背景：
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aosp15上SurfaceFlinger的dump部分新特性-无Layer信息输出如何解决？
给大家布置了一个小作业，那就是需要实现dumpsys SurfaceFlinger相关输出中可以携带上所有的Layer的详细信息需求，今天来带大家详细实现一下这个需求。
实战踩坑过程
本来想参考以前版本方式，直接使用mDrawingState.traverse的相关方法来进行遍历每一个Layer然后输出相关的信息。
cpp
std::string compositionLayers;
mDrawingState.traverseInReverseZOrder([&](Layer* layer) {
//输出相关的layer信息
auto* compositionState = layer->getCompositionState();
android::base::StringAppendF(&compositionLayers, "* Layer %p (%s)\n", layer,
layer->getDebugName() ? layer->getDebugName()
: "<unknown>");
compositionState->dump(compositionLayers);
});但是明显发现这个mDrawingState.traverse方法压根就不会进入对应的循环，一行代码都不会执行，所以自然没有任何输出。
其实从SurfaceFlinger.cpp的相关代码也可以看出相关的痕迹，要调用 mDrawingState.traverse相关方法一般都会有一个判断值mLayerLifecycleManagerEnabled：
bash
if (!mLayerLifecycleManagerEnabled) {
StringAppendF(&result, "Composition layers\n");
mDrawingState.traverseInZOrder([&](Layer* layer) {
auto* compositionState = layer->getCompositionState();
if (!compositionState || !compositionState->isVisible) return;
android::base::StringAppendF(&result, "* Layer %p (%s)\n", layer,
layer->getDebugName() ? layer->getDebugName()
: "<unknown>");
compositionState->dump(result);
});
StringAppendF(&result, "Offscreen Layers\n");
for (Layer* offscreenLayer : mOffscreenLayers) {
offscreenLayer->traverse(LayerVector::StateSet::Drawing,
[&](Layer* layer) { layer->dumpOffscreenDebugInfo(result); });
}
}但是在aosp15版本上这个mLayerLifecycleManagerEnabled值一直都是true，所以根本不会进入执行这块的mDrawingState.traverse，也就是说在aosp15版本的SurfaceFlinger已经弃用了这个mDrawingState.traverse。
正确实战实现
代码实现：
实现要采用2种方式
方式1--采用dumpsys SurfaceFlinger --带上参数，主要是可以单独dump layer数据
代码实现如下：
这个dumpsysAllLayer的实现代码如下：
方式2采用setprop方式然后控制prop可以整体进行dump
在总的dump方法最后，加入如下代码
这样就可以实现通过prop值控制是否在正常dumpsys SurfaceFlinger输出中带上所有Layer的信息。
使用方式：
方式1
adb shell dumpsys SurfaceFlinger --all-layer
bash
adb shell dumpsys SurfaceFlinger --all-layer
+ Layer (Display 0 name="Built-in Screen"#43) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000002, tr=[0.00, 0.00][0.00, 0.00]
parent=none
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (WindowedMagnification:0:31#3) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, 0, 0], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=Display 0 name="Built-in Screen"#43
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (HideDisplayCutout:0:14#4) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=WindowedMagnification:0:31#3
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (OneHanded:0:14#5) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=HideDisplayCutout:0:14#4
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (FullscreenMagnification:0:12#6) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=OneHanded:0:14#5
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (Leaf:0:1#7) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=FullscreenMagnification:0:12#6
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (WallpaperWindowToken{970337b token=android.os.Binder@2e0df0a}#62) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=Leaf:0:1#7
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000, 方式2
先进行prop的设置，开启dump所有的layers
bash
adb shell setprop debug.sf.dump_all_layers true然后再执行dumpsys SurfaceFlinger
bash
Window Infos:
max send vsync id: -1
max send delay (ns): 0 ns
unsent messages: 0 #正常情况下的结束地方
+ Layer (Display 0 name="Built-in Screen"#43) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000002, tr=[0.00, 0.00][0.00, 0.00]
parent=none
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (WindowedMagnification:0:31#3) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, 0, 0], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=Display 0 name="Built-in Screen"#43
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (HideDisplayCutout:0:14#4) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=WindowedMagnification:0:31#3
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (OneHanded:0:14#5) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=HideDisplayCutout:0:14#4
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (FullscreenMagnification:0:12#6) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=OneHanded:0:14#5
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (Leaf:0:1#7) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=FullscreenMagnification:0:12#6
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000,
+ Layer (WallpaperWindowToken{970337b token=android.os.Binder@2e0df0a}#62) uid=1000
Region TransparentRegion (this=0 count=0)
Region VisibleRegion (this=0 count=0)
Region SurfaceDamageRegion (this=0 count=0)
layerStack= 0, z= 0, pos=(0,0), size=( 0, 0), crop=[ 0, 0, -1, -1], cornerRadius=0.000000, isProtected=0, isTrustedOverlay=0, isOpaque=0, invalidate=0, dataspace=BT709 sRGB Full range, defaultPixelFormat=, backgroundBlurRadius=0, color=(-1.000,-1.000,-1.000,1.000), flags=0x00000000, tr=[0.00, 0.00][0.00, 0.00]
parent=Leaf:0:1#7
zOrderRelativeOf=none
activeBuffer=[ 0x 0: 0,Unknown/None], tr=[0.00, 0.00][0.00, 0.00] queued-frames=0 metadata={9:4bytes}, cornerRadiusCrop=[0.00, 0.00, 0.00, 0.00], shadowRadius=0.000, 默认情况下debug.sf.dump_all_layers是false，所以不会dump
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