簡(jiǎn)介
其實(shí)這篇寫的很爛，因?yàn)楹芏喔拍钗覜]有清楚，但是足夠反映一些認(rèn)知上的問題。
我們看到的Surface其實(shí)不是Surface是Layer，Layer就是我們宏觀的層級(jí)的概念，他里面有生產(chǎn)者消費(fèi)者，生產(chǎn)者顧名思義就是產(chǎn)生界面，消費(fèi)者就是消費(fèi)界面將界面進(jìn)行消費(fèi)顯示。所以今天主要是更正一個(gè)認(rèn)知，至少我之前是認(rèn)為，Surface就是一塊畫布。其實(shí)這樣理解沒有錯(cuò)，但是不準(zhǔn)確，準(zhǔn)確的時(shí)Suface時(shí)一個(gè)層，這個(gè)層上有有人生產(chǎn)有人消費(fèi)。
我們?cè)诳匆幌挛覀兊谝淮慰偨Y(jié)的調(diào)用在圖：
ActivityThread.handleLaunchActivity()
Activity a = performLaunchActivity()
activity = mInstrumentation.newActivity()
activity.attach()
mWindow = new PhoneWindow(this);
mWindow.setWindowManager((WindowManager)context.getSystemService(Context.WINDOW_SERVICE)...);
mWindowManager = ((WindowManagerImpl)mContext.getSystemService("window")).createLocalWindowManager(this);
return new WindowManagerImpl(mDisplay, parentWindow)
mWindowManager = mWindow.getWindowManager()
mInstrumentation.callActivityOnCreate(activity...)
activity.performCreate(...)
onCreate(...)
setContentView(R.id.xx)
getWindow().setContentView(layoutResID);
PhoneWindow.installDecor()
generateDecor()
return new DecorView();
handleResumeActivity()
wm.addView(decor...)
mGlobal.addView(view...)
root = new ViewRootImpl(...)
Surface mSurface = new Surface()//成員變量
mWindowSession = WindowManagerGlobal.getWindowSession()
IWindowManager windowManager = getWindowManagerService()
sWindowManagerService = IWindowManager.Stub.asInterface(ServiceManager.getService("window"))
sWindowSession = windowManager.openSession()
Session session = new Session()//在WMS中
mWindow = new W(this)//構(gòu)造函數(shù)
root.setView(view...)
mWindowSession.addToDisplay(mWindow...)
return mService.addWindow(...)//mService是WMS
token = new WindowToken(...)
WindowState win = new WindowState(...)
win.attach()
mSession.windowAddedLocked();
mSurfaceSession = new SurfaceSession();
mWindowMap.put(client.asBinder(), win)//將這個(gè)window加入列表中
requestLayout()
scheduleTraversals()
run(){doTraversal()}
performTraversals()
上節(jié)課我們分析到了這里
root.setView(view...)
mWindowSession.addToDisplay(mWindow...)
return mService.addWindow(...)//mService是WMS
Session.relayoutWindow()
token = new WindowToken(...)
WindowState win = new WindowState(...)
win.attach()
mSession.windowAddedLocked();
mSurfaceSession = new SurfaceSession();
mWindowMap.put(client.asBinder(), win)//將這個(gè)window加入列表中
requestLayout()
scheduleTraversals()
run(){doTraversal()}
performTraversals()
在WMS中調(diào)用了Session的relayoutWindow
public int relayoutWindow(Session session, IWindow client, int seq,
WindowManager.LayoutParams attrs, int requestedWidth,
int requestedHeight, int viewVisibility, int flags,
Rect outFrame, Rect outOverscanInsets, Rect outContentInsets,
Rect outVisibleInsets, Rect outStableInsets, Rect outOutsets, Configuration outConfig,
Surface outSurface) {
WindowState win = windowForClientLocked(session, client, false);
WindowStateAnimator winAnimator = win.mWinAnimator;
...
try {
if (!win.mHasSurface) {
surfaceChanged = true;
}
SurfaceControl surfaceControl = winAnimator.createSurfaceLocked();
if (surfaceControl != null) {
outSurface.copyFrom(surfaceControl);
} else {
outSurface.release();
}
} catch (Exception e) {
return 0;
}
...
