1. 含義
PRODUCT_BOOT_JARS 最終被編譯到system/framework惠勒，并被添加到BOOTCLASSPATH路徑；
2.1 引用makefile
PRODUCT_BOOT_JARS += xxx.jar
2.2 DEXPREOPT_BOOT_JARS_MODULES
core/dex_preopt.mk
DEXPREOPT_BOOT_JARS := $(subst $(space),:,$(PRODUCT_BOOT_JARS))
DEXPREOPT_BOOT_JARS_MODULES := $(PRODUCT_BOOT_JARS)
2.3 核心
core/dex_preopt.mk
PRODUCT_BOOTCLASSPATH := $(subst $(space),:,$(foreach m,$(DEXPREOPT_BOOT_JARS_MODULES),/system/framework/$(m).jar))
core/dex_preopt.mk
$(foreach b,$(DEXPREOPT_BOOT_JARS_MODULES),$(eval $(call _dexpreopt-boot-jar-remove-classes.dex,$(b))))
2.4 _dexpreopt-boot-jar-remove-classes.dex
core/dex_preopt.mk
# Special rules for building stripped boot jars that override java_library.mk rules
# $(1): boot jar module name
define _dexpreopt-boot-jar-remove-classes.dex
_dbj_jar_no_dex := $(DEXPREOPT_BOOT_JAR_DIR_FULL_PATH)/$(1)_nodex.jar
_dbj_src_jar := $(call intermediates-dir-for,JAVA_LIBRARIES,$(1),,COMMON)/javalib.jar
$$(_dbj_jar_no_dex) : $$(_dbj_src_jar) | $(ACP) $(AAPT)
$$(call copy-file-to-target)
ifneq ($(DEX_PREOPT_DEFAULT),nostripping)
$$(call dexpreopt-remove-classes.dex,$$@)
endif
_dbj_jar_no_dex :=
_dbj_src_jar :=
endef
注釋:
先編譯$$(_dbj_src_jar), 然后對$$(_dbj_jar_no_dex) 做$(ACP) $(AAPT)
2.5 AAPT
core/config.mk
AAPT := $(HOST_OUT_EXECUTABLES)/aapt$(HOST_EXECUTABLE_SUFFIX)
core/combo/HOST_windows-x86.mk
HOST_EXECUTABLE_SUFFIX := .exe
2.6 ACP
core/config.mk
ACP := $(BUILD_OUT_EXECUTABLES)/acp$(BUILD_EXECUTABLE_SUFFIX)
2.7 DEXPREOPT_BOOT_JAR_DIR_FULL_PATH
DEXPREOPT_BOOT_JAR_DIR_FULL_PATH := $(DEXPREOPT_PRODUCT_DIR_FULL_PATH)/$(DEXPREOPT_BOOT_JAR_DIR)
DEXPREOPT_PRODUCT_DIR_FULL_PATH := $(PRODUCT_OUT)/dex_bootjars
DEXPREOPT_BOOT_JAR_DIR := system/framework
2.8 copy-file-to-target
core/definitions.mk
# The -t option to acp and the -p option to cp is
# required for OSX. OSX has a ridiculous restriction
# where it's an error for a .a file's modification time
# to disagree with an internal timestamp, and this
# macro is used to install .a files (among other things).
# Copy a single file from one place to another,
# preserving permissions and overwriting any existing
# file.
# We disable the "-t" option for acp cannot handle
# high resolution timestamp correctly on file systems like ext4.
# Therefore copy-file-to-target is the same as copy-file-to-new-target.
define copy-file-to-target
@mkdir -p $(dir $@)
$(hide) $(ACP) -fp $< $@
endef
2.9 PRODUCT_BOOTCLASSPATH
core/product.mk
_product_stash_var_list := $(_product_var_list) \
PRODUCT_BOOTCLASSPATH \
...
2.10stash-product-vars
core/product.mk
#
# Stash values of the variables in _product_stash_var_list.
# $(1): Renamed prefix
#
define stash-product-vars
$(foreach v,$(_product_stash_var_list), \
$(eval $(strip $(1))_$(call rot13,$(v)):=$$($$(v))) \
)
endef
system_server jar > framework.jar
總結(jié)：
BOOTCLASSPATH中中的jar編譯為boot.art和boot.oat
實戰(zhàn)
3.1 編寫Jar包
結(jié)構(gòu)
fox
├── Android.mk
└── java
└── com
└── android
└── host
└── fox
└── HelloFox.java
3.1.1 Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := host-fox // 默認編譯到system/framework
#LOCAL_MODULE_TAGS := optional
LOCAL_SRC_FILES := $(call all-java-files-under,java)
include $(BUILD_JAVA_LIBRARY)
3.1.2 HelloFox.java
package com.android.host.fox;
public class HelloFox {
public String say() {
return "Hello, host fox";
}
}
3.1.3 在系統(tǒng)makefile添加模塊host-fox
# add jars
PRODUCT_PACKAGES += \
host-fox
// 添加到Android編譯系統(tǒng)
PRODUCT_BOOT_JARS += host-fox // 添加到BOOTCLASSPATH路徑
結(jié)果展示
host-fox.jpg
