Skip to content

Document MountItemDispatcher #41114

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
sammy-SC wants to merge 1 commit into from
Closed

Document MountItemDispatcher #41114

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions ...es/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1294,6 +1294,11 @@ public void doFrameGuarded(long frameTimeNanos) {
}

try {
// First, execute as many pre mount items as we can within frameTimeNanos time.
// If not all pre mount items were executed, following may happen:
// 1. In case there are view commands or mount items in MountItemDispatcher: execute
// remaining pre mount items.
// 2. In case there are no view commands or mount items, wait until next frame.
mMountItemDispatcher.dispatchPreMountItems(frameTimeNanos);
mMountItemDispatcher.tryDispatchMountItems();
} catch (Exception ex) {
Expand Down
16 changes: 15 additions & 1 deletion ...ve/ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/MountItemDispatcher.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -161,9 +161,17 @@ public void dispatchMountItems(Queue<MountItem> mountItems) {
}
}

/*
* Executes view commands, pre mount items and mount items in the respective order:
* 1. View commands.
* 2. Pre mount items.
* 3. Regular mount items.
*
* Does nothing if `viewCommandMountItemsToDispatch` and `mountItemsToDispatch` are empty.
* Nothing should call this directly except for `tryDispatchMountItems`.
*/
@UiThread
@ThreadConfined(UI)
/** Nothing should call this directly except for `tryDispatchMountItems`. */
private boolean dispatchMountItems() {
if (mReDispatchCounter == 0) {
mBatchedExecutionTime = 0;
Expand Down Expand Up @@ -296,6 +304,12 @@ private boolean dispatchMountItems() {
return true;
}

/*
* Executes pre mount items. Pre mount items are operations that can be executed before the mount items come. For example view preallocation.
* This is a performance optimisation to do as much work ahead of time as possible.
*
* `tryDispatchMountItems` will also execute pre mount items, but only if there are mount items to be executed.
*/
@UiThread
@ThreadConfined(UI)
public void dispatchPreMountItems(long frameTimeNanos) {
Expand Down