}
我們先看看win.mWinAnimator如何創(chuàng)建
final WindowState windowForClientLocked(Session session, IWindow client,
boolean throwOnError) {
return windowForClientLocked(session, client.asBinder(), throwOnError);
}
final WindowState windowForClientLocked(Session session, IBinder client,
boolean throwOnError) {
WindowState win = mWindowMap.get(client);
return win;
}
我們看見是從mWindowMap中得到：
public int addWindow(Session session, IWindow client, int seq,
WindowManager.LayoutParams attrs, int viewVisibility, int displayId,
Rect outContentInsets, Rect outStableInsets, Rect outOutsets,
InputChannel outInputChannel) {
WindowState win = new WindowState(...);
win.attach();
mWindowMap.put(client.asBinder(), win);
}
也就是說windowForClientLocked方法中拿到的是在addWindow時(shí)候生成的WindowState
那么winAnimator.createSurfaceLocked();是如何把SurfaceControl給整出來(lái)的
我們只能使勁研究：
SurfaceControl surfaceControl = winAnimator.createSurfaceLocked();
SurfaceControl createSurfaceLocked() {
...
mSurfaceControl = new SurfaceControl(mSession.mSurfaceSession,
attrs.getTitle().toString(),
width, height, format, flags);
...
}
public SurfaceControl(SurfaceSession session,
String name, int w, int h, int format, int flags)
throws OutOfResourcesException {
mName = name;
mNativeObject = nativeCreate(session, name, w, h, format, flags);
mCloseGuard.open("release");
}
static jlong nativeCreate(JNIEnv* env, jclass clazz, jobject sessionObj,
jstring nameStr, jint w, jint h, jint format, jint flags) {
ScopedUtfChars name(env, nameStr);
sp<SurfaceComposerClient> client(android_view_SurfaceSession_getClient(env, sessionObj));
sp<SurfaceControl> surface = client->createSurface(
String8(name.c_str()), w, h, format, flags);
if (surface == NULL) {
jniThrowException(env, OutOfResourcesException, NULL);
return 0;
}
surface->incStrong((void *)nativeCreate);
return reinterpret_cast<jlong>(surface.get());
}
class BpSurfaceComposerClient : public BpInterface<ISurfaceComposerClient>
{
public:
BpSurfaceComposerClient(const sp<IBinder>& impl)
: BpInterface<ISurfaceComposerClient>(impl) {
}
virtual ~BpSurfaceComposerClient();
virtual status_t createSurface(const String8& name, uint32_t width,
uint32_t height, PixelFormat format, uint32_t flags,
sp<IBinder>* handle,
sp<IGraphicBufferProducer>* gbp) {
Parcel data, reply;
data.writeInterfaceToken(ISurfaceComposerClient::getInterfaceDescriptor());
data.writeString8(name);
data.writeUint32(width);
data.writeUint32(height);
data.writeInt32(static_cast<int32_t>(format));
data.writeUint32(flags);
remote()->transact(CREATE_SURFACE, data, &reply);
*handle = reply.readStrongBinder();
*gbp = interface_cast<IGraphicBufferProducer>(reply.readStrongBinder());
return reply.readInt32();
}
我們可以看出來(lái)SurfaceComposerClient創(chuàng)建Surface，這個(gè)SurfaceComposerClient是一個(gè)Binder對(duì)象，這邊代理發(fā)消息，然后對(duì)端接收。
SurfaceComposerClient類是從RefBase派生所以：
void SurfaceComposerClient::onFirstRef() {
sp<ISurfaceComposer> sm(ComposerService::getComposerService());
if (sm != 0) {
sp<ISurfaceComposerClient> conn = sm->createConnection();
if (conn != 0) {
mClient = conn;
mStatus = NO_ERROR;
}
}
}
/*static*/ sp<ISurfaceComposer> ComposerService::getComposerService() {
ComposerService& instance = ComposerService::getInstance();
Mutex::Autolock _l(instance.mLock);
if (instance.mComposerService == NULL) {
ComposerService::getInstance().connectLocked();
assert(instance.mComposerService != NULL);
ALOGD("ComposerService reconnected");
}
return instance.mComposerService;
}
其實(shí)目的很明確就是得到SurfaceComposerClient指針
，這個(gè)時(shí)候還要明白，SurfaceComposerClient時(shí)ComposerService的客戶端。這個(gè)ComposerService實(shí)現(xiàn)了和SurfaceFlinger的關(guān)系，他把SurfaceFlinger服務(wù)包括在里面。
那我們就看看
void ComposerService::connectLocked() {
const String16 name("SurfaceFlinger");
while (getService(name, &mComposerService) != NO_ERROR) {
usleep(250000);
}
assert(mComposerService != NULL);
// Create the death listener.
