前言

我们接着androidP Surface到SurfaceFlinger --＞创建Surface （一）来看，当new SurfaceControl之后在其构造函数内都做了什么？这一步跟下去就到了SurfaceFlinger了。

SurfaceFlinger createLayer

对于上层应用所建立的Surface对应到SurfaceFlinger 就是 createLayer
我们来跟代码吧，还是从 SurfaceControl的构造函数开始

private SurfaceControl(SurfaceSession session, String name, int w, int h, int format, int flags,
SurfaceControl parent, int windowType, int ownerUid)
throws OutOfResourcesException, IllegalArgumentException {
if (session == null) {
throw new IllegalArgumentException("session must not be null");
}
if (name == null) {
throw new IllegalArgumentException("name must not be null");
}
if ((flags & SurfaceControl.HIDDEN) == 0) {
Log.w(TAG, "Surfaces should always be created with the HIDDEN flag set "
+ "to ensure that they are not made visible prematurely before "
+ "all of the surface's properties have been configured.
"
+ "Set the other properties and make the surface visible within "
+ "a transaction.
New surface name: " + name,
new Throwable());
}
mName = name;
mWidth = w;
mHeight = h;
// 这里传进去的参数有，session这个是session就是持有该SurfaceControl的SurfaceSession对象，
// name 就是window的名字
// w，h window的宽和高
// format 设置的view的格式
// windowType window的类型，就是层级吧
// ownerUid 创建的app的uid
mNativeObject = nativeCreate(session, name, w, h, format, flags,
parent != null ? parent.mNativeObject : 0, windowType, ownerUid);
... ...
}

frameworks/base/core/jni/android_view_SurfaceControl.cpp

static jlong nativeCreate(JNIEnv* env, jclass clazz, jobject sessionObj,
jstring nameStr, jint w, jint h, jint format, jint flags, jlong parentObject,
jint windowType, jint ownerUid) {
ScopedUtfChars name(env, nameStr);
// 前面我们知道已经创建过连接了，在new SurfaceSession的就持有了SurfaceComposerClient的对象这个直接用就可以了
sp<SurfaceComposerClient> client(android_view_SurfaceSession_getClient(env, sessionObj));
SurfaceControl *parent = reinterpret_cast<SurfaceControl*>(parentObject);
sp<SurfaceControl> surface;
// 调用 SurfaceComposerClient的createSurfaceChecked方法
status_t err = client->createSurfaceChecked(
String8(name.c_str()), w, h, format, &surface, flags, parent, windowType, ownerUid);
if (err == NAME_NOT_FOUND) {
jniThrowException(env, "java/lang/IllegalArgumentException", NULL);
return 0;
} else if (err != NO_ERROR) {
jniThrowException(env, OutOfResourcesException, NULL);
return 0;
}
surface->incStrong((void *)nativeCreate);
return reinterpret_cast<jlong>(surface.get());
}

status_t SurfaceComposerClient::createSurfaceChecked(
const String8& name,
uint32_t w,
uint32_t h,
PixelFormat format,
sp<SurfaceControl>* outSurface,
uint32_t flags,
SurfaceControl* parent,
int32_t windowType,
int32_t ownerUid)
{
sp<SurfaceControl> sur;
status_t err = mStatus;
if (mStatus == NO_ERROR) {
sp<IBinder> handle;
sp<IBinder> parentHandle;
// 注意哈，这里出现了IGraphicBufferProducer，生产者BufferQueueProducer的父类
sp<IGraphicBufferProducer> gbp;
if (parent != nullptr) {
parentHandle = parent->getHandle();
}
// gbp取地址给了createSurface，那一般就是要给gbp分配地址了，这个client就是ISurfaceComposerClient的本地实现类。
err = mClient->createSurface(name, w, h, format, flags, parentHandle,
windowType, ownerUid, &handle, &gbp);
ALOGE_IF(err, "SurfaceComposerClient::createSurface error %s", strerror(-err));
if (err == NO_ERROR) {
*outSurface = new SurfaceControl(this, handle, gbp, true /* owned */);
}
}
return err;
}

frameworks/native/services/surfaceflinger/Client.cpp

status_t Client::createSurface(
const String8& name,
uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
const sp<IBinder>& parentHandle, int32_t windowType, int32_t ownerUid,
sp<IBinder>* handle,
sp<IGraphicBufferProducer>* gbp)
{
sp<Layer> parent = nullptr;
if (parentHandle != nullptr) {
auto layerHandle = reinterpret_cast<Layer::Handle*>(parentHandle.get());
parent = layerHandle->owner.promote();
if (parent == nullptr) {
return NAME_NOT_FOUND;
}
}
if (parent == nullptr) {
bool parentDied;
parent = getParentLayer(&parentDied);
// If we had a parent, but it died, we've lost all
// our capabilities.
if (parentDied) {
return NAME_NOT_FOUND;
}
}
// 继续跟到SurfaceFlinger里面
return mFlinger->createLayer(name, this, w, h, format, flags, windowType,
ownerUid, handle, gbp, &parent);
}

