ANativeWindow是个什么东西

    公司经常组织一些培训，培训的都是些奇技淫巧。什么设计模式啦，开发策略啦，git啦，repo啦，另外就是培训一些开发流程的东东，例如CMMI啦。可是，却忘记了，程序员终究要归结到三个问题上：

    1.解决什么问题？

    2.为什么这样解决问题？

    3.有没有更好的解决方案？

    这些东东才是最核心的东东。但是却是一个程序员一辈子都无法完全掌握的东西。很多人以为写出了高难度的反射代码就是很牛，也有人认为利用C++模板来进行编程就多牛多牛，还有人觉得会写makefile文件，掌握了某种高难度语言很牛。但是我认为这些都不重要，重要的是要有思想。思考者比行动者在关键时候定大局。中国人的技术书籍缺乏的就是思想。在中国，可以肯定，没有几个人能写出像thinking in java这样的鸿篇巨著，更没有人能够超越 design pattern，来描述其思想。反之，像《自己动手写操作系统》，《21天学java》，《程序员的自我修养》，《面试宝典》，《C++面试一百例》, android内核开发要点等等等等一系列的书籍在中国却是层出不穷。为什么，因为缺乏思考，来不及思考，更或者懒得思考。然而，作为一名专业级的程序员，不思考就意味着退步，不学习就意味着淘汰。

   这几天一直在思考ANativeWindow是个什么东西，今天终于找到了，代码贴出来，大家参考一下。

  

struct ANativeWindow
{
#ifdef __cplusplus
    ANativeWindow()
        : flags(0), minSwapInterval(0), maxSwapInterval(0), xdpi(0), ydpi(0)
    {
        common.magic = ANDROID_NATIVE_WINDOW_MAGIC;
        common.version = sizeof(ANativeWindow);
        memset(common.reserved, 0, sizeof(common.reserved));
    }

    /* Implement the methods that sp<ANativeWindow> expects so that it
       can be used to automatically refcount ANativeWindow's. */
    void incStrong(const void* id) const {
        common.incRef(const_cast<android_native_base_t*>(&common));
    }
    void decStrong(const void* id) const {
        common.decRef(const_cast<android_native_base_t*>(&common));
    }
#endif

    struct android_native_base_t common;

    /* flags describing some attributes of this surface or its updater */
    const uint32_t flags;

    /* min swap interval supported by this updated */
    const int   minSwapInterval;

    /* max swap interval supported by this updated */
    const int   maxSwapInterval;

    /* horizontal and vertical resolution in DPI */
    const float xdpi;
    const float ydpi;

    /* Some storage reserved for the OEM's driver. */
    intptr_t    oem[4];

    /*
     * Set the swap interval for this surface.
     *
     * Returns 0 on success or -errno on error.
     */
    int     (*setSwapInterval)(struct ANativeWindow* window,
                int interval);

    /*
     * Hook called by EGL to acquire a buffer. After this call, the buffer
     * is not locked, so its content cannot be modified. This call may block if
     * no buffers are available.
     *
     * The window holds a reference to the buffer between dequeueBuffer and
     * either queueBuffer or cancelBuffer, so clients only need their own
     * reference if they might use the buffer after queueing or canceling it.
     * Holding a reference to a buffer after queueing or canceling it is only
     * allowed if a specific buffer count has been set.
     *
     * Returns 0 on success or -errno on error.
     */
    int     (*dequeueBuffer)(struct ANativeWindow* window,
                struct ANativeWindowBuffer** buffer);

    /*
     * hook called by EGL to lock a buffer. This MUST be called before modifying
     * the content of a buffer. The buffer must have been acquired with
     * dequeueBuffer first.
     *
     * Returns 0 on success or -errno on error.
     */
    int     (*lockBuffer)(struct ANativeWindow* window,
                struct ANativeWindowBuffer* buffer);
    /*
     * Hook called by EGL when modifications to the render buffer are done.
     * This unlocks and post the buffer.
     *
     * The window holds a reference to the buffer between dequeueBuffer and
     * either queueBuffer or cancelBuffer, so clients only need their own
     * reference if they might use the buffer after queueing or canceling it.
     * Holding a reference to a buffer after queueing or canceling it is only
     * allowed if a specific buffer count has been set.
     *
     * Buffers MUST be queued in the same order than they were dequeued.
     *
     * Returns 0 on success or -errno on error.
     */
    int     (*queueBuffer)(struct ANativeWindow* window,
                struct ANativeWindowBuffer* buffer);

    /*
     * hook used to retrieve information about the native window.
     *
     * Returns 0 on success or -errno on error.
     */
    int     (*query)(const struct ANativeWindow* window,
                int what, int* value);

    /*
     * hook used to perform various operations on the surface.
     * (*perform)() is a generic mechanism to add functionality to
     * ANativeWindow while keeping backward binary compatibility.
     *
     * DO NOT CALL THIS HOOK DIRECTLY.  Instead, use the helper functions
     * defined below.
     *
     *  (*perform)() returns -ENOENT if the 'what' parameter is not supported
     *  by the surface's implementation.
     *
     * The valid operations are:
     *     NATIVE_WINDOW_SET_USAGE
     *     NATIVE_WINDOW_CONNECT               (deprecated)
     *     NATIVE_WINDOW_DISCONNECT            (deprecated)
     *     NATIVE_WINDOW_SET_CROP
     *     NATIVE_WINDOW_SET_BUFFER_COUNT
     *     NATIVE_WINDOW_SET_BUFFERS_GEOMETRY  (deprecated)
     *     NATIVE_WINDOW_SET_BUFFERS_TRANSFORM
     *     NATIVE_WINDOW_SET_BUFFERS_TIMESTAMP
     *     NATIVE_WINDOW_SET_BUFFERS_DIMENSIONS
     *     NATIVE_WINDOW_SET_BUFFERS_FORMAT
     *     NATIVE_WINDOW_SET_SCALING_MODE
     *     NATIVE_WINDOW_LOCK                   (private)
     *     NATIVE_WINDOW_UNLOCK_AND_POST        (private)
     *     NATIVE_WINDOW_API_CONNECT            (private)
     *     NATIVE_WINDOW_API_DISCONNECT         (private)
     *
     */

    int     (*perform)(struct ANativeWindow* window,
                int operation, ... );

    /*
     * Hook used to cancel a buffer that has been dequeued.
     * No synchronization is performed between dequeue() and cancel(), so
     * either external synchronization is needed, or these functions must be
     * called from the same thread.
     *
     * The window holds a reference to the buffer between dequeueBuffer and
     * either queueBuffer or cancelBuffer, so clients only need their own
     * reference if they might use the buffer after queueing or canceling it.
     * Holding a reference to a buffer after queueing or canceling it is only
     * allowed if a specific buffer count has been set.
     */
    int     (*cancelBuffer)(struct ANativeWindow* window,
                struct ANativeWindowBuffer* buffer);


    void* reserved_proc[2];
};