class DeathObserver : public IBinder::DeathRecipient {
ComposerService& mComposerService;
virtual void binderDied(const wp<IBinder>& who) {
ALOGW("ComposerService remote (surfaceflinger) died [%p]",
who.unsafe_get());
mComposerService.composerServiceDied();
}
public:
DeathObserver(ComposerService& mgr) : mComposerService(mgr) { }
};
mDeathObserver = new DeathObserver(*const_cast<ComposerService*>(this));
IInterface::asBinder(mComposerService)->linkToDeath(mDeathObserver);
}
看到其實(shí)時(shí)在mComposerService中包裝著SurfaceFlinger
也就是說，SurfaceComposerClient對(duì)象時(shí)ComposerService的客戶端，而ComposerService代理的時(shí)SurfaceFlinger。下次直接調(diào)用在SurfaceFlinger中找。
那之前：
sp<SurfaceControl> surface = client->createSurface(
String8(name.c_str()), w, h, format, flags);
這個(gè)調(diào)用就好解釋多了，就去SurfaceFlinger中去找就對(duì)了。
握操?zèng)]找到，怎么辦，那我們?cè)倏纯词遣皇抢^續(xù)SurfaceFlinger代理這誰(shuí)。
從這個(gè)方法開始：
sp<ISurfaceComposerClient> SurfaceFlinger::createConnection()
{
sp<ISurfaceComposerClient> bclient;
sp<Client> client(new Client(this));
status_t err = client->initCheck();
if (err == NO_ERROR) {
bclient = client;
}
return bclient;
}
我們先是鏈接，鏈接返回了client。所以在client中找。
status_t Client::createSurface(
const String8& name,
uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
sp<IBinder>* handle,
sp<IGraphicBufferProducer>* gbp)
{
/*
* createSurface must be called from the GL thread so that it can
* have access to the GL context.
*/
class MessageCreateLayer : public MessageBase {
SurfaceFlinger* flinger;
Client* client;
sp<IBinder>* handle;
sp<IGraphicBufferProducer>* gbp;
status_t result;
const String8& name;
uint32_t w, h;
PixelFormat format;
uint32_t flags;
public:
MessageCreateLayer(SurfaceFlinger* flinger,
const String8& name, Client* client,
uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
sp<IBinder>* handle,
sp<IGraphicBufferProducer>* gbp)
: flinger(flinger), client(client),
handle(handle), gbp(gbp),
name(name), w(w), h(h), format(format), flags(flags) {
}
status_t getResult() const { return result; }
virtual bool handler() {
result = flinger->createLayer(name, client, w, h, format, flags,
handle, gbp);
return true;
}
};
sp<MessageBase> msg = new MessageCreateLayer(mFlinger.get(),
name, this, w, h, format, flags, handle, gbp);
mFlinger->postMessageSync(msg);
return static_cast<MessageCreateLayer*>( msg.get() )->getResult();
}
這段又跑到esult = flinger->createLayer(name, client, w, h, format, flags,
handle, gbp);
status_t SurfaceFlinger::createLayer(
const String8& name,
const sp<Client>& client,
uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
sp<IBinder>* handle, sp<IGraphicBufferProducer>* gbp)
{
//ALOGD("createLayer for (%d x %d), name=%s", w, h, name.string());
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;
}
status_t result = NO_ERROR;
sp<Layer> layer;
switch (flags & ISurfaceComposerClient::eFXSurfaceMask) {
case ISurfaceComposerClient::eFXSurfaceNormal:
result = createNormalLayer(client,
name, w, h, flags, format,
handle, gbp, &layer);
break;
case ISurfaceComposerClient::eFXSurfaceDim:
result = createDimLayer(client,
name, w, h, flags,
handle, gbp, &layer);
break;
default:
result = BAD_VALUE;
break;
}
if (result != NO_ERROR) {
return result;
}
result = addClientLayer(client, *handle, *gbp, layer);
if (result != NO_ERROR) {
return result;
}
setTransactionFlags(eTransactionNeeded);
return result;
}
我們?cè)谶@里拋出了層Layer的概念。
我們?cè)谡f一點(diǎn)下，就是SurfaceComposerClient鏈接鏈接最后到了Client中，然后通過Client去實(shí)現(xiàn)一些東東比如創(chuàng)建層。其實(shí)這里我們?cè)谀：幌赂拍?，我們?chuàng)建的Surface其實(shí)時(shí)Layer，
我們?cè)倏创a
*outLayer = new Layer(this, client, name, w, h, flags);
status_t err = (*outLayer)->setBuffers(w, h, format, flags);
if (err == NO_ERROR) {
*handle = (*outLayer)->getHandle();
*gbp = (*outLayer)->getProducer();
}
status_t Layer::setBuffers( uint32_t w, uint32_t h,
PixelFormat format, uint32_t flags)
{
uint32_t const maxSurfaceDims = min(
mFlinger->getMaxTextureSize(), mFlinger->getMaxViewportDims());
// never allow a surface larger than what our underlying GL implementation
// can handle.
