Android 编译系统解析系列文档
编译系统入口envsetup.sh解析
解析lunch的执行过程以及make执行过程中include文件的顺序
关注一些make执行过程中的几个关键点
对一些独特的语法结构进行解析
这个属性我们可以直接搜索源代码找到对应的位置
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ###### product_config.mk ###### # A list of property assignments, like "key = value", with zero or more # whitespace characters on either side of the '='. PRODUCT_PROPERTY_OVERRIDES := \ $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_PROPERTY_OVERRIDES)) ...... # Add the product-defined properties to the build properties. ADDITIONAL_BUILD_PROPERTIES := \ $(ADDITIONAL_BUILD_PROPERTIES) \ $(PRODUCT_PROPERTY_OVERRIDES)
从之前的继承系列的文章我们可以直到，PRODUCT_*系列的变量都有继承的功能，所以我们的PRODUCT_PROPERTY_OVERRIDES最终的取值就是$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_PROPERTY_OVERRIDES),其中INTERNAL_PRODUCT对应的是当前编译机型配置目录相对于源码根目录的相对路径
接着，将这个属性赋予ADDITIONAL_BUILD_PROPERTIES这个变量
这块代码高亮部分显示的ADDITIONAL_BUILD_PROPERTIES宏的值已经在这个文件之前的部分处理过了，是这块代码
1 2 3 4 5 6 7 8 # build.prop INSTALLED_BUILD_PROP_TARGET := $(TARGET_OUT)/build.prop ALL_DEFAULT_INSTALLED_MODULES += $(INSTALLED_BUILD_PROP_TARGET) ADDITIONAL_BUILD_PROPERTIES := \ $(call collapse-pairs, $(ADDITIONAL_BUILD_PROPERTIES)) ADDITIONAL_BUILD_PROPERTIES := $(call uniq-pairs-by-first-component, \ $(ADDITIONAL_BUILD_PROPERTIES),=)
这里同样有两个函数处理这个变量collapse-pairs与uniq-pairs-by-first-component
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 define collapse-pairs $(eval _cpSEP := $(strip $(if $(2 ),$(2 ),=)))\ $(subst $(space)$(_cpSEP)$(space),$(_cpSEP),$(strip \ $(subst $(_cpSEP), $(_cpSEP) ,$(1 )))) endef ########################################################### ## Given a list of pairs, if multiple pairs have the same ## first components, keep only the first pair. ## ## $(1 ): list of pairs ## $(2 ): the separator word, such as ":" , "=" , etc. define uniq-pairs-by-first-component $(eval _upbfc_fc_set :=)\ $(strip $(foreach w,$(1 ), $(eval _first := $(word 1 ,$(subst $(2 ),$(space),$(w))))\ $(if $(filter $(_upbfc_fc_set),$(_first)),,$(w)\ $(eval _upbfc_fc_set += $(_first)))))\ $(eval _upbfc_fc_set :=)\ $(eval _first:=) endef
collapse-pairs函数是用来格式化赋值语句的，去掉=两边的空格，例如a = b或a =b，都会格式化为a=b
uniq-pairs-by-first-component函数是用来剔除这些赋值语句中多次重复对一个属性进行赋值的语句，规则为我们根据第二个参数来过滤第一个参数中重复的list
1 2 ro.mm.ffmpeg =1 ro.mm.ffmpeg =0
对于以上的两个属性，后一条属性会被过滤掉，只保留前一条属性，这个规则和PRODUCT_COPY_FILES是一样的
