android权限源码解析

PackageManager.java持有PERMISSION_GRANTED和PERMISSION_DENIED

ContextImpl.java

    //权限检查
@Override
    public int checkSelfPermission(String permission) {
        if (permission == null) {
            throw new IllegalArgumentException("permission is null");
        }
        //是否在放弃申请的权限列表中，是则返回拒绝状态
        if (mParams.isRenouncedPermission(permission)) {
            Log.v(TAG, "Treating renounced permission " + permission + " as denied");
            return PERMISSION_DENIED;
        }

        return checkPermission(permission, Process.myPid(), Process.myUid());
    }
    
    // 最后执行checkPermission方法
    @Override
    public int checkPermission(String permission, int pid, int uid) {
        if (permission == null) {
            throw new IllegalArgumentException("permission is null");
        }
        if (mParams.isRenouncedPermission(permission)
                && pid == android.os.Process.myPid() && uid == android.os.Process.myUid()) {
            Log.v(TAG, "Treating renounced permission " + permission + " as denied");
            return PERMISSION_DENIED;
        }
        return PermissionManager.checkPermission(permission, pid, uid);
    }

PermissionManager.java
1、安装，卸载应用 
2、查询permission相关信息 
3、查询Application相关信息(application，activity，receiver，service，provider及相应属性等） 
4、查询已安装应用 
5、增加，删除permission 
6、清除用户数据、缓存，代码段等

  /** @hide */
   //缓存
    private static final PropertyInvalidatedCache<PermissionQuery, Integer> sPermissionCache =
            new PropertyInvalidatedCache<PermissionQuery, Integer>(
                    2048, CACHE_KEY_PACKAGE_INFO, "checkPermission") {
                @Override
                protected Integer recompute(PermissionQuery query) {
                    return checkPermissionUncached(query.permission, query.pid, query.uid);
                }
            };
            //方法执行
public static int checkPermission(@Nullable String permission, int pid, int uid) {
        return sPermissionCache.query(new PermissionQuery(permission, pid, uid));
}