if ((uint32_t(w)>maxSurfaceDims) || (uint32_t(h)>maxSurfaceDims)) {
ALOGE("dimensions too large %u x %u", uint32_t(w), uint32_t(h));
return BAD_VALUE;
}
mFormat = format;
mPotentialCursor = (flags & ISurfaceComposerClient::eCursorWindow) ? true : false;
mProtectedByApp = (flags & ISurfaceComposerClient::eProtectedByApp) ? true : false;
mCurrentOpacity = getOpacityForFormat(format);
mSurfaceFlingerConsumer->setDefaultBufferSize(w, h);
mSurfaceFlingerConsumer->setDefaultBufferFormat(format);
mSurfaceFlingerConsumer->setConsumerUsageBits(getEffectiveUsage(0));
return NO_ERROR;
}
sp<IBinder> Layer::getHandle() {
Mutex::Autolock _l(mLock);
LOG_ALWAYS_FATAL_IF(mHasSurface,
"Layer::getHandle() has already been called");
mHasSurface = true;
class Handle : public BBinder, public LayerCleaner {
wp<const Layer> mOwner;
public:
Handle(const sp<SurfaceFlinger>& flinger, const sp<Layer>& layer)
: LayerCleaner(flinger, layer), mOwner(layer) {
}
};
return new Handle(mFlinger, this);
}
sp<IGraphicBufferProducer> Layer::getProducer() const {
return mProducer;// sp<IGraphicBufferProducer> mProducer;
}
void Layer::onFirstRef() {
// Creates a custom BufferQueue for SurfaceFlingerConsumer to use
sp<IGraphicBufferProducer> producer;
sp<IGraphicBufferConsumer> consumer;
BufferQueue::createBufferQueue(&producer, &consumer);
mProducer = new MonitoredProducer(producer, mFlinger);
mSurfaceFlingerConsumer = new SurfaceFlingerConsumer(consumer, mTextureName);
mSurfaceFlingerConsumer->setConsumerUsageBits(getEffectiveUsage(0));
mSurfaceFlingerConsumer->setContentsChangedListener(this);
mSurfaceFlingerConsumer->setName(mName);
#ifdef TARGET_DISABLE_TRIPLE_BUFFERING
#warning "disabling triple buffering"
mSurfaceFlingerConsumer->setDefaultMaxBufferCount(2);
#else
mSurfaceFlingerConsumer->setDefaultMaxBufferCount(3);
#endif
const sp<const DisplayDevice> hw(mFlinger->getDefaultDisplayDevice());
updateTransformHint(hw);
}
現(xiàn)在說明冒出來(lái)很多概念
生產(chǎn)者，消費(fèi)者，BufferQueue，這是要鬧那樣。
我們下次分析。
重點(diǎn)分析
在WMS中調(diào)用了Session的relayoutWindow
public int relayoutWindow(Session session, IWindow client, int seq,
WindowManager.LayoutParams attrs, int requestedWidth,
int requestedHeight, int viewVisibility, int flags,
Rect outFrame, Rect outOverscanInsets, Rect outContentInsets,
Rect outVisibleInsets, Rect outStableInsets, Rect outOutsets, Configuration outConfig,
Surface outSurface) {
WindowState win = windowForClientLocked(session, client, false);
WindowStateAnimator winAnimator = win.mWinAnimator;
...
try {
if (!win.mHasSurface) {
surfaceChanged = true;
}
SurfaceControl surfaceControl = winAnimator.createSurfaceLocked();
if (surfaceControl != null) {
outSurface.copyFrom(surfaceControl);
} else {
outSurface.release();
}
} catch (Exception e) {
return 0;
}
...
}
執(zhí)行outSurface.copyFrom(surfaceControl);的時(shí)候我們看看：
public void copyFrom(SurfaceControl other) {
...
long surfaceControlPtr = other.mNativeObject;
...
long newNativeObject = nativeCreateFromSurfaceControl(surfaceControlPtr);
synchronized (mLock) {
if (mNativeObject != 0) {
nativeRelease(mNativeObject);
}
setNativeObjectLocked(newNativeObject);
}
}
static jlong nativeCreateFromSurfaceControl(JNIEnv* env, jclass clazz,
jlong surfaceControlNativeObj) {
sp<SurfaceControl> ctrl(reinterpret_cast<SurfaceControl *>(surfaceControlNativeObj));
sp<Surface> surface(ctrl->getSurface());
if (surface != NULL) {
surface->incStrong(&sRefBaseOwner);
}
return reinterpret_cast<jlong>(surface.get());
}
我們看出來(lái)，surfaceControlPtr代表的時(shí)native層的SurfaceControl對(duì)象，然后通過native層的SurfaceControl對(duì)象得到Surface
sp<Surface> SurfaceControl::getSurface() const
{
Mutex::Autolock _l(mLock);
if (mSurfaceData == 0) {
mSurfaceData = new Surface(mGraphicBufferProducer, false);
}
return mSurfaceData;
}
所以創(chuàng)建一個(gè)Surface，然后返回。
我們看到創(chuàng)建Surface的時(shí)候會(huì)傳遞mGraphicBufferProducer，這個(gè)是什么？
看到上面的分析，是不是就知道這個(gè)在Layer第一次調(diào)用的時(shí)候就有值了，是一個(gè)生產(chǎn)者。
