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Setup default font manager after engine created, to improve startup performance #18225

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May 29, 2020
Merged

Setup default font manager after engine created, to improve startup performance #18225

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2999d0c
Setup default font manager after engine created, to improve startup p…
scutlight May 8, 2020
322cd0b
Pre-warm default font manager, to reduce time cost of engine setup
scutlight May 18, 2020
e5b6447
Update changes as review requested.
scutlight May 20, 2020
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6 changes: 4 additions & 2 deletions lib/ui/text/font_collection.cc
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Expand Up @@ -47,8 +47,6 @@ void _LoadFontFromList(Dart_NativeArguments args) {

FontCollection::FontCollection()
: collection_(std::make_shared<txt::FontCollection>()) {
collection_->SetupDefaultFontManager();

dynamic_font_manager_ = sk_make_sp<txt::DynamicFontManager>();
collection_->SetDynamicFontManager(dynamic_font_manager_);
}
Expand All @@ -68,6 +66,10 @@ std::shared_ptr<txt::FontCollection> FontCollection::GetFontCollection() const {
return collection_;
}

void FontCollection::SetupDefaultFontManager() {
collection_->SetupDefaultFontManager();
}

void FontCollection::RegisterFonts(
std::shared_ptr<AssetManager> asset_manager) {
std::unique_ptr<fml::Mapping> manifest_mapping =
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2 changes: 2 additions & 0 deletions lib/ui/text/font_collection.h
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Expand Up @@ -29,6 +29,8 @@ class FontCollection {

std::shared_ptr<txt::FontCollection> GetFontCollection() const;

void SetupDefaultFontManager();

void RegisterFonts(std::shared_ptr<AssetManager> asset_manager);

void RegisterTestFonts();
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5 changes: 5 additions & 0 deletions shell/common/engine.cc
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Expand Up @@ -90,6 +90,11 @@ fml::WeakPtr<Engine> Engine::GetWeakPtr() const {
return weak_factory_.GetWeakPtr();
}

void Engine::SetupDefaultFontManager() {
TRACE_EVENT0("flutter", "Engine::SetupDefaultFontManager");
font_collection_.SetupDefaultFontManager();
}

bool Engine::UpdateAssetManager(
std::shared_ptr<AssetManager> new_asset_manager) {
if (asset_manager_ == new_asset_manager) {
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5 changes: 5 additions & 0 deletions shell/common/engine.h
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Expand Up @@ -363,6 +363,11 @@ class Engine final : public RuntimeDelegate, PointerDataDispatcher::Delegate {
///
[[nodiscard]] bool Restart(RunConfiguration configuration);

//----------------------------------------------------------------------------
/// @brief Setup default font manager according to specific platform.
///
void SetupDefaultFontManager();

//----------------------------------------------------------------------------
/// @brief Updates the asset manager referenced by the root isolate of a
/// Flutter application. This happens implicitly in the call to
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8 changes: 8 additions & 0 deletions shell/common/shell.cc
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Expand Up @@ -542,6 +542,14 @@ bool Shell::Setup(std::unique_ptr<PlatformView> platform_view,
weak_rasterizer_ = rasterizer_->GetWeakPtr();
weak_platform_view_ = platform_view_->GetWeakPtr();

// Setup the time-consuming default font manager right after engine created.
fml::TaskRunner::RunNowOrPostTask(task_runners_.GetUITaskRunner(),
[engine = weak_engine_] {
if (engine) {
engine->SetupDefaultFontManager();
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What protection do we have that someone won't use FontCollection.collection_ before this executes?

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The FontCollection is only usable on the UI thread, and UI thread tasks are executed in the order that they were queued. Therefore the task that completes setup of the FontCollection will execute before any task that might query the FontCollection.

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@gaaclarke gaaclarke May 21, 2020 •
edited
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There could already be something in the UI event queue that will use the FontCollection though.

platform_thread->execute({
  ui_thread->execute({ shell->setup(); });
  ui_thread->execute({ someFontCollectionUsingFunction(); });
});

There is no guarantee in this case that SetupDefaultFontManager will execute before someFontCollectionUsingFunction.

edit: If this is how things work this should be safe. All usages of the font collection on the ui thread are given a reference to a shell that has already been setup. This might be the case.

platform_thread->execute({
  shell->setup();
  ui_thread->execute({ someFontCollectionUsingFunction(shell); });
});

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The embedder APIs will not return a shell to the caller until Shell::Setup has completed and the SetupDefaultFontManager task has already been queued.

}
});

is_setup_ = true;

vm_->GetServiceProtocol()->AddHandler(this, GetServiceProtocolDescription());
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11 changes: 11 additions & 0 deletions shell/platform/android/flutter_main.cc
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Expand Up @@ -21,6 +21,7 @@
#include "flutter/shell/common/shell.h"
#include "flutter/shell/common/switches.h"
#include "third_party/dart/runtime/include/dart_tools_api.h"
#include "third_party/skia/include/core/SkFontMgr.h"

namespace flutter {

Expand Down Expand Up @@ -155,6 +156,11 @@ void FlutterMain::SetupObservatoryUriCallback(JNIEnv* env) {
});
}

static void PrefetchDefaultFontManager(JNIEnv* env, jclass jcaller) {
// Initialize a singleton owned by Skia.
SkFontMgr::RefDefault();
}

bool FlutterMain::Register(JNIEnv* env) {
static const JNINativeMethod methods[] = {
{
Expand All @@ -163,6 +169,11 @@ bool FlutterMain::Register(JNIEnv* env) {
"lang/String;Ljava/lang/String;Ljava/lang/String;J)V",
.fnPtr = reinterpret_cast<void*>(&Init),
},
{
.name = "nativePrefetchDefaultFontManager",
.signature = "()V",
.fnPtr = reinterpret_cast<void*>(&PrefetchDefaultFontManager),
},
};

jclass clazz = env->FindClass("io/flutter/embedding/engine/FlutterJNI");
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7 changes: 7 additions & 0 deletions shell/platform/android/io/flutter/embedding/engine/FlutterJNI.java
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Expand Up @@ -106,6 +106,13 @@ public static native void nativeInit(
@NonNull String engineCachesPath,
long initTimeMillis);

/**
* Prefetch the default font manager provided by SkFontMgr::RefDefault() which is a process-wide
* singleton owned by Skia. Note that, the first call to SkFontMgr::RefDefault() will take
* noticeable time, but later calls will return a reference to the preexisting font manager.
*/
public static native void nativePrefetchDefaultFontManager();

// TODO(mattcarroll): add javadocs
@UiThread
public native boolean nativeGetIsSoftwareRenderingEnabled();
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11 changes: 11 additions & 0 deletions shell/platform/android/io/flutter/embedding/engine/loader/FlutterLoader.java
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Expand Up @@ -144,6 +144,17 @@ public InitResult call() {

System.loadLibrary("flutter");

// Prefetch the default font manager as soon as possible on a background thread.
// It helps to reduce time cost of engine setup that blocks the platform thread.
Executors.newSingleThreadExecutor()
.execute(
new Runnable() {
@Override
public void run() {
FlutterJNI.nativePrefetchDefaultFontManager();
}
});

if (resourceExtractor != null) {
resourceExtractor.waitForCompletion();
}
Expand Down