h)) $(2) $(wordlist 2,9999,$(h))) \
103    $(subst |||,$(space),$(h)) \
104   , \
105    $(1) \
106 ))
107endef
108
109INHERIT_TAG := @inherit:
110
111#
112# Walks through the list of variables, each qualified by the prefix,
113# and finds instances of words beginning with INHERIT_TAG.  Scrape
114# off INHERIT_TAG from each matching word, and return the sorted,
115# unique set of those words.
116#
117# E.g., given
118#   PREFIX.A := A $(INHERIT_TAG)aaa B C
119#   PREFIX.B := B $(INHERIT_TAG)aaa C $(INHERIT_TAG)bbb D E
120# Then
121#   $(call get-inherited-nodes,PREFIX,A B)
122# returns
123#   aaa bbb
124#
125# $(1): variable prefix
126# $(2): list of variables to check
127#
128define get-inherited-nodes
129$(sort \
130  $(subst $(INHERIT_TAG),, \
131    $(filter $(INHERIT_TAG)%, \
132      $(foreach v,$(2),$($(1).$(v))) \
133 )))
134endef
135
136#
137# for each variable ( (prefix + name) * vars ):
138#   get list of inherited words; if not empty:
139#     for each inherit:
140#       replace the first occurrence with (prefix + inherited + var)
141#       clear the source var so we can't inherit the value twice
142#
143# $(1): context prefix
144# $(2): name of this node
145# $(3): list of node variable names
146# $(4): list of single value variable names (subset of $(3))
147#
148define _expand-inherited-values
149  $(foreach v,$(3), \
150    $(eval ### "Shorthand for the name of the target variable") \
151    $(eval _eiv_tv := $(1).$(2).$(v)) \
152    $(eval ### "Get the list of nodes that this variable inherits") \
153    $(eval _eiv_i := \
154        $(sort \
155            $(patsubst $(INHERIT_TAG)%,%, \
156                $(filter $(INHERIT_TAG)%, $($(_eiv_tv)) \
157     )))) \
158    $(eval ### "Whether this variable should only take a single value") \
159    $(eval _eiv_sv := $(filter $(v),$(4))) \
160    $(foreach i,$(_eiv_i), \
161      $(eval ### "Make sure that this inherit appears only once") \
162      $(eval $(_eiv_tv) := \
163          $(call uniq-word,$($(_eiv_tv)),$(INHERIT_TAG)$(i))) \
164      $(eval ### "The expanded value, empty if we want a single value and have one") \
165      $(eval _eiv_ev := \
166        $(if $(and $(_eiv_sv),$(filter-out $(INHERIT_TAG)%,$($(_eiv_tv)))),,\
167          $($(1).$(i).$(v)) \
168        ) \
169      ) \
170      $(eval ### "Expand the inherit tag") \
171      $(eval $(_eiv_tv) := \
172          $(strip $(patsubst $(INHERIT_TAG)$(i),$(_eiv_ev),$($(_eiv_tv))))) \
173      $(eval ### "Clear the child so DAGs don't create duplicate entries" ) \
174      $(eval $(1).$(i).$(v) :=) \
175      $(eval ### "If we just inherited ourselves, it's a cycle.") \
176      $(if $(filter $(INHERIT_TAG)$(2),$($(_eiv_tv))), \
177        $(warning Cycle detected between "$(2)" and "$(i)" for context "$(1)") \
178        $(error import of "$(2)" failed) \
179      ) \
180     ) \
181   ) \
182   $(eval _eiv_tv :=) \
183   $(eval _eiv_i :=)
184endef
185
186#
187# $(1): context prefix
188# $(2): makefile representing this node
189# $(3): list of node variable names
190# $(4): list of single value variable names (subset of $(3))
191#
192# _include_stack contains the list of included files, with the most recent files first.
193define _import-node
194  $(eval _include_stack := $(2) $$(_include_stack))
195  $(call clear-var-list, $(3))
196  $(eval LOCAL_PATH := $(patsubst %/,%,$(dir $(2))))
197  $(eval MAKEFILE_LIST :=)
198  $(eval include $(2))
199  $(eval _included := $(filter-out $(2),$(MAKEFILE_LIST)))
200  $(eval MAKEFILE_LIST :=)
201  $(eval LOCAL_PATH :=)
202  $(call copy-var-list, $(1).$(2), $(3))
203  $(call clear-var-list, $(3))
204
205  $(eval $(1).$(2).inherited := \
206      $(call get-inherited-nodes,$(1).$(2),$(3)))
207  $(call _import-nodes-inner,$(1),$($(1).$(2).inherited),$(3))
208
209  $(call _expand-inherited-values,$(1),$(2),$(3),$(4))
210
211  $(eval $(1).$(2).inherited :=)
212  $(eval _include_stack := $(wordlist 2,9999,$$(_include_stack)))
213endef
214
215#
216# This will generate a warning for _included above
217#  $(if $(_included), \
218#      $(eval $(warning product spec file: $(2)))\
219#      $(foreach _inc,$(_included),$(eval $(warning $(space)$(space)$(space)includes: $(_inc)))),)
220#
221
222#
223# $(1): context prefix
224# $(2): list of makefiles representing nodes to import
225# $(3): list of node variable names
226# $(4): list of single value variable names (subset of $(3))
227#
228#TODO: Make the "does not exist" message more helpful;
229#      should print out the name of the file trying to include it.
230define _import-nodes-inner
231  $(foreach _in,$(2), \
232    $(if $(wildcard $(_in)), \
233      $(if $($(1).$(_in).seen), \
234        $(eval ### "skipping already-imported $(_in)") \
235       , \
236        $(eval $(1).$(_in).seen := true) \
237        $(call _import-node,$(1),$(strip $(_in)),$(3),$(4)) \
238       ) \
239     , \
240      $(error $(1): "$(_in)" does not exist) \
241     ) \
242   )
243endef
244
245#
246# $(1): output list variable name, like "PRODUCTS" or "DEVICES"
247# $(2): list of makefiles representing nodes to import
248# $(3): list of node variable names
249# $(4): list with subset of variable names that take only a single value, instead
250#       of the default list semantics
251#
252define import-nodes
253$(if \
254  $(foreach _in,$(2), \
255    $(eval _node_import_context := _nic.$(1).[[$(_in)]]) \
256    $(if $(_include_stack),$(eval $(error ASSERTION FAILED: _include_stack \
257                should be empty here: $(_include_stack))),) \
258    $(eval _include_stack := ) \
259    $(call _import-nodes-inner,$(_node_import_context),$(_in),$(3),$(4)) \
260    $(call move-var-list,$(_node_import_context).$(_in),$(1).$(_in),$(3)) \
261    $(eval _node_import_context :=) \
262    $(eval $(1) := $($(1)) $(_in)) \
263    $(if $(_include_stack),$(eval $(error ASSERTION FAILED: _include_stack \
264                should be empty here: $(_include_stack))),) \
265   ) \
266,)
267endef
268