android编译分析之3—pathmap.mk

pathmap.mk就是集中定义path的地方，为了避免在Android.mk中的hard code，在这里hard code了一些目录路径。

## A central place to define mappings to paths, to avoid hard-coding# them in Android.mk files.## TODO: Allow each project to define stuff like this before the per-module#       Android.mk files are included, so we don't need to have a big central#       list.#

## A mapping from shorthand names to include directories.#pathmap_INCL := \    camera:system/media/camera/include \    frameworks-base:frameworks/base/include \    frameworks-native:frameworks/native/include \    libc:bionic/libc/include \    libhardware:hardware/libhardware/include \    libhardware_legacy:hardware/libhardware_legacy/include \    libhost:build/libs/host/include \    libm:bionic/libm/include \    libnativehelper:libnativehelper/include \    libpagemap:system/extras/libpagemap/include \    libril:hardware/ril/include \    libstdc++:bionic/libstdc++/include \    mkbootimg:system/core/mkbootimg \    opengl-tests-includes:frameworks/native/opengl/tests/include \    recovery:bootable/recovery \    system-core:system/core/include \    audio:system/media/audio/include \    audio-effects:system/media/audio_effects/include \    audio-utils:system/media/audio_utils/include \    audio-route:system/media/audio_route/include \    wilhelm:frameworks/wilhelm/include \    wilhelm-ut:frameworks/wilhelm/src/ut \    mediandk:frameworks/av/media/ndk/ \    speex:external/speex/include

上面定义了一些头文件目录和相关名称的映射。

## Returns the path to the requested module's include directory,# relative to the root of the source tree.  Does not handle external# modules.## $(1): a list of modules (or other named entities) to find the includes for#define include-path-for$(foreach n,$(1),$(patsubst $(n):%,%,$(filter $(n):%,$(pathmap_INCL))))endef

通过上面pathmap_INCL映射表中的名称找对应的目录的函数。

## Many modules expect to be able to say "#include <jni.h>",# so make it easy for them to find the correct path.#JNI_H_INCLUDE := $(call include-path-for,libnativehelper)/nativehelper

JNI的头文件jni.h。

## A list of all source roots under frameworks/base, which will be# built into the android.jar.#FRAMEWORKS_BASE_SUBDIRS := \    $(addsuffix /java, \        core \        graphics \        location \        media \        media/mca/effect \        media/mca/filterfw \        media/mca/filterpacks \        drm \        opengl \        sax \        telecomm \        telephony \        wifi \        keystore \        rs \     )## A version of FRAMEWORKS_BASE_SUBDIRS that is expanded to full paths from# the root of the tree.  This currently needs to be here so that other libraries# and apps can find the .aidl files in the framework, though we should really# figure out a better way to do this.#FRAMEWORKS_BASE_JAVA_SRC_DIRS := \    $(addprefix frameworks/base/,$(FRAMEWORKS_BASE_SUBDIRS))## A list of all source roots under frameworks/support.#FRAMEWORKS_SUPPORT_SUBDIRS := \        annotations \        v4 \        v7/gridlayout \        v7/cardview \        v7/mediarouter \        v7/palette \        v8/renderscript \        v13 \        v17/leanback \        design \        percent \        recommendation \        v7/preference \        v14/preference \        v17/preference-leanback \        customtabs## A list of all source roots under frameworks/multidex.#FRAMEWORKS_MULTIDEX_SUBDIRS := \        multidex/library/src \        multidex/instrumentation/src## A version of FRAMEWORKS_SUPPORT_SUBDIRS that is expanded to full paths from# the root of the tree.#FRAMEWORKS_SUPPORT_JAVA_SRC_DIRS := \    $(addprefix frameworks/support/,$(FRAMEWORKS_SUPPORT_SUBDIRS)) \    $(addprefix frameworks/,$(FRAMEWORKS_MULTIDEX_SUBDIRS)) \    frameworks/support/v7/appcompat/src \    frameworks/support/v7/recyclerview/src## A list of support library modules.# # 将FRAMEWORKS_SUPPORT_SUBDIRS中的路径分割符换成-，然后这些就是FRAMEWORKS_SUPPORT_JAVA_LIBRARIESFRAMEWORKS_SUPPORT_JAVA_LIBRARIES := \    $(foreach dir,$(FRAMEWORKS_SUPPORT_SUBDIRS),android-support-$(subst /,-,$(dir))) \    android-support-v7-appcompat \    android-support-v7-recyclerview \    android-support-multidex \    android-support-multidex-instrumentation## A list of all documented source roots under frameworks/data-binding.#FRAMEWORKS_DATA_BINDING_SUBDIRS := \        baseLibrary/src/main \        library/src/main \        library/src/doc## A version of FRAMEWORKS_DATA_BINDING_SUBDIRS that is expanded to full paths from# the root of the tree.#FRAMEWORKS_DATA_BINDING_JAVA_SRC_DIRS := \    $(addprefix frameworks/data-binding/,$(FRAMEWORKS_DATA_BINDING_SUBDIRS))

上面变量都是frameworks中一些目录，到目前为止，我们还看不出来frameworks中这么多的目录到底是干嘛的。