Commit 7c19b3cc authored Jan 29, 2024 by Yurii Zubrytskyi

[res] Speed up a check of a resource name for int

Resources.getIdentifier(name) and Resources.getValue(name) both
first check if the passed name is actually an ID in a string
form, and does it with Integer.parseInt(). Most of the time it
isn't, and that's reported via Java exception. So the most
common use case involves an exception on a regular path.

This change adds a simple check to filter out all names that
don't look like a number, and only try parsing those that are
'int-like', i.e. <=10 digits. This speeds up the calls by more
than 2x, and gets rid of most of heap usages

Bug: 282215580
Test: build + presubmits
Change-Id: I1cd6be728f4e4bec04cb97729911c6a3fae0d010

parent d3ca7f8a

core/java/android/content/res/ResourcesImpl.java

+17 −4

Original line number	Diff line number	Diff line
		@@ -273,15 +273,28 @@ public class ResourcesImpl {
		throw new NotFoundException("String resource name " + name);
		}

		private static boolean isIntLike(@NonNull String s) {
		if (s.isEmpty() \|\| s.length() > 10) return false;
		for (int i = 0, size = s.length(); i < size; i++) {
		final char c = s.charAt(i);
		if (c < '0' \|\| c > '9') {
		return false;
		}
		}
		return true;
		}

		int getIdentifier(String name, String defType, String defPackage) {
		if (name == null) {
		throw new NullPointerException("name is null");
		}
		if (isIntLike(name)) {
		try {
		return Integer.parseInt(name);
		} catch (Exception e) {
		// Ignore
		}
		}
		return mAssets.getResourceIdentifier(name, defType, defPackage);
		}