apt

apt-file

apt-file 是一个软件包，它索引可用存储库中软件包的内容，并允许您在所有可用软件包中搜索特定文件。例如，假设您下载一个软件尝试运行它时，收到一条消息，告诉您无法找到特定的库文件。您就可以使用 apt-file 快速找出包含特定库的软件包可以解决问题，满足该依赖关系。

apt-get install apt-file # 安装
apt-file update # 更新数据库
apt-file search <filename> # 可以查找包含指定文件的软件包
# example:
# apt-file search libmp3lame.so.0
# libmp3lame0: /usr/lib/x86_64-linux-gnu/libmp3lame.so.0
# 这告诉我们要满足文件libmp3lame.so.0的依赖关系，我们需要安装包libmp3lame0。您还会注意到，在结果中包名称的右侧，它告诉我们如果您安装该特定包，文件将被安装到哪里。在上面的示例中，通过安装软件包 libmp3lame0 ，我们搜索的文件“libmp3lame.so.0”的副本将安装到文件夹“/usr/lib/x86_64-linux-gnu/”中。

另一个方法

dpkg -S libmp3lame.so.0
libmp3lame0:amd64: /usr/lib/x86_64-linux-gnu/libmp3lame.so.0
# 展示了相同的基本信息。注意：apt-file适用于所有可用的软件包，无论是否安装。而dpkg -S仅查看已安装的软件包。

apt source {pkg}

apt source {pkg} # 可以用来下载指定包源码
# example
# apt source bash # 下载 bash 包源码(到当前目录)

以上如何帮助我们解决一个问题？

我们希望查找获取窗口状态的函数，通过手册我们找到了一个函数(gdk_window_get_state)但是使用上有问题，并非我们所熟知的最大化，最小化，全屏等状态，而是还重叠了聚焦，平铺等状态。而我们记得 xwininfo 工具函数是有打印过窗口状态的。

xwininfo -all

xwininfo: Please select the window about which you
          would like information by clicking the
          mouse in that window.

xwininfo: Window id: 0x3400007 "html : xwininfo — Konsole"

  Root window id: 0x752 (the root window) (has no name)
  Parent window id: 0x18003b5 (has no name)
     0 children.

  Absolute upper-left X:  0
  Absolute upper-left Y:  29
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 1920
  Height: 1005
  Depth: 32
  Visual: 0x73b
  Visual Class: TrueColor
  Border width: 0
  Class: InputOutput
  Colormap: 0x3400006 (not installed)
  Bit Gravity State: NorthWestGravity
  Window Gravity State: NorthWestGravity
  Backing Store State: NotUseful
  Save Under State: no
  Map State: IsViewable
  Override Redirect State: no
  Corners:  +0+29  -0+29  -0-46  +0-46
  -geometry 1920x1005+0+29

  Bit gravity: NorthWestGravity
  Window gravity: NorthWestGravity
  Backing-store hint: NotUseful
  Backing-planes to be preserved: 0xffffffff
  Backing pixel: 0
  Save-unders: No

  Someone wants these events:
      KeyPress
      KeyRelease
      ButtonPress
      ButtonRelease
      EnterWindow
      LeaveWindow
      PointerMotion
      ButtonMotion
      Exposure
      StructureNotify
      FocusChange
      PropertyChange
      ColormapChange
  Do not propagate these events:
  Override redirection?: No

  Window manager hints:
      Client accepts input or input focus: Yes
      Initial state is Normal State
      Displayed on desktop 0
      Window type:
          Normal
      Window state:
          Maximized Vert
          Maximized Horz
          Focused
      Process id: 160622 on host dev-computer
      Frame extents: 0, 0, 29, 0

  Normal window size hints:
      User supplied size: 1920 by 1005
      Program supplied minimum size: 65 by 65
      Program supplied window gravity: StaticGravity
  No zoom window size hints defined

  No window shape defined
  No border shape defined

那么我们能否直接找到 xwininfo 源码，参考他们的思路呢？

~: apt search xwininfo # 通过平时用的命令查找到包名
Sorting... Done
Full Text Search... Done
x11-utils/stable,now 7.7+5 amd64 [installed,automatic]
  X11 utilities

~: apt source x11-utils # 通过包名下载包源码(到当前目录)
Reading package lists... Done
NOTICE: 'x11-utils' packaging is maintained in the 'Git' version control system at:
https://salsa.debian.org/xorg-team/app/x11-utils.git
Please use:
git clone https://salsa.debian.org/xorg-team/app/x11-utils.git
to retrieve the latest (possibly unreleased) updates to the package.
Need to get 3,059 kB of source archives.
Get:1 https://mirrors.ustc.edu.cn/debian bullseye/main x11-utils 7.7+5 (dsc) [2,136 B]
Get:2 https://mirrors.ustc.edu.cn/debian bullseye/main x11-utils 7.7+5 (tar) [3,057 kB]
Fetched 3,059 kB in 0s (7,412 kB/s)
dpkg-source: info: extracting x11-utils in x11-utils-7.7+5
dpkg-source: info: unpacking x11-utils_7.7+5.tar.gz

~: ls -lah
x11-utils-7.7+5/
x11-utils_7.7+5.dsc
x11-utils_7.7+5.tar.gz

~: grep -rni "Window state" x11-utils-7.7+5 # 根据关键字搜索下载好的源码
x11-utils-7.7+5/xwininfo/xwininfo.c:1736:               printf ("      Window state:\n");
x11-utils-7.7+5/xprop/xprop.c:376:"\t\twindow state: ?$0=0(Withdrawn)?$0=1(Normal)?$0=3(Iconic)\n"\

~: vim x11-utils-7.7+5/xwininfo/xwininfo.cs

   7     if (atom_net_wm_state) {
   6     prop = xcb_get_property_reply (dpy, w->wm_state_cookie, NULL);
   5     if (prop && (prop->type != XCB_NONE) && (prop->value_len > 0)) {
   4         xcb_atom_t *atoms = xcb_get_property_value (prop);
   3         int atom_count = prop->value_len;
   2
   1         if (atom_count > 0) {
1736         printf ("      Window state:\n");
   1         for (i = 0; i < atom_count; i++)
   2             Display_Atom_Name (atoms[i], "_NET_WM_STATE_");
   3         }
   4     }
   5     free (prop);
   6     }