Merge "Teach API lint about package layering!" into lmp-dev

def verify_aidl(clazz):

    """Catch people exposing raw AIDL."""

    if "extends android.os.Binder" in clazz.raw:

    if "extends android.os.Binder" in clazz.raw or "implements android.os.IInterface" in clazz.raw:

        error(clazz, None, "Exposing raw AIDL interface")

def verify_internal(clazz):

    """Catch people exposing internal classes."""

    if clazz.pkg.name.startswith("com.android"):

        error(clazz, None, "Exposing internal class")

def verify_layering(clazz):

    """Catch package layering violations.

    For example, something in android.os depending on android.app."""

    ranking = [

        ["android.service","android.accessibilityservice","android.inputmethodservice","android.printservice","android.appwidget","android.webkit","android.preference","android.gesture","android.print"],

        "android.app",

        "android.widget",

        "android.view",

        "android.animation",

        "android.provider",

        "android.content",

        "android.database",

        "android.graphics",

        "android.text",

        "android.os",

        "android.util"

    ]

    def rank(p):

        for i in range(len(ranking)):

            if isinstance(ranking[i], list):

                for j in ranking[i]:

                    if p.startswith(j): return i

            else:

                if p.startswith(ranking[i]): return i

    cr = rank(clazz.pkg.name)

    if cr is None: return

    for f in clazz.fields:

        ir = rank(f.typ)

        if ir and ir < cr:

            warn(clazz, f, "Field type violates package layering")

    for m in clazz.methods:

        ir = rank(m.typ)

        if ir and ir < cr:

            warn(clazz, m, "Method return type violates package layering")

        for arg in m.args:

            ir = rank(arg)

            if ir and ir < cr:

                warn(clazz, m, "Method argument type violates package layering")

def verify_all(api):

    global failures

        verify_helper_classes(clazz)

        verify_builder(clazz)

        verify_aidl(clazz)

        verify_internal(clazz)

        verify_layering(clazz)

    return failures