frameworks/native/services/surfaceflinger/SurfaceFlinger.cpp

//从createSurface到了createLayer
status_t SurfaceFlinger::createLayer(
const String8& name,
const sp<Client>& client,
uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
int32_t windowType, int32_t ownerUid, sp<IBinder>* handle,
sp<IGraphicBufferProducer>* gbp, sp<Layer>* parent)
{
if (int32_t(w|h) < 0) {
ALOGE("createLayer() failed, w or h is negative (w=%d, h=%d)",
int(w), int(h));
return BAD_VALUE;
}
ALOGE("createLayer() -> name = %s, windowType = %d",
name.c_str(), windowType);
status_t result = NO_ERROR;
sp<Layer> layer;
String8 uniqueName = getUniqueLayerName(name);
// 该函数中根据flag创建不同的Layer，Layer前面说过了就是一个图层
switch (flags & ISurfaceComposerClient::eFXSurfaceMask) {
case ISurfaceComposerClient::eFXSurfaceNormal:
// 创建了BufferLayer
result = createBufferLayer(client,
uniqueName, w, h, flags, format,
handle, gbp, &layer);
break;
case ISurfaceComposerClient::eFXSurfaceColor:
result = createColorLayer(client,
uniqueName, w, h, flags,
handle, &layer);
break;
default:
result = BAD_VALUE;
break;
}
if (result != NO_ERROR) {
return result;
}
// window type is WINDOW_TYPE_DONT_SCREENSHOT from SurfaceControl.java
// TODO b/64227542
if (windowType == 441731) {
windowType = 2024; // TYPE_NAVIGATION_BAR_PANEL
layer->setPrimaryDisplayOnly();
}
layer->setInfo(windowType, ownerUid);
result = addClientLayer(client, *handle, *gbp, layer, *parent);
if (result != NO_ERROR) {
return result;
}
mInterceptor->saveSurfaceCreation(layer);
setTransactionFlags(eTransactionNeeded);
return result;
}

status_t SurfaceFlinger::createBufferLayer(const sp<Client>& client,
const String8& name, uint32_t w, uint32_t h, uint32_t flags, PixelFormat& format,
sp<IBinder>* handle, sp<IGraphicBufferProducer>* gbp, sp<Layer>* outLayer)
{
// initialize the surfaces
switch (format) {
case PIXEL_FORMAT_TRANSPARENT:
case PIXEL_FORMAT_TRANSLUCENT:
format = PIXEL_FORMAT_RGBA_8888;
break;
case PIXEL_FORMAT_OPAQUE:
format = PIXEL_FORMAT_RGBX_8888;
break;
}
// 创建出了一个BufferLayer，这个BufferLayer里面回去创建BufferCore
sp<BufferLayer> layer = new BufferLayer(this, client, name, w, h, flags);
status_t err = layer->setBuffers(w, h, format, flags);
if (err == NO_ERROR) {
*handle = layer->getHandle();
*gbp = layer->getProducer();
*outLayer = layer;
}
ALOGE_IF(err, "createBufferLayer() failed (%s)", strerror(-err));
return err;
}

BufferLayer被new出来的时候会走进它的onFirstRef()方法里面

void BufferLayer::onFirstRef() {
Layer::onFirstRef();
// Creates a custom BufferQueue for SurfaceFlingerConsumer to use
sp<IGraphicBufferProducer> producer;
sp<IGraphicBufferConsumer> consumer;
// 在这里面会给producer 和 consumer进行赋值
BufferQueue::createBufferQueue(&producer, &consumer, true);
mProducer = new MonitoredProducer(producer, mFlinger, this);
{
// Grab the SF state lock during this since it's the only safe way to access RenderEngine
Mutex::Autolock lock(mFlinger->mStateLock);
mConsumer = new BufferLayerConsumer(consumer, mFlinger->getRenderEngine(), mTextureName,
this);
}
mConsumer->setConsumerUsageBits(getEffectiveUsage(0));
mConsumer->setContentsChangedListener(this);
mConsumer->setName(mName);
if (mFlinger->isLayerTripleBufferingDisabled()) {
mProducer->setMaxDequeuedBufferCount(2);
}
const sp<const DisplayDevice> hw(mFlinger->getDefaultDisplayDevice());
updateTransformHint(hw);
}

void BufferQueue::createBufferQueue(sp<IGraphicBufferProducer>* outProducer,
sp<IGraphicBufferConsumer>* outConsumer,
bool consumerIsSurfaceFlinger) {
LOG_ALWAYS_FATAL_IF(outProducer == NULL,
"BufferQueue: outProducer must not be NULL");
LOG_ALWAYS_FATAL_IF(outConsumer == NULL,
"BufferQueue: outConsumer must not be NULL");
sp<BufferQueueCore> core(new BufferQueueCore());
LOG_ALWAYS_FATAL_IF(core == NULL,
"BufferQueue: failed to create BufferQueueCore");
// 给producer进行了赋值
sp<IGraphicBufferProducer> producer(new BufferQueueProducer(core, consumerIsSurfaceFlinger));
LOG_ALWAYS_FATAL_IF(producer == NULL,
"BufferQueue: failed to create BufferQueueProducer");
// 给consumer进行了赋值
sp<IGraphicBufferConsumer> consumer(new BufferQueueConsumer(core));
LOG_ALWAYS_FATAL_IF(consumer == NULL,
"BufferQueue: failed to create BufferQueueConsumer");
// 其实我们交接buffer的操作流程都知道，这里producer是应用用来承载数据的，consumer是surfaceFlinger用来消费数据的
*outProducer = producer;
*outConsumer = consumer;
}

后续会接上BufferQueue的交互流程。

最后

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