最终在Makefile中处理已经过滤完毕的属性，具体是在生成build.prop文件的时候，下边是主要的代码：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 $(INSTALLED_BUILD_PROP_TARGET): $(BUILDINFO_SH) $(INTERNAL_BUILD_ID_MAKEFILE) $(BUILD_SYSTEM)/version_defaults.mk $(system_prop_file) @echo Target buildinfo: $@ @mkdir -p $(dir $@) $(hide) echo > $@ ifneq ($(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_OEM_PROPERTIES),) $(hide) echo "#" >> $@; \ echo "# PRODUCT_OEM_PROPERTIES" >> $@; \ echo "#" >> $@; $(hide) $(foreach prop,$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_OEM_PROPERTIES), \ echo "import /oem/oem.prop $(prop)" >> $@;) endif $(hide) TARGET_BUILD_TYPE="$(TARGET_BUILD_VARIANT)" \ TARGET_BUILD_FLAVOR="$(TARGET_PRODUCT)-$(TARGET_BUILD_VARIANT)" \ TARGET_DEVICE="$(TARGET_DEVICE)" \ PRODUCT_NAME="$(TARGET_PRODUCT)" \ PRODUCT_BRAND="$(PRODUCT_BRAND)" \ PRODUCT_DEFAULT_LANGUAGE="$(call default-locale-language,$(PRODUCT_LOCALES))" \ PRODUCT_DEFAULT_REGION="$(call default-locale-region,$(PRODUCT_LOCALES))" \ PRODUCT_DEFAULT_WIFI_CHANNELS="$(PRODUCT_DEFAULT_WIFI_CHANNELS)" \ PRODUCT_MODEL="$(PRODUCT_MODEL)" \ PRODUCT_MANUFACTURER="$(PRODUCT_MANUFACTURER)" \ PRIVATE_BUILD_DESC="$(PRIVATE_BUILD_DESC)" \ BUILD_ID="$(BUILD_ID)" \ BUILD_DISPLAY_ID="$(BUILD_DISPLAY_ID)" \ BUILD_DISPLAY_ID_MASK="$(BUILD_DISPLAY_ID_MASK)" \ BUILD_INSIDE_ID_MASK="$(BUILD_INSIDE_ID_MASK)" \ BUILD_NUMBER="$(BUILD_NUMBER)" \ PLATFORM_VERSION="$(PLATFORM_VERSION)" \ PLATFORM_SDK_VERSION="$(PLATFORM_SDK_VERSION)" \ PLATFORM_VERSION_CODENAME="$(PLATFORM_VERSION_CODENAME)" \ PLATFORM_VERSION_ALL_CODENAMES="$(PLATFORM_VERSION_ALL_CODENAMES)" \ BUILD_VERSION_TAGS="$(BUILD_VERSION_TAGS)" \ TARGET_BOOTLOADER_BOARD_NAME="$(TARGET_BOOTLOADER_BOARD_NAME)" \ BUILD_FINGERPRINT="$(BUILD_FINGERPRINT)" \ $(if $(OEM_THUMBPRINT_PROPERTIES),BUILD_THUMBPRINT="$(BUILD_THUMBPRINT)") \ TARGET_BOARD_PLATFORM="$(TARGET_BOARD_PLATFORM)" \ TARGET_CPU_ABI_LIST="$(TARGET_CPU_ABI_LIST)" \ TARGET_CPU_ABI_LIST_32_BIT="$(TARGET_CPU_ABI_LIST_32_BIT)" \ TARGET_CPU_ABI_LIST_64_BIT="$(TARGET_CPU_ABI_LIST_64_BIT)" \ TARGET_CPU_ABI="$(TARGET_CPU_ABI)" \ TARGET_CPU_ABI2="$(TARGET_CPU_ABI2)" \ TARGET_AAPT_CHARACTERISTICS="$(TARGET_AAPT_CHARACTERISTICS)" \ bash $(BUILDINFO_SH) >> $@ $(hide) $(foreach file,$(system_prop_file), \ if [ -f "$(file)" ]; then \ echo "#" >> $@; \ echo Target buildinfo from: "$(file)"; \ echo "# from $(file)" >> $@; \ echo "#" >> $@; \ cat $(file) >> $@; \ fi;) >>==$(ADDITIONAL_BUILD_PROPERTIES), \ $(hide) echo >> $@; \ echo "#" >> $@; \ echo "# ADDITIONAL_BUILD_PROPERTIES" >> $@; \ echo "#" >> $@; ) $(hide) $(foreach line,$(ADDITIONAL_BUILD_PROPERTIES), \ echo "$(line)" >> $@;) $(hide) build/tools/post_process_props.py $@ $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SYSTEM_PROPERTY_BLACKLIST)==<< build_desc :=
至此，关于PRODUCT_PROPERTY_OVERRIDES相关的内容就解析完毕
