Preload full set of preview image metadata pages

This is the first step in mitigating the bottleneck of slow metadata
loading by proactively loading pages to the max window size.

Test: atest CursorPreviewsInteractorTest FetchPreviewsInteractorTest
Test: manual test using ShareTest with high metadata latency
BUG: 341923886
Flag: android.service.chooser.chooser_payload_toggling
Change-Id: I1192e7bdf7db77573990745dd5b05d7ef86d7f20

1 files changed, 34 insertions, 2 deletions

diff --git a/java/src/com/android/intentresolver/contentpreview/payloadtoggle/domain/interactor/CursorPreviewsInteractor.kt b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/domain/interactor/CursorPreviewsInteractor.kt
index 97b087e1..f02834e0 100644
--- a/java/src/com/android/intentresolver/contentpreview/payloadtoggle/domain/interactor/CursorPreviewsInteractor.kt
+++ b/java/src/com/android/intentresolver/contentpreview/payloadtoggle/domain/interactor/CursorPreviewsInteractor.kt
@@ -76,10 +76,42 @@ constructor(
                 .toMap(ConcurrentHashMap())
         val pagedCursor: PagedCursor<CursorRow?> = uriCursor.paged(pageSize)
         val startPosition = uriCursor.extras?.getInt(POSITION, 0) ?: 0
-        val state = readInitialState(pagedCursor, startPosition, unclaimedRecords)
+        val state =
+            loadToMaxPages(
+                initialState = readInitialState(pagedCursor, startPosition, unclaimedRecords),
+                pagedCursor = pagedCursor,
+                unclaimedRecords = unclaimedRecords,
+            )
         processLoadRequests(state, pagedCursor, unclaimedRecords)
     }
 
+    private suspend fun loadToMaxPages(
+        initialState: CursorWindow,
+        pagedCursor: PagedCursor<CursorRow?>,
+        unclaimedRecords: MutableUnclaimedMap,
+    ): CursorWindow {
+        var state = initialState
+        val startPageNum = state.firstLoadedPageNum
+        while ((state.hasMoreLeft || state.hasMoreRight) && state.numLoadedPages < maxLoadedPages) {
+            interactor.setPreviews(
+                previewsByKey = state.merged.values.toSet(),
+                startIndex = startPageNum,
+                hasMoreLeft = state.hasMoreLeft,
+                hasMoreRight = state.hasMoreRight,
+            )
+            val loadedLeft = startPageNum - state.firstLoadedPageNum
+            val loadedRight = state.lastLoadedPageNum - startPageNum
+            state =
+                when {
+                    state.hasMoreLeft && loadedLeft < loadedRight ->
+                        state.loadMoreLeft(pagedCursor, unclaimedRecords)
+                    state.hasMoreRight -> state.loadMoreRight(pagedCursor, unclaimedRecords)
+                    else -> state.loadMoreLeft(pagedCursor, unclaimedRecords)
+                }
+        }
+        return state
+    }
+
     /** Loop forever, processing any loading requests from the UI and updating local cache. */
     private suspend fun processLoadRequests(
         initialState: CursorWindow,
@@ -301,5 +333,5 @@ annotation class MaxLoadedPages
 object ShareouselConstants {
     @Provides @PageSize fun pageSize(): Int = 16
 
-    @Provides @MaxLoadedPages fun maxLoadedPages(): Int = 3
+    @Provides @MaxLoadedPages fun maxLoadedPages(): Int = 8
 }