tree 65e49d56b99270833e1376e1fa32b83264559040
parent 69daaf725f330cb95013409211f2ba77abd919dc
author Ian Lake <ilake@google.com> 1698186227 +0000
committer Android Build Coastguard Worker <android-build-coastguard-worker@google.com> 1698281291 +0000

Improve the performance of NavGraph.equals()

When comparing two graphs, as few allocations should
be done as possible and the comparision should short
circuit as much as possible.

By adding if (this === other) checks, we can
short circuit the exact same objects.

By using NavDestination's private _arguments field
rather than the public, immutable copy provided by
arguments, we can avoid copying the arguments multiple
times. Since we check whether the size of the arguments
are the same, we can avoid iterating through both lists
since one list matching means they are identical.

We can use Kotlin's built in equals() for Lists to
compare deep links rather than using intersect() since
ordering *does* matter here when determining a matching
deep link.

NavGraph does not to create a copy of its children just
to remove them, we can instead just iterate through
each child and verify that the same child exists in the
other graph.

Relnote: "Greatly improved the performance (both in
terms of time and number of allocations) of comparing
two graph. This means that calls such as `setGraph`
which internally compare the new graph to the existing
one are much faster and result in fewer skipped frames."
Test: Benchmark improved (2k ns from 77k ns, 10 allocations from 1,324)
BUG: 307253895
(cherry picked from https://android-review.googlesource.com/q/commit:06f18f70d5bffa981332fee3ab0973d26c852828)
Merged-In: I6ad62bef1fb9bbbe8a91839a6e24e1f85a8982e2
Change-Id: I6ad62bef1fb9bbbe8a91839a6e24e1f85a8982e2